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Remove unnecessary buf from msgReader 

Replace with bufio.Reader.Peek for short sizes
go17-redshift-test
Jack Christensen 2016-08-08 17:01:01 -05:00
parent 7e43eca3d3
commit bb73d84279
1 changed files with 33 additions and 24 deletions
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57
msg_reader.go
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@ -10,7 +10,6 @@ import (
// msgReader is a helper that reads values from a PostgreSQL message.
type msgReader struct {
reader *bufio.Reader
buf [128]byte
msgBytesRemaining int32
err error
log func(lvl int, msg string, ctx ...interface{})
@ -47,10 +46,15 @@ func (r *msgReader) rxMsg() (byte, error) {
}
}
b := r.buf[0:5]
_, err := io.ReadFull(r.reader, b)
b, err := r.reader.Peek(5)
if err != nil {
r.fatal(err)
return 0, err
}
msgType := b[0]
r.msgBytesRemaining = int32(binary.BigEndian.Uint32(b[1:])) - 4
return b[0], err
r.reader.Discard(5)
return msgType, nil
}
func (r *msgReader) readByte() byte {
@ -88,8 +92,7 @@ func (r *msgReader) readInt16() int16 {
return 0
}
b := r.buf[0:2]
_, err := io.ReadFull(r.reader, b)
b, err := r.reader.Peek(2)
if err != nil {
r.fatal(err)
return 0
@ -97,6 +100,8 @@ func (r *msgReader) readInt16() int16 {
n := int16(binary.BigEndian.Uint16(b))
r.reader.Discard(2)
if r.shouldLog(LogLevelTrace) {
r.log(LogLevelTrace, "msgReader.readInt16", "value", n, "msgBytesRemaining", r.msgBytesRemaining)
}
@ -115,8 +120,7 @@ func (r *msgReader) readInt32() int32 {
return 0
}
b := r.buf[0:4]
_, err := io.ReadFull(r.reader, b)
b, err := r.reader.Peek(4)
if err != nil {
r.fatal(err)
return 0
@ -124,6 +128,8 @@ func (r *msgReader) readInt32() int32 {
n := int32(binary.BigEndian.Uint32(b))
r.reader.Discard(4)
if r.shouldLog(LogLevelTrace) {
r.log(LogLevelTrace, "msgReader.readInt32", "value", n, "msgBytesRemaining", r.msgBytesRemaining)
}
@ -142,8 +148,7 @@ func (r *msgReader) readInt64() int64 {
return 0
}
b := r.buf[0:8]
_, err := io.ReadFull(r.reader, b)
b, err := r.reader.Peek(8)
if err != nil {
r.fatal(err)
return 0
@ -151,6 +156,8 @@ func (r *msgReader) readInt64() int64 {
n := int64(binary.BigEndian.Uint64(b))
r.reader.Discard(8)
if r.shouldLog(LogLevelTrace) {
r.log(LogLevelTrace, "msgReader.readInt64", "value", n, "msgBytesRemaining", r.msgBytesRemaining)
}
@ -190,32 +197,34 @@ func (r *msgReader) readCString() string {
}
// readString reads count bytes and returns as string
func (r *msgReader) readString(count int32) string {
func (r *msgReader) readString(countI32 int32) string {
if r.err != nil {
return ""
}
r.msgBytesRemaining -= count
r.msgBytesRemaining -= countI32
if r.msgBytesRemaining < 0 {
r.fatal(errors.New("read past end of message"))
return ""
}
var b []byte
if count <= int32(len(r.buf)) {
b = r.buf[0:int(count)]
count := int(countI32)
var s string
if r.reader.Buffered() >= count {
buf, _ := r.reader.Peek(count)
s = string(buf)
r.reader.Discard(count)
} else {
b = make([]byte, int(count))
buf := make([]byte, int(count))
_, err := io.ReadFull(r.reader, buf)
if err != nil {
r.fatal(err)
return ""
}
s = string(buf)
}
_, err := io.ReadFull(r.reader, b)
if err != nil {
r.fatal(err)
return ""
}
s := string(b)
if r.shouldLog(LogLevelTrace) {
r.log(LogLevelTrace, "msgReader.readString", "value", s, "msgBytesRemaining", r.msgBytesRemaining)
}