重新添加文件

GOPATH/src/github.com/go-sql-driver/mysql/AUTHORS

+# This is the official list of Go-MySQL-Driver authors for copyright purposes.
+
+# If you are submitting a patch, please add your name or the name of the
+# organization which holds the copyright to this list in alphabetical order.
+
+# Names should be added to this file as
+#	Name <email address>
+# The email address is not required for organizations.
+# Please keep the list sorted.
+
+
+# Individual Persons
+
+Aaron Hopkins <go-sql-driver at die.net>
+Achille Roussel <achille.roussel at gmail.com>
+Alex Snast <alexsn at fb.com>
+Alexey Palazhchenko <alexey.palazhchenko at gmail.com>
+Andrew Reid <andrew.reid at tixtrack.com>
+Animesh Ray <mail.rayanimesh at gmail.com>
+Arne Hormann <arnehormann at gmail.com>
+Ariel Mashraki <ariel at mashraki.co.il>
+Asta Xie <xiemengjun at gmail.com>
+Bulat Gaifullin <gaifullinbf at gmail.com>
+Caine Jette <jette at alum.mit.edu>
+Carlos Nieto <jose.carlos at menteslibres.net>
+Chris Moos <chris at tech9computers.com>
+Craig Wilson <craiggwilson at gmail.com>
+Daniel Montoya <dsmontoyam at gmail.com>
+Daniel Nichter <nil at codenode.com>
+Daniël van Eeden <git at myname.nl>
+Dave Protasowski <dprotaso at gmail.com>
+DisposaBoy <disposaboy at dby.me>
+Egor Smolyakov <egorsmkv at gmail.com>
+Erwan Martin <hello at erwan.io>
+Evan Shaw <evan at vendhq.com>
+Frederick Mayle <frederickmayle at gmail.com>
+Gustavo Kristic <gkristic at gmail.com>
+Hajime Nakagami <nakagami at gmail.com>
+Hanno Braun <mail at hannobraun.com>
+Henri Yandell <flamefew at gmail.com>
+Hirotaka Yamamoto <ymmt2005 at gmail.com>
+Huyiguang <hyg at webterren.com>
+ICHINOSE Shogo <shogo82148 at gmail.com>
+Ilia Cimpoes <ichimpoesh at gmail.com>
+INADA Naoki <songofacandy at gmail.com>
+Jacek Szwec <szwec.jacek at gmail.com>
+James Harr <james.harr at gmail.com>
+Jeff Hodges <jeff at somethingsimilar.com>
+Jeffrey Charles <jeffreycharles at gmail.com>
+Jerome Meyer <jxmeyer at gmail.com>
+Jiajia Zhong <zhong2plus at gmail.com>
+Jian Zhen <zhenjl at gmail.com>
+Joshua Prunier <joshua.prunier at gmail.com>
+Julien Lefevre <julien.lefevr at gmail.com>
+Julien Schmidt <go-sql-driver at julienschmidt.com>
+Justin Li <jli at j-li.net>
+Justin Nuß <nuss.justin at gmail.com>
+Kamil Dziedzic <kamil at klecza.pl>
+Kei Kamikawa <x00.x7f.x86 at gmail.com>
+Kevin Malachowski <kevin at chowski.com>
+Kieron Woodhouse <kieron.woodhouse at infosum.com>
+Lennart Rudolph <lrudolph at hmc.edu>
+Leonardo YongUk Kim <dalinaum at gmail.com>
+Linh Tran Tuan <linhduonggnu at gmail.com>
+Lion Yang <lion at aosc.xyz>
+Luca Looz <luca.looz92 at gmail.com>
+Lucas Liu <extrafliu at gmail.com>
+Luke Scott <luke at webconnex.com>
+Maciej Zimnoch <maciej.zimnoch at codilime.com>
+Michael Woolnough <michael.woolnough at gmail.com>
+Nathanial Murphy <nathanial.murphy at gmail.com>
+Nicola Peduzzi <thenikso at gmail.com>
+Olivier Mengué <dolmen at cpan.org>
+oscarzhao <oscarzhaosl at gmail.com>
+Paul Bonser <misterpib at gmail.com>
+Peter Schultz <peter.schultz at classmarkets.com>
+Rebecca Chin <rchin at pivotal.io>
+Reed Allman <rdallman10 at gmail.com>
+Richard Wilkes <wilkes at me.com>
+Robert Russell <robert at rrbrussell.com>
+Runrioter Wung <runrioter at gmail.com>
+Sho Iizuka <sho.i518 at gmail.com>
+Sho Ikeda <suicaicoca at gmail.com>
+Shuode Li <elemount at qq.com>
+Simon J Mudd <sjmudd at pobox.com>
+Soroush Pour <me at soroushjp.com>
+Stan Putrya <root.vagner at gmail.com>
+Stanley Gunawan <gunawan.stanley at gmail.com>
+Steven Hartland <steven.hartland at multiplay.co.uk>
+Tan Jinhua <312841925 at qq.com>
+Thomas Wodarek <wodarekwebpage at gmail.com>
+Tim Ruffles <timruffles at gmail.com>
+Tom Jenkinson <tom at tjenkinson.me>
+Vladimir Kovpak <cn007b at gmail.com>
+Vladyslav Zhelezniak <zhvladi at gmail.com>
+Xiangyu Hu <xiangyu.hu at outlook.com>
+Xiaobing Jiang <s7v7nislands at gmail.com>
+Xiuming Chen <cc at cxm.cc>
+Xuehong Chan <chanxuehong at gmail.com>
+Zhenye Xie <xiezhenye at gmail.com>
+Zhixin Wen <john.wenzhixin at gmail.com>
+
+# Organizations
+
+Barracuda Networks, Inc.
+Counting Ltd.
+DigitalOcean Inc.
+Facebook Inc.
+GitHub Inc.
+Google Inc.
+InfoSum Ltd.
+Keybase Inc.
+Multiplay Ltd.
+Percona LLC
+Pivotal Inc.
+Stripe Inc.
+Zendesk Inc.

GOPATH/src/github.com/go-sql-driver/mysql/CHANGELOG.md

+## Version 1.5 (2020-01-07)
+
+Changes:
+
+  - Dropped support Go 1.9 and lower (#823, #829, #886, #1016, #1017)
+  - Improve buffer handling (#890)
+  - Document potentially insecure TLS configs (#901)
+  - Use a double-buffering scheme to prevent data races (#943)
+  - Pass uint64 values without converting them to string (#838, #955)
+  - Update collations and make utf8mb4 default (#877, #1054)
+  - Make NullTime compatible with sql.NullTime in Go 1.13+ (#995)
+  - Removed CloudSQL support (#993, #1007)
+  - Add Go Module support (#1003)
+
+New Features:
+
+  - Implement support of optional TLS (#900)
+  - Check connection liveness (#934, #964, #997, #1048, #1051, #1052)
+  - Implement Connector Interface (#941, #958, #1020, #1035)
+
+Bugfixes:
+
+  - Mark connections as bad on error during ping (#875)
+  - Mark connections as bad on error during dial (#867)
+  - Fix connection leak caused by rapid context cancellation (#1024)
+  - Mark connections as bad on error during Conn.Prepare (#1030)
+
+
+## Version 1.4.1 (2018-11-14)
+
+Bugfixes:
+
+ - Fix TIME format for binary columns (#818)
+ - Fix handling of empty auth plugin names (#835)
+ - Fix caching_sha2_password with empty password (#826)
+ - Fix canceled context broke mysqlConn (#862)
+ - Fix OldAuthSwitchRequest support (#870)
+ - Fix Auth Response packet for cleartext password (#887)
+
+## Version 1.4 (2018-06-03)
+
+Changes:
+
+ - Documentation fixes (#530, #535, #567)
+ - Refactoring (#575, #579, #580, #581, #603, #615, #704)
+ - Cache column names (#444)
+ - Sort the DSN parameters in DSNs generated from a config (#637)
+ - Allow native password authentication by default (#644)
+ - Use the default port if it is missing in the DSN (#668)
+ - Removed the `strict` mode (#676)
+ - Do not query `max_allowed_packet` by default (#680)
+ - Dropped support Go 1.6 and lower (#696)
+ - Updated `ConvertValue()` to match the database/sql/driver implementation (#760)
+ - Document the usage of `0000-00-00T00:00:00` as the time.Time zero value (#783)
+ - Improved the compatibility of the authentication system (#807)
+
+New Features:
+
+ - Multi-Results support (#537)
+ - `rejectReadOnly` DSN option (#604)
+ - `context.Context` support (#608, #612, #627, #761)
+ - Transaction isolation level support (#619, #744)
+ - Read-Only transactions support (#618, #634)
+ - `NewConfig` function which initializes a config with default values (#679)
+ - Implemented the `ColumnType` interfaces (#667, #724)
+ - Support for custom string types in `ConvertValue` (#623)
+ - Implemented `NamedValueChecker`, improving support for uint64 with high bit set (#690, #709, #710)
+ - `caching_sha2_password` authentication plugin support (#794, #800, #801, #802)
+ - Implemented `driver.SessionResetter` (#779)
+ - `sha256_password` authentication plugin support (#808)
+
+Bugfixes:
+
+ - Use the DSN hostname as TLS default ServerName if `tls=true` (#564, #718)
+ - Fixed LOAD LOCAL DATA INFILE for empty files (#590)
+ - Removed columns definition cache since it sometimes cached invalid data (#592)
+ - Don't mutate registered TLS configs (#600)
+ - Make RegisterTLSConfig concurrency-safe (#613)
+ - Handle missing auth data in the handshake packet correctly (#646)
+ - Do not retry queries when data was written to avoid data corruption (#302, #736)
+ - Cache the connection pointer for error handling before invalidating it (#678)
+ - Fixed imports for appengine/cloudsql (#700)
+ - Fix sending STMT_LONG_DATA for 0 byte data (#734)
+ - Set correct capacity for []bytes read from length-encoded strings (#766)
+ - Make RegisterDial concurrency-safe (#773)
+
+
+## Version 1.3 (2016-12-01)
+
+Changes:
+
+ - Go 1.1 is no longer supported
+ - Use decimals fields in MySQL to format time types (#249)
+ - Buffer optimizations (#269)
+ - TLS ServerName defaults to the host (#283)
+ - Refactoring (#400, #410, #437)
+ - Adjusted documentation for second generation CloudSQL (#485)
+ - Documented DSN system var quoting rules (#502)
+ - Made statement.Close() calls idempotent to avoid errors in Go 1.6+ (#512)
+
+New Features:
+
+ - Enable microsecond resolution on TIME, DATETIME and TIMESTAMP (#249)
+ - Support for returning table alias on Columns() (#289, #359, #382)
+ - Placeholder interpolation, can be actived with the DSN parameter `interpolateParams=true` (#309, #318, #490)
+ - Support for uint64 parameters with high bit set (#332, #345)
+ - Cleartext authentication plugin support (#327)
+ - Exported ParseDSN function and the Config struct (#403, #419, #429)
+ - Read / Write timeouts (#401)
+ - Support for JSON field type (#414)
+ - Support for multi-statements and multi-results (#411, #431)
+ - DSN parameter to set the driver-side max_allowed_packet value manually (#489)
+ - Native password authentication plugin support (#494, #524)
+
+Bugfixes:
+
+ - Fixed handling of queries without columns and rows (#255)
+ - Fixed a panic when SetKeepAlive() failed (#298)
+ - Handle ERR packets while reading rows (#321)
+ - Fixed reading NULL length-encoded integers in MySQL 5.6+ (#349)
+ - Fixed absolute paths support in LOAD LOCAL DATA INFILE (#356)
+ - Actually zero out bytes in handshake response (#378)
+ - Fixed race condition in registering LOAD DATA INFILE handler (#383)
+ - Fixed tests with MySQL 5.7.9+ (#380)
+ - QueryUnescape TLS config names (#397)
+ - Fixed "broken pipe" error by writing to closed socket (#390)
+ - Fixed LOAD LOCAL DATA INFILE buffering (#424)
+ - Fixed parsing of floats into float64 when placeholders are used (#434)
+ - Fixed DSN tests with Go 1.7+ (#459)
+ - Handle ERR packets while waiting for EOF (#473)
+ - Invalidate connection on error while discarding additional results (#513)
+ - Allow terminating packets of length 0 (#516)
+
+
+## Version 1.2 (2014-06-03)
+
+Changes:
+
+ - We switched back to a "rolling release". `go get` installs the current master branch again
+ - Version v1 of the driver will not be maintained anymore. Go 1.0 is no longer supported by this driver
+ - Exported errors to allow easy checking from application code
+ - Enabled TCP Keepalives on TCP connections
+ - Optimized INFILE handling (better buffer size calculation, lazy init, ...)
+ - The DSN parser also checks for a missing separating slash
+ - Faster binary date / datetime to string formatting
+ - Also exported the MySQLWarning type
+ - mysqlConn.Close returns the first error encountered instead of ignoring all errors
+ - writePacket() automatically writes the packet size to the header
+ - readPacket() uses an iterative approach instead of the recursive approach to merge splitted packets
+
+New Features:
+
+ - `RegisterDial` allows the usage of a custom dial function to establish the network connection
+ - Setting the connection collation is possible with the `collation` DSN parameter. This parameter should be preferred over the `charset` parameter
+ - Logging of critical errors is configurable with `SetLogger`
+ - Google CloudSQL support
+
+Bugfixes:
+
+ - Allow more than 32 parameters in prepared statements
+ - Various old_password fixes
+ - Fixed TestConcurrent test to pass Go's race detection
+ - Fixed appendLengthEncodedInteger for large numbers
+ - Renamed readLengthEnodedString to readLengthEncodedString and skipLengthEnodedString to skipLengthEncodedString (fixed typo)
+
+
+## Version 1.1 (2013-11-02)
+
+Changes:
+
+  - Go-MySQL-Driver now requires Go 1.1
+  - Connections now use the collation `utf8_general_ci` by default. Adding `&charset=UTF8` to the DSN should not be necessary anymore
+  - Made closing rows and connections error tolerant. This allows for example deferring rows.Close() without checking for errors
+  - `[]byte(nil)` is now treated as a NULL value. Before, it was treated like an empty string / `[]byte("")`
+  - DSN parameter values must now be url.QueryEscape'ed. This allows text values to contain special characters, such as '&'.
+  - Use the IO buffer also for writing. This results in zero allocations (by the driver) for most queries
+  - Optimized the buffer for reading
+  - stmt.Query now caches column metadata
+  - New Logo
+  - Changed the copyright header to include all contributors
+  - Improved the LOAD INFILE documentation
+  - The driver struct is now exported to make the driver directly accessible
+  - Refactored the driver tests
+  - Added more benchmarks and moved all to a separate file
+  - Other small refactoring
+
+New Features:
+
+  - Added *old_passwords* support: Required in some cases, but must be enabled by adding `allowOldPasswords=true` to the DSN since it is insecure
+  - Added a `clientFoundRows` parameter: Return the number of matching rows instead of the number of rows changed on UPDATEs
+  - Added TLS/SSL support: Use a TLS/SSL encrypted connection to the server. Custom TLS configs can be registered and used
+
+Bugfixes:
+
+  - Fixed MySQL 4.1 support: MySQL 4.1 sends packets with lengths which differ from the specification
+  - Convert to DB timezone when inserting `time.Time`
+  - Splitted packets (more than 16MB) are now merged correctly
+  - Fixed false positive `io.EOF` errors when the data was fully read
+  - Avoid panics on reuse of closed connections
+  - Fixed empty string producing false nil values
+  - Fixed sign byte for positive TIME fields
+
+
+## Version 1.0 (2013-05-14)
+
+Initial Release

GOPATH/src/github.com/go-sql-driver/mysql/benchmark_test.go

+// Go MySQL Driver - A MySQL-Driver for Go's database/sql package
+//
+// Copyright 2013 The Go-MySQL-Driver Authors. All rights reserved.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package mysql
+
+import (
+	"bytes"
+	"context"
+	"database/sql"
+	"database/sql/driver"
+	"fmt"
+	"math"
+	"runtime"
+	"strings"
+	"sync"
+	"sync/atomic"
+	"testing"
+	"time"
+)
+
+type TB testing.B
+
+func (tb *TB) check(err error) {
+	if err != nil {
+		tb.Fatal(err)
+	}
+}
+
+func (tb *TB) checkDB(db *sql.DB, err error) *sql.DB {
+	tb.check(err)
+	return db
+}
+
+func (tb *TB) checkRows(rows *sql.Rows, err error) *sql.Rows {
+	tb.check(err)
+	return rows
+}
+
+func (tb *TB) checkStmt(stmt *sql.Stmt, err error) *sql.Stmt {
+	tb.check(err)
+	return stmt
+}
+
+func initDB(b *testing.B, queries ...string) *sql.DB {
+	tb := (*TB)(b)
+	db := tb.checkDB(sql.Open("mysql", dsn))
+	for _, query := range queries {
+		if _, err := db.Exec(query); err != nil {
+			b.Fatalf("error on %q: %v", query, err)
+		}
+	}
+	return db
+}
+
+const concurrencyLevel = 10
+
+func BenchmarkQuery(b *testing.B) {
+	tb := (*TB)(b)
+	b.StopTimer()
+	b.ReportAllocs()
+	db := initDB(b,
+		"DROP TABLE IF EXISTS foo",
+		"CREATE TABLE foo (id INT PRIMARY KEY, val CHAR(50))",
+		`INSERT INTO foo VALUES (1, "one")`,
+		`INSERT INTO foo VALUES (2, "two")`,
+	)
+	db.SetMaxIdleConns(concurrencyLevel)
+	defer db.Close()
+
+	stmt := tb.checkStmt(db.Prepare("SELECT val FROM foo WHERE id=?"))
+	defer stmt.Close()
+
+	remain := int64(b.N)
+	var wg sync.WaitGroup
+	wg.Add(concurrencyLevel)
+	defer wg.Wait()
+	b.StartTimer()
+
+	for i := 0; i < concurrencyLevel; i++ {
+		go func() {
+			for {
+				if atomic.AddInt64(&remain, -1) < 0 {
+					wg.Done()
+					return
+				}
+
+				var got string
+				tb.check(stmt.QueryRow(1).Scan(&got))
+				if got != "one" {
+					b.Errorf("query = %q; want one", got)
+					wg.Done()
+					return
+				}
+			}
+		}()
+	}
+}
+
+func BenchmarkExec(b *testing.B) {
+	tb := (*TB)(b)
+	b.StopTimer()
+	b.ReportAllocs()
+	db := tb.checkDB(sql.Open("mysql", dsn))
+	db.SetMaxIdleConns(concurrencyLevel)
+	defer db.Close()
+
+	stmt := tb.checkStmt(db.Prepare("DO 1"))
+	defer stmt.Close()
+
+	remain := int64(b.N)
+	var wg sync.WaitGroup
+	wg.Add(concurrencyLevel)
+	defer wg.Wait()
+	b.StartTimer()
+
+	for i := 0; i < concurrencyLevel; i++ {
+		go func() {
+			for {
+				if atomic.AddInt64(&remain, -1) < 0 {
+					wg.Done()
+					return
+				}
+
+				if _, err := stmt.Exec(); err != nil {
+					b.Logf("stmt.Exec failed: %v", err)
+					b.Fail()
+				}
+			}
+		}()
+	}
+}
+
+// data, but no db writes
+var roundtripSample []byte
+
+func initRoundtripBenchmarks() ([]byte, int, int) {
+	if roundtripSample == nil {
+		roundtripSample = []byte(strings.Repeat("0123456789abcdef", 1024*1024))
+	}
+	return roundtripSample, 16, len(roundtripSample)
+}
+
+func BenchmarkRoundtripTxt(b *testing.B) {
+	b.StopTimer()
+	sample, min, max := initRoundtripBenchmarks()
+	sampleString := string(sample)
+	b.ReportAllocs()
+	tb := (*TB)(b)
+	db := tb.checkDB(sql.Open("mysql", dsn))
+	defer db.Close()
+	b.StartTimer()
+	var result string
+	for i := 0; i < b.N; i++ {
+		length := min + i
+		if length > max {
+			length = max
+		}
+		test := sampleString[0:length]
+		rows := tb.checkRows(db.Query(`SELECT "` + test + `"`))
+		if !rows.Next() {
+			rows.Close()
+			b.Fatalf("crashed")
+		}
+		err := rows.Scan(&result)
+		if err != nil {
+			rows.Close()
+			b.Fatalf("crashed")
+		}
+		if result != test {
+			rows.Close()
+			b.Errorf("mismatch")
+		}
+		rows.Close()
+	}
+}
+
+func BenchmarkRoundtripBin(b *testing.B) {
+	b.StopTimer()
+	sample, min, max := initRoundtripBenchmarks()
+	b.ReportAllocs()
+	tb := (*TB)(b)
+	db := tb.checkDB(sql.Open("mysql", dsn))
+	defer db.Close()
+	stmt := tb.checkStmt(db.Prepare("SELECT ?"))
+	defer stmt.Close()
+	b.StartTimer()
+	var result sql.RawBytes
+	for i := 0; i < b.N; i++ {
+		length := min + i
+		if length > max {
+			length = max
+		}
+		test := sample[0:length]
+		rows := tb.checkRows(stmt.Query(test))
+		if !rows.Next() {
+			rows.Close()
+			b.Fatalf("crashed")
+		}
+		err := rows.Scan(&result)
+		if err != nil {
+			rows.Close()
+			b.Fatalf("crashed")
+		}
+		if !bytes.Equal(result, test) {
+			rows.Close()
+			b.Errorf("mismatch")
+		}
+		rows.Close()
+	}
+}
+
+func BenchmarkInterpolation(b *testing.B) {
+	mc := &mysqlConn{
+		cfg: &Config{
+			InterpolateParams: true,
+			Loc:               time.UTC,
+		},
+		maxAllowedPacket: maxPacketSize,
+		maxWriteSize:     maxPacketSize - 1,
+		buf:              newBuffer(nil),
+	}
+
+	args := []driver.Value{
+		int64(42424242),
+		float64(math.Pi),
+		false,
+		time.Unix(1423411542, 807015000),
+		[]byte("bytes containing special chars ' \" \a \x00"),
+		"string containing special chars ' \" \a \x00",
+	}
+	q := "SELECT ?, ?, ?, ?, ?, ?"
+
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_, err := mc.interpolateParams(q, args)
+		if err != nil {
+			b.Fatal(err)
+		}
+	}
+}
+
+func benchmarkQueryContext(b *testing.B, db *sql.DB, p int) {
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+	db.SetMaxIdleConns(p * runtime.GOMAXPROCS(0))
+
+	tb := (*TB)(b)
+	stmt := tb.checkStmt(db.PrepareContext(ctx, "SELECT val FROM foo WHERE id=?"))
+	defer stmt.Close()
+
+	b.SetParallelism(p)
+	b.ReportAllocs()
+	b.ResetTimer()
+	b.RunParallel(func(pb *testing.PB) {
+		var got string
+		for pb.Next() {
+			tb.check(stmt.QueryRow(1).Scan(&got))
+			if got != "one" {
+				b.Fatalf("query = %q; want one", got)
+			}
+		}
+	})
+}
+
+func BenchmarkQueryContext(b *testing.B) {
+	db := initDB(b,
+		"DROP TABLE IF EXISTS foo",
+		"CREATE TABLE foo (id INT PRIMARY KEY, val CHAR(50))",
+		`INSERT INTO foo VALUES (1, "one")`,
+		`INSERT INTO foo VALUES (2, "two")`,
+	)
+	defer db.Close()
+	for _, p := range []int{1, 2, 3, 4} {
+		b.Run(fmt.Sprintf("%d", p), func(b *testing.B) {
+			benchmarkQueryContext(b, db, p)
+		})
+	}
+}
+
+func benchmarkExecContext(b *testing.B, db *sql.DB, p int) {
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+	db.SetMaxIdleConns(p * runtime.GOMAXPROCS(0))
+
+	tb := (*TB)(b)
+	stmt := tb.checkStmt(db.PrepareContext(ctx, "DO 1"))
+	defer stmt.Close()
+
+	b.SetParallelism(p)
+	b.ReportAllocs()
+	b.ResetTimer()
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			if _, err := stmt.ExecContext(ctx); err != nil {
+				b.Fatal(err)
+			}
+		}
+	})
+}
+
+func BenchmarkExecContext(b *testing.B) {
+	db := initDB(b,
+		"DROP TABLE IF EXISTS foo",
+		"CREATE TABLE foo (id INT PRIMARY KEY, val CHAR(50))",
+		`INSERT INTO foo VALUES (1, "one")`,
+		`INSERT INTO foo VALUES (2, "two")`,
+	)
+	defer db.Close()
+	for _, p := range []int{1, 2, 3, 4} {
+		b.Run(fmt.Sprintf("%d", p), func(b *testing.B) {
+			benchmarkQueryContext(b, db, p)
+		})
+	}
+}
+
+// BenchmarkQueryRawBytes benchmarks fetching 100 blobs using sql.RawBytes.
+// "size=" means size of each blobs.
+func BenchmarkQueryRawBytes(b *testing.B) {
+	var sizes []int = []int{100, 1000, 2000, 4000, 8000, 12000, 16000, 32000, 64000, 256000}
+	db := initDB(b,
+		"DROP TABLE IF EXISTS bench_rawbytes",
+		"CREATE TABLE bench_rawbytes (id INT PRIMARY KEY, val LONGBLOB)",
+	)
+	defer db.Close()
+
+	blob := make([]byte, sizes[len(sizes)-1])
+	for i := range blob {
+		blob[i] = 42
+	}
+	for i := 0; i < 100; i++ {
+		_, err := db.Exec("INSERT INTO bench_rawbytes VALUES (?, ?)", i, blob)
+		if err != nil {
+			b.Fatal(err)
+		}
+	}
+
+	for _, s := range sizes {
+		b.Run(fmt.Sprintf("size=%v", s), func(b *testing.B) {
+			db.SetMaxIdleConns(0)
+			db.SetMaxIdleConns(1)
+			b.ReportAllocs()
+			b.ResetTimer()
+
+			for j := 0; j < b.N; j++ {
+				rows, err := db.Query("SELECT LEFT(val, ?) as v FROM bench_rawbytes", s)
+				if err != nil {
+					b.Fatal(err)
+				}
+				nrows := 0
+				for rows.Next() {
+					var buf sql.RawBytes
+					err := rows.Scan(&buf)
+					if err != nil {
+						b.Fatal(err)
+					}
+					if len(buf) != s {
+						b.Fatalf("size mismatch: expected %v, got %v", s, len(buf))
+					}
+					nrows++
+				}
+				rows.Close()
+				if nrows != 100 {
+					b.Fatalf("numbers of rows mismatch: expected %v, got %v", 100, nrows)
+				}
+			}
+		})
+	}
+}

GOPATH/src/github.com/go-sql-driver/mysql/buffer.go

+// Go MySQL Driver - A MySQL-Driver for Go's database/sql package
+//
+// Copyright 2013 The Go-MySQL-Driver Authors. All rights reserved.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package mysql
+
+import (
+	"io"
+	"net"
+	"time"
+)
+
+const defaultBufSize = 4096
+const maxCachedBufSize = 256 * 1024
+
+// A buffer which is used for both reading and writing.
+// This is possible since communication on each connection is synchronous.
+// In other words, we can't write and read simultaneously on the same connection.
+// The buffer is similar to bufio.Reader / Writer but zero-copy-ish
+// Also highly optimized for this particular use case.
+// This buffer is backed by two byte slices in a double-buffering scheme
+type buffer struct {
+	buf     []byte // buf is a byte buffer who's length and capacity are equal.
+	nc      net.Conn
+	idx     int
+	length  int
+	timeout time.Duration
+	dbuf    [2][]byte // dbuf is an array with the two byte slices that back this buffer
+	flipcnt uint      // flipccnt is the current buffer counter for double-buffering
+}
+
+// newBuffer allocates and returns a new buffer.
+func newBuffer(nc net.Conn) buffer {
+	fg := make([]byte, defaultBufSize)
+	return buffer{
+		buf:  fg,
+		nc:   nc,
+		dbuf: [2][]byte{fg, nil},
+	}
+}
+
+// flip replaces the active buffer with the background buffer
+// this is a delayed flip that simply increases the buffer counter;
+// the actual flip will be performed the next time we call `buffer.fill`
+func (b *buffer) flip() {
+	b.flipcnt += 1
+}
+
+// fill reads into the buffer until at least _need_ bytes are in it
+func (b *buffer) fill(need int) error {
+	n := b.length
+	// fill data into its double-buffering target: if we've called
+	// flip on this buffer, we'll be copying to the background buffer,
+	// and then filling it with network data; otherwise we'll just move
+	// the contents of the current buffer to the front before filling it
+	dest := b.dbuf[b.flipcnt&1]
+
+	// grow buffer if necessary to fit the whole packet.
+	if need > len(dest) {
+		// Round up to the next multiple of the default size
+		dest = make([]byte, ((need/defaultBufSize)+1)*defaultBufSize)
+
+		// if the allocated buffer is not too large, move it to backing storage
+		// to prevent extra allocations on applications that perform large reads
+		if len(dest) <= maxCachedBufSize {
+			b.dbuf[b.flipcnt&1] = dest
+		}
+	}
+
+	// if we're filling the fg buffer, move the existing data to the start of it.
+	// if we're filling the bg buffer, copy over the data
+	if n > 0 {
+		copy(dest[:n], b.buf[b.idx:])
+	}
+
+	b.buf = dest
+	b.idx = 0
+
+	for {
+		if b.timeout > 0 {
+			if err := b.nc.SetReadDeadline(time.Now().Add(b.timeout)); err != nil {
+				return err
+			}
+		}
+
+		nn, err := b.nc.Read(b.buf[n:])
+		n += nn
+
+		switch err {
+		case nil:
+			if n < need {
+				continue
+			}
+			b.length = n
+			return nil
+
+		case io.EOF:
+			if n >= need {
+				b.length = n
+				return nil
+			}
+			return io.ErrUnexpectedEOF
+
+		default:
+			return err
+		}
+	}
+}
+
+// returns next N bytes from buffer.
+// The returned slice is only guaranteed to be valid until the next read
+func (b *buffer) readNext(need int) ([]byte, error) {
+	if b.length < need {
+		// refill
+		if err := b.fill(need); err != nil {
+			return nil, err
+		}
+	}
+
+	offset := b.idx
+	b.idx += need
+	b.length -= need
+	return b.buf[offset:b.idx], nil
+}
+
+// takeBuffer returns a buffer with the requested size.
+// If possible, a slice from the existing buffer is returned.
+// Otherwise a bigger buffer is made.
+// Only one buffer (total) can be used at a time.
+func (b *buffer) takeBuffer(length int) ([]byte, error) {
+	if b.length > 0 {
+		return nil, ErrBusyBuffer
+	}
+
+	// test (cheap) general case first
+	if length <= cap(b.buf) {
+		return b.buf[:length], nil
+	}
+
+	if length < maxPacketSize {
+		b.buf = make([]byte, length)
+		return b.buf, nil
+	}
+
+	// buffer is larger than we want to store.
+	return make([]byte, length), nil
+}
+
+// takeSmallBuffer is shortcut which can be used if length is
+// known to be smaller than defaultBufSize.
+// Only one buffer (total) can be used at a time.
+func (b *buffer) takeSmallBuffer(length int) ([]byte, error) {
+	if b.length > 0 {
+		return nil, ErrBusyBuffer
+	}
+	return b.buf[:length], nil
+}
+
+// takeCompleteBuffer returns the complete existing buffer.
+// This can be used if the necessary buffer size is unknown.
+// cap and len of the returned buffer will be equal.
+// Only one buffer (total) can be used at a time.
+func (b *buffer) takeCompleteBuffer() ([]byte, error) {
+	if b.length > 0 {
+		return nil, ErrBusyBuffer
+	}
+	return b.buf, nil
+}
+
+// store stores buf, an updated buffer, if its suitable to do so.
+func (b *buffer) store(buf []byte) error {
+	if b.length > 0 {
+		return ErrBusyBuffer
+	} else if cap(buf) <= maxPacketSize && cap(buf) > cap(b.buf) {
+		b.buf = buf[:cap(buf)]
+	}
+	return nil
+}

GOPATH/src/github.com/go-sql-driver/mysql/collations.go

+// Go MySQL Driver - A MySQL-Driver for Go's database/sql package
+//
+// Copyright 2014 The Go-MySQL-Driver Authors. All rights reserved.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package mysql
+
+const defaultCollation = "utf8mb4_general_ci"
+const binaryCollation = "binary"
+
+// A list of available collations mapped to the internal ID.
+// To update this map use the following MySQL query:
+//     SELECT COLLATION_NAME, ID FROM information_schema.COLLATIONS WHERE ID<256 ORDER BY ID
+//
+// Handshake packet have only 1 byte for collation_id.  So we can't use collations with ID > 255.
+//
+// ucs2, utf16, and utf32 can't be used for connection charset.
+// https://dev.mysql.com/doc/refman/5.7/en/charset-connection.html#charset-connection-impermissible-client-charset
+// They are commented out to reduce this map.
+var collations = map[string]byte{
+	"big5_chinese_ci":      1,
+	"latin2_czech_cs":      2,
+	"dec8_swedish_ci":      3,
+	"cp850_general_ci":     4,
+	"latin1_german1_ci":    5,
+	"hp8_english_ci":       6,
+	"koi8r_general_ci":     7,
+	"latin1_swedish_ci":    8,
+	"latin2_general_ci":    9,
+	"swe7_swedish_ci":      10,
+	"ascii_general_ci":     11,
+	"ujis_japanese_ci":     12,
+	"sjis_japanese_ci":     13,
+	"cp1251_bulgarian_ci":  14,
+	"latin1_danish_ci":     15,
+	"hebrew_general_ci":    16,
+	"tis620_thai_ci":       18,
+	"euckr_korean_ci":      19,
+	"latin7_estonian_cs":   20,
+	"latin2_hungarian_ci":  21,
+	"koi8u_general_ci":     22,
+	"cp1251_ukrainian_ci":  23,
+	"gb2312_chinese_ci":    24,
+	"greek_general_ci":     25,
+	"cp1250_general_ci":    26,
+	"latin2_croatian_ci":   27,
+	"gbk_chinese_ci":       28,
+	"cp1257_lithuanian_ci": 29,
+	"latin5_turkish_ci":    30,
+	"latin1_german2_ci":    31,
+	"armscii8_general_ci":  32,
+	"utf8_general_ci":      33,
+	"cp1250_czech_cs":      34,
+	//"ucs2_general_ci":          35,
+	"cp866_general_ci":    36,
+	"keybcs2_general_ci":  37,
+	"macce_general_ci":    38,
+	"macroman_general_ci": 39,
+	"cp852_general_ci":    40,
+	"latin7_general_ci":   41,
+	"latin7_general_cs":   42,
+	"macce_bin":           43,
+	"cp1250_croatian_ci":  44,
+	"utf8mb4_general_ci":  45,
+	"utf8mb4_bin":         46,
+	"latin1_bin":          47,
+	"latin1_general_ci":   48,
+	"latin1_general_cs":   49,
+	"cp1251_bin":          50,
+	"cp1251_general_ci":   51,
+	"cp1251_general_cs":   52,
+	"macroman_bin":        53,
+	//"utf16_general_ci":         54,
+	//"utf16_bin":                55,
+	//"utf16le_general_ci":       56,
+	"cp1256_general_ci": 57,
+	"cp1257_bin":        58,
+	"cp1257_general_ci": 59,
+	//"utf32_general_ci":         60,
+	//"utf32_bin":                61,
+	//"utf16le_bin":              62,
+	"binary":          63,
+	"armscii8_bin":    64,
+	"ascii_bin":       65,
+	"cp1250_bin":      66,
+	"cp1256_bin":      67,
+	"cp866_bin":       68,
+	"dec8_bin":        69,
+	"greek_bin":       70,
+	"hebrew_bin":      71,
+	"hp8_bin":         72,
+	"keybcs2_bin":     73,
+	"koi8r_bin":       74,
+	"koi8u_bin":       75,
+	"utf8_tolower_ci": 76,
+	"latin2_bin":      77,
+	"latin5_bin":      78,
+	"latin7_bin":      79,
+	"cp850_bin":       80,
+	"cp852_bin":       81,
+	"swe7_bin":        82,
+	"utf8_bin":        83,
+	"big5_bin":        84,
+	"euckr_bin":       85,
+	"gb2312_bin":      86,
+	"gbk_bin":         87,
+	"sjis_bin":        88,
+	"tis620_bin":      89,
+	//"ucs2_bin":                 90,
+	"ujis_bin":            91,
+	"geostd8_general_ci":  92,
+	"geostd8_bin":         93,
+	"latin1_spanish_ci":   94,
+	"cp932_japanese_ci":   95,
+	"cp932_bin":           96,
+	"eucjpms_japanese_ci": 97,
+	"eucjpms_bin":         98,
+	"cp1250_polish_ci":    99,
+	//"utf16_unicode_ci":         101,
+	//"utf16_icelandic_ci":       102,
+	//"utf16_latvian_ci":         103,
+	//"utf16_romanian_ci":        104,
+	//"utf16_slovenian_ci":       105,
+	//"utf16_polish_ci":          106,
+	//"utf16_estonian_ci":        107,
+	//"utf16_spanish_ci":         108,
+	//"utf16_swedish_ci":         109,
+	//"utf16_turkish_ci":         110,
+	//"utf16_czech_ci":           111,
+	//"utf16_danish_ci":          112,
+	//"utf16_lithuanian_ci":      113,
+	//"utf16_slovak_ci":          114,
+	//"utf16_spanish2_ci":        115,
+	//"utf16_roman_ci":           116,
+	//"utf16_persian_ci":         117,
+	//"utf16_esperanto_ci":       118,
+	//"utf16_hungarian_ci":       119,
+	//"utf16_sinhala_ci":         120,
+	//"utf16_german2_ci":         121,
+	//"utf16_croatian_ci":        122,
+	//"utf16_unicode_520_ci":     123,
+	//"utf16_vietnamese_ci":      124,
+	//"ucs2_unicode_ci":          128,
+	//"ucs2_icelandic_ci":        129,
+	//"ucs2_latvian_ci":          130,
+	//"ucs2_romanian_ci":         131,
+	//"ucs2_slovenian_ci":        132,
+	//"ucs2_polish_ci":           133,
+	//"ucs2_estonian_ci":         134,
+	//"ucs2_spanish_ci":          135,
+	//"ucs2_swedish_ci":          136,
+	//"ucs2_turkish_ci":          137,
+	//"ucs2_czech_ci":            138,
+	//"ucs2_danish_ci":           139,
+	//"ucs2_lithuanian_ci":       140,
+	//"ucs2_slovak_ci":           141,
+	//"ucs2_spanish2_ci":         142,
+	//"ucs2_roman_ci":            143,
+	//"ucs2_persian_ci":          144,
+	//"ucs2_esperanto_ci":        145,
+	//"ucs2_hungarian_ci":        146,
+	//"ucs2_sinhala_ci":          147,
+	//"ucs2_german2_ci":          148,
+	//"ucs2_croatian_ci":         149,
+	//"ucs2_unicode_520_ci":      150,
+	//"ucs2_vietnamese_ci":       151,
+	//"ucs2_general_mysql500_ci": 159,
+	//"utf32_unicode_ci":         160,
+	//"utf32_icelandic_ci":       161,
+	//"utf32_latvian_ci":         162,
+	//"utf32_romanian_ci":        163,
+	//"utf32_slovenian_ci":       164,
+	//"utf32_polish_ci":          165,
+	//"utf32_estonian_ci":        166,
+	//"utf32_spanish_ci":         167,
+	//"utf32_swedish_ci":         168,
+	//"utf32_turkish_ci":         169,
+	//"utf32_czech_ci":           170,
+	//"utf32_danish_ci":          171,
+	//"utf32_lithuanian_ci":      172,
+	//"utf32_slovak_ci":          173,
+	//"utf32_spanish2_ci":        174,
+	//"utf32_roman_ci":           175,
+	//"utf32_persian_ci":         176,
+	//"utf32_esperanto_ci":       177,
+	//"utf32_hungarian_ci":       178,
+	//"utf32_sinhala_ci":         179,
+	//"utf32_german2_ci":         180,
+	//"utf32_croatian_ci":        181,
+	//"utf32_unicode_520_ci":     182,
+	//"utf32_vietnamese_ci":      183,
+	"utf8_unicode_ci":          192,
+	"utf8_icelandic_ci":        193,
+	"utf8_latvian_ci":          194,
+	"utf8_romanian_ci":         195,
+	"utf8_slovenian_ci":        196,
+	"utf8_polish_ci":           197,
+	"utf8_estonian_ci":         198,
+	"utf8_spanish_ci":          199,
+	"utf8_swedish_ci":          200,
+	"utf8_turkish_ci":          201,
+	"utf8_czech_ci":            202,
+	"utf8_danish_ci":           203,
+	"utf8_lithuanian_ci":       204,
+	"utf8_slovak_ci":           205,
+	"utf8_spanish2_ci":         206,
+	"utf8_roman_ci":            207,
+	"utf8_persian_ci":          208,
+	"utf8_esperanto_ci":        209,
+	"utf8_hungarian_ci":        210,
+	"utf8_sinhala_ci":          211,
+	"utf8_german2_ci":          212,
+	"utf8_croatian_ci":         213,
+	"utf8_unicode_520_ci":      214,
+	"utf8_vietnamese_ci":       215,
+	"utf8_general_mysql500_ci": 223,
+	"utf8mb4_unicode_ci":       224,
+	"utf8mb4_icelandic_ci":     225,
+	"utf8mb4_latvian_ci":       226,
+	"utf8mb4_romanian_ci":      227,
+	"utf8mb4_slovenian_ci":     228,
+	"utf8mb4_polish_ci":        229,
+	"utf8mb4_estonian_ci":      230,
+	"utf8mb4_spanish_ci":       231,
+	"utf8mb4_swedish_ci":       232,
+	"utf8mb4_turkish_ci":       233,
+	"utf8mb4_czech_ci":         234,
+	"utf8mb4_danish_ci":        235,
+	"utf8mb4_lithuanian_ci":    236,
+	"utf8mb4_slovak_ci":        237,
+	"utf8mb4_spanish2_ci":      238,
+	"utf8mb4_roman_ci":         239,
+	"utf8mb4_persian_ci":       240,
+	"utf8mb4_esperanto_ci":     241,
+	"utf8mb4_hungarian_ci":     242,
+	"utf8mb4_sinhala_ci":       243,
+	"utf8mb4_german2_ci":       244,
+	"utf8mb4_croatian_ci":      245,
+	"utf8mb4_unicode_520_ci":   246,
+	"utf8mb4_vietnamese_ci":    247,
+	"gb18030_chinese_ci":       248,
+	"gb18030_bin":              249,
+	"gb18030_unicode_520_ci":   250,
+	"utf8mb4_0900_ai_ci":       255,
+}
+
+// A denylist of collations which is unsafe to interpolate parameters.
+// These multibyte encodings may contains 0x5c (`\`) in their trailing bytes.
+var unsafeCollations = map[string]bool{
+	"big5_chinese_ci":        true,
+	"sjis_japanese_ci":       true,
+	"gbk_chinese_ci":         true,
+	"big5_bin":               true,
+	"gb2312_bin":             true,
+	"gbk_bin":                true,
+	"sjis_bin":               true,
+	"cp932_japanese_ci":      true,
+	"cp932_bin":              true,
+	"gb18030_chinese_ci":     true,
+	"gb18030_bin":            true,
+	"gb18030_unicode_520_ci": true,
+}

GOPATH/src/github.com/go-sql-driver/mysql/conncheck.go

+// Go MySQL Driver - A MySQL-Driver for Go's database/sql package
+//
+// Copyright 2019 The Go-MySQL-Driver Authors. All rights reserved.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+// +build linux darwin dragonfly freebsd netbsd openbsd solaris illumos
+
+package mysql
+
+import (
+	"errors"
+	"io"
+	"net"
+	"syscall"
+)
+
+var errUnexpectedRead = errors.New("unexpected read from socket")
+
+func connCheck(conn net.Conn) error {
+	var sysErr error
+
+	sysConn, ok := conn.(syscall.Conn)
+	if !ok {
+		return nil
+	}
+	rawConn, err := sysConn.SyscallConn()
+	if err != nil {
+		return err
+	}
+
+	err = rawConn.Read(func(fd uintptr) bool {
+		var buf [1]byte
+		n, err := syscall.Read(int(fd), buf[:])
+		switch {
+		case n == 0 && err == nil:
+			sysErr = io.EOF
+		case n > 0:
+			sysErr = errUnexpectedRead
+		case err == syscall.EAGAIN || err == syscall.EWOULDBLOCK:
+			sysErr = nil
+		default:
+			sysErr = err
+		}
+		return true
+	})
+	if err != nil {
+		return err
+	}
+
+	return sysErr
+}

GOPATH/src/github.com/go-sql-driver/mysql/conncheck_dummy.go

+// Go MySQL Driver - A MySQL-Driver for Go's database/sql package
+//
+// Copyright 2019 The Go-MySQL-Driver Authors. All rights reserved.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+// +build !linux,!darwin,!dragonfly,!freebsd,!netbsd,!openbsd,!solaris,!illumos
+
+package mysql
+
+import "net"
+
+func connCheck(conn net.Conn) error {
+	return nil
+}

GOPATH/src/github.com/go-sql-driver/mysql/conncheck_test.go

+// Go MySQL Driver - A MySQL-Driver for Go's database/sql package
+//
+// Copyright 2013 The Go-MySQL-Driver Authors. All rights reserved.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+// +build linux darwin dragonfly freebsd netbsd openbsd solaris illumos
+
+package mysql
+
+import (
+	"testing"
+	"time"
+)
+
+func TestStaleConnectionChecks(t *testing.T) {
+	runTests(t, dsn, func(dbt *DBTest) {
+		dbt.mustExec("SET @@SESSION.wait_timeout = 2")
+
+		if err := dbt.db.Ping(); err != nil {
+			dbt.Fatal(err)
+		}
+
+		// wait for MySQL to close our connection
+		time.Sleep(3 * time.Second)
+
+		tx, err := dbt.db.Begin()
+		if err != nil {
+			dbt.Fatal(err)
+		}
+
+		if err := tx.Rollback(); err != nil {
+			dbt.Fatal(err)
+		}
+	})
+}

GOPATH/src/github.com/go-sql-driver/mysql/connection_test.go

+// Go MySQL Driver - A MySQL-Driver for Go's database/sql package
+//
+// Copyright 2016 The Go-MySQL-Driver Authors. All rights reserved.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package mysql
+
+import (
+	"context"
+	"database/sql/driver"
+	"encoding/json"
+	"errors"
+	"net"
+	"testing"
+)
+
+func TestInterpolateParams(t *testing.T) {
+	mc := &mysqlConn{
+		buf:              newBuffer(nil),
+		maxAllowedPacket: maxPacketSize,
+		cfg: &Config{
+			InterpolateParams: true,
+		},
+	}
+
+	q, err := mc.interpolateParams("SELECT ?+?", []driver.Value{int64(42), "gopher"})
+	if err != nil {
+		t.Errorf("Expected err=nil, got %#v", err)
+		return
+	}
+	expected := `SELECT 42+'gopher'`
+	if q != expected {
+		t.Errorf("Expected: %q\nGot: %q", expected, q)
+	}
+}
+
+func TestInterpolateParamsJSONRawMessage(t *testing.T) {
+	mc := &mysqlConn{
+		buf:              newBuffer(nil),
+		maxAllowedPacket: maxPacketSize,
+		cfg: &Config{
+			InterpolateParams: true,
+		},
+	}
+
+	buf, err := json.Marshal(struct {
+		Value int `json:"value"`
+	}{Value: 42})
+	if err != nil {
+		t.Errorf("Expected err=nil, got %#v", err)
+		return
+	}
+	q, err := mc.interpolateParams("SELECT ?", []driver.Value{json.RawMessage(buf)})
+	if err != nil {
+		t.Errorf("Expected err=nil, got %#v", err)
+		return
+	}
+	expected := `SELECT '{\"value\":42}'`
+	if q != expected {
+		t.Errorf("Expected: %q\nGot: %q", expected, q)
+	}
+}
+
+func TestInterpolateParamsTooManyPlaceholders(t *testing.T) {
+	mc := &mysqlConn{
+		buf:              newBuffer(nil),
+		maxAllowedPacket: maxPacketSize,
+		cfg: &Config{
+			InterpolateParams: true,
+		},
+	}
+
+	q, err := mc.interpolateParams("SELECT ?+?", []driver.Value{int64(42)})
+	if err != driver.ErrSkip {
+		t.Errorf("Expected err=driver.ErrSkip, got err=%#v, q=%#v", err, q)
+	}
+}
+
+// We don't support placeholder in string literal for now.
+// https://github.com/go-sql-driver/mysql/pull/490
+func TestInterpolateParamsPlaceholderInString(t *testing.T) {
+	mc := &mysqlConn{
+		buf:              newBuffer(nil),
+		maxAllowedPacket: maxPacketSize,
+		cfg: &Config{
+			InterpolateParams: true,
+		},
+	}
+
+	q, err := mc.interpolateParams("SELECT 'abc?xyz',?", []driver.Value{int64(42)})
+	// When InterpolateParams support string literal, this should return `"SELECT 'abc?xyz', 42`
+	if err != driver.ErrSkip {
+		t.Errorf("Expected err=driver.ErrSkip, got err=%#v, q=%#v", err, q)
+	}
+}
+
+func TestInterpolateParamsUint64(t *testing.T) {
+	mc := &mysqlConn{
+		buf:              newBuffer(nil),
+		maxAllowedPacket: maxPacketSize,
+		cfg: &Config{
+			InterpolateParams: true,
+		},
+	}
+
+	q, err := mc.interpolateParams("SELECT ?", []driver.Value{uint64(42)})
+	if err != nil {
+		t.Errorf("Expected err=nil, got err=%#v, q=%#v", err, q)
+	}
+	if q != "SELECT 42" {
+		t.Errorf("Expected uint64 interpolation to work, got q=%#v", q)
+	}
+}
+
+func TestCheckNamedValue(t *testing.T) {
+	value := driver.NamedValue{Value: ^uint64(0)}
+	x := &mysqlConn{}
+	err := x.CheckNamedValue(&value)
+
+	if err != nil {
+		t.Fatal("uint64 high-bit not convertible", err)
+	}
+
+	if value.Value != ^uint64(0) {
+		t.Fatalf("uint64 high-bit converted, got %#v %T", value.Value, value.Value)
+	}
+}
+
+// TestCleanCancel tests passed context is cancelled at start.
+// No packet should be sent.  Connection should keep current status.
+func TestCleanCancel(t *testing.T) {
+	mc := &mysqlConn{
+		closech: make(chan struct{}),
+	}
+	mc.startWatcher()
+	defer mc.cleanup()
+
+	ctx, cancel := context.WithCancel(context.Background())
+	cancel()
+
+	for i := 0; i < 3; i++ { // Repeat same behavior
+		err := mc.Ping(ctx)
+		if err != context.Canceled {
+			t.Errorf("expected context.Canceled, got %#v", err)
+		}
+
+		if mc.closed.IsSet() {
+			t.Error("expected mc is not closed, closed actually")
+		}
+
+		if mc.watching {
+			t.Error("expected watching is false, but true")
+		}
+	}
+}
+
+func TestPingMarkBadConnection(t *testing.T) {
+	nc := badConnection{err: errors.New("boom")}
+	ms := &mysqlConn{
+		netConn:          nc,
+		buf:              newBuffer(nc),
+		maxAllowedPacket: defaultMaxAllowedPacket,
+	}
+
+	err := ms.Ping(context.Background())
+
+	if err != driver.ErrBadConn {
+		t.Errorf("expected driver.ErrBadConn, got  %#v", err)
+	}
+}
+
+func TestPingErrInvalidConn(t *testing.T) {
+	nc := badConnection{err: errors.New("failed to write"), n: 10}
+	ms := &mysqlConn{
+		netConn:          nc,
+		buf:              newBuffer(nc),
+		maxAllowedPacket: defaultMaxAllowedPacket,
+		closech:          make(chan struct{}),
+	}
+
+	err := ms.Ping(context.Background())
+
+	if err != ErrInvalidConn {
+		t.Errorf("expected ErrInvalidConn, got  %#v", err)
+	}
+}
+
+type badConnection struct {
+	n   int
+	err error
+	net.Conn
+}
+
+func (bc badConnection) Write(b []byte) (n int, err error) {
+	return bc.n, bc.err
+}
+
+func (bc badConnection) Close() error {
+	return nil
+}

GOPATH/src/github.com/go-sql-driver/mysql/connector.go

+// Go MySQL Driver - A MySQL-Driver for Go's database/sql package
+//
+// Copyright 2018 The Go-MySQL-Driver Authors. All rights reserved.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package mysql
+
+import (
+	"context"
+	"database/sql/driver"
+	"net"
+)
+
+type connector struct {
+	cfg *Config // immutable private copy.
+}
+
+// Connect implements driver.Connector interface.
+// Connect returns a connection to the database.
+func (c *connector) Connect(ctx context.Context) (driver.Conn, error) {
+	var err error
+
+	// New mysqlConn
+	mc := &mysqlConn{
+		maxAllowedPacket: maxPacketSize,
+		maxWriteSize:     maxPacketSize - 1,
+		closech:          make(chan struct{}),
+		cfg:              c.cfg,
+	}
+	mc.parseTime = mc.cfg.ParseTime
+
+	// Connect to Server
+	dialsLock.RLock()
+	dial, ok := dials[mc.cfg.Net]
+	dialsLock.RUnlock()
+	if ok {
+		dctx := ctx
+		if mc.cfg.Timeout > 0 {
+			var cancel context.CancelFunc
+			dctx, cancel = context.WithTimeout(ctx, c.cfg.Timeout)
+			defer cancel()
+		}
+		mc.netConn, err = dial(dctx, mc.cfg.Addr)
+	} else {
+		nd := net.Dialer{Timeout: mc.cfg.Timeout}
+		mc.netConn, err = nd.DialContext(ctx, mc.cfg.Net, mc.cfg.Addr)
+	}
+
+	if err != nil {
+		return nil, err
+	}
+
+	// Enable TCP Keepalives on TCP connections
+	if tc, ok := mc.netConn.(*net.TCPConn); ok {
+		if err := tc.SetKeepAlive(true); err != nil {
+			// Don't send COM_QUIT before handshake.
+			mc.netConn.Close()
+			mc.netConn = nil
+			return nil, err
+		}
+	}
+
+	// Call startWatcher for context support (From Go 1.8)
+	mc.startWatcher()
+	if err := mc.watchCancel(ctx); err != nil {
+		mc.cleanup()
+		return nil, err
+	}
+	defer mc.finish()
+
+	mc.buf = newBuffer(mc.netConn)
+
+	// Set I/O timeouts
+	mc.buf.timeout = mc.cfg.ReadTimeout
+	mc.writeTimeout = mc.cfg.WriteTimeout
+
+	// Reading Handshake Initialization Packet
+	authData, plugin, err := mc.readHandshakePacket()
+	if err != nil {
+		mc.cleanup()
+		return nil, err
+	}
+
+	if plugin == "" {
+		plugin = defaultAuthPlugin
+	}
+
+	// Send Client Authentication Packet
+	authResp, err := mc.auth(authData, plugin)
+	if err != nil {
+		// try the default auth plugin, if using the requested plugin failed
+		errLog.Print("could not use requested auth plugin '"+plugin+"': ", err.Error())
+		plugin = defaultAuthPlugin
+		authResp, err = mc.auth(authData, plugin)
+		if err != nil {
+			mc.cleanup()
+			return nil, err
+		}
+	}
+	if err = mc.writeHandshakeResponsePacket(authResp, plugin); err != nil {
+		mc.cleanup()
+		return nil, err
+	}
+
+	// Handle response to auth packet, switch methods if possible
+	if err = mc.handleAuthResult(authData, plugin); err != nil {
+		// Authentication failed and MySQL has already closed the connection
+		// (https://dev.mysql.com/doc/internals/en/authentication-fails.html).
+		// Do not send COM_QUIT, just cleanup and return the error.
+		mc.cleanup()
+		return nil, err
+	}
+
+	if mc.cfg.MaxAllowedPacket > 0 {
+		mc.maxAllowedPacket = mc.cfg.MaxAllowedPacket
+	} else {
+		// Get max allowed packet size
+		maxap, err := mc.getSystemVar("max_allowed_packet")
+		if err != nil {
+			mc.Close()
+			return nil, err
+		}
+		mc.maxAllowedPacket = stringToInt(maxap) - 1
+	}
+	if mc.maxAllowedPacket < maxPacketSize {
+		mc.maxWriteSize = mc.maxAllowedPacket
+	}
+
+	// Handle DSN Params
+	err = mc.handleParams()
+	if err != nil {
+		mc.Close()
+		return nil, err
+	}
+
+	return mc, nil
+}
+
+// Driver implements driver.Connector interface.
+// Driver returns &MySQLDriver{}.
+func (c *connector) Driver() driver.Driver {
+	return &MySQLDriver{}
+}

GOPATH/src/github.com/go-sql-driver/mysql/connector_test.go

+package mysql
+
+import (
+	"context"
+	"net"
+	"testing"
+	"time"
+)
+
+func TestConnectorReturnsTimeout(t *testing.T) {
+	connector := &connector{&Config{
+		Net:     "tcp",
+		Addr:    "1.1.1.1:1234",
+		Timeout: 10 * time.Millisecond,
+	}}
+
+	_, err := connector.Connect(context.Background())
+	if err == nil {
+		t.Fatal("error expected")
+	}
+
+	if nerr, ok := err.(*net.OpError); ok {
+		expected := "dial tcp 1.1.1.1:1234: i/o timeout"
+		if nerr.Error() != expected {
+			t.Fatalf("expected %q, got %q", expected, nerr.Error())
+		}
+	} else {
+		t.Fatalf("expected %T, got %T", nerr, err)
+	}
+}

GOPATH/src/github.com/go-sql-driver/mysql/const.go

+// Go MySQL Driver - A MySQL-Driver for Go's database/sql package
+//
+// Copyright 2012 The Go-MySQL-Driver Authors. All rights reserved.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package mysql
+
+const (
+	defaultAuthPlugin       = "mysql_native_password"
+	defaultMaxAllowedPacket = 4 << 20 // 4 MiB
+	minProtocolVersion      = 10
+	maxPacketSize           = 1<<24 - 1
+	timeFormat              = "2006-01-02 15:04:05.999999"
+)
+
+// MySQL constants documentation:
+// http://dev.mysql.com/doc/internals/en/client-server-protocol.html
+
+const (
+	iOK           byte = 0x00
+	iAuthMoreData byte = 0x01
+	iLocalInFile  byte = 0xfb
+	iEOF          byte = 0xfe
+	iERR          byte = 0xff
+)
+
+// https://dev.mysql.com/doc/internals/en/capability-flags.html#packet-Protocol::CapabilityFlags
+type clientFlag uint32
+
+const (
+	clientLongPassword clientFlag = 1 << iota
+	clientFoundRows
+	clientLongFlag
+	clientConnectWithDB
+	clientNoSchema
+	clientCompress
+	clientODBC
+	clientLocalFiles
+	clientIgnoreSpace
+	clientProtocol41
+	clientInteractive
+	clientSSL
+	clientIgnoreSIGPIPE
+	clientTransactions
+	clientReserved
+	clientSecureConn
+	clientMultiStatements
+	clientMultiResults
+	clientPSMultiResults
+	clientPluginAuth
+	clientConnectAttrs
+	clientPluginAuthLenEncClientData
+	clientCanHandleExpiredPasswords
+	clientSessionTrack
+	clientDeprecateEOF
+)
+
+const (
+	comQuit byte = iota + 1
+	comInitDB
+	comQuery
+	comFieldList
+	comCreateDB
+	comDropDB
+	comRefresh
+	comShutdown
+	comStatistics
+	comProcessInfo
+	comConnect
+	comProcessKill
+	comDebug
+	comPing
+	comTime
+	comDelayedInsert
+	comChangeUser
+	comBinlogDump
+	comTableDump
+	comConnectOut
+	comRegisterSlave
+	comStmtPrepare
+	comStmtExecute
+	comStmtSendLongData
+	comStmtClose
+	comStmtReset
+	comSetOption
+	comStmtFetch
+)
+
+// https://dev.mysql.com/doc/internals/en/com-query-response.html#packet-Protocol::ColumnType
+type fieldType byte
+
+const (
+	fieldTypeDecimal fieldType = iota
+	fieldTypeTiny
+	fieldTypeShort
+	fieldTypeLong
+	fieldTypeFloat
+	fieldTypeDouble
+	fieldTypeNULL
+	fieldTypeTimestamp
+	fieldTypeLongLong
+	fieldTypeInt24
+	fieldTypeDate
+	fieldTypeTime
+	fieldTypeDateTime
+	fieldTypeYear
+	fieldTypeNewDate
+	fieldTypeVarChar
+	fieldTypeBit
+)
+const (
+	fieldTypeJSON fieldType = iota + 0xf5
+	fieldTypeNewDecimal
+	fieldTypeEnum
+	fieldTypeSet
+	fieldTypeTinyBLOB
+	fieldTypeMediumBLOB
+	fieldTypeLongBLOB
+	fieldTypeBLOB
+	fieldTypeVarString
+	fieldTypeString
+	fieldTypeGeometry
+)
+
+type fieldFlag uint16
+
+const (
+	flagNotNULL fieldFlag = 1 << iota
+	flagPriKey
+	flagUniqueKey
+	flagMultipleKey
+	flagBLOB
+	flagUnsigned
+	flagZeroFill
+	flagBinary
+	flagEnum
+	flagAutoIncrement
+	flagTimestamp
+	flagSet
+	flagUnknown1
+	flagUnknown2
+	flagUnknown3
+	flagUnknown4
+)
+
+// http://dev.mysql.com/doc/internals/en/status-flags.html
+type statusFlag uint16
+
+const (
+	statusInTrans statusFlag = 1 << iota
+	statusInAutocommit
+	statusReserved // Not in documentation
+	statusMoreResultsExists
+	statusNoGoodIndexUsed
+	statusNoIndexUsed
+	statusCursorExists
+	statusLastRowSent
+	statusDbDropped
+	statusNoBackslashEscapes
+	statusMetadataChanged
+	statusQueryWasSlow
+	statusPsOutParams
+	statusInTransReadonly
+	statusSessionStateChanged
+)
+
+const (
+	cachingSha2PasswordRequestPublicKey          = 2
+	cachingSha2PasswordFastAuthSuccess           = 3
+	cachingSha2PasswordPerformFullAuthentication = 4
+)

GOPATH/src/github.com/go-sql-driver/mysql/driver.go

+// Copyright 2012 The Go-MySQL-Driver Authors. All rights reserved.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+// Package mysql provides a MySQL driver for Go's database/sql package.
+//
+// The driver should be used via the database/sql package:
+//
+//  import "database/sql"
+//  import _ "github.com/go-sql-driver/mysql"
+//
+//  db, err := sql.Open("mysql", "user:password@/dbname")
+//
+// See https://github.com/go-sql-driver/mysql#usage for details
+package mysql
+
+import (
+	"context"
+	"database/sql"
+	"database/sql/driver"
+	"net"
+	"sync"
+)
+
+// MySQLDriver is exported to make the driver directly accessible.
+// In general the driver is used via the database/sql package.
+type MySQLDriver struct{}
+
+// DialFunc is a function which can be used to establish the network connection.
+// Custom dial functions must be registered with RegisterDial
+//
+// Deprecated: users should register a DialContextFunc instead
+type DialFunc func(addr string) (net.Conn, error)
+
+// DialContextFunc is a function which can be used to establish the network connection.
+// Custom dial functions must be registered with RegisterDialContext
+type DialContextFunc func(ctx context.Context, addr string) (net.Conn, error)
+
+var (
+	dialsLock sync.RWMutex
+	dials     map[string]DialContextFunc
+)
+
+// RegisterDialContext registers a custom dial function. It can then be used by the
+// network address mynet(addr), where mynet is the registered new network.
+// The current context for the connection and its address is passed to the dial function.
+func RegisterDialContext(net string, dial DialContextFunc) {
+	dialsLock.Lock()
+	defer dialsLock.Unlock()
+	if dials == nil {
+		dials = make(map[string]DialContextFunc)
+	}
+	dials[net] = dial
+}
+
+// RegisterDial registers a custom dial function. It can then be used by the
+// network address mynet(addr), where mynet is the registered new network.
+// addr is passed as a parameter to the dial function.
+//
+// Deprecated: users should call RegisterDialContext instead
+func RegisterDial(network string, dial DialFunc) {
+	RegisterDialContext(network, func(_ context.Context, addr string) (net.Conn, error) {
+		return dial(addr)
+	})
+}
+
+// Open new Connection.
+// See https://github.com/go-sql-driver/mysql#dsn-data-source-name for how
+// the DSN string is formatted
+func (d MySQLDriver) Open(dsn string) (driver.Conn, error) {
+	cfg, err := ParseDSN(dsn)
+	if err != nil {
+		return nil, err
+	}
+	c := &connector{
+		cfg: cfg,
+	}
+	return c.Connect(context.Background())
+}
+
+func init() {
+	sql.Register("mysql", &MySQLDriver{})
+}
+
+// NewConnector returns new driver.Connector.
+func NewConnector(cfg *Config) (driver.Connector, error) {
+	cfg = cfg.Clone()
+	// normalize the contents of cfg so calls to NewConnector have the same
+	// behavior as MySQLDriver.OpenConnector
+	if err := cfg.normalize(); err != nil {
+		return nil, err
+	}
+	return &connector{cfg: cfg}, nil
+}
+
+// OpenConnector implements driver.DriverContext.
+func (d MySQLDriver) OpenConnector(dsn string) (driver.Connector, error) {
+	cfg, err := ParseDSN(dsn)
+	if err != nil {
+		return nil, err
+	}
+	return &connector{
+		cfg: cfg,
+	}, nil
+}

GOPATH/src/github.com/go-sql-driver/mysql/errors.go

+// Go MySQL Driver - A MySQL-Driver for Go's database/sql package
+//
+// Copyright 2013 The Go-MySQL-Driver Authors. All rights reserved.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package mysql
+
+import (
+	"errors"
+	"fmt"
+	"log"
+	"os"
+)
+
+// Various errors the driver might return. Can change between driver versions.
+var (
+	ErrInvalidConn       = errors.New("invalid connection")
+	ErrMalformPkt        = errors.New("malformed packet")
+	ErrNoTLS             = errors.New("TLS requested but server does not support TLS")
+	ErrCleartextPassword = errors.New("this user requires clear text authentication. If you still want to use it, please add 'allowCleartextPasswords=1' to your DSN")
+	ErrNativePassword    = errors.New("this user requires mysql native password authentication.")
+	ErrOldPassword       = errors.New("this user requires old password authentication. If you still want to use it, please add 'allowOldPasswords=1' to your DSN. See also https://github.com/go-sql-driver/mysql/wiki/old_passwords")
+	ErrUnknownPlugin     = errors.New("this authentication plugin is not supported")
+	ErrOldProtocol       = errors.New("MySQL server does not support required protocol 41+")
+	ErrPktSync           = errors.New("commands out of sync. You can't run this command now")
+	ErrPktSyncMul        = errors.New("commands out of sync. Did you run multiple statements at once?")
+	ErrPktTooLarge       = errors.New("packet for query is too large. Try adjusting the 'max_allowed_packet' variable on the server")
+	ErrBusyBuffer        = errors.New("busy buffer")
+
+	// errBadConnNoWrite is used for connection errors where nothing was sent to the database yet.
+	// If this happens first in a function starting a database interaction, it should be replaced by driver.ErrBadConn
+	// to trigger a resend.
+	// See https://github.com/go-sql-driver/mysql/pull/302
+	errBadConnNoWrite = errors.New("bad connection")
+)
+
+var errLog = Logger(log.New(os.Stderr, "[mysql] ", log.Ldate|log.Ltime|log.Lshortfile))
+
+// Logger is used to log critical error messages.
+type Logger interface {
+	Print(v ...interface{})
+}
+
+// SetLogger is used to set the logger for critical errors.
+// The initial logger is os.Stderr.
+func SetLogger(logger Logger) error {
+	if logger == nil {
+		return errors.New("logger is nil")
+	}
+	errLog = logger
+	return nil
+}
+
+// MySQLError is an error type which represents a single MySQL error
+type MySQLError struct {
+	Number  uint16
+	Message string
+}
+
+func (me *MySQLError) Error() string {
+	return fmt.Sprintf("Error %d: %s", me.Number, me.Message)
+}

GOPATH/src/github.com/go-sql-driver/mysql/errors_test.go

+// Go MySQL Driver - A MySQL-Driver for Go's database/sql package
+//
+// Copyright 2013 The Go-MySQL-Driver Authors. All rights reserved.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package mysql
+
+import (
+	"bytes"
+	"log"
+	"testing"
+)
+
+func TestErrorsSetLogger(t *testing.T) {
+	previous := errLog
+	defer func() {
+		errLog = previous
+	}()
+
+	// set up logger
+	const expected = "prefix: test\n"
+	buffer := bytes.NewBuffer(make([]byte, 0, 64))
+	logger := log.New(buffer, "prefix: ", 0)
+
+	// print
+	SetLogger(logger)
+	errLog.Print("test")
+
+	// check result
+	if actual := buffer.String(); actual != expected {
+		t.Errorf("expected %q, got %q", expected, actual)
+	}
+}
+
+func TestErrorsStrictIgnoreNotes(t *testing.T) {
+	runTests(t, dsn+"&sql_notes=false", func(dbt *DBTest) {
+		dbt.mustExec("DROP TABLE IF EXISTS does_not_exist")
+	})
+}

GOPATH/src/github.com/go-sql-driver/mysql/fields.go

+// Go MySQL Driver - A MySQL-Driver for Go's database/sql package
+//
+// Copyright 2017 The Go-MySQL-Driver Authors. All rights reserved.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package mysql
+
+import (
+	"database/sql"
+	"reflect"
+)
+
+func (mf *mysqlField) typeDatabaseName() string {
+	switch mf.fieldType {
+	case fieldTypeBit:
+		return "BIT"
+	case fieldTypeBLOB:
+		if mf.charSet != collations[binaryCollation] {
+			return "TEXT"
+		}
+		return "BLOB"
+	case fieldTypeDate:
+		return "DATE"
+	case fieldTypeDateTime:
+		return "DATETIME"
+	case fieldTypeDecimal:
+		return "DECIMAL"
+	case fieldTypeDouble:
+		return "DOUBLE"
+	case fieldTypeEnum:
+		return "ENUM"
+	case fieldTypeFloat:
+		return "FLOAT"
+	case fieldTypeGeometry:
+		return "GEOMETRY"
+	case fieldTypeInt24:
+		return "MEDIUMINT"
+	case fieldTypeJSON:
+		return "JSON"
+	case fieldTypeLong:
+		return "INT"
+	case fieldTypeLongBLOB:
+		if mf.charSet != collations[binaryCollation] {
+			return "LONGTEXT"
+		}
+		return "LONGBLOB"
+	case fieldTypeLongLong:
+		return "BIGINT"
+	case fieldTypeMediumBLOB:
+		if mf.charSet != collations[binaryCollation] {
+			return "MEDIUMTEXT"
+		}
+		return "MEDIUMBLOB"
+	case fieldTypeNewDate:
+		return "DATE"
+	case fieldTypeNewDecimal:
+		return "DECIMAL"
+	case fieldTypeNULL:
+		return "NULL"
+	case fieldTypeSet:
+		return "SET"
+	case fieldTypeShort:
+		return "SMALLINT"
+	case fieldTypeString:
+		if mf.charSet == collations[binaryCollation] {
+			return "BINARY"
+		}
+		return "CHAR"
+	case fieldTypeTime:
+		return "TIME"
+	case fieldTypeTimestamp:
+		return "TIMESTAMP"
+	case fieldTypeTiny:
+		return "TINYINT"
+	case fieldTypeTinyBLOB:
+		if mf.charSet != collations[binaryCollation] {
+			return "TINYTEXT"
+		}
+		return "TINYBLOB"
+	case fieldTypeVarChar:
+		if mf.charSet == collations[binaryCollation] {
+			return "VARBINARY"
+		}
+		return "VARCHAR"
+	case fieldTypeVarString:
+		if mf.charSet == collations[binaryCollation] {
+			return "VARBINARY"
+		}
+		return "VARCHAR"
+	case fieldTypeYear:
+		return "YEAR"
+	default:
+		return ""
+	}
+}
+
+var (
+	scanTypeFloat32   = reflect.TypeOf(float32(0))
+	scanTypeFloat64   = reflect.TypeOf(float64(0))
+	scanTypeInt8      = reflect.TypeOf(int8(0))
+	scanTypeInt16     = reflect.TypeOf(int16(0))
+	scanTypeInt32     = reflect.TypeOf(int32(0))
+	scanTypeInt64     = reflect.TypeOf(int64(0))
+	scanTypeNullFloat = reflect.TypeOf(sql.NullFloat64{})
+	scanTypeNullInt   = reflect.TypeOf(sql.NullInt64{})
+	scanTypeNullTime  = reflect.TypeOf(nullTime{})
+	scanTypeUint8     = reflect.TypeOf(uint8(0))
+	scanTypeUint16    = reflect.TypeOf(uint16(0))
+	scanTypeUint32    = reflect.TypeOf(uint32(0))
+	scanTypeUint64    = reflect.TypeOf(uint64(0))
+	scanTypeRawBytes  = reflect.TypeOf(sql.RawBytes{})
+	scanTypeUnknown   = reflect.TypeOf(new(interface{}))
+)
+
+type mysqlField struct {
+	tableName string
+	name      string
+	length    uint32
+	flags     fieldFlag
+	fieldType fieldType
+	decimals  byte
+	charSet   uint8
+}
+
+func (mf *mysqlField) scanType() reflect.Type {
+	switch mf.fieldType {
+	case fieldTypeTiny:
+		if mf.flags&flagNotNULL != 0 {
+			if mf.flags&flagUnsigned != 0 {
+				return scanTypeUint8
+			}
+			return scanTypeInt8
+		}
+		return scanTypeNullInt
+
+	case fieldTypeShort, fieldTypeYear:
+		if mf.flags&flagNotNULL != 0 {
+			if mf.flags&flagUnsigned != 0 {
+				return scanTypeUint16
+			}
+			return scanTypeInt16
+		}
+		return scanTypeNullInt
+
+	case fieldTypeInt24, fieldTypeLong:
+		if mf.flags&flagNotNULL != 0 {
+			if mf.flags&flagUnsigned != 0 {
+				return scanTypeUint32
+			}
+			return scanTypeInt32
+		}
+		return scanTypeNullInt
+
+	case fieldTypeLongLong:
+		if mf.flags&flagNotNULL != 0 {
+			if mf.flags&flagUnsigned != 0 {
+				return scanTypeUint64
+			}
+			return scanTypeInt64
+		}
+		return scanTypeNullInt
+
+	case fieldTypeFloat:
+		if mf.flags&flagNotNULL != 0 {
+			return scanTypeFloat32
+		}
+		return scanTypeNullFloat
+
+	case fieldTypeDouble:
+		if mf.flags&flagNotNULL != 0 {
+			return scanTypeFloat64
+		}
+		return scanTypeNullFloat
+
+	case fieldTypeDecimal, fieldTypeNewDecimal, fieldTypeVarChar,
+		fieldTypeBit, fieldTypeEnum, fieldTypeSet, fieldTypeTinyBLOB,
+		fieldTypeMediumBLOB, fieldTypeLongBLOB, fieldTypeBLOB,
+		fieldTypeVarString, fieldTypeString, fieldTypeGeometry, fieldTypeJSON,
+		fieldTypeTime:
+		return scanTypeRawBytes
+
+	case fieldTypeDate, fieldTypeNewDate,
+		fieldTypeTimestamp, fieldTypeDateTime:
+		// NullTime is always returned for more consistent behavior as it can
+		// handle both cases of parseTime regardless if the field is nullable.
+		return scanTypeNullTime
+
+	default:
+		return scanTypeUnknown
+	}
+}

GOPATH/src/github.com/go-sql-driver/mysql/fuzz.go

+// Go MySQL Driver - A MySQL-Driver for Go's database/sql package.
+//
+// Copyright 2020 The Go-MySQL-Driver Authors. All rights reserved.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+// +build gofuzz
+
+package mysql
+
+import (
+	"database/sql"
+)
+
+func Fuzz(data []byte) int {
+	db, err := sql.Open("mysql", string(data))
+	if err != nil {
+		return 0
+	}
+	db.Close()
+	return 1
+}

GOPATH/src/github.com/go-sql-driver/mysql/go.mod

+module github.com/go-sql-driver/mysql
+
+go 1.10

GOPATH/src/github.com/go-sql-driver/mysql/infile.go

+// Go MySQL Driver - A MySQL-Driver for Go's database/sql package
+//
+// Copyright 2013 The Go-MySQL-Driver Authors. All rights reserved.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package mysql
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"strings"
+	"sync"
+)
+
+var (
+	fileRegister       map[string]bool
+	fileRegisterLock   sync.RWMutex
+	readerRegister     map[string]func() io.Reader
+	readerRegisterLock sync.RWMutex
+)
+
+// RegisterLocalFile adds the given file to the file allowlist,
+// so that it can be used by "LOAD DATA LOCAL INFILE <filepath>".
+// Alternatively you can allow the use of all local files with
+// the DSN parameter 'allowAllFiles=true'
+//
+//  filePath := "/home/gopher/data.csv"
+//  mysql.RegisterLocalFile(filePath)
+//  err := db.Exec("LOAD DATA LOCAL INFILE '" + filePath + "' INTO TABLE foo")
+//  if err != nil {
+//  ...
+//
+func RegisterLocalFile(filePath string) {
+	fileRegisterLock.Lock()
+	// lazy map init
+	if fileRegister == nil {
+		fileRegister = make(map[string]bool)
+	}
+
+	fileRegister[strings.Trim(filePath, `"`)] = true
+	fileRegisterLock.Unlock()
+}
+
+// DeregisterLocalFile removes the given filepath from the allowlist.
+func DeregisterLocalFile(filePath string) {
+	fileRegisterLock.Lock()
+	delete(fileRegister, strings.Trim(filePath, `"`))
+	fileRegisterLock.Unlock()
+}
+
+// RegisterReaderHandler registers a handler function which is used
+// to receive a io.Reader.
+// The Reader can be used by "LOAD DATA LOCAL INFILE Reader::<name>".
+// If the handler returns a io.ReadCloser Close() is called when the
+// request is finished.
+//
+//  mysql.RegisterReaderHandler("data", func() io.Reader {
+//  	var csvReader io.Reader // Some Reader that returns CSV data
+//  	... // Open Reader here
+//  	return csvReader
+//  })
+//  err := db.Exec("LOAD DATA LOCAL INFILE 'Reader::data' INTO TABLE foo")
+//  if err != nil {
+//  ...
+//
+func RegisterReaderHandler(name string, handler func() io.Reader) {
+	readerRegisterLock.Lock()
+	// lazy map init
+	if readerRegister == nil {
+		readerRegister = make(map[string]func() io.Reader)
+	}
+
+	readerRegister[name] = handler
+	readerRegisterLock.Unlock()
+}
+
+// DeregisterReaderHandler removes the ReaderHandler function with
+// the given name from the registry.
+func DeregisterReaderHandler(name string) {
+	readerRegisterLock.Lock()
+	delete(readerRegister, name)
+	readerRegisterLock.Unlock()
+}
+
+func deferredClose(err *error, closer io.Closer) {
+	closeErr := closer.Close()
+	if *err == nil {
+		*err = closeErr
+	}
+}
+
+func (mc *mysqlConn) handleInFileRequest(name string) (err error) {
+	var rdr io.Reader
+	var data []byte
+	packetSize := 16 * 1024 // 16KB is small enough for disk readahead and large enough for TCP
+	if mc.maxWriteSize < packetSize {
+		packetSize = mc.maxWriteSize
+	}
+
+	if idx := strings.Index(name, "Reader::"); idx == 0 || (idx > 0 && name[idx-1] == '/') { // io.Reader
+		// The server might return an an absolute path. See issue #355.
+		name = name[idx+8:]
+
+		readerRegisterLock.RLock()
+		handler, inMap := readerRegister[name]
+		readerRegisterLock.RUnlock()
+
+		if inMap {
+			rdr = handler()
+			if rdr != nil {
+				if cl, ok := rdr.(io.Closer); ok {
+					defer deferredClose(&err, cl)
+				}
+			} else {
+				err = fmt.Errorf("Reader '%s' is <nil>", name)
+			}
+		} else {
+			err = fmt.Errorf("Reader '%s' is not registered", name)
+		}
+	} else { // File
+		name = strings.Trim(name, `"`)
+		fileRegisterLock.RLock()
+		fr := fileRegister[name]
+		fileRegisterLock.RUnlock()
+		if mc.cfg.AllowAllFiles || fr {
+			var file *os.File
+			var fi os.FileInfo
+
+			if file, err = os.Open(name); err == nil {
+				defer deferredClose(&err, file)
+
+				// get file size
+				if fi, err = file.Stat(); err == nil {
+					rdr = file
+					if fileSize := int(fi.Size()); fileSize < packetSize {
+						packetSize = fileSize
+					}
+				}
+			}
+		} else {
+			err = fmt.Errorf("local file '%s' is not registered", name)
+		}
+	}
+
+	// send content packets
+	// if packetSize == 0, the Reader contains no data
+	if err == nil && packetSize > 0 {
+		data := make([]byte, 4+packetSize)
+		var n int
+		for err == nil {
+			n, err = rdr.Read(data[4:])
+			if n > 0 {
+				if ioErr := mc.writePacket(data[:4+n]); ioErr != nil {
+					return ioErr
+				}
+			}
+		}
+		if err == io.EOF {
+			err = nil
+		}
+	}
+
+	// send empty packet (termination)
+	if data == nil {
+		data = make([]byte, 4)
+	}
+	if ioErr := mc.writePacket(data[:4]); ioErr != nil {
+		return ioErr
+	}
+
+	// read OK packet
+	if err == nil {
+		return mc.readResultOK()
+	}
+
+	mc.readPacket()
+	return err
+}

GOPATH/src/github.com/go-sql-driver/mysql/nulltime.go

+// Go MySQL Driver - A MySQL-Driver for Go's database/sql package
+//
+// Copyright 2013 The Go-MySQL-Driver Authors. All rights reserved.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package mysql
+
+import (
+	"database/sql/driver"
+	"fmt"
+	"time"
+)
+
+// Scan implements the Scanner interface.
+// The value type must be time.Time or string / []byte (formatted time-string),
+// otherwise Scan fails.
+func (nt *NullTime) Scan(value interface{}) (err error) {
+	if value == nil {
+		nt.Time, nt.Valid = time.Time{}, false
+		return
+	}
+
+	switch v := value.(type) {
+	case time.Time:
+		nt.Time, nt.Valid = v, true
+		return
+	case []byte:
+		nt.Time, err = parseDateTime(v, time.UTC)
+		nt.Valid = (err == nil)
+		return
+	case string:
+		nt.Time, err = parseDateTime([]byte(v), time.UTC)
+		nt.Valid = (err == nil)
+		return
+	}
+
+	nt.Valid = false
+	return fmt.Errorf("Can't convert %T to time.Time", value)
+}
+
+// Value implements the driver Valuer interface.
+func (nt NullTime) Value() (driver.Value, error) {
+	if !nt.Valid {
+		return nil, nil
+	}
+	return nt.Time, nil
+}

GOPATH/src/github.com/go-sql-driver/mysql/nulltime_go113.go

+// Go MySQL Driver - A MySQL-Driver for Go's database/sql package
+//
+// Copyright 2013 The Go-MySQL-Driver Authors. All rights reserved.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+// +build go1.13
+
+package mysql
+
+import (
+	"database/sql"
+)
+
+// NullTime represents a time.Time that may be NULL.
+// NullTime implements the Scanner interface so
+// it can be used as a scan destination:
+//
+//  var nt NullTime
+//  err := db.QueryRow("SELECT time FROM foo WHERE id=?", id).Scan(&nt)
+//  ...
+//  if nt.Valid {
+//     // use nt.Time
+//  } else {
+//     // NULL value
+//  }
+//
+// This NullTime implementation is not driver-specific
+//
+// Deprecated: NullTime doesn't honor the loc DSN parameter.
+// NullTime.Scan interprets a time as UTC, not the loc DSN parameter.
+// Use sql.NullTime instead.
+type NullTime sql.NullTime
+
+// for internal use.
+// the mysql package uses sql.NullTime if it is available.
+// if not, the package uses mysql.NullTime.
+type nullTime = sql.NullTime // sql.NullTime is available

GOPATH/src/github.com/go-sql-driver/mysql/nulltime_legacy.go

+// Go MySQL Driver - A MySQL-Driver for Go's database/sql package
+//
+// Copyright 2013 The Go-MySQL-Driver Authors. All rights reserved.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+// +build !go1.13
+
+package mysql
+
+import (
+	"time"
+)
+
+// NullTime represents a time.Time that may be NULL.
+// NullTime implements the Scanner interface so
+// it can be used as a scan destination:
+//
+//  var nt NullTime
+//  err := db.QueryRow("SELECT time FROM foo WHERE id=?", id).Scan(&nt)
+//  ...
+//  if nt.Valid {
+//     // use nt.Time
+//  } else {
+//     // NULL value
+//  }
+//
+// This NullTime implementation is not driver-specific
+type NullTime struct {
+	Time  time.Time
+	Valid bool // Valid is true if Time is not NULL
+}
+
+// for internal use.
+// the mysql package uses sql.NullTime if it is available.
+// if not, the package uses mysql.NullTime.
+type nullTime = NullTime // sql.NullTime is not available

GOPATH/src/github.com/go-sql-driver/mysql/nulltime_test.go

+// Go MySQL Driver - A MySQL-Driver for Go's database/sql package
+//
+// Copyright 2013 The Go-MySQL-Driver Authors. All rights reserved.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package mysql
+
+import (
+	"database/sql"
+	"database/sql/driver"
+	"testing"
+	"time"
+)
+
+var (
+	// Check implementation of interfaces
+	_ driver.Valuer = NullTime{}
+	_ sql.Scanner   = (*NullTime)(nil)
+)
+
+func TestScanNullTime(t *testing.T) {
+	var scanTests = []struct {
+		in    interface{}
+		error bool
+		valid bool
+		time  time.Time
+	}{
+		{tDate, false, true, tDate},
+		{sDate, false, true, tDate},
+		{[]byte(sDate), false, true, tDate},
+		{tDateTime, false, true, tDateTime},
+		{sDateTime, false, true, tDateTime},
+		{[]byte(sDateTime), false, true, tDateTime},
+		{tDate0, false, true, tDate0},
+		{sDate0, false, true, tDate0},
+		{[]byte(sDate0), false, true, tDate0},
+		{sDateTime0, false, true, tDate0},
+		{[]byte(sDateTime0), false, true, tDate0},
+		{"", true, false, tDate0},
+		{"1234", true, false, tDate0},
+		{0, true, false, tDate0},
+	}
+
+	var nt = NullTime{}
+	var err error
+
+	for _, tst := range scanTests {
+		err = nt.Scan(tst.in)
+		if (err != nil) != tst.error {
+			t.Errorf("%v: expected error status %t, got %t", tst.in, tst.error, (err != nil))
+		}
+		if nt.Valid != tst.valid {
+			t.Errorf("%v: expected valid status %t, got %t", tst.in, tst.valid, nt.Valid)
+		}
+		if nt.Time != tst.time {
+			t.Errorf("%v: expected time %v, got %v", tst.in, tst.time, nt.Time)
+		}
+	}
+}

GOPATH/src/github.com/go-sql-driver/mysql/packets_test.go

+// Go MySQL Driver - A MySQL-Driver for Go's database/sql package
+//
+// Copyright 2016 The Go-MySQL-Driver Authors. All rights reserved.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package mysql
+
+import (
+	"bytes"
+	"errors"
+	"net"
+	"testing"
+	"time"
+)
+
+var (
+	errConnClosed        = errors.New("connection is closed")
+	errConnTooManyReads  = errors.New("too many reads")
+	errConnTooManyWrites = errors.New("too many writes")
+)
+
+// struct to mock a net.Conn for testing purposes
+type mockConn struct {
+	laddr         net.Addr
+	raddr         net.Addr
+	data          []byte
+	written       []byte
+	queuedReplies [][]byte
+	closed        bool
+	read          int
+	reads         int
+	writes        int
+	maxReads      int
+	maxWrites     int
+}
+
+func (m *mockConn) Read(b []byte) (n int, err error) {
+	if m.closed {
+		return 0, errConnClosed
+	}
+
+	m.reads++
+	if m.maxReads > 0 && m.reads > m.maxReads {
+		return 0, errConnTooManyReads
+	}
+
+	n = copy(b, m.data)
+	m.read += n
+	m.data = m.data[n:]
+	return
+}
+func (m *mockConn) Write(b []byte) (n int, err error) {
+	if m.closed {
+		return 0, errConnClosed
+	}
+
+	m.writes++
+	if m.maxWrites > 0 && m.writes > m.maxWrites {
+		return 0, errConnTooManyWrites
+	}
+
+	n = len(b)
+	m.written = append(m.written, b...)
+
+	if n > 0 && len(m.queuedReplies) > 0 {
+		m.data = m.queuedReplies[0]
+		m.queuedReplies = m.queuedReplies[1:]
+	}
+	return
+}
+func (m *mockConn) Close() error {
+	m.closed = true
+	return nil
+}
+func (m *mockConn) LocalAddr() net.Addr {
+	return m.laddr
+}
+func (m *mockConn) RemoteAddr() net.Addr {
+	return m.raddr
+}
+func (m *mockConn) SetDeadline(t time.Time) error {
+	return nil
+}
+func (m *mockConn) SetReadDeadline(t time.Time) error {
+	return nil
+}
+func (m *mockConn) SetWriteDeadline(t time.Time) error {
+	return nil
+}
+
+// make sure mockConn implements the net.Conn interface
+var _ net.Conn = new(mockConn)
+
+func newRWMockConn(sequence uint8) (*mockConn, *mysqlConn) {
+	conn := new(mockConn)
+	mc := &mysqlConn{
+		buf:              newBuffer(conn),
+		cfg:              NewConfig(),
+		netConn:          conn,
+		closech:          make(chan struct{}),
+		maxAllowedPacket: defaultMaxAllowedPacket,
+		sequence:         sequence,
+	}
+	return conn, mc
+}
+
+func TestReadPacketSingleByte(t *testing.T) {
+	conn := new(mockConn)
+	mc := &mysqlConn{
+		buf: newBuffer(conn),
+	}
+
+	conn.data = []byte{0x01, 0x00, 0x00, 0x00, 0xff}
+	conn.maxReads = 1
+	packet, err := mc.readPacket()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(packet) != 1 {
+		t.Fatalf("unexpected packet length: expected %d, got %d", 1, len(packet))
+	}
+	if packet[0] != 0xff {
+		t.Fatalf("unexpected packet content: expected %x, got %x", 0xff, packet[0])
+	}
+}
+
+func TestReadPacketWrongSequenceID(t *testing.T) {
+	conn := new(mockConn)
+	mc := &mysqlConn{
+		buf: newBuffer(conn),
+	}
+
+	// too low sequence id
+	conn.data = []byte{0x01, 0x00, 0x00, 0x00, 0xff}
+	conn.maxReads = 1
+	mc.sequence = 1
+	_, err := mc.readPacket()
+	if err != ErrPktSync {
+		t.Errorf("expected ErrPktSync, got %v", err)
+	}
+
+	// reset
+	conn.reads = 0
+	mc.sequence = 0
+	mc.buf = newBuffer(conn)
+
+	// too high sequence id
+	conn.data = []byte{0x01, 0x00, 0x00, 0x42, 0xff}
+	_, err = mc.readPacket()
+	if err != ErrPktSyncMul {
+		t.Errorf("expected ErrPktSyncMul, got %v", err)
+	}
+}
+
+func TestReadPacketSplit(t *testing.T) {
+	conn := new(mockConn)
+	mc := &mysqlConn{
+		buf: newBuffer(conn),
+	}
+
+	data := make([]byte, maxPacketSize*2+4*3)
+	const pkt2ofs = maxPacketSize + 4
+	const pkt3ofs = 2 * (maxPacketSize + 4)
+
+	// case 1: payload has length maxPacketSize
+	data = data[:pkt2ofs+4]
+
+	// 1st packet has maxPacketSize length and sequence id 0
+	// ff ff ff 00 ...
+	data[0] = 0xff
+	data[1] = 0xff
+	data[2] = 0xff
+
+	// mark the payload start and end of 1st packet so that we can check if the
+	// content was correctly appended
+	data[4] = 0x11
+	data[maxPacketSize+3] = 0x22
+
+	// 2nd packet has payload length 0 and squence id 1
+	// 00 00 00 01
+	data[pkt2ofs+3] = 0x01
+
+	conn.data = data
+	conn.maxReads = 3
+	packet, err := mc.readPacket()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(packet) != maxPacketSize {
+		t.Fatalf("unexpected packet length: expected %d, got %d", maxPacketSize, len(packet))
+	}
+	if packet[0] != 0x11 {
+		t.Fatalf("unexpected payload start: expected %x, got %x", 0x11, packet[0])
+	}
+	if packet[maxPacketSize-1] != 0x22 {
+		t.Fatalf("unexpected payload end: expected %x, got %x", 0x22, packet[maxPacketSize-1])
+	}
+
+	// case 2: payload has length which is a multiple of maxPacketSize
+	data = data[:cap(data)]
+
+	// 2nd packet now has maxPacketSize length
+	data[pkt2ofs] = 0xff
+	data[pkt2ofs+1] = 0xff
+	data[pkt2ofs+2] = 0xff
+
+	// mark the payload start and end of the 2nd packet
+	data[pkt2ofs+4] = 0x33
+	data[pkt2ofs+maxPacketSize+3] = 0x44
+
+	// 3rd packet has payload length 0 and squence id 2
+	// 00 00 00 02
+	data[pkt3ofs+3] = 0x02
+
+	conn.data = data
+	conn.reads = 0
+	conn.maxReads = 5
+	mc.sequence = 0
+	packet, err = mc.readPacket()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(packet) != 2*maxPacketSize {
+		t.Fatalf("unexpected packet length: expected %d, got %d", 2*maxPacketSize, len(packet))
+	}
+	if packet[0] != 0x11 {
+		t.Fatalf("unexpected payload start: expected %x, got %x", 0x11, packet[0])
+	}
+	if packet[2*maxPacketSize-1] != 0x44 {
+		t.Fatalf("unexpected payload end: expected %x, got %x", 0x44, packet[2*maxPacketSize-1])
+	}
+
+	// case 3: payload has a length larger maxPacketSize, which is not an exact
+	// multiple of it
+	data = data[:pkt2ofs+4+42]
+	data[pkt2ofs] = 0x2a
+	data[pkt2ofs+1] = 0x00
+	data[pkt2ofs+2] = 0x00
+	data[pkt2ofs+4+41] = 0x44
+
+	conn.data = data
+	conn.reads = 0
+	conn.maxReads = 4
+	mc.sequence = 0
+	packet, err = mc.readPacket()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(packet) != maxPacketSize+42 {
+		t.Fatalf("unexpected packet length: expected %d, got %d", maxPacketSize+42, len(packet))
+	}
+	if packet[0] != 0x11 {
+		t.Fatalf("unexpected payload start: expected %x, got %x", 0x11, packet[0])
+	}
+	if packet[maxPacketSize+41] != 0x44 {
+		t.Fatalf("unexpected payload end: expected %x, got %x", 0x44, packet[maxPacketSize+41])
+	}
+}
+
+func TestReadPacketFail(t *testing.T) {
+	conn := new(mockConn)
+	mc := &mysqlConn{
+		buf:     newBuffer(conn),
+		closech: make(chan struct{}),
+	}
+
+	// illegal empty (stand-alone) packet
+	conn.data = []byte{0x00, 0x00, 0x00, 0x00}
+	conn.maxReads = 1
+	_, err := mc.readPacket()
+	if err != ErrInvalidConn {
+		t.Errorf("expected ErrInvalidConn, got %v", err)
+	}
+
+	// reset
+	conn.reads = 0
+	mc.sequence = 0
+	mc.buf = newBuffer(conn)
+
+	// fail to read header
+	conn.closed = true
+	_, err = mc.readPacket()
+	if err != ErrInvalidConn {
+		t.Errorf("expected ErrInvalidConn, got %v", err)
+	}
+
+	// reset
+	conn.closed = false
+	conn.reads = 0
+	mc.sequence = 0
+	mc.buf = newBuffer(conn)
+
+	// fail to read body
+	conn.maxReads = 1
+	_, err = mc.readPacket()
+	if err != ErrInvalidConn {
+		t.Errorf("expected ErrInvalidConn, got %v", err)
+	}
+}
+
+// https://github.com/go-sql-driver/mysql/pull/801
+// not-NUL terminated plugin_name in init packet
+func TestRegression801(t *testing.T) {
+	conn := new(mockConn)
+	mc := &mysqlConn{
+		buf:      newBuffer(conn),
+		cfg:      new(Config),
+		sequence: 42,
+		closech:  make(chan struct{}),
+	}
+
+	conn.data = []byte{72, 0, 0, 42, 10, 53, 46, 53, 46, 56, 0, 165, 0, 0, 0,
+		60, 70, 63, 58, 68, 104, 34, 97, 0, 223, 247, 33, 2, 0, 15, 128, 21, 0,
+		0, 0, 0, 0, 0, 0, 0, 0, 0, 98, 120, 114, 47, 85, 75, 109, 99, 51, 77,
+		50, 64, 0, 109, 121, 115, 113, 108, 95, 110, 97, 116, 105, 118, 101, 95,
+		112, 97, 115, 115, 119, 111, 114, 100}
+	conn.maxReads = 1
+
+	authData, pluginName, err := mc.readHandshakePacket()
+	if err != nil {
+		t.Fatalf("got error: %v", err)
+	}
+
+	if pluginName != "mysql_native_password" {
+		t.Errorf("expected plugin name 'mysql_native_password', got '%s'", pluginName)
+	}
+
+	expectedAuthData := []byte{60, 70, 63, 58, 68, 104, 34, 97, 98, 120, 114,
+		47, 85, 75, 109, 99, 51, 77, 50, 64}
+	if !bytes.Equal(authData, expectedAuthData) {
+		t.Errorf("expected authData '%v', got '%v'", expectedAuthData, authData)
+	}
+}

GOPATH/src/github.com/go-sql-driver/mysql/result.go

+// Go MySQL Driver - A MySQL-Driver for Go's database/sql package
+//
+// Copyright 2012 The Go-MySQL-Driver Authors. All rights reserved.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package mysql
+
+type mysqlResult struct {
+	affectedRows int64
+	insertId     int64
+}
+
+func (res *mysqlResult) LastInsertId() (int64, error) {
+	return res.insertId, nil
+}
+
+func (res *mysqlResult) RowsAffected() (int64, error) {
+	return res.affectedRows, nil
+}

GOPATH/src/github.com/go-sql-driver/mysql/rows.go

+// Go MySQL Driver - A MySQL-Driver for Go's database/sql package
+//
+// Copyright 2012 The Go-MySQL-Driver Authors. All rights reserved.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package mysql
+
+import (
+	"database/sql/driver"
+	"io"
+	"math"
+	"reflect"
+)
+
+type resultSet struct {
+	columns     []mysqlField
+	columnNames []string
+	done        bool
+}
+
+type mysqlRows struct {
+	mc     *mysqlConn
+	rs     resultSet
+	finish func()
+}
+
+type binaryRows struct {
+	mysqlRows
+}
+
+type textRows struct {
+	mysqlRows
+}
+
+func (rows *mysqlRows) Columns() []string {
+	if rows.rs.columnNames != nil {
+		return rows.rs.columnNames
+	}
+
+	columns := make([]string, len(rows.rs.columns))
+	if rows.mc != nil && rows.mc.cfg.ColumnsWithAlias {
+		for i := range columns {
+			if tableName := rows.rs.columns[i].tableName; len(tableName) > 0 {
+				columns[i] = tableName + "." + rows.rs.columns[i].name
+			} else {
+				columns[i] = rows.rs.columns[i].name
+			}
+		}
+	} else {
+		for i := range columns {
+			columns[i] = rows.rs.columns[i].name
+		}
+	}
+
+	rows.rs.columnNames = columns
+	return columns
+}
+
+func (rows *mysqlRows) ColumnTypeDatabaseTypeName(i int) string {
+	return rows.rs.columns[i].typeDatabaseName()
+}
+
+// func (rows *mysqlRows) ColumnTypeLength(i int) (length int64, ok bool) {
+// 	return int64(rows.rs.columns[i].length), true
+// }
+
+func (rows *mysqlRows) ColumnTypeNullable(i int) (nullable, ok bool) {
+	return rows.rs.columns[i].flags&flagNotNULL == 0, true
+}
+
+func (rows *mysqlRows) ColumnTypePrecisionScale(i int) (int64, int64, bool) {
+	column := rows.rs.columns[i]
+	decimals := int64(column.decimals)
+
+	switch column.fieldType {
+	case fieldTypeDecimal, fieldTypeNewDecimal:
+		if decimals > 0 {
+			return int64(column.length) - 2, decimals, true
+		}
+		return int64(column.length) - 1, decimals, true
+	case fieldTypeTimestamp, fieldTypeDateTime, fieldTypeTime:
+		return decimals, decimals, true
+	case fieldTypeFloat, fieldTypeDouble:
+		if decimals == 0x1f {
+			return math.MaxInt64, math.MaxInt64, true
+		}
+		return math.MaxInt64, decimals, true
+	}
+
+	return 0, 0, false
+}
+
+func (rows *mysqlRows) ColumnTypeScanType(i int) reflect.Type {
+	return rows.rs.columns[i].scanType()
+}
+
+func (rows *mysqlRows) Close() (err error) {
+	if f := rows.finish; f != nil {
+		f()
+		rows.finish = nil
+	}
+
+	mc := rows.mc
+	if mc == nil {
+		return nil
+	}
+	if err := mc.error(); err != nil {
+		return err
+	}
+
+	// flip the buffer for this connection if we need to drain it.
+	// note that for a successful query (i.e. one where rows.next()
+	// has been called until it returns false), `rows.mc` will be nil
+	// by the time the user calls `(*Rows).Close`, so we won't reach this
+	// see: https://github.com/golang/go/commit/651ddbdb5056ded455f47f9c494c67b389622a47
+	mc.buf.flip()
+
+	// Remove unread packets from stream
+	if !rows.rs.done {
+		err = mc.readUntilEOF()
+	}
+	if err == nil {
+		if err = mc.discardResults(); err != nil {
+			return err
+		}
+	}
+
+	rows.mc = nil
+	return err
+}
+
+func (rows *mysqlRows) HasNextResultSet() (b bool) {
+	if rows.mc == nil {
+		return false
+	}
+	return rows.mc.status&statusMoreResultsExists != 0
+}
+
+func (rows *mysqlRows) nextResultSet() (int, error) {
+	if rows.mc == nil {
+		return 0, io.EOF
+	}
+	if err := rows.mc.error(); err != nil {
+		return 0, err
+	}
+
+	// Remove unread packets from stream
+	if !rows.rs.done {
+		if err := rows.mc.readUntilEOF(); err != nil {
+			return 0, err
+		}
+		rows.rs.done = true
+	}
+
+	if !rows.HasNextResultSet() {
+		rows.mc = nil
+		return 0, io.EOF
+	}
+	rows.rs = resultSet{}
+	return rows.mc.readResultSetHeaderPacket()
+}
+
+func (rows *mysqlRows) nextNotEmptyResultSet() (int, error) {
+	for {
+		resLen, err := rows.nextResultSet()
+		if err != nil {
+			return 0, err
+		}
+
+		if resLen > 0 {
+			return resLen, nil
+		}
+
+		rows.rs.done = true
+	}
+}
+
+func (rows *binaryRows) NextResultSet() error {
+	resLen, err := rows.nextNotEmptyResultSet()
+	if err != nil {
+		return err
+	}
+
+	rows.rs.columns, err = rows.mc.readColumns(resLen)
+	return err
+}
+
+func (rows *binaryRows) Next(dest []driver.Value) error {
+	if mc := rows.mc; mc != nil {
+		if err := mc.error(); err != nil {
+			return err
+		}
+
+		// Fetch next row from stream
+		return rows.readRow(dest)
+	}
+	return io.EOF
+}
+
+func (rows *textRows) NextResultSet() (err error) {
+	resLen, err := rows.nextNotEmptyResultSet()
+	if err != nil {
+		return err
+	}
+
+	rows.rs.columns, err = rows.mc.readColumns(resLen)
+	return err
+}
+
+func (rows *textRows) Next(dest []driver.Value) error {
+	if mc := rows.mc; mc != nil {
+		if err := mc.error(); err != nil {
+			return err
+		}
+
+		// Fetch next row from stream
+		return rows.readRow(dest)
+	}
+	return io.EOF
+}

GOPATH/src/github.com/go-sql-driver/mysql/statement.go

+// Go MySQL Driver - A MySQL-Driver for Go's database/sql package
+//
+// Copyright 2012 The Go-MySQL-Driver Authors. All rights reserved.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package mysql
+
+import (
+	"database/sql/driver"
+	"encoding/json"
+	"fmt"
+	"io"
+	"reflect"
+)
+
+type mysqlStmt struct {
+	mc         *mysqlConn
+	id         uint32
+	paramCount int
+}
+
+func (stmt *mysqlStmt) Close() error {
+	if stmt.mc == nil || stmt.mc.closed.IsSet() {
+		// driver.Stmt.Close can be called more than once, thus this function
+		// has to be idempotent.
+		// See also Issue #450 and golang/go#16019.
+		//errLog.Print(ErrInvalidConn)
+		return driver.ErrBadConn
+	}
+
+	err := stmt.mc.writeCommandPacketUint32(comStmtClose, stmt.id)
+	stmt.mc = nil
+	return err
+}
+
+func (stmt *mysqlStmt) NumInput() int {
+	return stmt.paramCount
+}
+
+func (stmt *mysqlStmt) ColumnConverter(idx int) driver.ValueConverter {
+	return converter{}
+}
+
+func (stmt *mysqlStmt) CheckNamedValue(nv *driver.NamedValue) (err error) {
+	nv.Value, err = converter{}.ConvertValue(nv.Value)
+	return
+}
+
+func (stmt *mysqlStmt) Exec(args []driver.Value) (driver.Result, error) {
+	if stmt.mc.closed.IsSet() {
+		errLog.Print(ErrInvalidConn)
+		return nil, driver.ErrBadConn
+	}
+	// Send command
+	err := stmt.writeExecutePacket(args)
+	if err != nil {
+		return nil, stmt.mc.markBadConn(err)
+	}
+
+	mc := stmt.mc
+
+	mc.affectedRows = 0
+	mc.insertId = 0
+
+	// Read Result
+	resLen, err := mc.readResultSetHeaderPacket()
+	if err != nil {
+		return nil, err
+	}
+
+	if resLen > 0 {
+		// Columns
+		if err = mc.readUntilEOF(); err != nil {
+			return nil, err
+		}
+
+		// Rows
+		if err := mc.readUntilEOF(); err != nil {
+			return nil, err
+		}
+	}
+
+	if err := mc.discardResults(); err != nil {
+		return nil, err
+	}
+
+	return &mysqlResult{
+		affectedRows: int64(mc.affectedRows),
+		insertId:     int64(mc.insertId),
+	}, nil
+}
+
+func (stmt *mysqlStmt) Query(args []driver.Value) (driver.Rows, error) {
+	return stmt.query(args)
+}
+
+func (stmt *mysqlStmt) query(args []driver.Value) (*binaryRows, error) {
+	if stmt.mc.closed.IsSet() {
+		errLog.Print(ErrInvalidConn)
+		return nil, driver.ErrBadConn
+	}
+	// Send command
+	err := stmt.writeExecutePacket(args)
+	if err != nil {
+		return nil, stmt.mc.markBadConn(err)
+	}
+
+	mc := stmt.mc
+
+	// Read Result
+	resLen, err := mc.readResultSetHeaderPacket()
+	if err != nil {
+		return nil, err
+	}
+
+	rows := new(binaryRows)
+
+	if resLen > 0 {
+		rows.mc = mc
+		rows.rs.columns, err = mc.readColumns(resLen)
+	} else {
+		rows.rs.done = true
+
+		switch err := rows.NextResultSet(); err {
+		case nil, io.EOF:
+			return rows, nil
+		default:
+			return nil, err
+		}
+	}
+
+	return rows, err
+}
+
+var jsonType = reflect.TypeOf(json.RawMessage{})
+
+type converter struct{}
+
+// ConvertValue mirrors the reference/default converter in database/sql/driver
+// with _one_ exception.  We support uint64 with their high bit and the default
+// implementation does not.  This function should be kept in sync with
+// database/sql/driver defaultConverter.ConvertValue() except for that
+// deliberate difference.
+func (c converter) ConvertValue(v interface{}) (driver.Value, error) {
+	if driver.IsValue(v) {
+		return v, nil
+	}
+
+	if vr, ok := v.(driver.Valuer); ok {
+		sv, err := callValuerValue(vr)
+		if err != nil {
+			return nil, err
+		}
+		if driver.IsValue(sv) {
+			return sv, nil
+		}
+		// A value returend from the Valuer interface can be "a type handled by
+		// a database driver's NamedValueChecker interface" so we should accept
+		// uint64 here as well.
+		if u, ok := sv.(uint64); ok {
+			return u, nil
+		}
+		return nil, fmt.Errorf("non-Value type %T returned from Value", sv)
+	}
+	rv := reflect.ValueOf(v)
+	switch rv.Kind() {
+	case reflect.Ptr:
+		// indirect pointers
+		if rv.IsNil() {
+			return nil, nil
+		} else {
+			return c.ConvertValue(rv.Elem().Interface())
+		}
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return rv.Int(), nil
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
+		return rv.Uint(), nil
+	case reflect.Float32, reflect.Float64:
+		return rv.Float(), nil
+	case reflect.Bool:
+		return rv.Bool(), nil
+	case reflect.Slice:
+		switch t := rv.Type(); {
+		case t == jsonType:
+			return v, nil
+		case t.Elem().Kind() == reflect.Uint8:
+			return rv.Bytes(), nil
+		default:
+			return nil, fmt.Errorf("unsupported type %T, a slice of %s", v, t.Elem().Kind())
+		}
+	case reflect.String:
+		return rv.String(), nil
+	}
+	return nil, fmt.Errorf("unsupported type %T, a %s", v, rv.Kind())
+}
+
+var valuerReflectType = reflect.TypeOf((*driver.Valuer)(nil)).Elem()
+
+// callValuerValue returns vr.Value(), with one exception:
+// If vr.Value is an auto-generated method on a pointer type and the
+// pointer is nil, it would panic at runtime in the panicwrap
+// method. Treat it like nil instead.
+//
+// This is so people can implement driver.Value on value types and
+// still use nil pointers to those types to mean nil/NULL, just like
+// string/*string.
+//
+// This is an exact copy of the same-named unexported function from the
+// database/sql package.
+func callValuerValue(vr driver.Valuer) (v driver.Value, err error) {
+	if rv := reflect.ValueOf(vr); rv.Kind() == reflect.Ptr &&
+		rv.IsNil() &&
+		rv.Type().Elem().Implements(valuerReflectType) {
+		return nil, nil
+	}
+	return vr.Value()
+}

GOPATH/src/github.com/go-sql-driver/mysql/statement_test.go

+// Go MySQL Driver - A MySQL-Driver for Go's database/sql package
+//
+// Copyright 2017 The Go-MySQL-Driver Authors. All rights reserved.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package mysql
+
+import (
+	"bytes"
+	"database/sql/driver"
+	"encoding/json"
+	"testing"
+)
+
+func TestConvertDerivedString(t *testing.T) {
+	type derived string
+
+	output, err := converter{}.ConvertValue(derived("value"))
+	if err != nil {
+		t.Fatal("Derived string type not convertible", err)
+	}
+
+	if output != "value" {
+		t.Fatalf("Derived string type not converted, got %#v %T", output, output)
+	}
+}
+
+func TestConvertDerivedByteSlice(t *testing.T) {
+	type derived []uint8
+
+	output, err := converter{}.ConvertValue(derived("value"))
+	if err != nil {
+		t.Fatal("Byte slice not convertible", err)
+	}
+
+	if bytes.Compare(output.([]byte), []byte("value")) != 0 {
+		t.Fatalf("Byte slice not converted, got %#v %T", output, output)
+	}
+}
+
+func TestConvertDerivedUnsupportedSlice(t *testing.T) {
+	type derived []int
+
+	_, err := converter{}.ConvertValue(derived{1})
+	if err == nil || err.Error() != "unsupported type mysql.derived, a slice of int" {
+		t.Fatal("Unexpected error", err)
+	}
+}
+
+func TestConvertDerivedBool(t *testing.T) {
+	type derived bool
+
+	output, err := converter{}.ConvertValue(derived(true))
+	if err != nil {
+		t.Fatal("Derived bool type not convertible", err)
+	}
+
+	if output != true {
+		t.Fatalf("Derived bool type not converted, got %#v %T", output, output)
+	}
+}
+
+func TestConvertPointer(t *testing.T) {
+	str := "value"
+
+	output, err := converter{}.ConvertValue(&str)
+	if err != nil {
+		t.Fatal("Pointer type not convertible", err)
+	}
+
+	if output != "value" {
+		t.Fatalf("Pointer type not converted, got %#v %T", output, output)
+	}
+}
+
+func TestConvertSignedIntegers(t *testing.T) {
+	values := []interface{}{
+		int8(-42),
+		int16(-42),
+		int32(-42),
+		int64(-42),
+		int(-42),
+	}
+
+	for _, value := range values {
+		output, err := converter{}.ConvertValue(value)
+		if err != nil {
+			t.Fatalf("%T type not convertible %s", value, err)
+		}
+
+		if output != int64(-42) {
+			t.Fatalf("%T type not converted, got %#v %T", value, output, output)
+		}
+	}
+}
+
+type myUint64 struct {
+	value uint64
+}
+
+func (u myUint64) Value() (driver.Value, error) {
+	return u.value, nil
+}
+
+func TestConvertUnsignedIntegers(t *testing.T) {
+	values := []interface{}{
+		uint8(42),
+		uint16(42),
+		uint32(42),
+		uint64(42),
+		uint(42),
+		myUint64{uint64(42)},
+	}
+
+	for _, value := range values {
+		output, err := converter{}.ConvertValue(value)
+		if err != nil {
+			t.Fatalf("%T type not convertible %s", value, err)
+		}
+
+		if output != uint64(42) {
+			t.Fatalf("%T type not converted, got %#v %T", value, output, output)
+		}
+	}
+
+	output, err := converter{}.ConvertValue(^uint64(0))
+	if err != nil {
+		t.Fatal("uint64 high-bit not convertible", err)
+	}
+
+	if output != ^uint64(0) {
+		t.Fatalf("uint64 high-bit converted, got %#v %T", output, output)
+	}
+}
+
+func TestConvertJSON(t *testing.T) {
+	raw := json.RawMessage("{}")
+
+	out, err := converter{}.ConvertValue(raw)
+
+	if err != nil {
+		t.Fatal("json.RawMessage was failed in convert", err)
+	}
+
+	if _, ok := out.(json.RawMessage); !ok {
+		t.Fatalf("json.RawMessage converted, got %#v %T", out, out)
+	}
+}

GOPATH/src/github.com/go-sql-driver/mysql/transaction.go

+// Go MySQL Driver - A MySQL-Driver for Go's database/sql package
+//
+// Copyright 2012 The Go-MySQL-Driver Authors. All rights reserved.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package mysql
+
+type mysqlTx struct {
+	mc *mysqlConn
+}
+
+func (tx *mysqlTx) Commit() (err error) {
+	if tx.mc == nil || tx.mc.closed.IsSet() {
+		return ErrInvalidConn
+	}
+	err = tx.mc.exec("COMMIT")
+	tx.mc = nil
+	return
+}
+
+func (tx *mysqlTx) Rollback() (err error) {
+	if tx.mc == nil || tx.mc.closed.IsSet() {
+		return ErrInvalidConn
+	}
+	err = tx.mc.exec("ROLLBACK")
+	tx.mc = nil
+	return
+}

GOPATH/src/github.com/josharian/intern/README.md

+Docs: https://godoc.org/github.com/josharian/intern
+
+For a blog post introducing string interning, see: https://commaok.xyz/post/intern-strings/
+
+License: MIT

GOPATH/src/github.com/josharian/intern/go.mod

+module github.com/josharian/intern
+
+go 1.5

GOPATH/src/github.com/josharian/intern/intern.go

+// Package intern interns strings.
+// Interning is best effort only.
+// Interned strings may be removed automatically
+// at any time without notification.
+// All functions may be called concurrently
+// with themselves and each other.
+package intern
+
+import "sync"
+
+var (
+	pool sync.Pool = sync.Pool{
+		New: func() interface{} {
+			return make(map[string]string)
+		},
+	}
+)
+
+// String returns s, interned.
+func String(s string) string {
+	m := pool.Get().(map[string]string)
+	c, ok := m[s]
+	if ok {
+		pool.Put(m)
+		return c
+	}
+	m[s] = s
+	pool.Put(m)
+	return s
+}
+
+// Bytes returns b converted to a string, interned.
+func Bytes(b []byte) string {
+	m := pool.Get().(map[string]string)
+	c, ok := m[string(b)]
+	if ok {
+		pool.Put(m)
+		return c
+	}
+	s := string(b)
+	m[s] = s
+	pool.Put(m)
+	return s
+}

GOPATH/src/github.com/josharian/intern/intern_test.go

+// +build !race
+
+// When -race is enabled, sync.Pool is a no-op,
+// which will cause these tests to fail
+// and these benchmarks to be misleading.
+
+package intern
+
+import (
+	"bytes"
+	"reflect"
+	"testing"
+	"unsafe"
+)
+
+func TestString(t *testing.T) {
+	s := "abcde"
+	sub := String(s[1:4])
+	interned := String("bcd")
+	want := (*reflect.StringHeader)(unsafe.Pointer(&sub)).Data
+	got := (*reflect.StringHeader)(unsafe.Pointer(&interned)).Data
+	if want != got {
+		t.Errorf("failed to intern string")
+	}
+}
+
+func TestBytes(t *testing.T) {
+	s := bytes.Repeat([]byte("abc"), 100)
+	n := testing.AllocsPerRun(100, func() {
+		for i := 0; i < 100; i++ {
+			_ = Bytes(s[i*len("abc") : (i+1)*len("abc")])
+		}
+	})
+	if n > 0 {
+		t.Errorf("Bytes allocated %d, want 0", int(n))
+	}
+}
+
+func BenchmarkString(b *testing.B) {
+	in := "hello brad"
+	b.ReportAllocs()
+	b.SetBytes(int64(len(in)))
+	b.RunParallel(func(pb *testing.PB) {
+		var s string
+		for pb.Next() {
+			s = String(in[1:5])
+		}
+		_ = s
+	})
+}
+
+func BenchmarkBytes(b *testing.B) {
+	in := []byte("hello brad")
+	b.ReportAllocs()
+	b.SetBytes(int64(len(in)))
+	b.RunParallel(func(pb *testing.PB) {
+		var s string
+		for pb.Next() {
+			s = Bytes(in[1:5])
+		}
+		_ = s
+	})
+}

GOPATH/src/github.com/josharian/intern/license.md

+MIT License
+
+Copyright (c) 2019 Josh Bleecher Snyder
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

GOPATH/src/github.com/liuzl/cedar-go/README.md

+# cedar-go [![GoDoc](https://godoc.org/github.com/adamzy/cedar-go?status.svg)](https://godoc.org/github.com/adamzy/cedar-go)
+
+Package `cedar-go` implementes double-array trie.
+
+It is a [Golang](https://golang.org/) port of [cedar](http://www.tkl.iis.u-tokyo.ac.jp/~ynaga/cedar) which is written in C++ by Naoki Yoshinaga. `cedar-go` currently implements the `reduced` verion of cedar. 
+This package is not thread safe if there is one goroutine doing insertions or deletions. 
+
+## Install
+```
+go get github.com/adamzy/cedar-go
+```
+
+## Usage
+```go
+package main
+
+import (
+	"fmt"
+
+	"github.com/adamzy/cedar-go"
+)
+
+func main() {
+	// create a new cedar trie.
+	trie := cedar.New()
+
+	// a helper function to print the id-key-value triple given trie node id
+	printIdKeyValue := func(id int) {
+		// the key of node `id`.
+		key, _ := trie.Key(id)
+		// the value of node `id`.
+		value, _ := trie.Value(id)
+		fmt.Printf("%d\t%s:%v\n", id, key, value)
+	}
+
+	// Insert key-value pairs.
+    // The order of insertion is not important.
+	trie.Insert([]byte("How many"), 0)
+	trie.Insert([]byte("How many loved"), 1)
+	trie.Insert([]byte("How many loved your moments"), 2)
+	trie.Insert([]byte("How many loved your moments of glad grace"), 3)
+	trie.Insert([]byte("姑苏"), 4)
+	trie.Insert([]byte("姑苏城外"), 5)
+	trie.Insert([]byte("姑苏城外寒山寺"), 6)
+
+	// Get the associated value of a key directly.
+	value, _ := trie.Get([]byte("How many loved your moments of glad grace"))
+	fmt.Println(value)
+
+	// Or, jump to the node first,
+	id, _ := trie.Jump([]byte("How many loved your moments"), 0)
+	// then get the key and the value
+	printIdKeyValue(id)
+
+	fmt.Println("\nPrefixMatch\nid\tkey:value")
+	for _, id := range trie.PrefixMatch([]byte("How many loved your moments of glad grace"), 0) {
+		printIdKeyValue(id)
+	}
+
+	fmt.Println("\nPrefixPredict\nid\tkey:value")
+	for _, id := range trie.PrefixPredict([]byte("姑苏"), 0) {
+		printIdKeyValue(id)
+	}
+}
+```
+will produce
+```
+3
+281	How many loved your moments:2
+
+PrefixMatch
+id	key:value
+262	How many:0
+268	How many loved:1
+281	How many loved your moments:2
+296	How many loved your moments of glad grace:3
+
+PrefixPredict
+id	key:value
+303	姑苏:4
+309	姑苏城外:5
+318	姑苏城外寒山寺:6
+```

GOPATH/src/github.com/liuzl/cedar-go/api.go

+package cedar
+
+// Status reports the following statistics of the cedar:
+//	keys:		number of keys that are in the cedar,
+//	nodes:		number of trie nodes (slots in the base array) has been taken,
+//	size:			the size of the base array used by the cedar,
+//	capacity:		the capicity of the base array used by the cedar.
+func (da *Cedar) Status() (keys, nodes, size, capacity int) {
+	for i := 0; i < da.Size; i++ {
+		n := da.Array[i]
+		if n.Check >= 0 {
+			nodes++
+			if n.Value >= 0 {
+				keys++
+			}
+		}
+	}
+	return keys, nodes, da.Size, da.Capacity
+}
+
+// Jump travels from a node `from` to another node `to` by following the path `path`.
+// For example, if the following keys were inserted:
+//	id	key
+//	19	abc
+//	23	ab
+//	37	abcd
+// then
+//	Jump([]byte("ab"), 0) = 23, nil		// reach "ab" from root
+//	Jump([]byte("c"), 23) = 19, nil			// reach "abc" from "ab"
+//	Jump([]byte("cd"), 23) = 37, nil		// reach "abcd" from "ab"
+func (da *Cedar) Jump(path []byte, from int) (to int, err error) {
+	for _, b := range path {
+		if da.Array[from].Value >= 0 {
+			return from, ErrNoPath
+		}
+		to = da.Array[from].base() ^ int(b)
+		if da.Array[to].Check != from {
+			return from, ErrNoPath
+		}
+		from = to
+	}
+	return to, nil
+}
+
+// Key returns the key of the node with the given `id`.
+// It will return ErrNoPath, if the node does not exist.
+func (da *Cedar) Key(id int) (key []byte, err error) {
+	for id > 0 {
+		from := da.Array[id].Check
+		if from < 0 {
+			return nil, ErrNoPath
+		}
+		if char := byte(da.Array[from].base() ^ id); char != 0 {
+			key = append(key, char)
+		}
+		id = from
+	}
+	if id != 0 || len(key) == 0 {
+		return nil, ErrInvalidKey
+	}
+	for i := 0; i < len(key)/2; i++ {
+		key[i], key[len(key)-i-1] = key[len(key)-i-1], key[i]
+	}
+	return key, nil
+}
+
+// Value returns the value of the node with the given `id`.
+// It will return ErrNoValue, if the node does not have a value.
+func (da *Cedar) Value(id int) (value int, err error) {
+	value = da.Array[id].Value
+	if value >= 0 {
+		return value, nil
+	}
+	to := da.Array[id].base()
+	if da.Array[to].Check == id && da.Array[to].Value >= 0 {
+		return da.Array[to].Value, nil
+	}
+	return 0, ErrNoValue
+}
+
+// Insert adds a key-value pair into the cedar.
+// It will return ErrInvalidValue, if value < 0 or >= ValueLimit.
+func (da *Cedar) Insert(key []byte, value int) error {
+	if value < 0 || value >= ValueLimit {
+		return ErrInvalidValue
+	}
+	p := da.get(key, 0, 0)
+	*p = value
+	return nil
+}
+
+// Update increases the value associated with the `key`.
+// The `key` will be inserted if it is not in the cedar.
+// It will return ErrInvalidValue, if the updated value < 0 or >= ValueLimit.
+func (da *Cedar) Update(key []byte, value int) error {
+	p := da.get(key, 0, 0)
+
+	// key was not inserted
+	if *p == ValueLimit {
+		*p = value
+		return nil
+	}
+
+	// key was inserted before
+	if *p+value < 0 || *p+value >= ValueLimit {
+		return ErrInvalidValue
+	}
+	*p += value
+	return nil
+}
+
+// Delete removes a key-value pair from the cedar.
+// It will return ErrNoPath, if the key has not been added.
+func (da *Cedar) Delete(key []byte) error {
+	// if the path does not exist, or the end is not a leaf, nothing to delete
+	to, err := da.Jump(key, 0)
+	if err != nil {
+		return ErrNoPath
+	}
+
+	if da.Array[to].Value < 0 {
+		base := da.Array[to].base()
+		if da.Array[base].Check == to {
+			to = base
+		}
+	}
+
+	for to > 0 {
+		from := da.Array[to].Check
+		base := da.Array[from].base()
+		label := byte(to ^ base)
+
+		// if `to` has sibling, remove `to` from the sibling list, then stop
+		if da.Ninfos[to].Sibling != 0 || da.Ninfos[from].Child != label {
+			// delete the label from the child ring first
+			da.popSibling(from, base, label)
+			// then release the current node `to` to the empty node ring
+			da.pushEnode(to)
+			break
+		}
+		// otherwise, just release the current node `to` to the empty node ring
+		da.pushEnode(to)
+		// then check its parent node
+		to = from
+	}
+	return nil
+}
+
+// Get returns the value associated with the given `key`.
+// It is equivalent to
+//		id, err1 = Jump(key)
+//		value, err2 = Value(id)
+// Thus, it may return ErrNoPath or ErrNoValue,
+func (da *Cedar) Get(key []byte) (value int, err error) {
+	to, err := da.Jump(key, 0)
+	if err != nil {
+		return 0, err
+	}
+	return da.Value(to)
+}
+
+// PrefixMatch returns a list of at most `num` nodes which match the prefix of the key.
+// If `num` is 0, it returns all matches.
+// For example, if the following keys were inserted:
+//	id	key
+//	19	abc
+//	23	ab
+//	37	abcd
+// then
+//	PrefixMatch([]byte("abc"), 1) = [ 23 ]				// match ["ab"]
+//	PrefixMatch([]byte("abcd"), 0) = [ 23, 19, 37]		// match ["ab", "abc", "abcd"]
+func (da *Cedar) PrefixMatch(key []byte, num int) (ids []int) {
+	for from, i := 0, 0; i < len(key); i++ {
+		to, err := da.Jump(key[i:i+1], from)
+		if err != nil {
+			break
+		}
+		if _, err := da.Value(to); err == nil {
+			ids = append(ids, to)
+			num--
+			if num == 0 {
+				return
+			}
+		}
+		from = to
+	}
+	return
+}
+
+// PrefixPredict returns a list of at most `num` nodes which has the key as their prefix.
+// These nodes are ordered by their keys.
+// If `num` is 0, it returns all matches.
+// For example, if the following keys were inserted:
+//	id	key
+//	19	abc
+//	23	ab
+//	37	abcd
+// then
+//	PrefixPredict([]byte("ab"), 2) = [ 23, 19 ]			// predict ["ab", "abc"]
+//	PrefixPredict([]byte("ab"), 0) = [ 23, 19, 37 ]		// predict ["ab", "abc", "abcd"]
+func (da *Cedar) PrefixPredict(key []byte, num int) (ids []int) {
+	root, err := da.Jump(key, 0)
+	if err != nil {
+		return
+	}
+	for from, err := da.begin(root); err == nil; from, err = da.next(from, root) {
+		ids = append(ids, from)
+		num--
+		if num == 0 {
+			return
+		}
+	}
+	return
+}
+
+func (da *Cedar) begin(from int) (to int, err error) {
+	for c := da.Ninfos[from].Child; c != 0; {
+		to = da.Array[from].base() ^ int(c)
+		c = da.Ninfos[to].Child
+		from = to
+	}
+	if da.Array[from].base() > 0 {
+		return da.Array[from].base(), nil
+	}
+	return from, nil
+}
+
+func (da *Cedar) next(from int, root int) (to int, err error) {
+	c := da.Ninfos[from].Sibling
+	for c == 0 && from != root && da.Array[from].Check >= 0 {
+		from = da.Array[from].Check
+		c = da.Ninfos[from].Sibling
+	}
+	if from == root {
+		return 0, ErrNoPath
+	}
+	from = da.Array[da.Array[from].Check].base() ^ int(c)
+	return da.begin(from)
+}

GOPATH/src/github.com/liuzl/cedar-go/cedar.go

+package cedar
+
+const ValueLimit = int(^uint(0) >> 1)
+
+type node struct {
+	Value int
+	Check int
+}
+
+func (n *node) base() int { return -(n.Value + 1) }
+
+type ninfo struct {
+	Sibling, Child byte
+}
+
+type block struct {
+	Prev, Next, Num, Reject, Trial, Ehead int
+}
+
+func (b *block) init() {
+	b.Num = 256
+	b.Reject = 257
+}
+
+type Cedar struct {
+	*cedar
+}
+
+type cedar struct {
+	Array    []node
+	Ninfos   []ninfo
+	Blocks   []block
+	Reject   [257]int
+	BheadF   int
+	BheadC   int
+	BheadO   int
+	Capacity int
+	Size     int
+	Ordered  bool
+	MaxTrial int
+}
+
+func New() *Cedar {
+	da := cedar{
+		Array:    make([]node, 256),
+		Ninfos:   make([]ninfo, 256),
+		Blocks:   make([]block, 1),
+		Capacity: 256,
+		Size:     256,
+		Ordered:  true,
+		MaxTrial: 1,
+	}
+
+	da.Array[0] = node{-2, 0}
+	for i := 1; i < 256; i++ {
+		da.Array[i] = node{-(i - 1), -(i + 1)}
+	}
+	da.Array[1].Value = -255
+	da.Array[255].Check = -1
+
+	da.Blocks[0].Ehead = 1
+	da.Blocks[0].init()
+
+	for i := 0; i <= 256; i++ {
+		da.Reject[i] = i + 1
+	}
+
+	return &Cedar{&da}
+}
+
+// Get value by key, insert the key if not exist
+func (da *cedar) get(key []byte, from, pos int) *int {
+	for ; pos < len(key); pos++ {
+		if value := da.Array[from].Value; value >= 0 && value != ValueLimit {
+			to := da.follow(from, 0)
+			da.Array[to].Value = value
+		}
+		from = da.follow(from, key[pos])
+	}
+	to := from
+	if da.Array[from].Value < 0 {
+		to = da.follow(from, 0)
+	}
+	return &da.Array[to].Value
+}
+
+func (da *cedar) follow(from int, label byte) int {
+	base := da.Array[from].base()
+	to := base ^ int(label)
+	if base < 0 || da.Array[to].Check < 0 {
+		hasChild := false
+		if base >= 0 {
+			hasChild = (da.Array[base^int(da.Ninfos[from].Child)].Check == from)
+		}
+		to = da.popEnode(base, label, from)
+		da.pushSibling(from, to^int(label), label, hasChild)
+	} else if da.Array[to].Check != from {
+		to = da.resolve(from, base, label)
+	} else if da.Array[to].Check == from {
+	} else {
+		panic("cedar: internal error, should not be here")
+	}
+	return to
+}
+
+func (da *cedar) popBlock(bi int, head_in *int, last bool) {
+	if last {
+		*head_in = 0
+	} else {
+		b := &da.Blocks[bi]
+		da.Blocks[b.Prev].Next = b.Next
+		da.Blocks[b.Next].Prev = b.Prev
+		if bi == *head_in {
+			*head_in = b.Next
+		}
+	}
+}
+
+func (da *cedar) pushBlock(bi int, head_out *int, empty bool) {
+	b := &da.Blocks[bi]
+	if empty {
+		*head_out, b.Prev, b.Next = bi, bi, bi
+	} else {
+		tail_out := &da.Blocks[*head_out].Prev
+		b.Prev = *tail_out
+		b.Next = *head_out
+		*head_out, *tail_out, da.Blocks[*tail_out].Next = bi, bi, bi
+	}
+}
+
+func (da *cedar) addBlock() int {
+	if da.Size == da.Capacity {
+		da.Capacity *= 2
+
+		oldArray := da.Array
+		da.Array = make([]node, da.Capacity)
+		copy(da.Array, oldArray)
+
+		oldNinfo := da.Ninfos
+		da.Ninfos = make([]ninfo, da.Capacity)
+		copy(da.Ninfos, oldNinfo)
+
+		oldBlock := da.Blocks
+		da.Blocks = make([]block, da.Capacity>>8)
+		copy(da.Blocks, oldBlock)
+	}
+
+	da.Blocks[da.Size>>8].init()
+	da.Blocks[da.Size>>8].Ehead = da.Size
+
+	da.Array[da.Size] = node{-(da.Size + 255), -(da.Size + 1)}
+	for i := da.Size + 1; i < da.Size+255; i++ {
+		da.Array[i] = node{-(i - 1), -(i + 1)}
+	}
+	da.Array[da.Size+255] = node{-(da.Size + 254), -da.Size}
+
+	da.pushBlock(da.Size>>8, &da.BheadO, da.BheadO == 0)
+	da.Size += 256
+	return da.Size>>8 - 1
+}
+
+func (da *cedar) transferBlock(bi int, head_in, head_out *int) {
+	da.popBlock(bi, head_in, bi == da.Blocks[bi].Next)
+	da.pushBlock(bi, head_out, *head_out == 0 && da.Blocks[bi].Num != 0)
+}
+
+func (da *cedar) popEnode(base int, label byte, from int) int {
+	e := base ^ int(label)
+	if base < 0 {
+		e = da.findPlace()
+	}
+	bi := e >> 8
+	n := &da.Array[e]
+	b := &da.Blocks[bi]
+	b.Num--
+	if b.Num == 0 {
+		if bi != 0 {
+			da.transferBlock(bi, &da.BheadC, &da.BheadF)
+		}
+	} else {
+		da.Array[-n.Value].Check = n.Check
+		da.Array[-n.Check].Value = n.Value
+		if e == b.Ehead {
+			b.Ehead = -n.Check
+		}
+		if bi != 0 && b.Num == 1 && b.Trial != da.MaxTrial {
+			da.transferBlock(bi, &da.BheadO, &da.BheadC)
+		}
+	}
+	n.Value = ValueLimit
+	n.Check = from
+	if base < 0 {
+		da.Array[from].Value = -(e ^ int(label)) - 1
+	}
+	return e
+}
+
+func (da *cedar) pushEnode(e int) {
+	bi := e >> 8
+	b := &da.Blocks[bi]
+	b.Num++
+	if b.Num == 1 {
+		b.Ehead = e
+		da.Array[e] = node{-e, -e}
+		if bi != 0 {
+			da.transferBlock(bi, &da.BheadF, &da.BheadC)
+		}
+	} else {
+		prev := b.Ehead
+		next := -da.Array[prev].Check
+		da.Array[e] = node{-prev, -next}
+		da.Array[prev].Check = -e
+		da.Array[next].Value = -e
+		if b.Num == 2 || b.Trial == da.MaxTrial {
+			if bi != 0 {
+				da.transferBlock(bi, &da.BheadC, &da.BheadO)
+			}
+		}
+		b.Trial = 0
+	}
+	if b.Reject < da.Reject[b.Num] {
+		b.Reject = da.Reject[b.Num]
+	}
+	da.Ninfos[e] = ninfo{}
+}
+
+// hasChild: wherether the `from` node has children
+func (da *cedar) pushSibling(from, base int, label byte, hasChild bool) {
+	c := &da.Ninfos[from].Child
+	keepOrder := *c == 0
+	if da.Ordered {
+		keepOrder = label > *c
+	}
+	if hasChild && keepOrder {
+		c = &da.Ninfos[base^int(*c)].Sibling
+		for da.Ordered && *c != 0 && *c < label {
+			c = &da.Ninfos[base^int(*c)].Sibling
+		}
+	}
+	da.Ninfos[base^int(label)].Sibling = *c
+	*c = label
+}
+
+func (da *cedar) popSibling(from, base int, label byte) {
+	c := &da.Ninfos[from].Child
+	for *c != label {
+		c = &da.Ninfos[base^int(*c)].Sibling
+	}
+	*c = da.Ninfos[base^int(*c)].Sibling
+}
+
+func (da *cedar) consult(base_n, base_p int, c_n, c_p byte) bool {
+	c_n = da.Ninfos[base_n^int(c_n)].Sibling
+	c_p = da.Ninfos[base_p^int(c_p)].Sibling
+	for c_n != 0 && c_p != 0 {
+		c_n = da.Ninfos[base_n^int(c_n)].Sibling
+		c_p = da.Ninfos[base_p^int(c_p)].Sibling
+	}
+	return c_p != 0
+}
+
+func (da *cedar) setChild(base int, c byte, label byte, flag bool) []byte {
+	child := make([]byte, 0, 257)
+	if c == 0 {
+		child = append(child, c)
+		c = da.Ninfos[base^int(c)].Sibling
+	}
+	if da.Ordered {
+		for c != 0 && c <= label {
+			child = append(child, c)
+			c = da.Ninfos[base^int(c)].Sibling
+		}
+	}
+	if flag {
+		child = append(child, label)
+	}
+	for c != 0 {
+		child = append(child, c)
+		c = da.Ninfos[base^int(c)].Sibling
+	}
+	return child
+}
+
+func (da *cedar) findPlace() int {
+	if da.BheadC != 0 {
+		return da.Blocks[da.BheadC].Ehead
+	}
+	if da.BheadO != 0 {
+		return da.Blocks[da.BheadO].Ehead
+	}
+	return da.addBlock() << 8
+}
+
+func (da *cedar) findPlaces(child []byte) int {
+	bi := da.BheadO
+	if bi != 0 {
+		bz := da.Blocks[da.BheadO].Prev
+		nc := len(child)
+		for {
+			b := &da.Blocks[bi]
+			if b.Num >= nc && nc < b.Reject {
+				for e := b.Ehead; ; {
+					base := e ^ int(child[0])
+					for i := 0; da.Array[base^int(child[i])].Check < 0; i++ {
+						if i == len(child)-1 {
+							b.Ehead = e
+							return e
+						}
+					}
+					e = -da.Array[e].Check
+					if e == b.Ehead {
+						break
+					}
+				}
+			}
+			b.Reject = nc
+			if b.Reject < da.Reject[b.Num] {
+				da.Reject[b.Num] = b.Reject
+			}
+			bi_ := b.Next
+			b.Trial++
+			if b.Trial == da.MaxTrial {
+				da.transferBlock(bi, &da.BheadO, &da.BheadC)
+			}
+			if bi == bz {
+				break
+			}
+			bi = bi_
+		}
+	}
+	return da.addBlock() << 8
+}
+
+func (da *cedar) resolve(from_n, base_n int, label_n byte) int {
+	to_pn := base_n ^ int(label_n)
+	from_p := da.Array[to_pn].Check
+	base_p := da.Array[from_p].base()
+
+	flag := da.consult(base_n, base_p, da.Ninfos[from_n].Child, da.Ninfos[from_p].Child)
+	var children []byte
+	if flag {
+		children = da.setChild(base_n, da.Ninfos[from_n].Child, label_n, true)
+	} else {
+		children = da.setChild(base_p, da.Ninfos[from_p].Child, 255, false)
+	}
+	var base int
+	if len(children) == 1 {
+		base = da.findPlace()
+	} else {
+		base = da.findPlaces(children)
+	}
+	base ^= int(children[0])
+	var from int
+	var base_ int
+	if flag {
+		from = from_n
+		base_ = base_n
+	} else {
+		from = from_p
+		base_ = base_p
+	}
+	if flag && children[0] == label_n {
+		da.Ninfos[from].Child = label_n
+	}
+	da.Array[from].Value = -base - 1
+	for i := 0; i < len(children); i++ {
+		to := da.popEnode(base, children[i], from)
+		to_ := base_ ^ int(children[i])
+		if i == len(children)-1 {
+			da.Ninfos[to].Sibling = 0
+		} else {
+			da.Ninfos[to].Sibling = children[i+1]
+		}
+		if flag && to_ == to_pn { // new node has no child
+			continue
+		}
+		n := &da.Array[to]
+		n_ := &da.Array[to_]
+		n.Value = n_.Value
+		if n.Value < 0 && children[i] != 0 {
+			// this node has children, fix their check
+			c := da.Ninfos[to_].Child
+			da.Ninfos[to].Child = c
+			da.Array[n.base()^int(c)].Check = to
+			c = da.Ninfos[n.base()^int(c)].Sibling
+			for c != 0 {
+				da.Array[n.base()^int(c)].Check = to
+				c = da.Ninfos[n.base()^int(c)].Sibling
+			}
+		}
+		if !flag && to_ == from_n { // parent node moved
+			from_n = to
+		}
+		if !flag && to_ == to_pn {
+			da.pushSibling(from_n, to_pn^int(label_n), label_n, true)
+			da.Ninfos[to_].Child = 0
+			n_.Value = ValueLimit
+			n_.Check = from_n
+		} else {
+			da.pushEnode(to_)
+		}
+	}
+	if flag {
+		return base ^ int(label_n)
+	}
+	return to_pn
+}

GOPATH/src/github.com/liuzl/cedar-go/cedar_test.go

+package cedar
+
+import (
+	"fmt"
+	"os"
+	"testing"
+)
+
+var (
+	cd    *Cedar
+	words = []string{
+		"a", "aa", "ab", "ac", "abc", "abd",
+		"abcd", "abde", "abdf", "abcdef", "abcde",
+		"abcdefghijklmn", "bcd", "b", "xyz",
+		"中国", "中国北京", "中国上海", "中国广州",
+		"中华", "中华文明", "中华民族", "中华人民共和国",
+		"this", "this is", "this is a sentence.",
+	}
+)
+
+func loadTestData() {
+	if cd != nil {
+		return
+	}
+	cd = New()
+	// cd.Ordered = false
+
+	// add the keys
+	for i, word := range words {
+		if err := cd.Insert([]byte(word), i); err != nil {
+			panic(err)
+		}
+	}
+
+	for _, word := range words {
+		if err := cd.Delete([]byte(word)); err != nil {
+			panic(err)
+		}
+	}
+
+	for i, word := range words {
+		if err := cd.Update([]byte(word), i); err != nil {
+			panic(err)
+		}
+	}
+
+	// delete some keys
+	for i := 0; i < len(words); i += 4 {
+		if err := cd.Delete([]byte(words[i])); err != nil {
+			panic(err)
+		}
+	}
+	return
+}
+
+func TestBasic(t *testing.T) {
+	loadTestData()
+	// check the consistency
+	checkConsistency(cd)
+}
+
+func TestSaveAndLoad(t *testing.T) {
+	loadTestData()
+
+	cd.SaveToFile("cedar.gob", "gob")
+	defer os.Remove("cedar.gob")
+	daGob := New()
+	if err := daGob.LoadFromFile("cedar.gob", "gob"); err != nil {
+		panic(err)
+	}
+	checkConsistency(daGob)
+
+	cd.SaveToFile("cedar.json", "json")
+	defer os.Remove("cedar.json")
+	daJson := New()
+	if err := daJson.LoadFromFile("cedar.json", "json"); err != nil {
+		panic(err)
+	}
+	checkConsistency(daJson)
+}
+
+func TestPrefixMatch(t *testing.T) {
+	var ids []int
+	var keys []string
+	var values []int
+
+	ids = cd.PrefixMatch([]byte("abcdefg"), 0)
+	keys = []string{"ab", "abcd", "abcde", "abcdef"}
+	values = []int{2, 6, 10, 9}
+	check(cd, ids, keys, values)
+
+	ids = cd.PrefixMatch([]byte("中华人民共和国"), 0)
+	keys = []string{"中华", "中华人民共和国"}
+	values = []int{19, 22}
+	check(cd, ids, keys, values)
+
+	ids = cd.PrefixMatch([]byte("this is a sentence."), 0)
+	keys = []string{"this", "this is a sentence."}
+	values = []int{23, 25}
+	check(cd, ids, keys, values)
+}
+
+func check(cd *Cedar, ids []int, keys []string, values []int) {
+	if len(ids) != len(keys) {
+		panic("wrong prefix match")
+	}
+	for i, n := range ids {
+		key, _ := cd.Key(n)
+		val, _ := cd.Value(n)
+		if string(key) != keys[i] || val != values[i] {
+			panic("wrong prefix match")
+		}
+	}
+}
+
+func TestOrder(t *testing.T) {
+	c := New()
+	c.Insert([]byte("a"), 1)
+	c.Insert([]byte("b"), 3)
+	c.Insert([]byte("d"), 6)
+	c.Insert([]byte("ab"), 2)
+	c.Insert([]byte("c"), 5)
+	c.Insert([]byte(""), 0)
+	c.Insert([]byte("bb"), 4)
+	ids := c.PrefixPredict([]byte(""), 0)
+	if len(ids) != 7 {
+		panic("wrong order")
+	}
+	for i, n := range ids {
+		val, _ := c.Value(n)
+		if i != val {
+			panic("wrong order")
+		}
+	}
+}
+
+func TestPrefixPredict(t *testing.T) {
+	var ids []int
+	var keys []string
+	var values []int
+	ids = cd.PrefixPredict([]byte("中华"), 0)
+	keys = []string{"中华", "中华人民共和国", "中华民族"}
+	values = []int{19, 22, 21}
+	check(cd, ids, keys, values)
+
+	ids = cd.PrefixPredict([]byte("中国"), 0)
+	keys = []string{"中国", "中国上海", "中国广州"}
+	values = []int{15, 17, 18}
+	check(cd, ids, keys, values)
+}
+
+func checkConsistency(cd *Cedar) {
+	for i, word := range words {
+		id, err := cd.Jump([]byte(word), 0)
+		if i%4 == 0 {
+			if err == ErrNoPath {
+				continue
+			}
+			_, err := cd.Value(id)
+			if err == ErrNoValue {
+				continue
+			}
+			panic("not deleted")
+		}
+		key, err := cd.Key(id)
+		if err != nil {
+			panic(err)
+		}
+		if string(key) != word {
+			panic("key error")
+		}
+		value, err := cd.Value(id)
+		if err != nil || value != i {
+			fmt.Println(word, i, value, err)
+			panic("value error")
+		}
+	}
+}

GOPATH/src/github.com/liuzl/cedar-go/dict_test.go

+package cedar
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"log"
+	"os"
+	"testing"
+)
+
+type item struct {
+	key   []byte
+	value int
+}
+
+var dict []item
+
+var trie = New()
+
+func loadDict() {
+	f, err := os.Open("testdata/dict.txt")
+	if err != nil {
+		panic("failed to open testdata/dict.txt")
+	}
+
+	defer f.Close()
+	in := bufio.NewReader(f)
+
+	added := make(map[string]struct{})
+	var key string
+	var freq int
+	var pos string
+	for {
+		_, err := fmt.Fscanln(in, &key, &freq, &pos)
+		if err == io.EOF {
+			break
+		}
+		if _, ok := added[string(key)]; !ok {
+			dict = append(dict, item{[]byte(key), freq})
+			added[string(key)] = struct{}{}
+		}
+	}
+}
+
+func TestLargeDict(t *testing.T) {
+	loadDict()
+	size := len(dict)
+	log.Println("dict size:", size)
+
+	exist := func(i int) {
+		item := dict[i]
+		// fmt.Println(i, string(item.key))
+		id, err := trie.Jump(item.key, 0)
+		failIfError(err)
+		key, err := trie.Key(id)
+		failIfError(err)
+		value, err := trie.Value(id)
+		failIfError(err)
+		if string(key) != string(item.key) || value != item.value {
+			v, _ := trie.Get(item.key)
+			fmt.Println(i, string(key), string(item.key), value, item.value, v)
+			panic("large dict test fail: no equal")
+		}
+	}
+	notExist := func(i int) {
+		_, err := trie.Get(dict[i].key)
+		// fmt.Println(i, err)
+		if err != ErrNoPath && err != ErrNoValue {
+			panic("large dict test fail: should not exist")
+		}
+	}
+	checkSize := func(exp int) {
+		if keys, _, _, _ := trie.Status(); keys != exp {
+			panic("not correct status")
+		}
+	}
+
+	// Insert the first half of the dict.
+	for i := 0; i < size/2; i++ {
+		item := dict[i]
+		if i%2 == 0 {
+			if err := trie.Insert(item.key, item.value); err != nil {
+				panic(err)
+			}
+		} else {
+			if err := trie.Update(item.key, item.value); err != nil {
+				panic(err)
+			}
+		}
+	}
+	checkSize(size / 2)
+
+	// Check the first half of the dict.
+	for i := 0; i < size/2; i++ {
+		exist(i)
+	}
+	log.Println("first half OK")
+
+	// Delete even items in the first half.
+	for i := 0; i < size/2; i += 2 {
+		err := trie.Delete(dict[i].key)
+		failIfError(err)
+	}
+	checkSize(size / 2 / 2)
+
+	// Make sure even items were deleted, and the rest are fine.
+	for i := 0; i < size/2; i++ {
+		if i%2 == 0 {
+			notExist(i)
+		} else {
+			exist(i)
+		}
+	}
+	log.Println("first half odd OK")
+
+	// Insert the second half of the dict.
+	for i := size / 2; i < size; i++ {
+		item := dict[i]
+		trie.Insert(item.key, item.value)
+	}
+	checkSize(size/2/2 + (size - size/2))
+
+	for i := 0; i < size/2; i++ {
+		if i%2 == 0 {
+			notExist(i)
+		} else {
+			exist(i)
+		}
+	}
+	log.Println("first half odd still OK")
+
+	// Delete even items in the second half.
+	half := size / 2
+	if half%2 == 1 {
+		half++
+	}
+	for i := half; i < size; i += 2 {
+		err := trie.Delete(dict[i].key)
+		failIfError(err)
+	}
+	// Make sure even items were deleted, and the rest are fine.
+	for i := 0; i < size; i++ {
+		if i%2 == 0 {
+			notExist(i)
+		} else {
+			exist(i)
+		}
+	}
+	log.Println("odd OK")
+
+	// Insert all even terms.
+	for i := 0; i < size; i += 2 {
+		item := dict[i]
+		notExist(i)
+		trie.Update([]byte(item.key), item.value)
+	}
+	for i := 0; i < size; i += 1 {
+		exist(i)
+	}
+	log.Println("all OK")
+
+	// Insert every item again, should be fine.
+	for i := 1; i < size; i++ {
+		item := dict[i]
+		trie.Insert([]byte(item.key), item.value)
+	}
+	for i := 1; i < size; i += 2 {
+		exist(i)
+	}
+	log.Println("still OK")
+}
+
+func failIfError(err error) {
+	if err != nil {
+		panic(err)
+	}
+}

GOPATH/src/github.com/liuzl/cedar-go/doc.go

+// Package cedar-go implements double-array trie.
+//
+// It is a golang port of cedar (http://www.tkl.iis.u-tokyo.ac.jp/~ynaga/cedar) which is written in C++ by Naoki Yoshinaga.
+// Currently cedar-go implements the `reduced` verion of cedar.
+// This package is not thread safe if there is one goroutine doing
+// insertions or deletions.
+//
+// Note
+//
+// key must be `[]byte` without zero items,
+// while value must be integer in the range [0, 2<<63-2] or [0, 2<<31-2] depends on the platform.
+package cedar

GOPATH/src/github.com/liuzl/cedar-go/errors.go

+package cedar
+
+import "errors"
+
+var (
+	ErrInvalidDataType = errors.New("cedar: invalid datatype")
+	ErrInvalidValue    = errors.New("cedar: invalid value")
+	ErrInvalidKey      = errors.New("cedar: invalid key")
+	ErrNoPath          = errors.New("cedar: no path")
+	ErrNoValue         = errors.New("cedar: no value")
+)

GOPATH/src/github.com/liuzl/cedar-go/example_test.go

+package cedar_test
+
+import (
+	"fmt"
+
+	"github.com/adamzy/cedar-go"
+)
+
+var trie *cedar.Cedar
+
+func Example() {
+	trie = cedar.New()
+
+	// Insert key-value pairs.
+	// The order of insertion is not important.
+	trie.Insert([]byte("How many"), 0)
+	trie.Insert([]byte("How many loved"), 1)
+	trie.Insert([]byte("How many loved your moments"), 2)
+	trie.Insert([]byte("How many loved your moments of glad grace"), 3)
+	trie.Insert([]byte("姑苏"), 4)
+	trie.Insert([]byte("姑苏城外"), 5)
+	trie.Insert([]byte("姑苏城外寒山寺"), 6)
+
+	// Get the associated value of a key directly.
+	value, _ := trie.Get([]byte("How many loved your moments of glad grace"))
+	fmt.Println(value)
+
+	// Or, use `jump` to get the id of the trie node fist,
+	id, _ := trie.Jump([]byte("How many loved your moments"), 0)
+	// then get the key and the value.
+	key, _ := trie.Key(id)
+	value, _ = trie.Value(id)
+	fmt.Printf("%d\t%s:%v\n", id, key, value)
+
+	// Output:
+	// 3
+	// 281	How many loved your moments:2
+}
+
+func Example_prefixMatch() {
+	fmt.Println("id\tkey:value")
+	for _, id := range trie.PrefixMatch([]byte("How many loved your moments of glad grace"), 0) {
+		key, _ := trie.Key(id)
+		value, _ := trie.Value(id)
+		fmt.Printf("%d\t%s:%v\n", id, key, value)
+	}
+	// Output:
+	// id	key:value
+	// 262	How many:0
+	// 268	How many loved:1
+	// 281	How many loved your moments:2
+	// 296	How many loved your moments of glad grace:3
+}
+
+func Example_prefixPredict() {
+	fmt.Println("id\tkey:value")
+	for _, id := range trie.PrefixPredict([]byte("姑苏"), 0) {
+		key, _ := trie.Key(id)
+		value, _ := trie.Value(id)
+		fmt.Printf("%d\t%s:%v\n", id, key, value)
+	}
+	// Output:
+	// id	key:value
+	// 303	姑苏:4
+	// 309	姑苏城外:5
+	// 318	姑苏城外寒山寺:6
+}
+
+func Example_saveAndLoad() {
+	trie.SaveToFile("cedar.gob", "gob")
+	trie.SaveToFile("cedar.json", "json")
+
+	trie.LoadFromFile("cedar.gob", "gob")
+	trie.LoadFromFile("cedar.json", "json")
+}