widget/windows/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 /*
   6  * Windows widget support for event loop instrumentation.
   7  * See toolkit/xre/EventTracer.cpp for more details.
   8  */
   9
  10 #include <stdio.h>
  11 #include <windows.h>
  12
  13 #include "mozilla/WidgetTraceEvent.h"
  14 #include "nsAppShellCID.h"
  15 #include "nsComponentManagerUtils.h"
  16 #include "nsCOMPtr.h"
  17 #include "nsIAppShellService.h"
  18 #include "nsIBaseWindow.h"
  19 #include "nsIDocShell.h"
  20 #include "nsIWidget.h"
  21 #include "nsIXULWindow.h"
  22 #include "nsAutoPtr.h"
  23 #include "nsServiceManagerUtils.h"
  24 #include "nsThreadUtils.h"
  25 #include "nsTraceRefcnt.h"
  26 #include "nsWindowDefs.h"
  27
  28 namespace {
  29
  30 // Used for signaling the background thread from the main thread.
  31 HANDLE sEventHandle = nullptr;
  32
  33 // We need a runnable in order to find the hidden window on the main
  34 // thread.
  35 class HWNDGetter : public nsRunnable {
  36 public:
  37   HWNDGetter() : hidden_window_hwnd(nullptr) {
  38     MOZ_COUNT_CTOR(HWNDGetter);
  39   }
  40   ~HWNDGetter() {
  41     MOZ_COUNT_DTOR(HWNDGetter);
  42   }
  43
  44   HWND hidden_window_hwnd;
  45
  46   NS_IMETHOD Run() {
  47     // Jump through some hoops to locate the hidden window.
  48     nsCOMPtr<nsIAppShellService> appShell(do_GetService(NS_APPSHELLSERVICE_CONTRACTID));
  49     nsCOMPtr<nsIXULWindow> hiddenWindow;
  50
  51     nsresult rv = appShell->GetHiddenWindow(getter_AddRefs(hiddenWindow));
  52     if (NS_FAILED(rv)) {
  53       return rv;
  54     }
  55
  56     nsCOMPtr<nsIDocShell> docShell;
  57     rv = hiddenWindow->GetDocShell(getter_AddRefs(docShell));
  58     if (NS_FAILED(rv) || !docShell) {
  59       return rv;
  60     }
  61
  62     nsCOMPtr<nsIBaseWindow> baseWindow(do_QueryInterface(docShell));
  63
  64     if (!baseWindow)
  65       return NS_ERROR_FAILURE;
  66
  67     nsCOMPtr<nsIWidget> widget;
  68     baseWindow->GetMainWidget(getter_AddRefs(widget));
  69
  70     if (!widget)
  71       return NS_ERROR_FAILURE;
  72
  73     hidden_window_hwnd = (HWND)widget->GetNativeData(NS_NATIVE_WINDOW);
  74
  75     return NS_OK;
  76   }
  77 };
  78
  79 HWND GetHiddenWindowHWND()
  80 {
  81   // Need to dispatch this to the main thread because plenty of
  82   // the things it wants to access are main-thread-only.
  83   nsRefPtr<HWNDGetter> getter = new HWNDGetter();
  84   NS_DispatchToMainThread(getter, NS_DISPATCH_SYNC);
  85   return getter->hidden_window_hwnd;
  86 }
  87
  88 } // namespace
  89
  90 namespace mozilla {
  91
  92 bool InitWidgetTracing()
  93 {
  94   sEventHandle = CreateEvent(nullptr, FALSE, FALSE, nullptr);
  95   return sEventHandle != nullptr;
  96 }
  97
  98 void CleanUpWidgetTracing()
  99 {
 100   CloseHandle(sEventHandle);
 101   sEventHandle = nullptr;
 102 }
 103
 104 // This function is called from the main (UI) thread.
 105 void SignalTracerThread()
 106 {
 107   if (sEventHandle != nullptr)
 108     SetEvent(sEventHandle);
 109 }
 110
 111 // This function is called from the background tracer thread.
 112 bool FireAndWaitForTracerEvent()
 113 {
 114   NS_ABORT_IF_FALSE(sEventHandle, "Tracing not initialized!");
 115
 116   // First, try to find the hidden window.
 117   static HWND hidden_window = nullptr;
 118   if (hidden_window == nullptr) {
 119     hidden_window = GetHiddenWindowHWND();
 120   }
 121
 122   if (hidden_window == nullptr)
 123     return false;
 124
 125   // Post the tracer message into the hidden window's message queue,
 126   // and then block until it's processed.
 127   PostMessage(hidden_window, MOZ_WM_TRACE, 0, 0);
 128   WaitForSingleObject(sEventHandle, INFINITE);
 129   return true;
 130 }
 131
 132 }  // namespace mozilla