Tracing pre-filtering

base/trace_event/trace_event.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_TRACE_EVENT_TRACE_EVENT_H_
 #define BASE_TRACE_EVENT_TRACE_EVENT_H_
 
 // This header file defines implementation details of how the trace macros in
 // trace_event_common.h collect and store trace events. Anything not
 // implementation-specific should go in trace_event_common.h instead of here.
@@ skipping 60 matching lines @@
 
 #define TRACE_EVENT_API_CURRENT_THREAD_ID \
   static_cast<int>(base::PlatformThread::CurrentId())
 
 #define INTERNAL_TRACE_EVENT_CATEGORY_GROUP_ENABLED_FOR_RECORDING_MODE() \
   UNLIKELY(*INTERNAL_TRACE_EVENT_UID(category_group_enabled) &           \
            (base::trace_event::TraceLog::ENABLED_FOR_RECORDING |         \
             base::trace_event::TraceLog::ENABLED_FOR_EVENT_CALLBACK |    \
             base::trace_event::TraceLog::ENABLED_FOR_ETW_EXPORT))
 
+#define INTERNAL_TRACE_EVENT_CATEGORY_GROUP_ENABLED_FOR_FILTERING_MODE( \
+    category_group_enabled)                                             \
+  UNLIKELY(category_group_enabled&                                      \
+               base::trace_event::TraceLog::ENABLED_FOR_FILTERING)

[shatch, 2016/08/15 21:25:47]

nit: indentation seems off here

[oystein (OOO til 10th of July), 2016/08/16 22:17:52]

Yeah it looks weird, but I think it's actually correct; second line's four
spaces intended from the start of the statement inside of the UNLIKELY(

+
 ////////////////////////////////////////////////////////////////////////////////
 // Implementation specific tracing API definitions.
 
 // Get a pointer to the enabled state of the given trace category. Only
 // long-lived literal strings should be given as the category group. The
 // returned pointer can be held permanently in a local static for example. If
 // the unsigned char is non-zero, tracing is enabled. If tracing is enabled,
 // TRACE_EVENT_API_ADD_TRACE_EVENT can be called. It's OK if tracing is disabled
 // between the load of the tracing state and the call to
 // TRACE_EVENT_API_ADD_TRACE_EVENT, because this flag only provides an early out
@@ skipping 87 matching lines @@
       ->AddTraceEventWithThreadIdAndTimestamp
 
 // Set the duration field of a COMPLETE trace event.
 // void TRACE_EVENT_API_UPDATE_TRACE_EVENT_DURATION(
 //     const unsigned char* category_group_enabled,
 //     const char* name,
 //     base::trace_event::TraceEventHandle id)
 #define TRACE_EVENT_API_UPDATE_TRACE_EVENT_DURATION \
     base::trace_event::TraceLog::GetInstance()->UpdateTraceEventDuration
 
+// Call EndEvent on the filter for a filtered event.
+// void TRACE_EVENT_API_UPDATE_TRACE_EVENT_DURATION(
+//     const unsigned char* category_group_enabled,
+//     const char* name,
+//     base::trace_event::TraceEventHandle id)
+#define TRACE_EVENT_API_END_FILTERED_EVENT \
+  base::trace_event::TraceLog::GetInstance()->EndFilteredEvent
+
 // Adds a metadata event to the trace log. The |AppendValueAsTraceFormat| method
 // on the convertable value will be called at flush time.
 // TRACE_EVENT_API_ADD_METADATA_EVENT(
 //     const unsigned char* category_group_enabled,
 //     const char* event_name,
 //     const char* arg_name,
 //     std::unique_ptr<ConvertableToTraceFormat> arg_value)
 #define TRACE_EVENT_API_ADD_METADATA_EVENT \
     trace_event_internal::AddMetadataEvent
 
@@ skipping 794 matching lines @@
       arg_values, nullptr, TRACE_EVENT_FLAG_NONE);
 }
 
 // Used by TRACE_EVENTx macros. Do not use directly.
 class TRACE_EVENT_API_CLASS_EXPORT ScopedTracer {
  public:
   // Note: members of data_ intentionally left uninitialized. See Initialize.
   ScopedTracer() : p_data_(NULL) {}
 
   ~ScopedTracer() {
-    if (p_data_ && *data_.category_group_enabled)
+    if (p_data_ && *data_.category_group_enabled) {
       TRACE_EVENT_API_UPDATE_TRACE_EVENT_DURATION(
           data_.category_group_enabled, data_.name, data_.event_handle);
+      if (INTERNAL_TRACE_EVENT_CATEGORY_GROUP_ENABLED_FOR_FILTERING_MODE(
+              *data_.category_group_enabled)) {
+        TRACE_EVENT_API_END_FILTERED_EVENT(data_.category_group_enabled,
+                                           data_.name, data_.event_handle);
+      }
+    }
   }
 
   void Initialize(const unsigned char* category_group_enabled,
                   const char* name,
                   base::trace_event::TraceEventHandle event_handle) {
     data_.category_group_enabled = category_group_enabled;
     data_.name = name;
     data_.event_handle = event_handle;
     p_data_ = &data_;
   }
@@ skipping 93 matching lines @@
   const char* name_;
   IDType id_;
 
   DISALLOW_COPY_AND_ASSIGN(TraceScopedTrackableObject);
 };
 
 }  // namespace trace_event
 }  // namespace base
 
 #endif  // BASE_TRACE_EVENT_TRACE_EVENT_H_