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      1 // Copyright 2006-2009 the V8 project authors. All rights reserved.
      2 // Redistribution and use in source and binary forms, with or without
      3 // modification, are permitted provided that the following conditions are
      4 // met:
      5 //
      6 //     * Redistributions of source code must retain the above copyright
      7 //       notice, this list of conditions and the following disclaimer.
      8 //     * Redistributions in binary form must reproduce the above
      9 //       copyright notice, this list of conditions and the following
     10 //       disclaimer in the documentation and/or other materials provided
     11 //       with the distribution.
     12 //     * Neither the name of Google Inc. nor the names of its
     13 //       contributors may be used to endorse or promote products derived
     14 //       from this software without specific prior written permission.
     15 //
     16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     17 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     18 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     19 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     20 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     21 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     22 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     23 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     24 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     25 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     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 
     33 namespace v8 {
     34 namespace internal {
     35 
     36 class Logger;
     37 
     38 // Functions and data for performing output of log messages.
     39 class Log {
     40  public:
     41   // Performs process-wide initialization.
     42   void Initialize();
     43 
     44   // Disables logging, but preserves acquired resources.
     45   void stop() { is_stopped_ = true; }
     46 
     47   // Frees all resources acquired in Initialize and Open... functions.
     48   // When a temporary file is used for the log, returns its stream descriptor,
     49   // leaving the file open.
     50   FILE* Close();
     51 
     52   // Returns whether logging is enabled.
     53   bool IsEnabled() {
     54     return !is_stopped_ && output_handle_ != NULL;
     55   }
     56 
     57   // Size of buffer used for formatting log messages.
     58   static const int kMessageBufferSize = 2048;
     59 
     60   // This mode is only used in tests, as temporary files are automatically
     61   // deleted on close and thus can't be accessed afterwards.
     62   static const char* const kLogToTemporaryFile;
     63 
     64  private:
     65   explicit Log(Logger* logger);
     66 
     67   // Opens stdout for logging.
     68   void OpenStdout();
     69 
     70   // Opens file for logging.
     71   void OpenFile(const char* name);
     72 
     73   // Opens a temporary file for logging.
     74   void OpenTemporaryFile();
     75 
     76   // Implementation of writing to a log file.
     77   int WriteToFile(const char* msg, int length) {
     78     ASSERT(output_handle_ != NULL);
     79     size_t rv = fwrite(msg, 1, length, output_handle_);
     80     ASSERT(static_cast<size_t>(length) == rv);
     81     USE(rv);
     82     fflush(output_handle_);
     83     return length;
     84   }
     85 
     86   // Whether logging is stopped (e.g. due to insufficient resources).
     87   bool is_stopped_;
     88 
     89   // When logging is active output_handle_ is used to store a pointer to log
     90   // destination.  mutex_ should be acquired before using output_handle_.
     91   FILE* output_handle_;
     92 
     93   // Used when low-level profiling is active.
     94   FILE* ll_output_handle_;
     95 
     96   // mutex_ is a Mutex used for enforcing exclusive
     97   // access to the formatting buffer and the log file or log memory buffer.
     98   Mutex* mutex_;
     99 
    100   // Buffer used for formatting log messages. This is a singleton buffer and
    101   // mutex_ should be acquired before using it.
    102   char* message_buffer_;
    103 
    104   Logger* logger_;
    105 
    106   friend class Logger;
    107   friend class LogMessageBuilder;
    108 };
    109 
    110 
    111 // Utility class for formatting log messages. It fills the message into the
    112 // static buffer in Log.
    113 class LogMessageBuilder BASE_EMBEDDED {
    114  public:
    115   // Create a message builder starting from position 0. This acquires the mutex
    116   // in the log as well.
    117   explicit LogMessageBuilder(Logger* logger);
    118   ~LogMessageBuilder() { }
    119 
    120   // Append string data to the log message.
    121   void Append(const char* format, ...);
    122 
    123   // Append string data to the log message.
    124   void AppendVA(const char* format, va_list args);
    125 
    126   // Append a character to the log message.
    127   void Append(const char c);
    128 
    129   // Append a heap string.
    130   void Append(String* str);
    131 
    132   // Appends an address.
    133   void AppendAddress(Address addr);
    134 
    135   void AppendDetailed(String* str, bool show_impl_info);
    136 
    137   // Append a portion of a string.
    138   void AppendStringPart(const char* str, int len);
    139 
    140   // Write the log message to the log file currently opened.
    141   void WriteToLogFile();
    142 
    143  private:
    144   Log* log_;
    145   ScopedLock sl;
    146   int pos_;
    147 };
    148 
    149 } }  // namespace v8::internal
    150 
    151 #endif  // V8_LOG_UTILS_H_
    152