summaryrefslogtreecommitdiff
path: root/libgo/go/log/log.go
blob: d34af9e5e4548406a32b5eb3f6f14df95535253f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// Simple logging package. It defines a type, Logger, with methods
// for formatting output. It also has a predefined 'standard' Logger
// accessible through helper functions Print[f|ln], Exit[f|ln], and
// Panic[f|ln], which are easier to use than creating a Logger manually.
// That logger writes to standard error and prints the date and time
// of each logged message.
// The Exit functions call os.Exit(1) after writing the log message.
// The Panic functions call panic after writing the log message.
package log

import (
	"bytes"
	"fmt"
	"io"
	"runtime"
	"os"
	"time"
	"sync"
)

// These flags define which text to prefix to each log entry generated by the Logger.
const (
	// Bits or'ed together to control what's printed. There is no control over the
	// order they appear (the order listed here) or the format they present (as
	// described in the comments).  A colon appears after these items:
	//	2009/0123 01:23:23.123123 /a/b/c/d.go:23: message
	Ldate         = 1 << iota // the date: 2009/0123
	Ltime                     // the time: 01:23:23
	Lmicroseconds             // microsecond resolution: 01:23:23.123123.  assumes Ltime.
	Llongfile                 // full file name and line number: /a/b/c/d.go:23
	Lshortfile                // final file name element and line number: d.go:23. overrides Llongfile
)

// A Logger represents an active logging object that generates lines of
// output to an io.Writer.  Each logging operation makes a single call to
// the Writer's Write method.  A Logger can be used simultaneously from
// multiple goroutines; it guarantees to serialize access to the Writer.
type Logger struct {
	mu     sync.Mutex // ensures atomic writes
	out    io.Writer  // destination for output
	prefix string     // prefix to write at beginning of each line
	flag   int        // properties
}

// New creates a new Logger.   The out variable sets the
// destination to which log data will be written.
// The prefix appears at the beginning of each generated log line.
// The flag argument defines the logging properties.
func New(out io.Writer, prefix string, flag int) *Logger {
	return &Logger{out: out, prefix: prefix, flag: flag}
}

var std = New(os.Stderr, "", Ldate|Ltime)

// Cheap integer to fixed-width decimal ASCII.  Give a negative width to avoid zero-padding.
// Knows the buffer has capacity.
func itoa(buf *bytes.Buffer, i int, wid int) {
	var u uint = uint(i)
	if u == 0 && wid <= 1 {
		buf.WriteByte('0')
		return
	}

	// Assemble decimal in reverse order.
	var b [32]byte
	bp := len(b)
	for ; u > 0 || wid > 0; u /= 10 {
		bp--
		wid--
		b[bp] = byte(u%10) + '0'
	}

	// avoid slicing b to avoid an allocation.
	for bp < len(b) {
		buf.WriteByte(b[bp])
		bp++
	}
}

func (l *Logger) formatHeader(buf *bytes.Buffer, ns int64, calldepth int) {
	buf.WriteString(l.prefix)
	if l.flag&(Ldate|Ltime|Lmicroseconds) != 0 {
		t := time.SecondsToLocalTime(ns / 1e9)
		if l.flag&Ldate != 0 {
			itoa(buf, int(t.Year), 4)
			buf.WriteByte('/')
			itoa(buf, int(t.Month), 2)
			buf.WriteByte('/')
			itoa(buf, int(t.Day), 2)
			buf.WriteByte(' ')
		}
		if l.flag&(Ltime|Lmicroseconds) != 0 {
			itoa(buf, int(t.Hour), 2)
			buf.WriteByte(':')
			itoa(buf, int(t.Minute), 2)
			buf.WriteByte(':')
			itoa(buf, int(t.Second), 2)
			if l.flag&Lmicroseconds != 0 {
				buf.WriteByte('.')
				itoa(buf, int(ns%1e9)/1e3, 6)
			}
			buf.WriteByte(' ')
		}
	}
	if l.flag&(Lshortfile|Llongfile) != 0 {
		_, file, line, ok := runtime.Caller(calldepth)
		if ok {
			if l.flag&Lshortfile != 0 {
				short := file
				for i := len(file) - 1; i > 0; i-- {
					if file[i] == '/' {
						short = file[i+1:]
						break
					}
				}
				file = short
			}
		} else {
			file = "???"
			line = 0
		}
		buf.WriteString(file)
		buf.WriteByte(':')
		itoa(buf, line, -1)
		buf.WriteString(": ")
	}
}

// Output writes the output for a logging event.  The string s contains
// the text to print after the prefix specified by the flags of the
// Logger.  A newline is appended if the last character of s is not
// already a newline.  Calldepth is used to recover the PC and is
// provided for generality, although at the moment on all pre-defined
// paths it will be 2.
func (l *Logger) Output(calldepth int, s string) os.Error {
	now := time.Nanoseconds() // get this early.
	buf := new(bytes.Buffer)
	l.formatHeader(buf, now, calldepth+1)
	buf.WriteString(s)
	if len(s) > 0 && s[len(s)-1] != '\n' {
		buf.WriteByte('\n')
	}
	l.mu.Lock()
	defer l.mu.Unlock()
	_, err := l.out.Write(buf.Bytes())
	return err
}

// Printf calls l.Output to print to the logger.
// Arguments are handled in the manner of fmt.Printf.
func (l *Logger) Printf(format string, v ...interface{}) {
	l.Output(2, fmt.Sprintf(format, v...))
}

// Print calls l.Output to print to the logger.
// Arguments are handled in the manner of fmt.Print.
func (l *Logger) Print(v ...interface{}) { l.Output(2, fmt.Sprint(v...)) }

// Println calls l.Output to print to the logger.
// Arguments are handled in the manner of fmt.Println.
func (l *Logger) Println(v ...interface{}) { l.Output(2, fmt.Sprintln(v...)) }

// Exit is equivalent to l.Print() followed by a call to os.Exit(1).
func (l *Logger) Exit(v ...interface{}) {
	l.Output(2, fmt.Sprint(v...))
	os.Exit(1)
}

// Exitf is equivalent to l.Printf() followed by a call to os.Exit(1).
func (l *Logger) Exitf(format string, v ...interface{}) {
	l.Output(2, fmt.Sprintf(format, v...))
	os.Exit(1)
}

// Exitln is equivalent to l.Println() followed by a call to os.Exit(1).
func (l *Logger) Exitln(v ...interface{}) {
	l.Output(2, fmt.Sprintln(v...))
	os.Exit(1)
}

// Panic is equivalent to l.Print() followed by a call to panic().
func (l *Logger) Panic(v ...interface{}) {
	s := fmt.Sprint(v...)
	l.Output(2, s)
	panic(s)
}

// Panicf is equivalent to l.Printf() followed by a call to panic().
func (l *Logger) Panicf(format string, v ...interface{}) {
	s := fmt.Sprintf(format, v...)
	l.Output(2, s)
	panic(s)
}

// Panicln is equivalent to l.Println() followed by a call to panic().
func (l *Logger) Panicln(v ...interface{}) {
	s := fmt.Sprintln(v...)
	l.Output(2, s)
	panic(s)
}

// SetOutput sets the output destination for the standard logger.
func SetOutput(w io.Writer) {
	std.out = w
}

// SetFlags sets the output flags for the standard logger.
func SetFlags(flag int) {
	std.flag = flag
}

// SetPrefix sets the output prefix for the standard logger.
func SetPrefix(prefix string) {
	std.prefix = prefix
}

// These functions write to the standard logger.

// Print calls Output to print to the standard logger.
// Arguments are handled in the manner of fmt.Print.
func Print(v ...interface{}) {
	std.Output(2, fmt.Sprint(v...))
}

// Printf calls Output to print to the standard logger.
// Arguments are handled in the manner of fmt.Printf.
func Printf(format string, v ...interface{}) {
	std.Output(2, fmt.Sprintf(format, v...))
}

// Println calls Output to print to the standard logger.
// Arguments are handled in the manner of fmt.Println.
func Println(v ...interface{}) {
	std.Output(2, fmt.Sprintln(v...))
}

// Exit is equivalent to Print() followed by a call to os.Exit(1).
func Exit(v ...interface{}) {
	std.Output(2, fmt.Sprint(v...))
	os.Exit(1)
}

// Exitf is equivalent to Printf() followed by a call to os.Exit(1).
func Exitf(format string, v ...interface{}) {
	std.Output(2, fmt.Sprintf(format, v...))
	os.Exit(1)
}

// Exitln is equivalent to Println() followed by a call to os.Exit(1).
func Exitln(v ...interface{}) {
	std.Output(2, fmt.Sprintln(v...))
	os.Exit(1)
}

// Panic is equivalent to Print() followed by a call to panic().
func Panic(v ...interface{}) {
	s := fmt.Sprint(v...)
	std.Output(2, s)
	panic(s)
}

// Panicf is equivalent to Printf() followed by a call to panic().
func Panicf(format string, v ...interface{}) {
	s := fmt.Sprintf(format, v...)
	std.Output(2, s)
	panic(s)
}

// Panicln is equivalent to Println() followed by a call to panic().
func Panicln(v ...interface{}) {
	s := fmt.Sprintln(v...)
	std.Output(2, s)
	panic(s)
}