pkg/jsonlog/jsonlogbytes.go
unclejack 90c3318cb6 pkg/jsonlog: add JSONLogBytes for low allocations
Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com>
2015-04-01 01:02:18 +03:00

115 lines
2.3 KiB
Go

package jsonlog
import (
"bytes"
"unicode/utf8"
)
// JSONLogBytes is based on JSONLog.
// It allows marshalling JSONLog from Log as []byte
// and an already marshalled Created timestamp.
type JSONLogBytes struct {
Log []byte `json:"log,omitempty"`
Stream string `json:"stream,omitempty"`
Created string `json:"time"`
}
// MarshalJSONBuf is based on the same method from JSONLog
// It has been modified to take into account the necessary changes.
func (mj *JSONLogBytes) MarshalJSONBuf(buf *bytes.Buffer) error {
var first = true
buf.WriteString(`{`)
if len(mj.Log) != 0 {
if first == true {
first = false
} else {
buf.WriteString(`,`)
}
buf.WriteString(`"log":`)
ffjson_WriteJsonBytesAsString(buf, mj.Log)
}
if len(mj.Stream) != 0 {
if first == true {
first = false
} else {
buf.WriteString(`,`)
}
buf.WriteString(`"stream":`)
ffjson_WriteJsonString(buf, mj.Stream)
}
if first == true {
first = false
} else {
buf.WriteString(`,`)
}
buf.WriteString(`"time":`)
buf.WriteString(mj.Created)
buf.WriteString(`}`)
return nil
}
// This is based on ffjson_WriteJsonString. It has been changed
// to accept a string passed as a slice of bytes.
func ffjson_WriteJsonBytesAsString(buf *bytes.Buffer, s []byte) {
const hex = "0123456789abcdef"
buf.WriteByte('"')
start := 0
for i := 0; i < len(s); {
if b := s[i]; b < utf8.RuneSelf {
if 0x20 <= b && b != '\\' && b != '"' && b != '<' && b != '>' && b != '&' {
i++
continue
}
if start < i {
buf.Write(s[start:i])
}
switch b {
case '\\', '"':
buf.WriteByte('\\')
buf.WriteByte(b)
case '\n':
buf.WriteByte('\\')
buf.WriteByte('n')
case '\r':
buf.WriteByte('\\')
buf.WriteByte('r')
default:
buf.WriteString(`\u00`)
buf.WriteByte(hex[b>>4])
buf.WriteByte(hex[b&0xF])
}
i++
start = i
continue
}
c, size := utf8.DecodeRune(s[i:])
if c == utf8.RuneError && size == 1 {
if start < i {
buf.Write(s[start:i])
}
buf.WriteString(`\ufffd`)
i += size
start = i
continue
}
if c == '\u2028' || c == '\u2029' {
if start < i {
buf.Write(s[start:i])
}
buf.WriteString(`\u202`)
buf.WriteByte(hex[c&0xF])
i += size
start = i
continue
}
i += size
}
if start < len(s) {
buf.Write(s[start:])
}
buf.WriteByte('"')
}