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// 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.
// Rudimentary logging package. Defines a type, Logger, with simple
// methods for formatting output to one or two destinations. Also has
// predefined Loggers accessible through helper functions Stdout[f],
// Stderr[f], Exit[f], and Crash[f].
// Exit exits when written to.
// Crash causes a crash when written to.
package log
import (
"fmt";
"io";
"os";
"time";
)
const (
// Flags
Lok = iota;
Lexit; // terminate execution when written
Lcrash; // crash (panic) when written
// 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
lAllBits = Ldate | Ltime | Lmicroseconds | Llongfile | Lshortfile;
)
type Logger struct {
out0 io.Write;
out1 io.Write;
prefix string;
flag int;
}
func NewLogger(out0, out1 io.Write, prefix string, flag int) *Logger {
return &Logger{out0, out1, prefix, flag}
}
var (
stdout = NewLogger(os.Stdout, nil, "", Lok|Ldate|Ltime);
stderr = NewLogger(os.Stderr, nil, "", Lok|Ldate|Ltime);
exit = NewLogger(os.Stderr, nil, "", Lexit|Ldate|Ltime);
crash = NewLogger(os.Stderr, nil, "", Lcrash|Ldate|Ltime);
)
var shortnames = make(map[string] string) // cache of short names to avoid allocation.
// Cheap integer to fixed-width decimal ASCII. Use a negative width to avoid zero-padding
func itoa(i int, wid int) string {
var u uint = uint(i);
if u == 0 && wid <= 1 {
return "0"
}
// 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';
}
return string(b[bp:len(b)])
}
func (l *Logger) formatHeader(ns int64, calldepth int) string {
h := l.prefix;
if l.flag & (Ldate | Ltime | Lmicroseconds) != 0 {
t := time.SecondsToLocalTime(ns/1e9);
if l.flag & (Ldate) != 0 {
h += itoa(int(t.Year), 4) + "/" + itoa(t.Month, 2) + itoa(t.Day, 2) + " "
}
if l.flag & (Ltime | Lmicroseconds) != 0 {
h += itoa(t.Hour, 2) + ":" + itoa(t.Minute, 2) + ":" + itoa(t.Second, 2);
if l.flag & Lmicroseconds != 0 {
h += "." + itoa(int(ns % 1e9)/1e3, 6);
}
h += " ";
}
}
if l.flag & (Lshortfile | Llongfile) != 0 {
pc, file, line, ok := sys.Caller(calldepth);
if ok {
if l.flag & Lshortfile != 0 {
short, ok := shortnames[file];
if !ok {
short = file;
for i := len(file) - 1; i > 0; i-- {
if file[i] == '/' {
short = file[i+1:len(file)];
break;
}
}
shortnames[file] = short;
}
file = short;
}
} else {
file = "???";
line = 0;
}
h += file + ":" + itoa(line, -1) + ": ";
}
return h;
}
// The calldepth is provided for generality, although at the moment on all paths it will be 2.
func (l *Logger) Output(calldepth int, s string) {
now := time.Nanoseconds(); // get this early.
newline := "\n";
if len(s) > 0 && s[len(s)-1] == '\n' {
newline = ""
}
s = l.formatHeader(now, calldepth+1) + s + newline;
io.WriteString(l.out0, s);
if l.out1 != nil {
io.WriteString(l.out1, s);
}
switch l.flag & ^lAllBits {
case Lcrash:
panic("log: fatal error");
case Lexit:
sys.Exit(1);
}
}
// Basic methods on Logger, analogous to Printf and Print
func (l *Logger) Logf(format string, v ...) {
l.Output(2, fmt.Sprintf(format, v))
}
func (l *Logger) Log(v ...) {
l.Output(2, fmt.Sprintln(v))
}
// Helper functions for lightweight simple logging to predefined Loggers.
func Stdout(v ...) {
stdout.Output(2, fmt.Sprint(v))
}
func Stderr(v ...) {
stdout.Output(2, fmt.Sprintln(v))
}
func Stdoutf(format string, v ...) {
stdout.Output(2, fmt.Sprintf(format, v))
}
func Stderrf(format string, v ...) {
stderr.Output(2, fmt.Sprintf(format, v))
}
func Exit(v ...) {
exit.Output(2, fmt.Sprintln(v))
}
func Exitf(format string, v ...) {
exit.Output(2, fmt.Sprintf(format, v))
}
func Crash(v ...) {
crash.Output(2, fmt.Sprintln(v))
}
func Crashf(format string, v ...) {
crash.Output(2, fmt.Sprintf(format, v))
}
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