1// Copyright 2006-2009 the V8 project authors. All rights reserved.
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3// modification, are permitted provided that the following conditions are
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15//
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26// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27
28#ifndef V8_LOG_UTILS_H_
29#define V8_LOG_UTILS_H_
30
31#include "allocation.h"
32
33namespace v8 {
34namespace internal {
35
36class Logger;
37
38// Functions and data for performing output of log messages.
39class Log {
40 public:
41  // Performs process-wide initialization.
42  void Initialize(const char* log_file_name);
43
44  // Disables logging, but preserves acquired resources.
45  void stop() { is_stopped_ = true; }
46
47  static bool InitLogAtStart() {
48    return FLAG_log || FLAG_log_runtime || FLAG_log_api
49        || FLAG_log_code || FLAG_log_gc || FLAG_log_handles || FLAG_log_suspect
50        || FLAG_log_regexp || FLAG_ll_prof || FLAG_log_internal_timer_events;
51  }
52
53  // Frees all resources acquired in Initialize and Open... functions.
54  // When a temporary file is used for the log, returns its stream descriptor,
55  // leaving the file open.
56  FILE* Close();
57
58  // Returns whether logging is enabled.
59  bool IsEnabled() {
60    return !is_stopped_ && output_handle_ != NULL;
61  }
62
63  // Size of buffer used for formatting log messages.
64  static const int kMessageBufferSize = 2048;
65
66  // This mode is only used in tests, as temporary files are automatically
67  // deleted on close and thus can't be accessed afterwards.
68  static const char* const kLogToTemporaryFile;
69  static const char* const kLogToConsole;
70
71  // Utility class for formatting log messages. It fills the message into the
72  // static buffer in Log.
73  class MessageBuilder BASE_EMBEDDED {
74   public:
75    // Create a message builder starting from position 0.
76    // This acquires the mutex in the log as well.
77    explicit MessageBuilder(Log* log);
78    ~MessageBuilder() { }
79
80    // Append string data to the log message.
81    void Append(const char* format, ...);
82
83    // Append string data to the log message.
84    void AppendVA(const char* format, va_list args);
85
86    // Append a character to the log message.
87    void Append(const char c);
88
89    // Append double quoted string to the log message.
90    void AppendDoubleQuotedString(const char* string);
91
92    // Append a heap string.
93    void Append(String* str);
94
95    // Appends an address.
96    void AppendAddress(Address addr);
97
98    void AppendSymbolName(Symbol* symbol);
99
100    void AppendDetailed(String* str, bool show_impl_info);
101
102    // Append a portion of a string.
103    void AppendStringPart(const char* str, int len);
104
105    // Write the log message to the log file currently opened.
106    void WriteToLogFile();
107
108   private:
109    Log* log_;
110    ScopedLock sl;
111    int pos_;
112  };
113
114 private:
115  explicit Log(Logger* logger);
116
117  // Opens stdout for logging.
118  void OpenStdout();
119
120  // Opens file for logging.
121  void OpenFile(const char* name);
122
123  // Opens a temporary file for logging.
124  void OpenTemporaryFile();
125
126  // Implementation of writing to a log file.
127  int WriteToFile(const char* msg, int length) {
128    ASSERT(output_handle_ != NULL);
129    size_t rv = fwrite(msg, 1, length, output_handle_);
130    ASSERT(static_cast<size_t>(length) == rv);
131    USE(rv);
132    fflush(output_handle_);
133    return length;
134  }
135
136  // Whether logging is stopped (e.g. due to insufficient resources).
137  bool is_stopped_;
138
139  // When logging is active output_handle_ is used to store a pointer to log
140  // destination.  mutex_ should be acquired before using output_handle_.
141  FILE* output_handle_;
142
143  // mutex_ is a Mutex used for enforcing exclusive
144  // access to the formatting buffer and the log file or log memory buffer.
145  Mutex* mutex_;
146
147  // Buffer used for formatting log messages. This is a singleton buffer and
148  // mutex_ should be acquired before using it.
149  char* message_buffer_;
150
151  Logger* logger_;
152
153  friend class Logger;
154};
155
156
157} }  // namespace v8::internal
158
159#endif  // V8_LOG_UTILS_H_
160