Adding raw tracing to trace framework.

base/debug/trace_event.h

Index: base/debug/trace_event.h
diff --git a/base/debug/trace_event.h b/base/debug/trace_event.h
index 07863ad997b3d56fd46f8033a0775f08b56b279a..1b1e5fd700e43589f4d25bd37aa2db8622fe5787 100644
--- a/base/debug/trace_event.h
+++ b/base/debug/trace_event.h
@@ -265,6 +265,19 @@
         category, name, TRACE_EVENT_FLAG_COPY, arg1_name, arg1_val, \
         arg2_name, arg2_val)
 
+// Similar to TRACE_EVENT_BEGINx but with a custom |at| timestamp provided.
+// - |id| is used to match the _BEGIN event with the _END event.
+//   Events are considered to match if their category, 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.
+#define TRACE_EVENT_BEGIN_EXPLICIT0(category, name, tid, id, ts) \
+    INTERNAL_TRACE_EVENT_ADD_EXPLICIT(TRACE_EVENT_PHASE_ASYNC_BEGIN, \
+        category, name, tid, ts, id, TRACE_EVENT_FLAG_NONE)
+#define TRACE_EVENT_COPY_BEGIN_EXPLICIT0(category, name, tid, id, ts) \
+    INTERNAL_TRACE_EVENT_ADD_EXPLICIT(TRACE_EVENT_PHASE_ASYNC_BEGIN, \
+        category, name, tid, ts, id, TRACE_EVENT_FLAG_COPY)
+
 // Records a single END event for "name" immediately. If the category
 // is not enabled, then this does nothing.
 // - category and name strings must have application lifetime (statics or
@@ -292,6 +305,19 @@
         category, name, TRACE_EVENT_FLAG_COPY, arg1_name, arg1_val, \
         arg2_name, arg2_val)
 
+// Similar to TRACE_EVENT_ENDx but with a custom |at| timestamp provided.
+// - |id| is used to match the _BEGIN event with the _END event.
+//   Events are considered to match if their category, 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.
+#define TRACE_EVENT_END_EXPLICIT0(category, name, tid, id, ts) \
+    INTERNAL_TRACE_EVENT_ADD_EXPLICIT(TRACE_EVENT_PHASE_ASYNC_END, \
+        category, name, tid, ts, id, TRACE_EVENT_FLAG_NONE)
+#define TRACE_EVENT_COPY_END_EXPLICIT0(category, name, tid, id, ts) \
+    INTERNAL_TRACE_EVENT_ADD_EXPLICIT(TRACE_EVENT_PHASE_ASYNC_END, \
+        category, name, tid, ts, id, TRACE_EVENT_FLAG_COPY)
+
 // Time threshold event:
 // Only record the event if the duration is greater than the specified
 // threshold_us (time in microseconds).
@@ -597,6 +623,25 @@
 #define TRACE_EVENT_API_ADD_TRACE_EVENT \
     base::debug::TraceLog::GetInstance()->AddTraceEvent
 
+// Add a trace event to the platform tracing system. Returns thresholdBeginId
+// for use in a corresponding end TRACE_EVENT_API_ADD_TRACE_EVENT_EXPLICIT call.
+// int TRACE_EVENT_API_ADD_TRACE_EVENT_EXPLICIT(
+//                    char phase,
+//                    const unsigned char* category_enabled,
+//                    const char* name,
+//                    int thread_id,
+//                    int64 timestamp,
+//                    unsigned long long id,
+//                    int num_args,
+//                    const char** arg_names,
+//                    const unsigned char* arg_types,
+//                    const unsigned long long* arg_values,
+//                    int threshold_begin_id,
+//                    long long threshold,
+//                    unsigned char flags)
+#define TRACE_EVENT_API_ADD_TRACE_EVENT_EXPLICIT \

[nduca, 2012/12/11 19:40:58]

How about always providing the tid? And always providing the ts? It'll be more
edits to the header but it keeps us to one entry point which was a design goal
believe it or not.

[dsinclair, 2012/12/14 16:08:20]

Done.

+    base::debug::TraceLog::GetInstance()->AddTraceEventExplicit
+
 ////////////////////////////////////////////////////////////////////////////////
 
 // Implementation detail: trace event macros create temporary variables
@@ -638,6 +683,23 @@
       } \
     } while (0)
 
+// Implementation detail: internal macro to create static category and add
+// event if the category is enabled.
+#define INTERNAL_TRACE_EVENT_ADD_EXPLICIT(phase, category, name, tid, \
+        ts, id, flags, ...) \
+    do { \
+      INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO(category); \
+      if (*INTERNAL_TRACE_EVENT_UID(catstatic)) { \
+        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::AddTraceEventExplicit( \
+            phase, INTERNAL_TRACE_EVENT_UID(catstatic), \
+            name, tid, ts, trace_event_trace_id.data(), \
+            trace_event_flags, ##__VA_ARGS__); \
+      } \
+    } while (0)
+
 // Implementation detail: internal macro to create static category and add begin
 // event if the category is enabled. Also adds the end event when the scope
 // ends.
@@ -930,6 +992,18 @@ static inline int AddTraceEvent(char phase,
       kNoThreshholdBeginId, kNoThresholdValue, flags);
 }
 
+static inline int AddTraceEventExplicit(char phase,
+                                        const unsigned char* category_enabled,
+                                        const char* name,
+                                        int thread_id,
+                                        int64 timestamp,
+                                        unsigned long long id,
+                                        unsigned char flags) {
+  return TRACE_EVENT_API_ADD_TRACE_EVENT_EXPLICIT(
+      phase, category_enabled, name, thread_id, timestamp, id, kZeroNumArgs,
+      NULL, NULL, NULL, kNoThreshholdBeginId, kNoThresholdValue, flags);
+}
+
 // Used by TRACE_EVENTx macro. Do not use directly.
 class BASE_EXPORT TraceEndOnScopeClose {
  public: