widget/gtk/WidgetTraceEvent.cpp

   1 /* This Source Code Form is subject to the terms of the Mozilla Public
   2  * License, v. 2.0. If a copy of the MPL was not distributed with this
   3  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   4
   5 #include "mozilla/WidgetTraceEvent.h"
   6
   7 #include <glib.h>
   8 #include <mozilla/CondVar.h>
   9 #include <mozilla/Mutex.h>
  10 #include <stdio.h>
  11
  12 using mozilla::CondVar;
  13 using mozilla::Mutex;
  14 using mozilla::MutexAutoLock;
  15
  16 namespace {
  17
  18 Mutex* sMutex = nullptr;
  19 CondVar* sCondVar = nullptr;
  20 bool sTracerProcessed = false;
  21
  22 // This function is called from the main (UI) thread.
  23 gboolean TracerCallback(gpointer data)
  24 {
  25   mozilla::SignalTracerThread();
  26   return FALSE;
  27 }
  28
  29 } // namespace
  30
  31 namespace mozilla {
  32
  33 bool InitWidgetTracing()
  34 {
  35   sMutex = new Mutex("Event tracer thread mutex");
  36   sCondVar = new CondVar(*sMutex, "Event tracer thread condvar");
  37   return sMutex && sCondVar;
  38 }
  39
  40 void CleanUpWidgetTracing()
  41 {
  42   delete sMutex;
  43   delete sCondVar;
  44   sMutex = nullptr;
  45   sCondVar = nullptr;
  46 }
  47
  48 // This function is called from the background tracer thread.
  49 bool FireAndWaitForTracerEvent()
  50 {
  51   NS_ABORT_IF_FALSE(sMutex && sCondVar, "Tracing not initialized!");
  52
  53   // Send a default-priority idle event through the
  54   // event loop, and wait for it to finish.
  55   MutexAutoLock lock(*sMutex);
  56   NS_ABORT_IF_FALSE(!sTracerProcessed, "Tracer synchronization state is wrong");
  57   g_idle_add_full(G_PRIORITY_DEFAULT,
  58                   TracerCallback,
  59                   nullptr,
  60                   nullptr);
  61   while (!sTracerProcessed)
  62     sCondVar->Wait();
  63   sTracerProcessed = false;
  64   return true;
  65 }
  66
  67 void SignalTracerThread()
  68 {
  69   if (!sMutex || !sCondVar)
  70     return;
  71   MutexAutoLock lock(*sMutex);
  72   if (!sTracerProcessed) {
  73     sTracerProcessed = true;
  74     sCondVar->Notify();
  75   }
  76 }
  77
  78 }  // namespace mozilla