/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "mozilla/WidgetTraceEvent.h"

#include <glib.h>

#include <mozilla/CondVar.h>

#include <mozilla/Mutex.h>

#include <stdio.h>

using mozilla::CondVar;

using mozilla::Mutex;

using mozilla::MutexAutoLock;

namespace {

Mutex* sMutex = nullptr;

CondVar* sCondVar = nullptr;

bool sTracerProcessed = false;

// This function is called from the main (UI) thread.

gboolean TracerCallback(gpointer data)

{

  mozilla::SignalTracerThread();

  return FALSE;

}

} // namespace

namespace mozilla {

bool InitWidgetTracing()

{

  sMutex = new Mutex("Event tracer thread mutex");

  sCondVar = new CondVar(*sMutex, "Event tracer thread condvar");

  return true;

}

void CleanUpWidgetTracing()

{

  delete sMutex;

  delete sCondVar;

  sMutex = nullptr;

  sCondVar = nullptr;

}

// This function is called from the background tracer thread.

bool FireAndWaitForTracerEvent()

{

  MOZ_ASSERT(sMutex && sCondVar, "Tracing not initialized!");

  // Send a default-priority idle event through the

  // event loop, and wait for it to finish.

  MutexAutoLock lock(*sMutex);

  MOZ_ASSERT(!sTracerProcessed, "Tracer synchronization state is wrong");

  g_idle_add_full(G_PRIORITY_DEFAULT,

                  TracerCallback,

                  nullptr,

                  nullptr);

  while (!sTracerProcessed)

    sCondVar->Wait();

  sTracerProcessed = false;

  return true;

}

void SignalTracerThread()

{

  if (!sMutex || !sCondVar)

    return;

  MutexAutoLock lock(*sMutex);

  if (!sTracerProcessed) {

    sTracerProcessed = true;

    sCondVar->Notify();

  }

}

} // namespace mozilla