Initial commit

vendor/github.com/go-sql-driver/mysql/connection.go

@@ -0,0 +1,650 @@
+// 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 (
+	"context"
+	"database/sql"
+	"database/sql/driver"
+	"encoding/json"
+	"io"
+	"net"
+	"strconv"
+	"strings"
+	"time"
+)
+
+type mysqlConn struct {
+	buf              buffer
+	netConn          net.Conn
+	rawConn          net.Conn // underlying connection when netConn is TLS connection.
+	affectedRows     uint64
+	insertId         uint64
+	cfg              *Config
+	maxAllowedPacket int
+	maxWriteSize     int
+	writeTimeout     time.Duration
+	flags            clientFlag
+	status           statusFlag
+	sequence         uint8
+	parseTime        bool
+	reset            bool // set when the Go SQL package calls ResetSession
+
+	// for context support (Go 1.8+)
+	watching bool
+	watcher  chan<- context.Context
+	closech  chan struct{}
+	finished chan<- struct{}
+	canceled atomicError // set non-nil if conn is canceled
+	closed   atomicBool  // set when conn is closed, before closech is closed
+}
+
+// Handles parameters set in DSN after the connection is established
+func (mc *mysqlConn) handleParams() (err error) {
+	var cmdSet strings.Builder
+	for param, val := range mc.cfg.Params {
+		switch param {
+		// Charset: character_set_connection, character_set_client, character_set_results
+		case "charset":
+			charsets := strings.Split(val, ",")
+			for i := range charsets {
+				// ignore errors here - a charset may not exist
+				err = mc.exec("SET NAMES " + charsets[i])
+				if err == nil {
+					break
+				}
+			}
+			if err != nil {
+				return
+			}
+
+		// Other system vars accumulated in a single SET command
+		default:
+			if cmdSet.Len() == 0 {
+				// Heuristic: 29 chars for each other key=value to reduce reallocations
+				cmdSet.Grow(4 + len(param) + 1 + len(val) + 30*(len(mc.cfg.Params)-1))
+				cmdSet.WriteString("SET ")
+			} else {
+				cmdSet.WriteByte(',')
+			}
+			cmdSet.WriteString(param)
+			cmdSet.WriteByte('=')
+			cmdSet.WriteString(val)
+		}
+	}
+
+	if cmdSet.Len() > 0 {
+		err = mc.exec(cmdSet.String())
+		if err != nil {
+			return
+		}
+	}
+
+	return
+}
+
+func (mc *mysqlConn) markBadConn(err error) error {
+	if mc == nil {
+		return err
+	}
+	if err != errBadConnNoWrite {
+		return err
+	}
+	return driver.ErrBadConn
+}
+
+func (mc *mysqlConn) Begin() (driver.Tx, error) {
+	return mc.begin(false)
+}
+
+func (mc *mysqlConn) begin(readOnly bool) (driver.Tx, error) {
+	if mc.closed.IsSet() {
+		errLog.Print(ErrInvalidConn)
+		return nil, driver.ErrBadConn
+	}
+	var q string
+	if readOnly {
+		q = "START TRANSACTION READ ONLY"
+	} else {
+		q = "START TRANSACTION"
+	}
+	err := mc.exec(q)
+	if err == nil {
+		return &mysqlTx{mc}, err
+	}
+	return nil, mc.markBadConn(err)
+}
+
+func (mc *mysqlConn) Close() (err error) {
+	// Makes Close idempotent
+	if !mc.closed.IsSet() {
+		err = mc.writeCommandPacket(comQuit)
+	}
+
+	mc.cleanup()
+
+	return
+}
+
+// Closes the network connection and unsets internal variables. Do not call this
+// function after successfully authentication, call Close instead. This function
+// is called before auth or on auth failure because MySQL will have already
+// closed the network connection.
+func (mc *mysqlConn) cleanup() {
+	if !mc.closed.TrySet(true) {
+		return
+	}
+
+	// Makes cleanup idempotent
+	close(mc.closech)
+	if mc.netConn == nil {
+		return
+	}
+	if err := mc.netConn.Close(); err != nil {
+		errLog.Print(err)
+	}
+}
+
+func (mc *mysqlConn) error() error {
+	if mc.closed.IsSet() {
+		if err := mc.canceled.Value(); err != nil {
+			return err
+		}
+		return ErrInvalidConn
+	}
+	return nil
+}
+
+func (mc *mysqlConn) Prepare(query string) (driver.Stmt, error) {
+	if mc.closed.IsSet() {
+		errLog.Print(ErrInvalidConn)
+		return nil, driver.ErrBadConn
+	}
+	// Send command
+	err := mc.writeCommandPacketStr(comStmtPrepare, query)
+	if err != nil {
+		// STMT_PREPARE is safe to retry.  So we can return ErrBadConn here.
+		errLog.Print(err)
+		return nil, driver.ErrBadConn
+	}
+
+	stmt := &mysqlStmt{
+		mc: mc,
+	}
+
+	// Read Result
+	columnCount, err := stmt.readPrepareResultPacket()
+	if err == nil {
+		if stmt.paramCount > 0 {
+			if err = mc.readUntilEOF(); err != nil {
+				return nil, err
+			}
+		}
+
+		if columnCount > 0 {
+			err = mc.readUntilEOF()
+		}
+	}
+
+	return stmt, err
+}
+
+func (mc *mysqlConn) interpolateParams(query string, args []driver.Value) (string, error) {
+	// Number of ? should be same to len(args)
+	if strings.Count(query, "?") != len(args) {
+		return "", driver.ErrSkip
+	}
+
+	buf, err := mc.buf.takeCompleteBuffer()
+	if err != nil {
+		// can not take the buffer. Something must be wrong with the connection
+		errLog.Print(err)
+		return "", ErrInvalidConn
+	}
+	buf = buf[:0]
+	argPos := 0
+
+	for i := 0; i < len(query); i++ {
+		q := strings.IndexByte(query[i:], '?')
+		if q == -1 {
+			buf = append(buf, query[i:]...)
+			break
+		}
+		buf = append(buf, query[i:i+q]...)
+		i += q
+
+		arg := args[argPos]
+		argPos++
+
+		if arg == nil {
+			buf = append(buf, "NULL"...)
+			continue
+		}
+
+		switch v := arg.(type) {
+		case int64:
+			buf = strconv.AppendInt(buf, v, 10)
+		case uint64:
+			// Handle uint64 explicitly because our custom ConvertValue emits unsigned values
+			buf = strconv.AppendUint(buf, v, 10)
+		case float64:
+			buf = strconv.AppendFloat(buf, v, 'g', -1, 64)
+		case bool:
+			if v {
+				buf = append(buf, '1')
+			} else {
+				buf = append(buf, '0')
+			}
+		case time.Time:
+			if v.IsZero() {
+				buf = append(buf, "'0000-00-00'"...)
+			} else {
+				buf = append(buf, '\'')
+				buf, err = appendDateTime(buf, v.In(mc.cfg.Loc))
+				if err != nil {
+					return "", err
+				}
+				buf = append(buf, '\'')
+			}
+		case json.RawMessage:
+			buf = append(buf, '\'')
+			if mc.status&statusNoBackslashEscapes == 0 {
+				buf = escapeBytesBackslash(buf, v)
+			} else {
+				buf = escapeBytesQuotes(buf, v)
+			}
+			buf = append(buf, '\'')
+		case []byte:
+			if v == nil {
+				buf = append(buf, "NULL"...)
+			} else {
+				buf = append(buf, "_binary'"...)
+				if mc.status&statusNoBackslashEscapes == 0 {
+					buf = escapeBytesBackslash(buf, v)
+				} else {
+					buf = escapeBytesQuotes(buf, v)
+				}
+				buf = append(buf, '\'')
+			}
+		case string:
+			buf = append(buf, '\'')
+			if mc.status&statusNoBackslashEscapes == 0 {
+				buf = escapeStringBackslash(buf, v)
+			} else {
+				buf = escapeStringQuotes(buf, v)
+			}
+			buf = append(buf, '\'')
+		default:
+			return "", driver.ErrSkip
+		}
+
+		if len(buf)+4 > mc.maxAllowedPacket {
+			return "", driver.ErrSkip
+		}
+	}
+	if argPos != len(args) {
+		return "", driver.ErrSkip
+	}
+	return string(buf), nil
+}
+
+func (mc *mysqlConn) Exec(query string, args []driver.Value) (driver.Result, error) {
+	if mc.closed.IsSet() {
+		errLog.Print(ErrInvalidConn)
+		return nil, driver.ErrBadConn
+	}
+	if len(args) != 0 {
+		if !mc.cfg.InterpolateParams {
+			return nil, driver.ErrSkip
+		}
+		// try to interpolate the parameters to save extra roundtrips for preparing and closing a statement
+		prepared, err := mc.interpolateParams(query, args)
+		if err != nil {
+			return nil, err
+		}
+		query = prepared
+	}
+	mc.affectedRows = 0
+	mc.insertId = 0
+
+	err := mc.exec(query)
+	if err == nil {
+		return &mysqlResult{
+			affectedRows: int64(mc.affectedRows),
+			insertId:     int64(mc.insertId),
+		}, err
+	}
+	return nil, mc.markBadConn(err)
+}
+
+// Internal function to execute commands
+func (mc *mysqlConn) exec(query string) error {
+	// Send command
+	if err := mc.writeCommandPacketStr(comQuery, query); err != nil {
+		return mc.markBadConn(err)
+	}
+
+	// Read Result
+	resLen, err := mc.readResultSetHeaderPacket()
+	if err != nil {
+		return err
+	}
+
+	if resLen > 0 {
+		// columns
+		if err := mc.readUntilEOF(); err != nil {
+			return err
+		}
+
+		// rows
+		if err := mc.readUntilEOF(); err != nil {
+			return err
+		}
+	}
+
+	return mc.discardResults()
+}
+
+func (mc *mysqlConn) Query(query string, args []driver.Value) (driver.Rows, error) {
+	return mc.query(query, args)
+}
+
+func (mc *mysqlConn) query(query string, args []driver.Value) (*textRows, error) {
+	if mc.closed.IsSet() {
+		errLog.Print(ErrInvalidConn)
+		return nil, driver.ErrBadConn
+	}
+	if len(args) != 0 {
+		if !mc.cfg.InterpolateParams {
+			return nil, driver.ErrSkip
+		}
+		// try client-side prepare to reduce roundtrip
+		prepared, err := mc.interpolateParams(query, args)
+		if err != nil {
+			return nil, err
+		}
+		query = prepared
+	}
+	// Send command
+	err := mc.writeCommandPacketStr(comQuery, query)
+	if err == nil {
+		// Read Result
+		var resLen int
+		resLen, err = mc.readResultSetHeaderPacket()
+		if err == nil {
+			rows := new(textRows)
+			rows.mc = mc
+
+			if resLen == 0 {
+				rows.rs.done = true
+
+				switch err := rows.NextResultSet(); err {
+				case nil, io.EOF:
+					return rows, nil
+				default:
+					return nil, err
+				}
+			}
+
+			// Columns
+			rows.rs.columns, err = mc.readColumns(resLen)
+			return rows, err
+		}
+	}
+	return nil, mc.markBadConn(err)
+}
+
+// Gets the value of the given MySQL System Variable
+// The returned byte slice is only valid until the next read
+func (mc *mysqlConn) getSystemVar(name string) ([]byte, error) {
+	// Send command
+	if err := mc.writeCommandPacketStr(comQuery, "SELECT @@"+name); err != nil {
+		return nil, err
+	}
+
+	// Read Result
+	resLen, err := mc.readResultSetHeaderPacket()
+	if err == nil {
+		rows := new(textRows)
+		rows.mc = mc
+		rows.rs.columns = []mysqlField{{fieldType: fieldTypeVarChar}}
+
+		if resLen > 0 {
+			// Columns
+			if err := mc.readUntilEOF(); err != nil {
+				return nil, err
+			}
+		}
+
+		dest := make([]driver.Value, resLen)
+		if err = rows.readRow(dest); err == nil {
+			return dest[0].([]byte), mc.readUntilEOF()
+		}
+	}
+	return nil, err
+}
+
+// finish is called when the query has canceled.
+func (mc *mysqlConn) cancel(err error) {
+	mc.canceled.Set(err)
+	mc.cleanup()
+}
+
+// finish is called when the query has succeeded.
+func (mc *mysqlConn) finish() {
+	if !mc.watching || mc.finished == nil {
+		return
+	}
+	select {
+	case mc.finished <- struct{}{}:
+		mc.watching = false
+	case <-mc.closech:
+	}
+}
+
+// Ping implements driver.Pinger interface
+func (mc *mysqlConn) Ping(ctx context.Context) (err error) {
+	if mc.closed.IsSet() {
+		errLog.Print(ErrInvalidConn)
+		return driver.ErrBadConn
+	}
+
+	if err = mc.watchCancel(ctx); err != nil {
+		return
+	}
+	defer mc.finish()
+
+	if err = mc.writeCommandPacket(comPing); err != nil {
+		return mc.markBadConn(err)
+	}
+
+	return mc.readResultOK()
+}
+
+// BeginTx implements driver.ConnBeginTx interface
+func (mc *mysqlConn) BeginTx(ctx context.Context, opts driver.TxOptions) (driver.Tx, error) {
+	if mc.closed.IsSet() {
+		return nil, driver.ErrBadConn
+	}
+
+	if err := mc.watchCancel(ctx); err != nil {
+		return nil, err
+	}
+	defer mc.finish()
+
+	if sql.IsolationLevel(opts.Isolation) != sql.LevelDefault {
+		level, err := mapIsolationLevel(opts.Isolation)
+		if err != nil {
+			return nil, err
+		}
+		err = mc.exec("SET TRANSACTION ISOLATION LEVEL " + level)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return mc.begin(opts.ReadOnly)
+}
+
+func (mc *mysqlConn) QueryContext(ctx context.Context, query string, args []driver.NamedValue) (driver.Rows, error) {
+	dargs, err := namedValueToValue(args)
+	if err != nil {
+		return nil, err
+	}
+
+	if err := mc.watchCancel(ctx); err != nil {
+		return nil, err
+	}
+
+	rows, err := mc.query(query, dargs)
+	if err != nil {
+		mc.finish()
+		return nil, err
+	}
+	rows.finish = mc.finish
+	return rows, err
+}
+
+func (mc *mysqlConn) ExecContext(ctx context.Context, query string, args []driver.NamedValue) (driver.Result, error) {
+	dargs, err := namedValueToValue(args)
+	if err != nil {
+		return nil, err
+	}
+
+	if err := mc.watchCancel(ctx); err != nil {
+		return nil, err
+	}
+	defer mc.finish()
+
+	return mc.Exec(query, dargs)
+}
+
+func (mc *mysqlConn) PrepareContext(ctx context.Context, query string) (driver.Stmt, error) {
+	if err := mc.watchCancel(ctx); err != nil {
+		return nil, err
+	}
+
+	stmt, err := mc.Prepare(query)
+	mc.finish()
+	if err != nil {
+		return nil, err
+	}
+
+	select {
+	default:
+	case <-ctx.Done():
+		stmt.Close()
+		return nil, ctx.Err()
+	}
+	return stmt, nil
+}
+
+func (stmt *mysqlStmt) QueryContext(ctx context.Context, args []driver.NamedValue) (driver.Rows, error) {
+	dargs, err := namedValueToValue(args)
+	if err != nil {
+		return nil, err
+	}
+
+	if err := stmt.mc.watchCancel(ctx); err != nil {
+		return nil, err
+	}
+
+	rows, err := stmt.query(dargs)
+	if err != nil {
+		stmt.mc.finish()
+		return nil, err
+	}
+	rows.finish = stmt.mc.finish
+	return rows, err
+}
+
+func (stmt *mysqlStmt) ExecContext(ctx context.Context, args []driver.NamedValue) (driver.Result, error) {
+	dargs, err := namedValueToValue(args)
+	if err != nil {
+		return nil, err
+	}
+
+	if err := stmt.mc.watchCancel(ctx); err != nil {
+		return nil, err
+	}
+	defer stmt.mc.finish()
+
+	return stmt.Exec(dargs)
+}
+
+func (mc *mysqlConn) watchCancel(ctx context.Context) error {
+	if mc.watching {
+		// Reach here if canceled,
+		// so the connection is already invalid
+		mc.cleanup()
+		return nil
+	}
+	// When ctx is already cancelled, don't watch it.
+	if err := ctx.Err(); err != nil {
+		return err
+	}
+	// When ctx is not cancellable, don't watch it.
+	if ctx.Done() == nil {
+		return nil
+	}
+	// When watcher is not alive, can't watch it.
+	if mc.watcher == nil {
+		return nil
+	}
+
+	mc.watching = true
+	mc.watcher <- ctx
+	return nil
+}
+
+func (mc *mysqlConn) startWatcher() {
+	watcher := make(chan context.Context, 1)
+	mc.watcher = watcher
+	finished := make(chan struct{})
+	mc.finished = finished
+	go func() {
+		for {
+			var ctx context.Context
+			select {
+			case ctx = <-watcher:
+			case <-mc.closech:
+				return
+			}
+
+			select {
+			case <-ctx.Done():
+				mc.cancel(ctx.Err())
+			case <-finished:
+			case <-mc.closech:
+				return
+			}
+		}
+	}()
+}
+
+func (mc *mysqlConn) CheckNamedValue(nv *driver.NamedValue) (err error) {
+	nv.Value, err = converter{}.ConvertValue(nv.Value)
+	return
+}
+
+// ResetSession implements driver.SessionResetter.
+// (From Go 1.10)
+func (mc *mysqlConn) ResetSession(ctx context.Context) error {
+	if mc.closed.IsSet() {
+		return driver.ErrBadConn
+	}
+	mc.reset = true
+	return nil
+}
+
+// IsValid implements driver.Validator interface
+// (From Go 1.15)
+func (mc *mysqlConn) IsValid() bool {
+	return !mc.closed.IsSet()
+}