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/. */
6 * Windows widget support for event loop instrumentation.
7 * See toolkit/xre/EventTracer.cpp for more details.
13 #include "mozilla/RefPtr.h"
14 #include "mozilla/WidgetTraceEvent.h"
15 #include "nsAppShellCID.h"
16 #include "nsComponentManagerUtils.h"
18 #include "nsIAppShellService.h"
19 #include "nsIBaseWindow.h"
20 #include "nsIDocShell.h"
21 #include "nsISupportsImpl.h"
22 #include "nsIWidget.h"
23 #include "nsIAppWindow.h"
24 #include "nsServiceManagerUtils.h"
25 #include "nsThreadUtils.h"
26 #include "nsWindowDefs.h"
30 // Used for signaling the background thread from the main thread.
31 HANDLE sEventHandle
= nullptr;
33 // We need a runnable in order to find the hidden window on the main
35 class HWNDGetter
: public mozilla::Runnable
{
37 HWNDGetter() : Runnable("HWNDGetter"), hidden_window_hwnd(nullptr) {}
39 HWND hidden_window_hwnd
;
41 NS_IMETHOD
Run() override
{
42 // Jump through some hoops to locate the hidden window.
43 nsCOMPtr
<nsIAppShellService
> appShell(
44 do_GetService(NS_APPSHELLSERVICE_CONTRACTID
));
45 nsCOMPtr
<nsIAppWindow
> hiddenWindow
;
47 nsresult rv
= appShell
->GetHiddenWindow(getter_AddRefs(hiddenWindow
));
52 nsCOMPtr
<nsIDocShell
> docShell
;
53 rv
= hiddenWindow
->GetDocShell(getter_AddRefs(docShell
));
54 if (NS_FAILED(rv
) || !docShell
) {
58 nsCOMPtr
<nsIBaseWindow
> baseWindow(do_QueryInterface(docShell
));
60 if (!baseWindow
) return NS_ERROR_FAILURE
;
62 nsCOMPtr
<nsIWidget
> widget
;
63 baseWindow
->GetMainWidget(getter_AddRefs(widget
));
65 if (!widget
) return NS_ERROR_FAILURE
;
67 hidden_window_hwnd
= (HWND
)widget
->GetNativeData(NS_NATIVE_WINDOW
);
73 HWND
GetHiddenWindowHWND() {
74 // Need to dispatch this to the main thread because plenty of
75 // the things it wants to access are main-thread-only.
76 RefPtr
<HWNDGetter
> getter
= new HWNDGetter();
77 NS_DispatchToMainThread(getter
, NS_DISPATCH_SYNC
);
78 return getter
->hidden_window_hwnd
;
85 bool InitWidgetTracing() {
86 sEventHandle
= CreateEventW(nullptr, FALSE
, FALSE
, nullptr);
87 return sEventHandle
!= nullptr;
90 void CleanUpWidgetTracing() {
91 CloseHandle(sEventHandle
);
92 sEventHandle
= nullptr;
95 // This function is called from the main (UI) thread.
96 void SignalTracerThread() {
97 if (sEventHandle
!= nullptr) SetEvent(sEventHandle
);
100 // This function is called from the background tracer thread.
101 bool FireAndWaitForTracerEvent() {
102 MOZ_ASSERT(sEventHandle
, "Tracing not initialized!");
104 // First, try to find the hidden window.
105 static HWND hidden_window
= nullptr;
106 if (hidden_window
== nullptr) {
107 hidden_window
= GetHiddenWindowHWND();
110 if (hidden_window
== nullptr) return false;
112 // Post the tracer message into the hidden window's message queue,
113 // and then block until it's processed.
114 PostMessage(hidden_window
, MOZ_WM_TRACE
, 0, 0);
115 WaitForSingleObject(sEventHandle
, INFINITE
);
119 } // namespace mozilla