1// mgo - MongoDB driver for Go
2//
3// Copyright (c) 2010-2012 - Gustavo Niemeyer <gustavo@niemeyer.net>
4//
5// All rights reserved.
6//
7// Redistribution and use in source and binary forms, with or without
8// modification, are permitted provided that the following conditions are met:
9//
10// 1. Redistributions of source code must retain the above copyright notice, this
11//    list of conditions and the following disclaimer.
12// 2. Redistributions in binary form must reproduce the above copyright notice,
13//    this list of conditions and the following disclaimer in the documentation
14//    and/or other materials provided with the distribution.
15//
16// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
17// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
18// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
19// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
20// ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
21// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
22// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
23// ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
25// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26
27package mgo
28
29import (
30	"fmt"
31	"sync"
32)
33
34// ---------------------------------------------------------------------------
35// Logging integration.
36
37// Avoid importing the log type information unnecessarily.  There's a small cost
38// associated with using an interface rather than the type.  Depending on how
39// often the logger is plugged in, it would be worth using the type instead.
40type log_Logger interface {
41	Output(calldepth int, s string) error
42}
43
44var (
45	globalLogger log_Logger
46	globalDebug  bool
47	globalMutex  sync.Mutex
48)
49
50// RACE WARNING: There are known data races when logging, which are manually
51// silenced when the race detector is in use. These data races won't be
52// observed in typical use, because logging is supposed to be set up once when
53// the application starts. Having raceDetector as a constant, the compiler
54// should elide the locks altogether in actual use.
55
56// Specify the *log.Logger object where log messages should be sent to.
57func SetLogger(logger log_Logger) {
58	if raceDetector {
59		globalMutex.Lock()
60		defer globalMutex.Unlock()
61	}
62	globalLogger = logger
63}
64
65// Enable the delivery of debug messages to the logger.  Only meaningful
66// if a logger is also set.
67func SetDebug(debug bool) {
68	if raceDetector {
69		globalMutex.Lock()
70		defer globalMutex.Unlock()
71	}
72	globalDebug = debug
73}
74
75func log(v ...interface{}) {
76	if raceDetector {
77		globalMutex.Lock()
78		defer globalMutex.Unlock()
79	}
80	if globalLogger != nil {
81		globalLogger.Output(2, fmt.Sprint(v...))
82	}
83}
84
85func logln(v ...interface{}) {
86	if raceDetector {
87		globalMutex.Lock()
88		defer globalMutex.Unlock()
89	}
90	if globalLogger != nil {
91		globalLogger.Output(2, fmt.Sprintln(v...))
92	}
93}
94
95func logf(format string, v ...interface{}) {
96	if raceDetector {
97		globalMutex.Lock()
98		defer globalMutex.Unlock()
99	}
100	if globalLogger != nil {
101		globalLogger.Output(2, fmt.Sprintf(format, v...))
102	}
103}
104
105func debug(v ...interface{}) {
106	if raceDetector {
107		globalMutex.Lock()
108		defer globalMutex.Unlock()
109	}
110	if globalDebug && globalLogger != nil {
111		globalLogger.Output(2, fmt.Sprint(v...))
112	}
113}
114
115func debugln(v ...interface{}) {
116	if raceDetector {
117		globalMutex.Lock()
118		defer globalMutex.Unlock()
119	}
120	if globalDebug && globalLogger != nil {
121		globalLogger.Output(2, fmt.Sprintln(v...))
122	}
123}
124
125func debugf(format string, v ...interface{}) {
126	if raceDetector {
127		globalMutex.Lock()
128		defer globalMutex.Unlock()
129	}
130	if globalDebug && globalLogger != nil {
131		globalLogger.Output(2, fmt.Sprintf(format, v...))
132	}
133}
134