Initial QSfera import

Server/vendor/github.com/go-sql-driver/mysql/connector.go

@@ -0,0 +1,229 @@
+// 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"
+	"fmt"
+	"net"
+	"os"
+	"strconv"
+	"strings"
+)
+
+type connector struct {
+	cfg               *Config // immutable private copy.
+	encodedAttributes string  // Encoded connection attributes.
+}
+
+func encodeConnectionAttributes(cfg *Config) string {
+	connAttrsBuf := make([]byte, 0)
+
+	// default connection attributes
+	connAttrsBuf = appendLengthEncodedString(connAttrsBuf, connAttrClientName)
+	connAttrsBuf = appendLengthEncodedString(connAttrsBuf, connAttrClientNameValue)
+	connAttrsBuf = appendLengthEncodedString(connAttrsBuf, connAttrOS)
+	connAttrsBuf = appendLengthEncodedString(connAttrsBuf, connAttrOSValue)
+	connAttrsBuf = appendLengthEncodedString(connAttrsBuf, connAttrPlatform)
+	connAttrsBuf = appendLengthEncodedString(connAttrsBuf, connAttrPlatformValue)
+	connAttrsBuf = appendLengthEncodedString(connAttrsBuf, connAttrPid)
+	connAttrsBuf = appendLengthEncodedString(connAttrsBuf, strconv.Itoa(os.Getpid()))
+	serverHost, _, _ := net.SplitHostPort(cfg.Addr)
+	if serverHost != "" {
+		connAttrsBuf = appendLengthEncodedString(connAttrsBuf, connAttrServerHost)
+		connAttrsBuf = appendLengthEncodedString(connAttrsBuf, serverHost)
+	}
+
+	// user-defined connection attributes
+	for connAttr := range strings.SplitSeq(cfg.ConnectionAttributes, ",") {
+		k, v, found := strings.Cut(connAttr, ":")
+		if !found {
+			continue
+		}
+		connAttrsBuf = appendLengthEncodedString(connAttrsBuf, k)
+		connAttrsBuf = appendLengthEncodedString(connAttrsBuf, v)
+	}
+
+	return string(connAttrsBuf)
+}
+
+func newConnector(cfg *Config) *connector {
+	encodedAttributes := encodeConnectionAttributes(cfg)
+	return &connector{
+		cfg:               cfg,
+		encodedAttributes: encodedAttributes,
+	}
+}
+
+// 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
+
+	// Invoke beforeConnect if present, with a copy of the configuration
+	cfg := c.cfg
+	if c.cfg.beforeConnect != nil {
+		cfg = c.cfg.Clone()
+		err = c.cfg.beforeConnect(ctx, cfg)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	// New mysqlConn
+	mc := &mysqlConn{
+		maxAllowedPacket: maxPacketSize,
+		maxWriteSize:     maxPacketSize - 1,
+		closech:          make(chan struct{}),
+		cfg:              cfg,
+		connector:        c,
+	}
+	mc.parseTime = mc.cfg.ParseTime
+
+	// Connect to Server
+	dctx := ctx
+	if mc.cfg.Timeout > 0 {
+		var cancel context.CancelFunc
+		dctx, cancel = context.WithTimeout(ctx, c.cfg.Timeout)
+		defer cancel()
+	}
+
+	if c.cfg.DialFunc != nil {
+		mc.netConn, err = c.cfg.DialFunc(dctx, mc.cfg.Net, mc.cfg.Addr)
+	} else {
+		dialsLock.RLock()
+		dial, ok := dials[mc.cfg.Net]
+		dialsLock.RUnlock()
+		if ok {
+			mc.netConn, err = dial(dctx, mc.cfg.Addr)
+		} else {
+			nd := net.Dialer{}
+			mc.netConn, err = nd.DialContext(dctx, mc.cfg.Net, mc.cfg.Addr)
+		}
+	}
+	if err != nil {
+		return nil, err
+	}
+	mc.rawConn = mc.netConn
+
+	// Enable TCP Keepalives on TCP connections
+	if tc, ok := mc.netConn.(*net.TCPConn); ok {
+		if err := tc.SetKeepAlive(true); err != nil {
+			c.cfg.Logger.Print(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()
+
+	// Reading Handshake Initialization Packet
+	authData, serverCapabilities, serverExtCapabilities, 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
+		c.cfg.Logger.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
+		}
+	}
+	mc.initCapabilities(serverCapabilities, serverExtCapabilities, mc.cfg)
+	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/dev/mysql-server/latest/page_protocol_connection_phase.html#sect_protocol_connection_phase_fast_path_fails).
+		// Do not send COM_QUIT, just cleanup and return the error.
+		mc.cleanup()
+		return nil, err
+	}
+
+	// compression is enabled after auth, not right after sending handshake response.
+	if mc.capabilities&clientCompress > 0 {
+		mc.compress = true
+		mc.compIO = newCompIO(mc)
+	}
+	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
+		}
+		n, err := strconv.Atoi(maxap)
+		if err != nil {
+			mc.Close()
+			return nil, fmt.Errorf("invalid max_allowed_packet value (%q): %w", maxap, err)
+		}
+		mc.maxAllowedPacket = n - 1
+	}
+	if mc.maxAllowedPacket < maxPacketSize {
+		mc.maxWriteSize = mc.maxAllowedPacket
+	}
+
+	// Charset: character_set_connection, character_set_client, character_set_results
+	if len(mc.cfg.charsets) > 0 {
+		for _, cs := range mc.cfg.charsets {
+			// ignore errors here - a charset may not exist
+			if mc.cfg.Collation != "" {
+				err = mc.exec("SET NAMES " + cs + " COLLATE " + mc.cfg.Collation)
+			} else {
+				err = mc.exec("SET NAMES " + cs)
+			}
+			if err == nil {
+				break
+			}
+		}
+		if err != nil {
+			mc.Close()
+			return nil, err
+		}
+	}
+
+	// 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{}
+}