Merge pull request #2418 from deepak1556/content_tracing_api_patch

tracing: fix api and docs

atom/browser/api/atom_api_content_tracing.cc

@@ -7,6 +7,7 @@
 
 #include "atom/common/native_mate_converters/file_path_converter.h"
 #include "base/bind.h"
+#include "base/files/file_util.h"
 #include "content/public/browser/tracing_controller.h"
 #include "native_mate/callback.h"
 #include "native_mate/dictionary.h"
@@ -46,6 +47,31 @@ struct Converter<base::trace_event::TraceOptions> {
 
 namespace {
 
+using CompletionCallback = base::Callback<void(const base::FilePath&)>;
+
+scoped_refptr<TracingController::TraceDataSink> GetTraceDataSink(
+    const base::FilePath& path, const CompletionCallback& callback) {
+  base::FilePath result_file_path = path;
+  if (result_file_path.empty() && !base::CreateTemporaryFile(&result_file_path))
+    LOG(ERROR) << "Creating temporary file failed";
+
+  return TracingController::CreateFileSink(result_file_path,
+                                           base::Bind(callback,
+                                                      result_file_path));
+}
+
+void StopRecording(const base::FilePath& path,
+                   const CompletionCallback& callback) {
+  TracingController::GetInstance()->DisableRecording(
+      GetTraceDataSink(path, callback));
+}
+
+void CaptureMonitoringSnapshot(const base::FilePath& path,
+                               const CompletionCallback& callback) {
+  TracingController::GetInstance()->CaptureMonitoringSnapshot(
+      GetTraceDataSink(path, callback));
+}
+
 void Initialize(v8::Local<v8::Object> exports, v8::Local<v8::Value> unused,
                 v8::Local<v8::Context> context, void* priv) {
   auto controller = base::Unretained(TracingController::GetInstance());
@@ -54,14 +80,12 @@ void Initialize(v8::Local<v8::Object> exports, v8::Local<v8::Value> unused,
       &TracingController::GetCategories, controller));
   dict.SetMethod("startRecording", base::Bind(
       &TracingController::EnableRecording, controller));
-  dict.SetMethod("stopRecording", base::Bind(
-      &TracingController::DisableRecording, controller, nullptr));
+  dict.SetMethod("stopRecording", &StopRecording);
   dict.SetMethod("startMonitoring", base::Bind(
       &TracingController::EnableMonitoring, controller));
   dict.SetMethod("stopMonitoring", base::Bind(
       &TracingController::DisableMonitoring, controller));
-  dict.SetMethod("captureMonitoringSnapshot", base::Bind(
-      &TracingController::CaptureMonitoringSnapshot, controller, nullptr));
+  dict.SetMethod("captureMonitoringSnapshot", &CaptureMonitoringSnapshot);
   dict.SetMethod("getTraceBufferUsage", base::Bind(
       &TracingController::GetTraceBufferUsage, controller));
   dict.SetMethod("setWatchEvent", base::Bind(

atom/browser/api/lib/content-tracing.coffee

@@ -1,7 +1 @@
 module.exports = process.atomBinding 'content_tracing'
-
-# Mirrored from content::TracingController::Options
-module.exports.DEFAULT_OPTIONS = 0
-module.exports.ENABLE_SYSTRACE = 1 << 0
-module.exports.ENABLE_SAMPLING = 1 << 1
-module.exports.RECORD_CONTINUOUSLY = 1 << 2

docs/api/content-tracing.md

@@ -28,10 +28,10 @@ are reached.
 Once all child processes have acked to the `getCategories` request, `callback`
 is invoked with an array of category groups.
 
-## tracing.startRecording(categoryFilter, options, callback)
+## tracing.startRecording(categoryFilter, traceOptions, callback)
 
 * `categoryFilter` String
-* `options` Integer
+* `traceOptions` String
 * `callback` Function
 
 Start recording on all processes.
@@ -51,9 +51,23 @@ Examples:
 * `test_MyTest*,test_OtherStuff`,
 * `"-excluded_category1,-excluded_category2`
 
-`options` controls what kind of tracing is enabled, it could be a OR-ed
-combination of `tracing.DEFAULT_OPTIONS`, `tracing.ENABLE_SYSTRACE`,
-`tracing.ENABLE_SAMPLING` and `tracing.RECORD_CONTINUOUSLY`.
+`traceOptions` controls what kind of tracing is enabled, it is a comma-delimited list.
+Possible options are:
+
+* `record-until-full`
+* `record-continuously`
+* `trace-to-console`
+* `enable-sampling`
+* `enable-systrace`
+
+The first 3 options are trace recoding modes and hence mutually exclusive.
+If more than one trace recording modes appear in the `traceOptions` string,
+the last one takes precedence. If none of the trace recording mode is specified,
+recording mode is `record-until-full`.
+
+The trace option will first be reset to the default option (record_mode set to
+`record-until-full`, enable_sampling and enable_systrace set to false)
+before options parsed from `traceOptions` are applied on it.
 
 ## tracing.stopRecording(resultFilePath, callback)
 
@@ -75,10 +89,10 @@ Trace data will be written into `resultFilePath` if it is not empty, or into a
 temporary file. The actual file path will be passed to `callback` if it's not
 null.
 
-## tracing.startMonitoring(categoryFilter, options, callback)
+## tracing.startMonitoring(categoryFilter, traceOptions, callback)
 
 * `categoryFilter` String
-* `options` Integer
+* `traceOptions` String
 * `callback` Function
 
 Start monitoring on all processes.
@@ -107,7 +121,7 @@ Get the current monitoring traced data.
 
 Child processes typically are caching trace data and only rarely flush and send
 trace data back to the main process. That is because it may be an expensive
-operation to send the trace data over IPC, and we would like to avoid unneeded 
+operation to send the trace data over IPC, and we would like to avoid unneeded
 runtime overhead of tracing. So, to end tracing, we must asynchronously ask all
 child processes to flush any pending trace data.