Add granular file tracing.

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.
 
 // This header file defines the set of trace_event macros without specifying
 // how the events actually get collected and stored. If you need to expose trace
 // events to some other universe, you can copy-and-paste this file as well as
 // trace_event.h, modifying the macros contained there as necessary for the
 // target platform. The end result is that multiple libraries can funnel events
 // through to a shared trace event collector.
@@ skipping 524 matching lines @@
 
 #define TRACE_EVENT_SAMPLE_WITH_TID_AND_TIMESTAMP2(category_group, name,       \
                                                    thread_id, timestamp,       \
                                                    arg1_name, arg1_val,        \
                                                    arg2_name, arg2_val)        \
   INTERNAL_TRACE_EVENT_ADD_WITH_ID_TID_AND_TIMESTAMP(                          \
       TRACE_EVENT_PHASE_SAMPLE, category_group, name, 0, thread_id, timestamp, \
       TRACE_EVENT_FLAG_NONE, arg1_name, arg1_val, arg2_name, arg2_val)
 
 // ASYNC_STEP_* APIs should be only used by legacy code. New code should
-// consider using NESTABLE_ASYNC_* APIs to describe substeps within an async
+// consider using NESTABLE_ASYNC* APIs to describe substeps within an async
 // event.
 // Records a single ASYNC_BEGIN event called "name" immediately, with 0, 1 or 2
 // associated arguments. If the category is not enabled, then this
 // does nothing.
 // - category and name strings must have application lifetime (statics or
 //   literals). They may not include " chars.
 // - |id| is used to match the ASYNC_BEGIN event with the ASYNC_END event. ASYNC
 //   events are considered to match if their category_group, name and id values
 //   all match. |id| must either be a pointer or an integer value up to 64 bits.
 //   If it's a pointer, the bits will be xored with a hash of the process ID so
@@ skipping 119 matching lines @@
         arg1_name, arg1_val, arg2_name, arg2_val)
 
 // Similar to TRACE_EVENT_ASYNC_ENDx but with a custom |at| timestamp provided.
 #define TRACE_EVENT_ASYNC_END_WITH_TIMESTAMP0(category_group, \
         name, id, timestamp) \
     INTERNAL_TRACE_EVENT_ADD_WITH_ID_TID_AND_TIMESTAMP( \
         TRACE_EVENT_PHASE_ASYNC_END, category_group, name, id, \
         static_cast<int>(base::PlatformThread::CurrentId()), \
         timestamp, TRACE_EVENT_FLAG_NONE)
 
-// NESTABLE_ASYNC_* APIs are used to describe an async operation, which can
+// NESTABLE_ASYNC* APIs are used to describe an async operation, which can
 // be nested within a NESTABLE_ASYNC event and/or have inner NESTABLE_ASYNC
 // events.
 // - category and name strings must have application lifetime (statics or
 //   literals). They may not include " chars.
 // - A pair of NESTABLE_ASYNC_BEGIN event and NESTABLE_ASYNC_END event is
 //   considered as a match if their category_group, name and id all match.
 // - |id| must either be a pointer or an integer value up to 64 bits.
 //   If it's a pointer, the bits will be xored with a hash of the process ID so
 //   that the same pointer on two different processes will not collide.
 // - |id| is used to match a child NESTABLE_ASYNC event with its parent
 //   NESTABLE_ASYNC event. Therefore, events in the same nested event tree must
 //   be logged using the same id and category_group.
 //
 // Unmatched NESTABLE_ASYNC_END event will be parsed as an event that starts
 // at the first NESTABLE_ASYNC event of that id, and unmatched
 // NESTABLE_ASYNC_BEGIN event will be parsed as an event that ends at the last
 // NESTABLE_ASYNC event of that id. Corresponding warning messages for
 // unmatched events will be shown in the analysis view.
 
-// Records a single NESTABLE_ASYNC_BEGIN event called "name" immediately, with 2
-// associated arguments. If the category is not enabled, then this does nothing.
+// Records a single NESTABLE_ASYNC_BEGIN event called "name" immediately, with 0
+// or 2 associated arguments. If the category is not enabled, then this does
+// nothing.
+#define TRACE_EVENT_NESTABLE_ASYNC_BEGIN0(category_group, name, id) \
+    INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_NESTABLE_ASYNC_BEGIN, \
+        category_group, name, id, TRACE_EVENT_FLAG_NONE)
 #define TRACE_EVENT_NESTABLE_ASYNC_BEGIN2(category_group, name, id, arg1_name, \
         arg1_val, arg2_name, arg2_val) \
     INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_NESTABLE_ASYNC_BEGIN, \
         category_group, name, id, TRACE_EVENT_FLAG_NONE, arg1_name, arg1_val, \
         arg2_name, arg2_val)
 // Records a single NESTABLE_ASYNC_END event called "name" immediately, with 2
 // associated arguments. If the category is not enabled, then this does nothing.
+#define TRACE_EVENT_NESTABLE_ASYNC_END0(category_group, name, id) \
+    INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_NESTABLE_ASYNC_END, \
+        category_group, name, id, TRACE_EVENT_FLAG_NONE)
+#define TRACE_EVENT_NESTABLE_ASYNC_END1(category_group, name, id, arg1_name, \
+        arg1_val) \
+    INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_NESTABLE_ASYNC_END, \
+        category_group, name, id, TRACE_EVENT_FLAG_NONE, arg1_name, arg1_val)
 #define TRACE_EVENT_NESTABLE_ASYNC_END2(category_group, name, id, arg1_name, \
         arg1_val, arg2_name, arg2_val) \
     INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_NESTABLE_ASYNC_END, \
         category_group, name, id, TRACE_EVENT_FLAG_NONE, arg1_name, arg1_val, \
         arg2_name, arg2_val)
 // Records a single NESTABLE_ASYNC_INSTANT event called "name" immediately,
 // with 2 associated arguments. If the category is not enabled, then this
 // does nothing.
 #define TRACE_EVENT_NESTABLE_ASYNC_INSTANT2(category_group, name, id, \
         arg1_name, arg1_val, arg2_name, arg2_val) \
     INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_NESTABLE_ASYNC_INSTANT, \
         category_group, name, id, TRACE_EVENT_FLAG_NONE, arg1_name, arg1_val, \
         arg2_name, arg2_val)
 
+// Call TRACE_EVENT_NESTABLE_ASYNC_BEGIN* to set up a nestable id before calling
+// TRACE_EVENT_NESTABLE_ASYNC*. Records a nested pair of begin and end events
+// called "name" for the current scope and assocated with the id passed to
+// _BEGIN. Handles 0, 1 or 2 associated arguments. If the category is
+// not enabled, then this does nothing.
+// - category and name strings must have application lifetime (statics or
+//   literals). They may not include " chars.
+#define TRACE_EVENT_NESTABLE_ASYNC0(category_group, name, id) \
+    INTERNAL_TRACE_EVENT_ADD_SCOPED_WITH_ID( \
+        TRACE_EVENT_PHASE_NESTABLE_ASYNC_COMPLETE, category_group, name, id, \
+        TRACE_EVENT_FLAG_NONE)
+#define TRACE_EVENT_NESTABLE_ASYNC1( \
+        category_group, name, id, arg1_name, arg1_val) \
+    INTERNAL_TRACE_EVENT_ADD_SCOPED_WITH_ID( \
+        TRACE_EVENT_PHASE_NESTABLE_ASYNC_COMPLETE, category_group, name, id, \
+        TRACE_EVENT_FLAG_NONE, arg1_name, arg1_val)
+#define TRACE_EVENT_NESTABLE_ASYNC2( \
+        category_group, name, id, arg1_name, arg1_val, arg2_name, arg2_val) \
+    INTERNAL_TRACE_EVENT_ADD_SCOPED_WITH_ID( \
+        TRACE_EVENT_PHASE_NESTABLE_ASYNC_COMPLETE, category_group, name, id, \
+        TRACE_EVENT_FLAG_NONE, arg1_name, arg1_val, arg2_name, arg2_val)
+
 // Records a single FLOW_BEGIN event called "name" immediately, with 0, 1 or 2
 // associated arguments. If the category is not enabled, then this
 // does nothing.
 // - category and name strings must have application lifetime (statics or
 //   literals). They may not include " chars.
 // - |id| is used to match the FLOW_BEGIN event with the FLOW_END event. FLOW
 //   events are considered to match if their category_group, name and id values
 //   all match. |id| must either be a pointer or an integer value up to 64 bits.
 //   If it's a pointer, the bits will be xored with a hash of the process ID so
 //   that the same pointer on two different processes will not collide.
@@ skipping 282 matching lines @@
         trace_event_internal::TraceID trace_event_trace_id( \
             id, &trace_event_flags); \
         trace_event_internal::AddTraceEvent( \
             phase, INTERNAL_TRACE_EVENT_UID(category_group_enabled), \
             name, trace_event_trace_id.data(), trace_event_flags, \
             ##__VA_ARGS__); \
       } \
     } while (0)
 
 // Implementation detail: internal macro to create static category and add
+// event if the category is enabled. Also adds the end event when the scope
+// ends.
+#define INTERNAL_TRACE_EVENT_ADD_SCOPED_WITH_ID( \
+        phase, category_group, name, id, flags, ...) \
+    INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO(category_group); \
+    trace_event_internal::ScopedTracer INTERNAL_TRACE_EVENT_UID(tracer); \
+    if (INTERNAL_TRACE_EVENT_CATEGORY_GROUP_ENABLED_FOR_RECORDING_MODE()) { \
+      unsigned char trace_event_flags = flags | TRACE_EVENT_FLAG_HAS_ID; \
+      trace_event_internal::TraceID trace_event_trace_id( \
+          id, &trace_event_flags); \
+      base::trace_event::TraceEventHandle h = \
+          trace_event_internal::AddTraceEvent( \
+              phase, INTERNAL_TRACE_EVENT_UID(category_group_enabled), \
+              name, trace_event_trace_id.data(), trace_event_flags, \
+              ##__VA_ARGS__); \
+      INTERNAL_TRACE_EVENT_UID(tracer).Initialize( \
+          INTERNAL_TRACE_EVENT_UID(category_group_enabled), name, h); \
+    }
+
+// Implementation detail: internal macro to create static category and add
 // event if the category is enabled.
 #define INTERNAL_TRACE_EVENT_ADD_WITH_ID_TID_AND_TIMESTAMP(phase, \
         category_group, name, id, thread_id, timestamp, flags, ...) \
     do { \
       INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO(category_group); \
       if (INTERNAL_TRACE_EVENT_CATEGORY_GROUP_ENABLED_FOR_RECORDING_MODE()) { \
         unsigned char trace_event_flags = flags | TRACE_EVENT_FLAG_HAS_ID; \
         trace_event_internal::TraceID trace_event_trace_id( \
             id, &trace_event_flags); \
         trace_event_internal::AddTraceEventWithThreadIdAndTimestamp( \
@@ skipping 14 matching lines @@
 #define TRACE_EVENT_PHASE_BEGIN    ('B')
 #define TRACE_EVENT_PHASE_END      ('E')
 #define TRACE_EVENT_PHASE_COMPLETE ('X')
 #define TRACE_EVENT_PHASE_INSTANT  ('I')
 #define TRACE_EVENT_PHASE_ASYNC_BEGIN ('S')
 #define TRACE_EVENT_PHASE_ASYNC_STEP_INTO  ('T')
 #define TRACE_EVENT_PHASE_ASYNC_STEP_PAST  ('p')
 #define TRACE_EVENT_PHASE_ASYNC_END   ('F')
 #define TRACE_EVENT_PHASE_NESTABLE_ASYNC_BEGIN ('b')
 #define TRACE_EVENT_PHASE_NESTABLE_ASYNC_END ('e')
+#define TRACE_EVENT_PHASE_NESTABLE_ASYNC_COMPLETE ('x')
 #define TRACE_EVENT_PHASE_NESTABLE_ASYNC_INSTANT ('n')
 #define TRACE_EVENT_PHASE_FLOW_BEGIN ('s')
 #define TRACE_EVENT_PHASE_FLOW_STEP  ('t')
 #define TRACE_EVENT_PHASE_FLOW_END   ('f')
 #define TRACE_EVENT_PHASE_METADATA ('M')
 #define TRACE_EVENT_PHASE_COUNTER  ('C')
 #define TRACE_EVENT_PHASE_SAMPLE  ('P')
 #define TRACE_EVENT_PHASE_CREATE_OBJECT ('N')
 #define TRACE_EVENT_PHASE_SNAPSHOT_OBJECT ('O')
 #define TRACE_EVENT_PHASE_DELETE_OBJECT ('D')
@@ skipping 440 matching lines @@
   return AddTraceEventWithThreadIdAndTimestamp(phase, category_group_enabled,
                                                name, id, thread_id, now, flags,
                                                arg1_name, arg1_val,
                                                arg2_name, arg2_val);
 }
 
 // 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() : initialized_(false) {}

[Dan Beam, 2015/04/30 04:40:13]

forgot i did this. can revert if you want...

 
   ~ScopedTracer() {
-    if (p_data_ && *data_.category_group_enabled)
+    if (initialized_ && *data_.category_group_enabled)
       TRACE_EVENT_API_UPDATE_TRACE_EVENT_DURATION(
           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_;
+    initialized_ = true;
   }
 
  private:
   // This Data struct workaround is to avoid initializing all the members
   // in Data during construction of this object, since this object is always
   // constructed, even when tracing is disabled. If the members of Data were
   // members of this class instead, compiler warnings occur about potential
   // uninitialized accesses.
   struct Data {
     const unsigned char* category_group_enabled;
     const char* name;
     base::trace_event::TraceEventHandle event_handle;
   };
-  Data* p_data_;
+  bool initialized_;
   Data data_;
 };
 
 // Used by TRACE_EVENT_BINARY_EFFICIENTx macro. Do not use directly.
 class TRACE_EVENT_API_CLASS_EXPORT ScopedTraceBinaryEfficient {
  public:
   ScopedTraceBinaryEfficient(const char* category_group, const char* name);
   ~ScopedTraceBinaryEfficient();
 
  private:
@@ skipping 70 matching lines @@
   const char* name_;
   IDType id_;
 
   DISALLOW_COPY_AND_ASSIGN(TraceScopedTrackableObject);
 };
 
 }  // namespace trace_event
 }  // namespace base
 
 #endif  // BASE_TRACE_EVENT_TRACE_EVENT_H_