Initial pass at simple event tracing. I added a few traces to tcp_socket and test_shell to get an idea of what a simple trace might look like.

Here's a sample output line:
11:24:19.660604 0x1e278:0x1e24c BEGIN url.load [0x5 http://mail.google.com/mail/] <E:\src\cr\src\webkit\tools\test_shell\test_webview_delegate.cc:189>

format is:hh:mm:ss.us pid:tid TYPE NAME [id, extra] <file:line>


git-svn-id: svn://svn.chromium.org/chrome/trunk/src@1641 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 132 insertions, 0 deletions

diff --git a/base/trace_event.h b/base/trace_event.h
new file mode 100644
index 0000000..b01a71e
--- /dev/null
+++ b/base/trace_event.h
@@ -0,0 +1,132 @@
+// 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.
+
+// Trace events to track application performance.  Events consist of a name
+// a type (BEGIN, END or INSTANT), a tracking id and extra string data.
+// In addition, the current process id, thread id, a timestamp down to the
+// microsecond and a file and line number of the calling location.
+//
+// The current implementation logs these events into a log file of the form
+// trace_<pid>.log where it's designed to be post-processed to generate a
+// trace report.  In the future, it may use another mechansim to facilitate
+// real-time analysis.
+
+#ifndef BASE_TRACE_EVENT_H_
+#define BASE_TRACE_EVENT_H_
+
+#include "build/build_config.h"
+
+#if defined(OS_WIN)
+#include <windows.h>
+#endif
+
+#include <string>
+
+#include "base/lock.h"
+#include "base/singleton.h"
+#include "base/time.h"
+
+// Use the following macros rather than using the TraceLog class directly as the
+// underlying implementation may change in the future.  Here's a sample usage:
+// TRACE_EVENT_BEGIN("v8.run", documentId, scriptLocation);
+// RunScript(script);
+// TRACE_EVENT_END("v8.run", documentId, scriptLocation);
+
+#if defined(OS_WIN)
+
+// Record that an event (of name, id) has begun.  All BEGIN events should have
+// corresponding END events with a matching (name, id).
+#define TRACE_EVENT_BEGIN(name, id, extra) \
+  Singleton<base::TraceLog>::get()->Trace(name, \
+                                          base::TraceLog::EVENT_BEGIN, \
+                                          reinterpret_cast<void*>(id), \
+                                          extra, \
+                                          __FILE__, \
+                                          __LINE__)
+
+// Record that an event (of name, id) has ended.  All END events should have
+// corresponding BEGIN events with a matching (name, id).
+#define TRACE_EVENT_END(name, id, extra) \
+  Singleton<base::TraceLog>::get()->Trace(name, \
+                                          base::TraceLog::EVENT_END, \
+                                          reinterpret_cast<void*>(id), \
+                                          extra, \
+                                          __FILE__, \
+                                          __LINE__)
+
+// Record that an event (of name, id) with no duration has happened.
+#define TRACE_EVENT_INSTANT(name, id, extra) \
+  Singleton<base::TraceLog>::get()->Trace(name, \
+                                          base::TraceLog::EVENT_INSTANT, \
+                                          reinterpret_cast<void*>(id), \
+                                          extra, \
+                                          __FILE__, \
+                                          __LINE__)
+#else
+// TODO(erikkay): temporarily disable the macros on other platforms
+// until I can add the files to the other platform build files.
+#define TRACE_EVENT_BEGIN(name, id, extra)
+#define TRACE_EVENT_END(name, id, extra)
+#define TRACE_EVENT_INSTANT(name, id, extra)
+#endif
+
+#if defined(OS_WIN)
+typedef HANDLE FileHandle;
+#else
+typedef FILE* FileHandle;
+#endif
+
+namespace base {
+
+class TraceLog {
+ public:
+  enum EventType {
+    EVENT_BEGIN,
+    EVENT_END,
+    EVENT_INSTANT
+  };
+
+  // Is tracing currently enabled.
+  static bool IsTracing();
+  // Start logging trace events.
+  static bool StartTracing();
+  // Stop logging trace events.
+  static void StopTracing();
+
+  // Log a trace event of (name, type, id) with the optional extra string.
+  void Trace(const std::string& name, 
+             EventType type,
+             void* id,
+             const std::wstring& extra,
+             const char* file, 
+             int line);
+  void Trace(const std::string& name, 
+             EventType type,
+             void* id,
+             const std::string& extra,
+             const char* file, 
+             int line);
+
+ private:
+  // This allows constructor and destructor to be private and usable only
+  // by the Singleton class.
+  friend struct DefaultSingletonTraits<TraceLog>;
+
+  TraceLog();
+  ~TraceLog();
+  bool OpenLogFile();
+  void CloseLogFile();
+  bool Start();
+  void Stop();
+  void Log(const std::string& msg);
+
+  bool enabled_;
+  FileHandle log_file_;
+  Lock file_lock_;
+  TimeTicks trace_start_time_;
+};
+
+} // namespace base
+
+#endif // BASE_TRACE_EVENT_H_