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.  Avoids a dependency on base.
6//
7// LOG(tag) prints messages.  Tags are INFO, WARNING, ERROR and FATAL.
8// INFO prints to stdout, the others to stderr.  FATAL aborts after printing.
9//
10// LOG_IF(tag, predicate) logs if predicate evaluates to true, else silent.
11//
12// VLOG(level) logs INFO messages where level is less than or equal to the
13// verbosity level set with SetVerbose().
14//
15// VLOG_IF(level, predicate) logs INFO if predicate evaluates to true,
16// else silent.
17//
18// CHECK(predicate) logs a FATAL error if predicate is false.
19// NOTREACHED() always aborts.
20// Log streams can be changed with SetStreams().  Logging is not thread-safe.
21//
22
23#ifndef TOOLS_RELOCATION_PACKER_SRC_DEBUG_H_
24#define TOOLS_RELOCATION_PACKER_SRC_DEBUG_H_
25
26#include <limits.h>
27#include <ostream>
28#include <sstream>
29
30namespace relocation_packer {
31
32class Logger {
33 public:
34  enum Severity {INFO = 0, WARNING, ERROR, FATAL};
35
36  // Construct a new message logger.  Prints if level is less than or
37  // equal to the level set with SetVerbose() and predicate is true.
38  // |severity| is an enumerated severity.
39  // |level| is the verbosity level.
40  // |predicate| controls if the logger prints or is silent.
41  Logger(Severity severity, int level, bool predicate);
42
43  // On destruction, flush and print the strings accumulated in stream_.
44  ~Logger();
45
46  // Return the stream for this logger.
47  std::ostream& GetStream() { return stream_; }
48
49  // Set verbosity level.  Messages with a level less than or equal to
50  // this level are printed, others are discarded.  Static, not thread-safe.
51  static void SetVerbose(int level) { max_level_ = level; }
52
53  // Set info and error logging streams.  Static, not thread-safe.
54  static void SetStreams(std::ostream* info_stream,
55                         std::ostream* error_stream) {
56    info_stream_ = info_stream;
57    error_stream_ = error_stream;
58  }
59
60  // Reset to initial state.
61  static void Reset();
62
63 private:
64  // Message severity, verbosity level, and predicate.
65  Severity severity_;
66  int level_;
67  bool predicate_;
68
69  // String stream, accumulates message text.
70  std::ostringstream stream_;
71
72  // Verbosity for INFO messages.  Not thread-safe.
73  static int max_level_;
74
75  // Logging streams.  Not thread-safe.
76  static std::ostream* info_stream_;
77  static std::ostream* error_stream_;
78};
79
80}  // namespace relocation_packer
81
82// Make logging severities visible globally.
83typedef relocation_packer::Logger::Severity LogSeverity;
84const LogSeverity INFO = relocation_packer::Logger::INFO;
85const LogSeverity WARNING = relocation_packer::Logger::WARNING;
86const LogSeverity ERROR = relocation_packer::Logger::ERROR;
87const LogSeverity FATAL = relocation_packer::Logger::FATAL;
88
89// LOG(severity) prints a message with the given severity, and aborts if
90// severity is FATAL.  LOG_IF(severity, predicate) does the same but only if
91// predicate is true.  INT_MIN is guaranteed to be less than or equal to
92// any verbosity level.
93#define LOG(severity) \
94    (relocation_packer::Logger(severity, INT_MIN, true).GetStream())
95#define LOG_IF(severity, predicate) \
96    (relocation_packer::Logger(severity, INT_MIN, (predicate)).GetStream())
97
98// VLOG(level) prints its message as INFO if level is less than or equal to
99// the current verbosity level.
100#define VLOG(level) \
101    (relocation_packer::Logger(INFO, (level), true).GetStream())
102#define VLOG_IF(level, predicate) \
103    (relocation_packer::Logger(INFO, (level), (predicate)).GetStream())
104
105// CHECK(predicate) fails with a FATAL log message if predicate is false.
106#define CHECK(predicate) (LOG_IF(FATAL, !(predicate)) \
107    << __FILE__ << ":" << __LINE__ << ": " \
108    << __FUNCTION__ << ": CHECK '" #predicate "' failed")
109
110// NOTREACHED() always fails with a FATAL log message.
111#define NOTREACHED(_) (LOG(FATAL) \
112    << __FILE__ << ":" << __LINE__ << ": " \
113    << __FUNCTION__ << ": NOTREACHED() hit")
114
115#endif  // TOOLS_RELOCATION_PACKER_SRC_DEBUG_H_
116