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/compiler-specific.h" 14 #include "src/base/platform/mutex.h" 15 #include "src/flags.h" 16 17 namespace v8 { 18 namespace internal { 19 20 class Logger; 21 22 // Functions and data for performing output of log messages. 23 class Log { 24 public: 25 // Performs process-wide initialization. 26 void Initialize(const char* log_file_name); 27 28 // Disables logging, but preserves acquired resources. 29 void stop() { is_stopped_ = true; } 30 31 static bool InitLogAtStart() { 32 return FLAG_log || FLAG_log_api || FLAG_log_code || FLAG_log_gc || 33 FLAG_log_handles || FLAG_log_suspect || FLAG_ll_prof || 34 FLAG_perf_basic_prof || FLAG_perf_prof || 35 FLAG_log_internal_timer_events || FLAG_prof_cpp || FLAG_trace_ic; 36 } 37 38 // Frees all resources acquired in Initialize and Open... functions. 39 // When a temporary file is used for the log, returns its stream descriptor, 40 // leaving the file open. 41 FILE* Close(); 42 43 // Returns whether logging is enabled. 44 bool IsEnabled() { 45 return !is_stopped_ && output_handle_ != NULL; 46 } 47 48 // Size of buffer used for formatting log messages. 49 static const int kMessageBufferSize = 2048; 50 51 // This mode is only used in tests, as temporary files are automatically 52 // deleted on close and thus can't be accessed afterwards. 53 static const char* const kLogToTemporaryFile; 54 static const char* const kLogToConsole; 55 56 // Utility class for formatting log messages. It fills the message into the 57 // static buffer in Log. 58 class MessageBuilder BASE_EMBEDDED { 59 public: 60 // Create a message builder starting from position 0. 61 // This acquires the mutex in the log as well. 62 explicit MessageBuilder(Log* log); 63 ~MessageBuilder() { } 64 65 // Append string data to the log message. 66 void PRINTF_FORMAT(2, 3) Append(const char* format, ...); 67 68 // Append string data to the log message. 69 void PRINTF_FORMAT(2, 0) AppendVA(const char* format, va_list args); 70 71 // Append a character to the log message. 72 void Append(const char c); 73 74 // Append double quoted string to the log message. 75 void AppendDoubleQuotedString(const char* string); 76 77 // Append a heap string. 78 void Append(String* str); 79 80 // Appends an address. 81 void AppendAddress(Address addr); 82 83 void AppendSymbolName(Symbol* symbol); 84 85 void AppendDetailed(String* str, bool show_impl_info); 86 87 // Append a portion of a string. 88 void AppendStringPart(const char* str, int len); 89 90 // Write the log message to the log file currently opened. 91 void WriteToLogFile(); 92 93 private: 94 Log* log_; 95 base::LockGuard<base::Mutex> lock_guard_; 96 int pos_; 97 }; 98 99 private: 100 explicit Log(Logger* logger); 101 102 // Opens stdout for logging. 103 void OpenStdout(); 104 105 // Opens file for logging. 106 void OpenFile(const char* name); 107 108 // Opens a temporary file for logging. 109 void OpenTemporaryFile(); 110 111 // Implementation of writing to a log file. 112 int WriteToFile(const char* msg, int length) { 113 DCHECK_NOT_NULL(output_handle_); 114 size_t rv = fwrite(msg, 1, length, output_handle_); 115 DCHECK_EQ(length, rv); 116 USE(rv); 117 fflush(output_handle_); 118 return length; 119 } 120 121 // Whether logging is stopped (e.g. due to insufficient resources). 122 bool is_stopped_; 123 124 // When logging is active output_handle_ is used to store a pointer to log 125 // destination. mutex_ should be acquired before using output_handle_. 126 FILE* output_handle_; 127 128 // mutex_ is a Mutex used for enforcing exclusive 129 // access to the formatting buffer and the log file or log memory buffer. 130 base::Mutex mutex_; 131 132 // Buffer used for formatting log messages. This is a singleton buffer and 133 // mutex_ should be acquired before using it. 134 char* message_buffer_; 135 136 Logger* logger_; 137 138 friend class Logger; 139 }; 140 141 142 } // namespace internal 143 } // namespace v8 144 145 #endif // V8_LOG_UTILS_H_ 146
