* Change output of trace_event log to JSON to enable easier integration with ...

base/trace_event.cc

 // Copyright (c) 2006-2008 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/trace_event.h"
 
 #include "base/file_util.h"
 #include "base/path_service.h"
 #include "base/platform_thread.h"
 #include "base/process_util.h"
 #include "base/string_util.h"
 #include "base/time.h"
 
 #define USE_UNRELIABLE_NOW
 
 namespace base {
 
 static const char* kEventTypeNames[] = {
   "BEGIN",
   "END",
   "INSTANT"
 };
 
 static const wchar_t* kLogFileName = L"trace_%d.log";
 
 TraceLog::TraceLog() : enabled_(false), log_file_(NULL) {
+  ProcessHandle proc = process_util::GetCurrentProcessHandle();
+  process_metrics_.reset(process_util::ProcessMetrics::CreateProcessMetrics(proc));
 }
 
 TraceLog::~TraceLog() {
   Stop();
 }
 
 // static
 bool TraceLog::IsTracing() {
   TraceLog* trace = Singleton<TraceLog>::get();
   return trace->enabled_;
 }
 
 // static
 bool TraceLog::StartTracing() {
   TraceLog* trace = Singleton<TraceLog>::get();
   return trace->Start();
 }
 
 bool TraceLog::Start() {
   if (enabled_)
     return true;
   enabled_ = OpenLogFile();
-  if (enabled_)
+  if (enabled_) {
+    Log("var raw_trace_events = [\r\n");
     trace_start_time_ = TimeTicks::Now();
+    timer_.Start(TimeDelta::FromMilliseconds(250), this, &TraceLog::Heartbeat);
+  }
   return enabled_;
 }
 
 // static
 void TraceLog::StopTracing() {
   TraceLog* trace = Singleton<TraceLog>::get();
   return trace->Stop();
 }
 
 void TraceLog::Stop() {
   if (enabled_) {
     enabled_ = false;
+    Log("];\r\n");
     CloseLogFile();
+    timer_.Stop();
   }
 }
 
+void TraceLog::Heartbeat() {
+  std::string cpu = StringPrintf("%d", process_metrics_->GetCPUUsage());
+  TRACE_EVENT_INSTANT("heartbeat.cpu", 0, cpu);
+}
+
 void TraceLog::CloseLogFile() {
   if (log_file_) {
 #if defined(OS_WIN)
     ::CloseHandle(log_file_);
 #elif defined(OS_POSIX)
     fclose(log_file_);
 #endif
   }
 }
 
@@ skipping 21 matching lines @@
 #elif defined(OS_POSIX)
   log_file_ = fopen(WideToUTF8(log_file_name).c_str(), "a");
   if (log_file_ == NULL)
     return false;
 #endif
   return true;
 }
 
 void TraceLog::Trace(const std::string& name, 
                      EventType type,
-                     void* id,
+                     const void* id,
                      const std::wstring& extra,
                      const char* file, 
                      int line) {
   if (!enabled_)
     return;
   Trace(name, type, id, WideToUTF8(extra), file, line);
 }
 
 void TraceLog::Trace(const std::string& name, 
                      EventType type,
-                     void* id,
+                     const void* id,
                      const std::string& extra,
                      const char* file, 
                      int line) {
   if (!enabled_)
     return;
 
 #ifdef USE_UNRELIABLE_NOW
   TimeTicks tick = TimeTicks::UnreliableHighResNow();
 #else
   TimeTicks tick = TimeTicks::Now();
 #endif
   TimeDelta delta = tick - trace_start_time_;
   int64 usec = delta.InMicroseconds();
   std::string msg = 
-    StringPrintf("%I64d 0x%lx:0x%lx %s %s [0x%lx %s] <%s:%d>\r\n",
-                 usec,
+    StringPrintf("{'pid':'0x%lx', 'tid':'0x%lx', 'type':'%s', "
+                 "'name':'%s', 'id':'0x%lx', 'extra':'%s', 'file':'%s', "
+                 "'line_number':'%d', 'usec_begin': %I64d},\r\n", 
                  process_util::GetCurrentProcId(),
                  PlatformThread::CurrentId(),
                  kEventTypeNames[type],
                  name.c_str(),
                  id,
                  extra.c_str(),
                  file, 
-                 line);
+                 line,
+                 usec);
 
   Log(msg);
 }
 
 void TraceLog::Log(const std::string& msg) {
   AutoLock lock(file_lock_);
 
 #if defined (OS_WIN)
   SetFilePointer(log_file_, 0, 0, SEEK_END);
   DWORD num;
   WriteFile(log_file_, (void*)msg.c_str(), (DWORD)msg.length(), &num, NULL);
 #elif defined (OS_POSIX)
   fprintf(log_file_, "%s", msg.c_str());
 #endif
 }
 
 } // namespace base