1// Copyright 2006-2009 the V8 project 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#ifndef V8_LOG_UTILS_H_
6#define V8_LOG_UTILS_H_
7
8#include "src/allocation.h"
9
10namespace v8 {
11namespace internal {
12
13class Logger;
14
15// Functions and data for performing output of log messages.
16class Log {
17 public:
18  // Performs process-wide initialization.
19  void Initialize(const char* log_file_name);
20
21  // Disables logging, but preserves acquired resources.
22  void stop() { is_stopped_ = true; }
23
24  static bool InitLogAtStart() {
25    return FLAG_log || FLAG_log_api || FLAG_log_code || FLAG_log_gc
26        || FLAG_log_handles || FLAG_log_suspect || FLAG_log_regexp
27        || FLAG_ll_prof || FLAG_perf_basic_prof || FLAG_perf_jit_prof
28        || FLAG_log_internal_timer_events;
29  }
30
31  // Frees all resources acquired in Initialize and Open... functions.
32  // When a temporary file is used for the log, returns its stream descriptor,
33  // leaving the file open.
34  FILE* Close();
35
36  // Returns whether logging is enabled.
37  bool IsEnabled() {
38    return !is_stopped_ && output_handle_ != NULL;
39  }
40
41  // Size of buffer used for formatting log messages.
42  static const int kMessageBufferSize = 2048;
43
44  // This mode is only used in tests, as temporary files are automatically
45  // deleted on close and thus can't be accessed afterwards.
46  static const char* const kLogToTemporaryFile;
47  static const char* const kLogToConsole;
48
49  // Utility class for formatting log messages. It fills the message into the
50  // static buffer in Log.
51  class MessageBuilder BASE_EMBEDDED {
52   public:
53    // Create a message builder starting from position 0.
54    // This acquires the mutex in the log as well.
55    explicit MessageBuilder(Log* log);
56    ~MessageBuilder() { }
57
58    // Append string data to the log message.
59    void Append(const char* format, ...);
60
61    // Append string data to the log message.
62    void AppendVA(const char* format, va_list args);
63
64    // Append a character to the log message.
65    void Append(const char c);
66
67    // Append double quoted string to the log message.
68    void AppendDoubleQuotedString(const char* string);
69
70    // Append a heap string.
71    void Append(String* str);
72
73    // Appends an address.
74    void AppendAddress(Address addr);
75
76    void AppendSymbolName(Symbol* symbol);
77
78    void AppendDetailed(String* str, bool show_impl_info);
79
80    // Append a portion of a string.
81    void AppendStringPart(const char* str, int len);
82
83    // Write the log message to the log file currently opened.
84    void WriteToLogFile();
85
86   private:
87    Log* log_;
88    base::LockGuard<base::Mutex> lock_guard_;
89    int pos_;
90  };
91
92 private:
93  explicit Log(Logger* logger);
94
95  // Opens stdout for logging.
96  void OpenStdout();
97
98  // Opens file for logging.
99  void OpenFile(const char* name);
100
101  // Opens a temporary file for logging.
102  void OpenTemporaryFile();
103
104  // Implementation of writing to a log file.
105  int WriteToFile(const char* msg, int length) {
106    DCHECK(output_handle_ != NULL);
107    size_t rv = fwrite(msg, 1, length, output_handle_);
108    DCHECK(static_cast<size_t>(length) == rv);
109    USE(rv);
110    fflush(output_handle_);
111    return length;
112  }
113
114  // Whether logging is stopped (e.g. due to insufficient resources).
115  bool is_stopped_;
116
117  // When logging is active output_handle_ is used to store a pointer to log
118  // destination.  mutex_ should be acquired before using output_handle_.
119  FILE* output_handle_;
120
121  // mutex_ is a Mutex used for enforcing exclusive
122  // access to the formatting buffer and the log file or log memory buffer.
123  base::Mutex mutex_;
124
125  // Buffer used for formatting log messages. This is a singleton buffer and
126  // mutex_ should be acquired before using it.
127  char* message_buffer_;
128
129  Logger* logger_;
130
131  friend class Logger;
132};
133
134
135} }  // namespace v8::internal
136
137#endif  // V8_LOG_UTILS_H_
138