Add NESTABLE_ASYNC APIs to Tracing

base/debug/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 492 matching lines @@
         category_group, name, id, TRACE_EVENT_FLAG_NONE, \
         value1_name, static_cast<int>(value1_val), \
         value2_name, static_cast<int>(value2_val))
 #define TRACE_COPY_COUNTER_ID2(category_group, name, id, value1_name, \
         value1_val, value2_name, value2_val) \
     INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_COUNTER, \
         category_group, name, id, TRACE_EVENT_FLAG_COPY, \
         value1_name, static_cast<int>(value1_val), \
         value2_name, static_cast<int>(value2_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
+// 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
 //   that the same pointer on two different processes will not collide.
@@ skipping 103 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
+// 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.
+// - |id| is used to match the NESTABLE_ASYNC_BEGIN event with the
+//   NESTABLE_ASYNC_END event. 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.
+//
+// Unmatched NESTABLE_ASYNC_END event will be parsed as an instant event,
+// and unmatched NESTABLE_ASYNC_BEGIN event will be parsed as an event that
+// ends at the last NESTABLE_ASYNC_END event of that |id|.
+
+// Records a single NESTABLE_ASYNC_BEGIN event called "name" immediately, with 2
+// associated arguments. If the category is not enabled, then this does nothing.
+#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_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)
+
 // 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 309 matching lines @@
 
 // Phase indicates the nature of an event entry. E.g. part of a begin/end pair.
 #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_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 550 matching lines @@
   const char* name_;
   IDType id_;
 
   DISALLOW_COPY_AND_ASSIGN(TraceScopedTrackableObject);
 };
 
 } // namespace debug
 } // namespace base
 
 #endif /* BASE_DEBUG_TRACE_EVENT_H_ */