debug.h revision f8ee788a64d60abd8f2d742a5fdedde054ecd910 
1// Copyright 2014 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5// Logging and checks.
6//
7// Log messages to stdout.  LOG() prints normal user messages, VLOG()
8// is verbose, for tracing and debugging.  SetVerbose() enables/disables
9// VLOG() output.
10//
11// LOG() and VLOG() are printf-like, and arguments are checked by gcc.
12// LOG_IF() and VLOG_IF() call LOG/VLOG if their predicate is true.
13// CHECK() aborts if its predicate is false.  NOTREACHED() always aborts.
14// Logging is not thread-safe.
15//
16
17#ifndef TOOLS_RELOCATION_PACKER_SRC_DEBUG_H_
18#define TOOLS_RELOCATION_PACKER_SRC_DEBUG_H_
19
20#ifdef NDEBUG
21#undef NDEBUG
22#include <assert.h>
23#define NDEBUG
24#else
25#include <assert.h>
26#endif
27
28#include <stdarg.h>
29#include <string.h>
30
31namespace relocation_packer {
32
33// If gcc, define PRINTF_ATTRIBUTE so that gcc checks Log() as printf-like.
34#if defined(__GNUC__) && (__GNUC__ >= 3)
35#define PRINTF_ATTRIBUTE(string_index, first_to_check) \
36    __attribute__((__format__(__printf__, string_index, first_to_check)))
37#else
38#define PRINTF_ATTRIBUTE(string_index, first_to_check)
39#endif
40
41// Logging and checking macros.
42#define LOG(...) ::relocation_packer::Logger::Log(__VA_ARGS__)
43#define VLOG(...) ::relocation_packer::Logger::VLog(__VA_ARGS__)
44#define LOG_IF(cond, ...)  \
45  do {                     \
46    if ((cond))            \
47      LOG(__VA_ARGS__);    \
48  } while (0)
49#define VLOG_IF(cond, ...) \
50  do {                     \
51    if ((cond))            \
52      VLOG(__VA_ARGS__);   \
53  } while (0)
54
55#define CHECK(expr) assert((expr))
56#define NOTREACHED(_) assert(false)
57
58class Logger {
59 public:
60  // Log and verbose log to stdout.
61  // |format| is a printf format string.
62  static void Log(const char* format, ...) PRINTF_ATTRIBUTE(1, 2);
63  static void VLog(const char* format, ...) PRINTF_ATTRIBUTE(1, 2);
64
65  // Set verbose mode.
66  // |flag| is true to enable verbose logging, false to disable it.
67  static void SetVerbose(bool flag);
68
69 private:
70  Logger() : is_verbose_(false) { }
71  ~Logger() {}
72
73  // Implementation of log to stdout.
74  // |format| is a printf format string.
75  // |args| is a varargs list of printf arguments.
76  void Log(const char* format, va_list args);
77
78  // If set, VLOG is enabled, otherwise it is a no-op.
79  bool is_verbose_;
80
81  // Singleton support.  Not thread-safe.
82  static Logger* GetInstance();
83  static Logger* instance_;
84};
85
86}  // namespace relocation_packer
87
88#endif  // TOOLS_RELOCATION_PACKER_SRC_DEBUG_H_
89