Slow Reports - Embed Metadata in Traces

content/browser/tracing/tracing_controller_impl_data_sinks.cc

 // Copyright 2015 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.
 #include "content/browser/tracing/tracing_controller_impl.h"
 
 #include "base/bind.h"
 #include "base/files/file_util.h"
 #include "content/public/browser/browser_thread.h"
 #include "third_party/zlib/zlib.h"
 
@@ skipping 110 matching lines @@
   void AddTraceChunkAndPassToEndpoint(const std::string& chunk) {
     trace_ += chunk;
 
     endpoint_->ReceiveTraceChunk(chunk);
   }
 
   void SetSystemTrace(const std::string& data) override {
     system_trace_ = data;
   }
 
+  void SetMetadata(const std::string& data) override {
+    metadata_ = data;
+  }
+
   void Close() override {
     AddTraceChunkAndPassToEndpoint("]");
     if (!system_trace_.empty())
       AddTraceChunkAndPassToEndpoint(",\"systemTraceEvents\": " +
                                      system_trace_);
+    if (!metadata_.empty())
+      AddTraceChunkAndPassToEndpoint(",\"metadata\": " + metadata_);

[dsinclair, 2015/06/12 19:38:51]

Does this produce a valid file? This works above for system_trace_ because it's
an encoded array, so has [] around the content. With metadata_ it's just a
string, does it have the correct "" around the content? (And, if it doesn't, we
have to make sure it's escaped before we can add it)

[shatch, 2015/06/12 20:53:48]

It's actually a dict, so the contents the results are more like:

"metadata": {"foo1": "1"}

     AddTraceChunkAndPassToEndpoint("}");
 
     endpoint_->ReceiveTraceFinalContents(trace_);
   }
 
  private:
   ~StringTraceDataSink() override {}
 
   scoped_refptr<TracingController::TraceDataEndpoint> endpoint_;
   std::string trace_;
   std::string system_trace_;
+  std::string metadata_;
 
   DISALLOW_COPY_AND_ASSIGN(StringTraceDataSink);
 };
 
 class CompressedStringTraceDataSink : public TracingController::TraceDataSink {
  public:
   explicit CompressedStringTraceDataSink(
       scoped_refptr<TracingController::TraceDataEndpoint> endpoint)
       : endpoint_(endpoint), already_tried_open_(false) {}
 
   void AddTraceChunk(const std::string& chunk) override {
     std::string tmp = chunk;
     scoped_refptr<base::RefCountedString> chunk_ptr =
         base::RefCountedString::TakeString(&tmp);
     BrowserThread::PostTask(
         BrowserThread::FILE, FROM_HERE,
         base::Bind(&CompressedStringTraceDataSink::AddTraceChunkOnFileThread,
                    this, chunk_ptr));
   }
 
   void SetSystemTrace(const std::string& data) override {
     system_trace_ = data;
   }
 
+  void SetMetadata(const std::string& data) override {
+    metadata_ = data;
+  }
+
   void Close() override {
     BrowserThread::PostTask(
         BrowserThread::FILE, FROM_HERE,
         base::Bind(&CompressedStringTraceDataSink::CloseOnFileThread, this));
   }
 
  private:
   ~CompressedStringTraceDataSink() override {}
 
   bool OpenZStreamOnFileThread() {
@@ skipping 67 matching lines @@
       return;
 
     if (compressed_trace_data_.empty())
       AddTraceChunkAndCompressOnFileThread("{\"traceEvents\":[", false);
 
     AddTraceChunkAndCompressOnFileThread("]", false);
     if (!system_trace_.empty()) {
       AddTraceChunkAndCompressOnFileThread(
           ",\"systemTraceEvents\": " + system_trace_, false);
     }
+    if (!metadata_.empty())

[oystein (OOO til 10th of July), 2015/06/12 19:29:16]

nit: braces

[shatch, 2015/06/12 20:53:48]

Done.

+      AddTraceChunkAndCompressOnFileThread(",\"metadata\": " + metadata_,
+                                           false);
     AddTraceChunkAndCompressOnFileThread("}", true);
 
     deflateEnd(stream_.get());
     stream_.reset();
 
     endpoint_->ReceiveTraceFinalContents(compressed_trace_data_);
   }
 
   scoped_refptr<TracingController::TraceDataEndpoint> endpoint_;
   scoped_ptr<z_stream> stream_;
   bool already_tried_open_;
   std::string compressed_trace_data_;
   std::string system_trace_;
+  std::string metadata_;
 
   DISALLOW_COPY_AND_ASSIGN(CompressedStringTraceDataSink);
 };
 
 }  // namespace
 
 scoped_refptr<TracingController::TraceDataSink>
 TracingController::CreateStringSink(
     const base::Callback<void(base::RefCountedString*)>& callback) {
   return new StringTraceDataSink(new StringTraceDataEndpoint(callback));
@@ skipping 12 matching lines @@
       CreateFileEndpoint(file_path, callback));
 }
 
 scoped_refptr<TracingController::TraceDataEndpoint>
 TracingController::CreateFileEndpoint(const base::FilePath& file_path,
                                       const base::Closure& callback) {
   return new FileTraceDataEndpoint(file_path, callback);
 }
 
 }  // namespace content