Revert of Revert "Revert 237280 "Remove TraceController""

base/debug/trace_event_impl.h

 // Copyright (c) 2012 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.
 
 
 #ifndef BASE_DEBUG_TRACE_EVENT_IMPL_H_
 #define BASE_DEBUG_TRACE_EVENT_IMPL_H_
 
 #include <stack>
 #include <string>
@@ skipping 336 matching lines @@
 
   StringList included_;
   StringList disabled_;
   StringList excluded_;
 };
 
 class TraceSamplingThread;
 
 class BASE_EXPORT TraceLog {
  public:
+  // Notification is a mask of one or more of the following events.
+  enum Notification {
+    // The trace buffer does not flush dynamically, so when it fills up,
+    // subsequent trace events will be dropped. This callback is generated when
+    // the trace buffer is full. The callback must be thread safe.
+    TRACE_BUFFER_FULL = 1 << 0,
+    // A subscribed trace-event occurred.
+    EVENT_WATCH_NOTIFICATION = 1 << 1
+  };
+
   // Options determines how the trace buffer stores data.
   enum Options {
     // Record until the trace buffer is full.
     RECORD_UNTIL_FULL = 1 << 0,
 
     // Record until the user ends the trace. The trace buffer is a fixed size
     // and we use it as a ring buffer during recording.
     RECORD_CONTINUOUSLY = 1 << 1,
 
     // Enable the sampling profiler in the recording mode.
@@ skipping 11 matching lines @@
   // The TRACE_EVENT macros should only use the value as a bool.
   enum CategoryGroupEnabledFlags {
     // Normal enabled flag for category groups enabled by SetEnabled().
     ENABLED_FOR_RECORDING = 1 << 0,
     // Category group enabled by SetEventCallbackEnabled().
     ENABLED_FOR_EVENT_CALLBACK = 1 << 1,
   };
 
   static TraceLog* GetInstance();
 
+  // Convert the given string to trace options. Defaults to RECORD_UNTIL_FULL if
+  // the string does not provide valid options.
+  static Options TraceOptionsFromString(const std::string& str);
+
   // Get set of known category groups. This can change as new code paths are
   // reached. The known category groups are inserted into |category_groups|.
   void GetKnownCategoryGroups(std::vector<std::string>* category_groups);
 
   // Retrieves a copy (for thread-safety) of the current CategoryFilter.
   CategoryFilter GetCurrentCategoryFilter();
 
   Options trace_options() const {
     return static_cast<Options>(subtle::NoBarrier_Load(&trace_options_));
   }
@@ skipping 33 matching lines @@
 
     // Called just after the tracing system disables, outside of the |lock_|.
     // TraceLog::IsEnabled() is false at this point.
     virtual void OnTraceLogDisabled() = 0;
   };
   void AddEnabledStateObserver(EnabledStateObserver* listener);
   void RemoveEnabledStateObserver(EnabledStateObserver* listener);
   bool HasEnabledStateObserver(EnabledStateObserver* listener) const;
 
   float GetBufferPercentFull() const;
-  bool BufferIsFull() const;
+
+  // Set the thread-safe notification callback. The callback can occur at any
+  // time and from any thread. WARNING: It is possible for the previously set
+  // callback to be called during OR AFTER a call to SetNotificationCallback.
+  // Therefore, the target of the callback must either be a global function,
+  // ref-counted object or a LazyInstance with Leaky traits (or equivalent).
+  typedef base::Callback<void(int)> NotificationCallback;
+  void SetNotificationCallback(const NotificationCallback& cb);
 
   // Not using base::Callback because of its limited by 7 parameters.
   // Also, using primitive type allows directly passing callback from WebCore.
   // WARNING: It is possible for the previously set callback to be called
   // after a call to SetEventCallbackEnabled() that replaces or a call to
   // SetEventCallbackDisabled() that disables the callback.
   // This callback may be invoked on any thread.
   // For TRACE_EVENT_PHASE_COMPLETE events, the client will still receive pairs
   // of TRACE_EVENT_PHASE_BEGIN and TRACE_EVENT_PHASE_END events to keep the
   // interface simple.
@@ skipping 67 matching lines @@
                                const char* extra);
   static void AddTraceEventEtw(char phase,
                                const char* category_group,
                                const void* id,
                                const std::string& extra);
 
   void UpdateTraceEventDuration(const unsigned char* category_group_enabled,
                                 const char* name,
                                 TraceEventHandle handle);
 
-  // For every matching event, the callback will be called.
-  typedef base::Callback<void()> WatchEventCallback;
+  // For every matching event, a notification will be fired. NOTE: the
+  // notification will fire for each matching event that has already occurred
+  // since tracing was started (including before tracing if the process was
+  // started with tracing turned on).
   void SetWatchEvent(const std::string& category_name,
-                     const std::string& event_name,
-                     const WatchEventCallback& callback);
+                     const std::string& event_name);
   // Cancel the watch event. If tracing is enabled, this may race with the
   // watch event notification firing.
   void CancelWatchEvent();
 
   int process_id() const { return process_id_; }
 
   // Exposed for unittesting:
 
   void WaitSamplingEventForTesting();
 
@@ skipping 48 matching lines @@
   friend struct DefaultSingletonTraits<TraceLog>;
 
   // Enable/disable each category group based on the current enabled_,
   // category_filter_, event_callback_ and event_callback_category_filter_.
   // Enable the category group if enabled_ is true and category_filter_ matches
   // the category group, or event_callback_ is not null and
   // event_callback_category_filter_ matches the category group.
   void UpdateCategoryGroupEnabledFlags();
   void UpdateCategoryGroupEnabledFlag(int category_index);
 
+  // Helper class for managing notification_thread_count_ and running
+  // notification callbacks. This is very similar to a reader-writer lock, but
+  // shares the lock with TraceLog and manages the notification flags.
+  class NotificationHelper {
+   public:
+    inline explicit NotificationHelper(TraceLog* trace_log);
+    inline ~NotificationHelper();
+
+    // Called only while TraceLog::lock_ is held. This ORs the given
+    // notification with any existing notifications.
+    inline void AddNotificationWhileLocked(int notification);
+
+    // Called only while TraceLog::lock_ is NOT held. If there are any pending
+    // notifications from previous calls to AddNotificationWhileLocked, this
+    // will call the NotificationCallback.
+    inline void SendNotificationIfAny();
+
+   private:
+    TraceLog* trace_log_;
+    NotificationCallback callback_copy_;
+    int notification_;
+  };
+
   class ThreadLocalEventBuffer;
   class OptionalAutoLock;
 
   TraceLog();
   ~TraceLog();
   const unsigned char* GetCategoryGroupEnabledInternal(const char* name);
   void AddMetadataEventsWhileLocked();
 
   TraceBuffer* trace_buffer() const { return logged_events_.get(); }
   TraceBuffer* CreateTraceBuffer();
 
   void OutputEventToConsoleWhileLocked(unsigned char phase,
                                        const TimeTicks& timestamp,
                                        TraceEvent* trace_event);
 
-  TraceEvent* AddEventToThreadSharedChunkWhileLocked(TraceEventHandle* handle,
-                                                     bool check_buffer_is_full);
-  void CheckIfBufferIsFullWhileLocked();
-  void SetDisabledWhileLocked();
+  TraceEvent* AddEventToThreadSharedChunkWhileLocked(
+      NotificationHelper* notifier, TraceEventHandle* handle);
+  void CheckIfBufferIsFullWhileLocked(NotificationHelper* notifier);
 
   TraceEvent* GetEventByHandleInternal(TraceEventHandle handle,
                                        OptionalAutoLock* lock);
 
   // |generation| is used in the following callbacks to check if the callback
   // is called for the flush of the current |logged_events_|.
   void FlushCurrentThread(int generation);
   void ConvertTraceEventsToTraceFormat(scoped_ptr<TraceBuffer> logged_events,
       const TraceLog::OutputCallback& flush_output_callback);
   void FinishFlush(int generation);
@@ skipping 10 matching lines @@
   }
 
   TimeTicks OffsetNow() const {
     return OffsetTimestamp(TimeTicks::NowFromSystemTraceTime());
   }
   TimeTicks OffsetTimestamp(const TimeTicks& timestamp) const {
     return timestamp - time_offset_;
   }
 
   // This lock protects TraceLog member accesses from arbitrary threads.
-  mutable Lock lock_;
+  Lock lock_;
   int locked_line_;
   bool enabled_;
   int num_traces_recorded_;
+  subtle::AtomicWord /* bool */ buffer_is_full_;
+  NotificationCallback notification_callback_;
   scoped_ptr<TraceBuffer> logged_events_;
   subtle::AtomicWord /* EventCallback */ event_callback_;
   bool dispatching_to_observer_list_;
   std::vector<EnabledStateObserver*> enabled_state_observer_list_;
 
   std::string process_name_;
   base::hash_map<int, std::string> process_labels_;
   int process_sort_index_;
   base::hash_map<int, int> thread_sort_indices_;
   base::hash_map<int, std::string> thread_names_;
 
   // The following two maps are used only when ECHO_TO_CONSOLE.
   base::hash_map<int, std::stack<TimeTicks> > thread_event_start_times_;
   base::hash_map<std::string, int> thread_colors_;
 
   // XORed with TraceID to make it unlikely to collide with other processes.
   unsigned long long process_id_hash_;
 
   int process_id_;
 
   TimeDelta time_offset_;
 
   // Allow tests to wake up when certain events occur.
-  WatchEventCallback watch_event_callback_;
   subtle::AtomicWord /* const unsigned char* */ watch_category_;
   std::string watch_event_name_;
 
   subtle::AtomicWord /* Options */ trace_options_;
 
   // Sampling thread handles.
   scoped_ptr<TraceSamplingThread> sampling_thread_;
   PlatformThreadHandle sampling_thread_handle_;
 
   CategoryFilter category_filter_;
@@ skipping 17 matching lines @@
   scoped_refptr<MessageLoopProxy> flush_message_loop_proxy_;
   subtle::AtomicWord generation_;
 
   DISALLOW_COPY_AND_ASSIGN(TraceLog);
 };
 
 }  // namespace debug
 }  // namespace base
 
 #endif  // BASE_DEBUG_TRACE_EVENT_IMPL_H_