content/browser/tracing/trace_message_filter.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.

#ifndef CONTENT_BROWSER_TRACING_TRACE_MESSAGE_FILTER_H_
#define CONTENT_BROWSER_TRACING_TRACE_MESSAGE_FILTER_H_

#include <stdint.h>

#include <string>
#include <vector>

#include "base/macros.h"
#include "base/trace_event/trace_event.h"
#include "content/public/browser/browser_message_filter.h"

namespace content {

// This class sends and receives trace messages on the browser process.
// See also: tracing_controller.h
// See also: child_trace_message_filter.h
class TraceMessageFilter : public BrowserMessageFilter {
 public:
  explicit TraceMessageFilter(int child_process_id);

  // BrowserMessageFilter implementation.
  void OnChannelConnected(int32_t peer_pid) override;
  void OnChannelClosing() override;
  bool OnMessageReceived(const IPC::Message& message) override;

  void SendSetWatchEvent(const std::string& category_name,
                         const std::string& event_name);
  void SendCancelWatchEvent();

 protected:
  ~TraceMessageFilter() override;

 private:
  // Message handlers.
  void OnChildSupportsTracing();
  void OnWatchEventMatched();
  void OnTriggerBackgroundTrace(const std::string& histogram_name);
  void OnAbortBackgroundTrace();

  // For registering/unregistering the filter to different tracing
  // managers/controllers.
  void Register();
  void Unregister();

  // ChildTraceMessageFilter exists:
  bool has_child_;

  // Hash of id of the child process.
  uint64_t tracing_process_id_;

  DISALLOW_COPY_AND_ASSIGN(TraceMessageFilter);
};

}  // namespace content

#endif  // CONTENT_BROWSER_TRACING_TRACE_MESSAGE_FILTER_H_