forked from thoj/go-mysqlpure
/
mysql_stmt.go
166 lines (155 loc) · 4.41 KB
/
mysql_stmt.go
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package mysql
import (
"bufio"
"encoding/binary"
"os"
"fmt"
"strconv"
)
type MySQLStatement struct {
StatementId uint32
Columns uint16
Parameters uint16
Warnings uint16
FieldCount uint8
ResultSet *MySQLResultSet
mysql *MySQLInstance
}
// Encode values fro each field
func encodeParamValues(a []interface{}) ([]byte, int) {
var b []byte
for i := 0; i < len(a); i++ {
f := a[i];
switch t := f.(type) {
case string:
b = append(b, packString(string(t))...)
case int:
b = append(b, packString(strconv.Itoa(int(t)))...)
case float32:
b = append(b, packString(strconv.Ftoa32(float32(t), 'f', -1))...)
case float64:
b = append(b, packString(strconv.Ftoa64(float64(t), 'f', -1))...)
}
}
return b, len(b)
}
func putuint16(b []byte, v uint16) {
b[0] = byte(v)
b[1] = byte(v >> 8)
}
// For each field encode 2 byte type code. First bit is signed/unsigned
// Cheats and only bind parameters as strings
func encodeParamTypes(a []interface{}) ([]byte, int) {
buf := make([]byte, len(a)*2)
off := 0
for i := 0; i < len(a); i++ {
f := a[i];
if f == nil {
putuint16(buf[off:off+2], uint16(MYSQL_TYPE_NULL))
continue
}
putuint16(buf[off:off+2], uint16(MYSQL_TYPE_STRING))
off += 2
}
return buf, off
}
func readPrepareInit(br *bufio.Reader) (s *MySQLStatement, err os.Error) {
var ph *PacketHeader
ph, err = readHeader(br)
if err != nil { return }
s = new(MySQLStatement)
err = binary.Read(br, binary.LittleEndian, &s.FieldCount)
if err != nil { return }
if s.FieldCount == uint8(0xff) {
return nil, readErrorPacket(br, int(ph.Len))
}
err = binary.Read(br, binary.LittleEndian, &s.StatementId)
if err != nil { return }
err = binary.Read(br, binary.LittleEndian, &s.Columns)
if err != nil { return }
err = binary.Read(br, binary.LittleEndian, &s.Parameters)
if err != nil { return }
if ph.Len >= 12 {
err = ignoreBytes(br, 1)
if err != nil { return }
err = binary.Read(br, binary.LittleEndian, &s.Warnings)
if err != nil { return }
}
return
}
//Currently just skips the pakets as I'm not sure if they are useful.
func readPrepareParameters(br *bufio.Reader, s *MySQLStatement) os.Error {
for i := uint16(0); i < s.Parameters; i++ {
ph, err := readHeader(br)
if err != nil { return err }
err = ignoreBytes(br, ph.Len)
if err != nil { return err }
}
return nil
}
func (sth *MySQLStatement) execute(a []interface{}) (res *MySQLResponse, err os.Error) {
if a == nil || int(sth.Parameters) != len(a) {
return nil, os.ErrorString(fmt.Sprintf("Parameter count mismatch. Expected %d parameters, got %d", sth.Parameters, len(a)))
}
type_parm, tn := encodeParamTypes(a)
value_parm, vn := encodeParamValues(a)
bitmap_len := (len(a) + 7) / 8
mysql := sth.mysql
err = packUint24(mysql.writer, uint32(11+bitmap_len+tn+vn))
if err != nil { return }
err = packUint8(mysql.writer, uint8(0))
if err != nil { return }
err = packUint8(mysql.writer, uint8(COM_STMT_EXECUTE))
if err != nil { return }
err = packUint32(mysql.writer, uint32(sth.StatementId))
if err != nil { return }
err = packUint8(mysql.writer, uint8(0))
if err != nil { return }
err = packUint32(mysql.writer, uint32(1))
if err != nil { return }
b := make([]byte, bitmap_len)
_, err = mysql.writer.Write(b) //TODO: Support null params.
if err != nil { return }
err = packUint8(mysql.writer, uint8(1))
if err != nil { return }
_, err = mysql.writer.Write(type_parm)
if err != nil { return }
_, err = mysql.writer.Write(value_parm)
if err != nil { return }
err = mysql.writer.Flush()
if err != nil { return }
res, err = mysql.readResult()
if err != nil { return }
res.Prepared = true
return
}
func (mysql *MySQLInstance) prepare(arg string) (sth *MySQLStatement, err os.Error) {
plen := len(arg) + 1
head := make([]byte,5)
head[0] = byte(plen)
head[1] = byte(plen >> 8)
head[2] = byte(plen >> 16)
head[3] = 0
head[4] = uint8(COM_STMT_PREPARE)
_, err = mysql.writer.Write(head)
if err != nil { return }
_, err = mysql.writer.WriteString(arg)
if err != nil { return }
err = mysql.writer.Flush()
if err != nil { return }
sth, err = readPrepareInit(mysql.reader)
if err != nil { return }
if sth.Parameters > 0 {
err = readPrepareParameters(mysql.reader, sth)
if err != nil { return }
err = readEOFPacket(mysql.reader)
if err != nil { return }
}
if sth.Columns > 0 {
rs, err := mysql.readResultSet(uint64(sth.Columns))
if err != nil { return nil, err }
sth.ResultSet = rs
}
sth.mysql = mysql
return
}