Add ability for embedder to provide private timeline trace data

runtime/vm/dart_api_impl.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "include/dart_api.h"
 #include "include/dart_mirrors_api.h"
 #include "include/dart_native_api.h"
 
 #include "platform/assert.h"
 #include "lib/stacktrace.h"
@@ skipping 5872 matching lines @@
     cursor += remaining;
     remaining -= remaining;
   }
   ASSERT(cursor == output_length);
   ASSERT(remaining == 0);
 }
 
 
 static bool StreamTraceEvents(Dart_StreamConsumer consumer,
                               void* user_data,
-                              JSONStream* js) {
+                              JSONStream* js,
+                              bool insert_comma) {
   ASSERT(js != NULL);
   // Steal output from JSONStream.
   char* output = NULL;
   intptr_t output_length = 0;
   js->Steal(const_cast<const char**>(&output), &output_length);
   if (output_length < 3) {
     // Empty JSON array.
     free(output);
     return false;
   }
   // We want to send the JSON array without the leading '[' or trailing ']'
   // characters.
   ASSERT(output[0] == '[');
   ASSERT(output[output_length - 1] == ']');
   // Replace the ']' with the null character.
   output[output_length - 1] = '\0';
-  // We are skipping the '['.
-  output_length -= 1;
-
-  // Start the stream.
-  StartStreamToConsumer(consumer, user_data, "timeline");
+  char* start = &output[1];
+  if (insert_comma) {
+    output[0] = ',';
+    start = &output[0];
+  } else {
+    // We are skipping the '['.
+    output_length -= 1;
+  }
 
   DataStreamToConsumer(consumer,
                        user_data,
-                       &output[1],
+                       start,
                        output_length,
                        "timeline");
 
   // We stole the JSONStream's output buffer, free it.
   free(output);
 
-  // Finish the stream.
-  FinishStreamToConsumer(consumer, user_data, "timeline");
   return true;
 }
 
 
 DART_EXPORT bool Dart_TimelineGetTrace(Dart_StreamConsumer consumer,
                                        void* user_data) {
   if (!FLAG_support_timeline) {
     return false;
   }
   Isolate* isolate = Isolate::Current();
   CHECK_ISOLATE(isolate);
   if (consumer == NULL) {
     return false;
   }
   TimelineEventRecorder* timeline_recorder = Timeline::recorder();
   if (timeline_recorder == NULL) {
     // Nothing has been recorded.
     return false;
   }
   Thread* T = Thread::Current();
   StackZone zone(T);
   Timeline::ReclaimCachedBlocksFromThreads();
   JSONStream js;
   IsolateTimelineEventFilter filter(isolate->main_port());
   timeline_recorder->PrintTraceEvent(&js, &filter);
-  return StreamTraceEvents(consumer, user_data, &js);
+  StartStreamToConsumer(consumer, user_data, "timeline");
+  bool success = StreamTraceEvents(consumer, user_data, &js, false);
+  FinishStreamToConsumer(consumer, user_data, "timeline");
+  return success;
 }
 
 
+DART_EXPORT void Dart_SetEmbedderTimelineCallbacks(
+    Dart_EmbedderTimelineStartRecording start_recording,
+    Dart_EmbedderTimelineStopRecording stop_recording,
+    Dart_EmbedderTimelineGetTimeline get_timeline) {
+  Timeline::set_start_recording_cb(start_recording);
+  Timeline::set_stop_recording_cb(stop_recording);
+  Timeline::set_get_timeline_cb(get_timeline);
+}
+
+
 DART_EXPORT bool Dart_GlobalTimelineGetTrace(Dart_StreamConsumer consumer,
                                              void* user_data) {
   if (!FLAG_support_timeline) {
     return false;
   }
   // To support various embedders, it must be possible to call this function
   // from a thread for which we have not entered an Isolate and set up a Thread
   // TLS object. Therefore, a Zone may not be available, a StackZone cannot be
   // created, and no ZoneAllocated objects can be allocated.
   if (consumer == NULL) {
     return false;
   }
   TimelineEventRecorder* timeline_recorder = Timeline::recorder();
   if (timeline_recorder == NULL) {
     // Nothing has been recorded.
     return false;
   }
   Timeline::ReclaimCachedBlocksFromThreads();
   JSONStream js;
   TimelineEventFilter filter;
   timeline_recorder->PrintTraceEvent(&js, &filter);
-  return StreamTraceEvents(consumer, user_data, &js);
+  StartStreamToConsumer(consumer, user_data, "timeline");
+  bool success = false;
+  if (Timeline::get_get_timeline_cb() != NULL) {
+    if (Timeline::get_get_timeline_cb()(consumer, user_data)) {
+      success = true;
+    }
+  }
+  if (StreamTraceEvents(consumer, user_data, &js, success)) {
+    success = true;
+  }
+  FinishStreamToConsumer(consumer, user_data, "timeline");
+  return success;
 }
 
 
 DART_EXPORT Dart_Handle Dart_TimelineDuration(const char* label,
                                               int64_t start_micros,
                                               int64_t end_micros) {
   if (!FLAG_support_timeline) {
     return Api::Success();
   }
   Isolate* isolate = Isolate::Current();
@@ skipping 104 matching lines @@
   TimelineStream* stream = isolate->GetEmbedderStream();
   ASSERT(stream != NULL);
   TimelineEvent* event = stream->StartEvent();
   if (event != NULL) {
     event->AsyncEnd(label, async_id);
     event->Complete();
   }
   return Api::Success();
 }
 
-
 // The precompiler is included in dart_bootstrap and dart_noopt, and
 // excluded from dart and dart_precompiled_runtime.
 #if !defined(DART_PRECOMPILER)
 
 DART_EXPORT Dart_Handle Dart_Precompile(
     Dart_QualifiedFunctionName entry_points[],
     bool reset_fields) {
   UNREACHABLE();
   return 0;
 }
@@ skipping 85 matching lines @@
   return Api::Success();
 }
 #endif  // DART_PRECOMPILER
 
 
 DART_EXPORT bool Dart_IsRunningPrecompiledCode() {
   return Dart::IsRunningPrecompiledCode();
 }
 
 }  // namespace dart