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 <stdio.h> 9 10 #include <cstdarg> 11 12 #include "src/allocation.h" 13 #include "src/base/platform/mutex.h" 14 #include "src/flags.h" 15 16 namespace v8 { 17 namespace internal { 18 19 class Logger; 20 21 // Functions and data for performing output of log messages. 22 class Log { 23 public: 24 // Performs process-wide initialization. 25 void Initialize(const char* log_file_name); 26 27 // Disables logging, but preserves acquired resources. 28 void stop() { is_stopped_ = true; } 29 30 static bool InitLogAtStart() { 31 return FLAG_log || FLAG_log_api || FLAG_log_code || FLAG_log_gc || 32 FLAG_log_handles || FLAG_log_suspect || FLAG_log_regexp || 33 FLAG_ll_prof || FLAG_perf_basic_prof || 34 FLAG_log_internal_timer_events || FLAG_prof_cpp; 35 } 36 37 // Frees all resources acquired in Initialize and Open... functions. 38 // When a temporary file is used for the log, returns its stream descriptor, 39 // leaving the file open. 40 FILE* Close(); 41 42 // Returns whether logging is enabled. 43 bool IsEnabled() { 44 return !is_stopped_ && output_handle_ != NULL; 45 } 46 47 // Size of buffer used for formatting log messages. 48 static const int kMessageBufferSize = 2048; 49 50 // This mode is only used in tests, as temporary files are automatically 51 // deleted on close and thus can't be accessed afterwards. 52 static const char* const kLogToTemporaryFile; 53 static const char* const kLogToConsole; 54 55 // Utility class for formatting log messages. It fills the message into the 56 // static buffer in Log. 57 class MessageBuilder BASE_EMBEDDED { 58 public: 59 // Create a message builder starting from position 0. 60 // This acquires the mutex in the log as well. 61 explicit MessageBuilder(Log* log); 62 ~MessageBuilder() { } 63 64 // Append string data to the log message. 65 void Append(const char* format, ...); 66 67 // Append string data to the log message. 68 void AppendVA(const char* format, va_list args); 69 70 // Append a character to the log message. 71 void Append(const char c); 72 73 // Append double quoted string to the log message. 74 void AppendDoubleQuotedString(const char* string); 75 76 // Append a heap string. 77 void Append(String* str); 78 79 // Appends an address. 80 void AppendAddress(Address addr); 81 82 void AppendSymbolName(Symbol* symbol); 83 84 void AppendDetailed(String* str, bool show_impl_info); 85 86 // Append a portion of a string. 87 void AppendStringPart(const char* str, int len); 88 89 // Write the log message to the log file currently opened. 90 void WriteToLogFile(); 91 92 private: 93 Log* log_; 94 base::LockGuard<base::Mutex> lock_guard_; 95 int pos_; 96 }; 97 98 private: 99 explicit Log(Logger* logger); 100 101 // Opens stdout for logging. 102 void OpenStdout(); 103 104 // Opens file for logging. 105 void OpenFile(const char* name); 106 107 // Opens a temporary file for logging. 108 void OpenTemporaryFile(); 109 110 // Implementation of writing to a log file. 111 int WriteToFile(const char* msg, int length) { 112 DCHECK(output_handle_ != NULL); 113 size_t rv = fwrite(msg, 1, length, output_handle_); 114 DCHECK(static_cast<size_t>(length) == rv); 115 USE(rv); 116 fflush(output_handle_); 117 return length; 118 } 119 120 // Whether logging is stopped (e.g. due to insufficient resources). 121 bool is_stopped_; 122 123 // When logging is active output_handle_ is used to store a pointer to log 124 // destination. mutex_ should be acquired before using output_handle_. 125 FILE* output_handle_; 126 127 // mutex_ is a Mutex used for enforcing exclusive 128 // access to the formatting buffer and the log file or log memory buffer. 129 base::Mutex mutex_; 130 131 // Buffer used for formatting log messages. This is a singleton buffer and 132 // mutex_ should be acquired before using it. 133 char* message_buffer_; 134 135 Logger* logger_; 136 137 friend class Logger; 138 }; 139 140 141 } // namespace internal 142 } // namespace v8 143 144 #endif // V8_LOG_UTILS_H_ 145
