support multiple log message handlers in base/logging.h

base/logging_win.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/logging_win.h"
 #include "base/memory/singleton.h"
 #include <initguid.h>  // NOLINT
 
 namespace logging {
 
 using base::win::EtwEventLevel;
 using base::win::EtwMofEvent;
 
 DEFINE_GUID(kLogEventId,
     0x7fe69228, 0x633e, 0x4f06, 0x80, 0xc1, 0x52, 0x7f, 0xea, 0x23, 0xe3, 0xa7);
 
 LogEventProvider::LogEventProvider() : old_log_level_(LOG_NONE) {
 }
 
 LogEventProvider* LogEventProvider::GetInstance() {
   return base::Singleton<LogEventProvider, base::StaticMemorySingletonTraits<
                                                LogEventProvider>>::get();
 }
 
 bool LogEventProvider::LogMessage(logging::LogSeverity severity,
-    const char* file, int line, size_t message_start,
-    const std::string& message) {
+                                  const std::string& file,
+                                  int line,
+                                  const std::string& message) {
   EtwEventLevel level = TRACE_LEVEL_NONE;
 
   // Convert the log severity to the most appropriate ETW trace level.
   if (severity >= 0) {
     switch (severity) {
       case LOG_INFO:
         level = TRACE_LEVEL_INFORMATION;
         break;
       case LOG_WARNING:
         level = TRACE_LEVEL_WARNING;
@@ skipping 11 matching lines @@
 
   // Bail if we're not logging, not at that level,
   // or if we're post-atexit handling.
   LogEventProvider* provider = LogEventProvider::GetInstance();
   if (provider == NULL || level > provider->enable_level())
     return false;
 
   // And now log the event.
   if (provider->enable_flags() & ENABLE_LOG_MESSAGE_ONLY) {
     EtwMofEvent<1> event(kLogEventId, LOG_MESSAGE, level);
-    event.SetField(0, message.length() + 1 - message_start,
-        message.c_str() + message_start);
+    event.SetField(0, message.length() + 1, message.c_str());
 
     provider->Log(event.get());
   } else {
     const size_t kMaxBacktraceDepth = 32;
     void* backtrace[kMaxBacktraceDepth];
     DWORD depth = 0;
 
     // Capture a stack trace if one is requested.
     // requested per our enable flags.
     if (provider->enable_flags() & ENABLE_STACK_TRACE_CAPTURE)
       depth = CaptureStackBackTrace(2, kMaxBacktraceDepth, backtrace, NULL);
 
     EtwMofEvent<5> event(kLogEventId, LOG_MESSAGE_FULL, level);
-    if (file == NULL)
-      file = "";
 
     // Add the stack trace.
     event.SetField(0, sizeof(depth), &depth);
     event.SetField(1, sizeof(backtrace[0]) * depth, &backtrace);
     // The line.
     event.SetField(2, sizeof(line), &line);
     // The file.
-    event.SetField(3, strlen(file) + 1, file);
+    event.SetField(3, file.length() + 1, file.c_str());
     // And finally the message.
-    event.SetField(4, message.length() + 1 - message_start,
-        message.c_str() + message_start);
+    event.SetField(4, message.length() + 1, message.c_str());
 
     provider->Log(event.get());
   }
 
   // Don't increase verbosity in other log destinations.
   if (severity < provider->old_log_level_)
     return true;
 
   return false;
 }
 
 void LogEventProvider::Initialize(const GUID& provider_name) {
   LogEventProvider* provider = LogEventProvider::GetInstance();
 
   provider->set_provider_name(provider_name);
   provider->Register();
 
   // Register our message handler with logging.
-  SetLogMessageHandler(LogMessage);
+  AddLogMessageHandler(LogMessage);
 }
 
 void LogEventProvider::Uninitialize() {
   LogEventProvider::GetInstance()->Unregister();
 }
 
 void LogEventProvider::OnEventsEnabled() {
   // Grab the old log level so we can restore it later.
   old_log_level_ = GetMinLogLevel();
 
@@ skipping 13 matching lines @@
     SetMinLogLevel(TRACE_LEVEL_INFORMATION - level);
   }
 }
 
 void LogEventProvider::OnEventsDisabled() {
   // Restore the old log level.
   SetMinLogLevel(old_log_level_);
 }
 
 }  // namespace logging