WindowsMessageLoop.cpp
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* vim: sw=2 ts=2 et :
*/
/* 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/DebugOnly.h"
#include "WindowsMessageLoop.h"
#include "MessageChannel.h"
#include "nsAutoPtr.h"
#include "nsServiceManagerUtils.h"
#include "nsString.h"
#include "nsIXULAppInfo.h"
#include "mozilla/PaintTracker.h"
using namespace mozilla;
using namespace mozilla::ipc;
using namespace mozilla::ipc::windows;
/**
* The Windows-only code below exists to solve a general problem with deadlocks
* that we experience when sending synchronous IPC messages to processes that
* contain native windows (i.e. HWNDs). Windows (the OS) sends synchronous
* messages between parent and child HWNDs in multiple circumstances (e.g.
* WM_PARENTNOTIFY, WM_NCACTIVATE, etc.), even when those HWNDs are controlled
* by different threads or different processes. Thus we can very easily end up
* in a deadlock by a call stack like the following:
*
* Process A:
* - CreateWindow(...) creates a "parent" HWND.
* - SendCreateChildWidget(HWND) is a sync IPC message that sends the "parent"
* HWND over to Process B. Process A blocks until a response is received
* from Process B.
*
* Process B:
* - RecvCreateWidget(HWND) gets the "parent" HWND from Process A.
* - CreateWindow(..., HWND) creates a "child" HWND with the parent from
* process A.
* - Windows (the OS) generates a WM_PARENTNOTIFY message that is sent
* synchronously to Process A. Process B blocks until a response is
* received from Process A. Process A, however, is blocked and cannot
* process the message. Both processes are deadlocked.
*
* The example above has a few different workarounds (e.g. setting the
* WS_EX_NOPARENTNOTIFY style on the child window) but the general problem is
* persists. Once two HWNDs are parented we must not block their owning
* threads when manipulating either HWND.
*
* Windows requires any application that hosts native HWNDs to always process
* messages or risk deadlock. Given our architecture the only way to meet
* Windows' requirement and allow for synchronous IPC messages is to pump a
* miniature message loop during a sync IPC call. We avoid processing any
* queued messages during the loop (with one exception, see below), but
* "nonqueued" messages (see
* http://msdn.microsoft.com/en-us/library/ms644927(VS.85).aspx under the
* section "Nonqueued messages") cannot be avoided. Those messages are trapped
* in a special window procedure where we can either ignore the message or
* process it in some fashion.
*
* Queued and "non-queued" messages will be processed during Interrupt calls if
* modal UI related api calls block an Interrupt in-call in the child. To prevent
* windows from freezing, and to allow concurrent processing of critical
* events (such as painting), we spin a native event dispatch loop while
* these in-calls are blocked.
*/
#if defined(ACCESSIBILITY)
// pulled from accessibility's win utils
extern const wchar_t* kPropNameTabContent;
#endif
// widget related message id constants we need to defer
namespace mozilla {
namespace widget {
extern UINT sAppShellGeckoMsgId;
#ifdef MOZ_METRO
extern UINT sDefaultBrowserMsgId;
#endif
}
}
namespace {
const wchar_t kOldWndProcProp[] = L"MozillaIPCOldWndProc";
// This isn't defined before Windows XP.
enum { WM_XP_THEMECHANGED = 0x031A };
PRUnichar gAppMessageWindowName[256] = { 0 };
int32_t gAppMessageWindowNameLength = 0;
nsTArray<HWND>* gNeuteredWindows = nullptr;
typedef nsTArray<nsAutoPtr<DeferredMessage> > DeferredMessageArray;
DeferredMessageArray* gDeferredMessages = nullptr;
HHOOK gDeferredGetMsgHook = nullptr;
HHOOK gDeferredCallWndProcHook = nullptr;
DWORD gUIThreadId = 0;
LRESULT CALLBACK
DeferredMessageHook(int nCode,
WPARAM wParam,
LPARAM lParam)
{
// XXX This function is called for *both* the WH_CALLWNDPROC hook and the
// WH_GETMESSAGE hook, but they have different parameters. We don't
// use any of them except nCode which has the same meaning.
// Only run deferred messages if all of these conditions are met:
// 1. The |nCode| indicates that this hook should do something.
// 2. We have deferred messages to run.
// 3. We're not being called from the PeekMessage within the WaitFor*Notify
// function (indicated with MessageChannel::IsPumpingMessages). We really
// only want to run after returning to the main event loop.
if (nCode >= 0 && gDeferredMessages && !MessageChannel::IsPumpingMessages()) {
NS_ASSERTION(gDeferredGetMsgHook && gDeferredCallWndProcHook,
"These hooks must be set if we're being called!");
NS_ASSERTION(gDeferredMessages->Length(), "No deferred messages?!");
// Unset hooks first, in case we reenter below.
UnhookWindowsHookEx(gDeferredGetMsgHook);
UnhookWindowsHookEx(gDeferredCallWndProcHook);
gDeferredGetMsgHook = 0;
gDeferredCallWndProcHook = 0;
// Unset the global and make sure we delete it when we're done here.
nsAutoPtr<DeferredMessageArray> messages(gDeferredMessages);
gDeferredMessages = nullptr;
// Run all the deferred messages in order.
uint32_t count = messages->Length();
for (uint32_t index = 0; index < count; index++) {
messages->ElementAt(index)->Run();
}
}
// Always call the next hook.
return CallNextHookEx(nullptr, nCode, wParam, lParam);
}
void
ScheduleDeferredMessageRun()
{
if (gDeferredMessages &&
!(gDeferredGetMsgHook && gDeferredCallWndProcHook)) {
NS_ASSERTION(gDeferredMessages->Length(), "No deferred messages?!");
gDeferredGetMsgHook = ::SetWindowsHookEx(WH_GETMESSAGE, DeferredMessageHook,
nullptr, gUIThreadId);
gDeferredCallWndProcHook = ::SetWindowsHookEx(WH_CALLWNDPROC,
DeferredMessageHook, nullptr,
gUIThreadId);
NS_ASSERTION(gDeferredGetMsgHook && gDeferredCallWndProcHook,
"Failed to set hooks!");
}
}
LRESULT
ProcessOrDeferMessage(HWND hwnd,
UINT uMsg,
WPARAM wParam,
LPARAM lParam)
{
DeferredMessage* deferred = nullptr;
// Most messages ask for 0 to be returned if the message is processed.
LRESULT res = 0;
switch (uMsg) {
// Messages that can be deferred as-is. These must not contain pointers in
// their wParam or lParam arguments!
case WM_ACTIVATE:
case WM_ACTIVATEAPP:
case WM_CANCELMODE:
case WM_CAPTURECHANGED:
case WM_CHILDACTIVATE:
case WM_DESTROY:
case WM_ENABLE:
case WM_IME_NOTIFY:
case WM_IME_SETCONTEXT:
case WM_KILLFOCUS:
case WM_MOUSEWHEEL:
case WM_NCDESTROY:
case WM_PARENTNOTIFY:
case WM_SETFOCUS:
case WM_SYSCOMMAND:
case WM_DISPLAYCHANGE:
case WM_SHOWWINDOW: // Intentional fall-through.
case WM_XP_THEMECHANGED: {
deferred = new DeferredSendMessage(hwnd, uMsg, wParam, lParam);
break;
}
case WM_DEVICECHANGE:
case WM_POWERBROADCAST:
case WM_NCACTIVATE: // Intentional fall-through.
case WM_SETCURSOR: {
// Friggin unconventional return value...
res = TRUE;
deferred = new DeferredSendMessage(hwnd, uMsg, wParam, lParam);
break;
}
case WM_MOUSEACTIVATE: {
res = MA_NOACTIVATE;
deferred = new DeferredSendMessage(hwnd, uMsg, wParam, lParam);
break;
}
// These messages need to use the RedrawWindow function to generate the
// right kind of message. We can't simply fake them as the MSDN docs say
// explicitly that paint messages should not be sent by an application.
case WM_ERASEBKGND: {
UINT flags = RDW_INVALIDATE | RDW_ERASE | RDW_NOINTERNALPAINT |
RDW_NOFRAME | RDW_NOCHILDREN | RDW_ERASENOW;
deferred = new DeferredRedrawMessage(hwnd, flags);
break;
}
// This message will generate a WM_PAINT message if there are invalid
// areas.
case WM_PAINT: {
deferred = new DeferredUpdateMessage(hwnd);
break;
}
// This message holds a string in its lParam that we must copy.
case WM_SETTINGCHANGE: {
deferred = new DeferredSettingChangeMessage(hwnd, uMsg, wParam, lParam);
break;
}
// These messages are faked via a call to SetWindowPos.
case WM_WINDOWPOSCHANGED: {
deferred = new DeferredWindowPosMessage(hwnd, lParam);
break;
}
case WM_NCCALCSIZE: {
deferred = new DeferredWindowPosMessage(hwnd, lParam, true, wParam);
break;
}
case WM_COPYDATA: {
deferred = new DeferredCopyDataMessage(hwnd, uMsg, wParam, lParam);
res = TRUE;
break;
}
case WM_STYLECHANGED: {
deferred = new DeferredStyleChangeMessage(hwnd, wParam, lParam);
break;
}
case WM_SETICON: {
deferred = new DeferredSetIconMessage(hwnd, uMsg, wParam, lParam);
break;
}
// Messages that are safe to pass to DefWindowProc go here.
case WM_ENTERIDLE:
case WM_GETICON:
case WM_NCPAINT: // (never trap nc paint events)
case WM_GETMINMAXINFO:
case WM_GETTEXT:
case WM_NCHITTEST:
case WM_STYLECHANGING: // Intentional fall-through.
case WM_WINDOWPOSCHANGING: {
return DefWindowProc(hwnd, uMsg, wParam, lParam);
}
// Just return, prevents DefWindowProc from messaging the window
// syncronously with other events, which may be deferred. Prevents
// random shutdown of aero composition on the window.
case WM_SYNCPAINT:
return 0;
default: {
if (uMsg && uMsg == mozilla::widget::sAppShellGeckoMsgId) {
// Widget's registered native event callback
deferred = new DeferredSendMessage(hwnd, uMsg, wParam, lParam);
#ifdef MOZ_METRO
} else if (uMsg && uMsg == mozilla::widget::sDefaultBrowserMsgId) {
// Metro widget's system shutdown message
deferred = new DeferredSendMessage(hwnd, uMsg, wParam, lParam);
#endif
} else {
// Unknown messages only
#ifdef DEBUG
nsAutoCString log("Received \"nonqueued\" message ");
log.AppendInt(uMsg);
log.AppendLiteral(" during a synchronous IPC message for window ");
log.AppendInt((int64_t)hwnd);
wchar_t className[256] = { 0 };
if (GetClassNameW(hwnd, className, sizeof(className) - 1) > 0) {
log.AppendLiteral(" (\"");
log.Append(NS_ConvertUTF16toUTF8((PRUnichar*)className));
log.AppendLiteral("\")");
}
log.AppendLiteral(", sending it to DefWindowProc instead of the normal "
"window procedure.");
NS_ERROR(log.get());
#endif
return DefWindowProc(hwnd, uMsg, wParam, lParam);
}
}
}
NS_ASSERTION(deferred, "Must have a message here!");
// Create the deferred message array if it doesn't exist already.
if (!gDeferredMessages) {
gDeferredMessages = new nsTArray<nsAutoPtr<DeferredMessage> >(20);
NS_ASSERTION(gDeferredMessages, "Out of memory!");
}
// Save for later. The array takes ownership of |deferred|.
gDeferredMessages->AppendElement(deferred);
return res;
}
} // anonymous namespace
// We need the pointer value of this in PluginInstanceChild.
LRESULT CALLBACK
NeuteredWindowProc(HWND hwnd,
UINT uMsg,
WPARAM wParam,
LPARAM lParam)
{
WNDPROC oldWndProc = (WNDPROC)GetProp(hwnd, kOldWndProcProp);
if (!oldWndProc) {
// We should really never ever get here.
NS_ERROR("No old wndproc!");
return DefWindowProc(hwnd, uMsg, wParam, lParam);
}
// See if we care about this message. We may either ignore it, send it to
// DefWindowProc, or defer it for later.
return ProcessOrDeferMessage(hwnd, uMsg, wParam, lParam);
}
namespace {
static bool
WindowIsDeferredWindow(HWND hWnd)
{
if (!IsWindow(hWnd)) {
NS_WARNING("Window has died!");
return false;
}
PRUnichar buffer[256] = { 0 };
int length = GetClassNameW(hWnd, (wchar_t*)buffer, sizeof(buffer) - 1);
if (length <= 0) {
NS_WARNING("Failed to get class name!");
return false;
}
#if defined(ACCESSIBILITY)
// Tab content creates a window that responds to accessible WM_GETOBJECT
// calls. This window can safely be ignored.
if (::GetPropW(hWnd, kPropNameTabContent)) {
return false;
}
#endif
// Common mozilla windows we must defer messages to.
nsDependentString className(buffer, length);
if (StringBeginsWith(className, NS_LITERAL_STRING("Mozilla")) ||
StringBeginsWith(className, NS_LITERAL_STRING("Gecko")) ||
className.EqualsLiteral("nsToolkitClass") ||
className.EqualsLiteral("nsAppShell:EventWindowClass")) {
return true;
}
#ifdef MOZ_METRO
// immersive UI ICoreWindow
if (className.EqualsLiteral("Windows.UI.Core.CoreWindow")) {
return true;
}
#endif
// Plugin windows that can trigger ipc calls in child:
// 'ShockwaveFlashFullScreen' - flash fullscreen window
// 'AGFullScreenWinClass' - silverlight fullscreen window
if (className.EqualsLiteral("ShockwaveFlashFullScreen") ||
className.EqualsLiteral("AGFullScreenWinClass")) {
return true;
}
// Google Earth bridging msg window between the plugin instance and a separate
// earth process. The earth process can trigger a plugin incall on the browser
// at any time, which is badness if the instance is already making an incall.
if (className.EqualsLiteral("__geplugin_bridge_window__")) {
return true;
}
// nsNativeAppSupport makes a window like "FirefoxMessageWindow" based on the
// toolkit app's name. It's pretty expensive to calculate this so we only try
// once.
if (gAppMessageWindowNameLength == 0) {
nsCOMPtr<nsIXULAppInfo> appInfo =
do_GetService("@mozilla.org/xre/app-info;1");
if (appInfo) {
nsAutoCString appName;
if (NS_SUCCEEDED(appInfo->GetName(appName))) {
appName.Append("MessageWindow");
nsDependentString windowName(gAppMessageWindowName);
CopyUTF8toUTF16(appName, windowName);
gAppMessageWindowNameLength = windowName.Length();
}
}
// Don't try again if that failed.
if (gAppMessageWindowNameLength == 0) {
gAppMessageWindowNameLength = -1;
}
}
if (gAppMessageWindowNameLength != -1 &&
className.Equals(nsDependentString(gAppMessageWindowName,
gAppMessageWindowNameLength))) {
return true;
}
return false;
}
bool
NeuterWindowProcedure(HWND hWnd)
{
if (!WindowIsDeferredWindow(hWnd)) {
// Some other kind of window, skip.
return false;
}
NS_ASSERTION(!GetProp(hWnd, kOldWndProcProp), "This should always be null!");
// It's possible to get nullptr out of SetWindowLongPtr, and the only way to
// know if that's a valid old value is to use GetLastError. Clear the error
// here so we can tell.
SetLastError(ERROR_SUCCESS);
LONG_PTR currentWndProc =
SetWindowLongPtr(hWnd, GWLP_WNDPROC, (LONG_PTR)NeuteredWindowProc);
if (!currentWndProc) {
if (ERROR_SUCCESS == GetLastError()) {
// No error, so we set something and must therefore reset it.
SetWindowLongPtr(hWnd, GWLP_WNDPROC, currentWndProc);
}
return false;
}
NS_ASSERTION(currentWndProc != (LONG_PTR)NeuteredWindowProc,
"This shouldn't be possible!");
if (!SetProp(hWnd, kOldWndProcProp, (HANDLE)currentWndProc)) {
// Cleanup
NS_WARNING("SetProp failed!");
SetWindowLongPtr(hWnd, GWLP_WNDPROC, currentWndProc);
RemoveProp(hWnd, kOldWndProcProp);
return false;
}
return true;
}
void
RestoreWindowProcedure(HWND hWnd)
{
NS_ASSERTION(WindowIsDeferredWindow(hWnd),
"Not a deferred window, this shouldn't be in our list!");
LONG_PTR oldWndProc = (LONG_PTR)GetProp(hWnd, kOldWndProcProp);
if (oldWndProc) {
NS_ASSERTION(oldWndProc != (LONG_PTR)NeuteredWindowProc,
"This shouldn't be possible!");
DebugOnly<LONG_PTR> currentWndProc =
SetWindowLongPtr(hWnd, GWLP_WNDPROC, oldWndProc);
NS_ASSERTION(currentWndProc == (LONG_PTR)NeuteredWindowProc,
"This should never be switched out from under us!");
}
RemoveProp(hWnd, kOldWndProcProp);
}
LRESULT CALLBACK
CallWindowProcedureHook(int nCode,
WPARAM wParam,
LPARAM lParam)
{
if (nCode >= 0) {
NS_ASSERTION(gNeuteredWindows, "This should never be null!");
HWND hWnd = reinterpret_cast<CWPSTRUCT*>(lParam)->hwnd;
if (!gNeuteredWindows->Contains(hWnd) && NeuterWindowProcedure(hWnd)) {
if (!gNeuteredWindows->AppendElement(hWnd)) {
NS_ERROR("Out of memory!");
RestoreWindowProcedure(hWnd);
}
}
}
return CallNextHookEx(nullptr, nCode, wParam, lParam);
}
inline void
AssertWindowIsNotNeutered(HWND hWnd)
{
#ifdef DEBUG
// Make sure our neutered window hook isn't still in place.
LONG_PTR wndproc = GetWindowLongPtr(hWnd, GWLP_WNDPROC);
NS_ASSERTION(wndproc != (LONG_PTR)NeuteredWindowProc, "Window is neutered!");
#endif
}
void
UnhookNeuteredWindows()
{
if (!gNeuteredWindows)
return;
uint32_t count = gNeuteredWindows->Length();
for (uint32_t index = 0; index < count; index++) {
RestoreWindowProcedure(gNeuteredWindows->ElementAt(index));
}
gNeuteredWindows->Clear();
}
void
Init()
{
// If we aren't setup before a call to NotifyWorkerThread, we'll hang
// on startup.
if (!gUIThreadId) {
gUIThreadId = GetCurrentThreadId();
}
NS_ASSERTION(gUIThreadId, "ThreadId should not be 0!");
NS_ASSERTION(gUIThreadId == GetCurrentThreadId(),
"Running on different threads!");
}
// This timeout stuff assumes a sane value of mTimeoutMs (less than the overflow
// value for GetTickCount(), which is something like 50 days). It uses the
// cheapest (and least accurate) method supported by Windows 2000.
struct TimeoutData
{
DWORD startTicks;
DWORD targetTicks;
};
void
InitTimeoutData(TimeoutData* aData,
int32_t aTimeoutMs)
{
aData->startTicks = GetTickCount();
if (!aData->startTicks) {
// How unlikely is this!
aData->startTicks++;
}
aData->targetTicks = aData->startTicks + aTimeoutMs;
}
bool
TimeoutHasExpired(const TimeoutData& aData)
{
if (!aData.startTicks) {
return false;
}
DWORD now = GetTickCount();
if (aData.targetTicks < aData.startTicks) {
// Overflow
return now < aData.startTicks && now >= aData.targetTicks;
}
return now >= aData.targetTicks;
}
} // anonymous namespace
MessageChannel::SyncStackFrame::SyncStackFrame(MessageChannel* channel, bool interrupt)
: mInterrupt(interrupt)
, mSpinNestedEvents(false)
, mListenerNotified(false)
, mChannel(channel)
, mPrev(mChannel->mTopFrame)
, mStaticPrev(sStaticTopFrame)
{
mChannel->mTopFrame = this;
sStaticTopFrame = this;
if (!mStaticPrev) {
NS_ASSERTION(!gNeuteredWindows, "Should only set this once!");
gNeuteredWindows = new nsAutoTArray<HWND, 20>();
NS_ASSERTION(gNeuteredWindows, "Out of memory!");
}
}
MessageChannel::SyncStackFrame::~SyncStackFrame()
{
NS_ASSERTION(this == mChannel->mTopFrame,
"Mismatched interrupt stack frames");
NS_ASSERTION(this == sStaticTopFrame,
"Mismatched static Interrupt stack frames");
mChannel->mTopFrame = mPrev;
sStaticTopFrame = mStaticPrev;
if (!mStaticPrev) {
NS_ASSERTION(gNeuteredWindows, "Bad pointer!");
delete gNeuteredWindows;
gNeuteredWindows = nullptr;
}
}
MessageChannel::SyncStackFrame* MessageChannel::sStaticTopFrame;
// nsAppShell's notification that gecko events are being processed.
// If we are here and there is an Interrupt Incall active, we are spinning
// a nested gecko event loop. In which case the remote process needs
// to know about it.
void /* static */
MessageChannel::NotifyGeckoEventDispatch()
{
// sStaticTopFrame is only valid for Interrupt channels
if (!sStaticTopFrame || sStaticTopFrame->mListenerNotified)
return;
sStaticTopFrame->mListenerNotified = true;
MessageChannel* channel = static_cast<MessageChannel*>(sStaticTopFrame->mChannel);
channel->Listener()->ProcessRemoteNativeEventsInInterruptCall();
}
// invoked by the module that receives the spin event loop
// message.
void
MessageChannel::ProcessNativeEventsInInterruptCall()
{
if (!mTopFrame) {
NS_ERROR("Spin logic error: no Interrupt frame");
return;
}
mTopFrame->mSpinNestedEvents = true;
}
// Spin loop is called in place of WaitFor*Notify when modal ui is being shown
// in a child. There are some intricacies in using it however. Spin loop is
// enabled for a particular Interrupt frame by the client calling
// MessageChannel::ProcessNativeEventsInInterrupt().
// This call can be nested for multiple Interrupt frames in a single plugin or
// multiple unrelated plugins.
void
MessageChannel::SpinInternalEventLoop()
{
if (mozilla::PaintTracker::IsPainting()) {
NS_RUNTIMEABORT("Don't spin an event loop while painting.");
}
NS_ASSERTION(mTopFrame && mTopFrame->mSpinNestedEvents,
"Spinning incorrectly");
// Nested windows event loop we trigger when the child enters into modal
// event loops.
// Note, when we return, we always reset the notify worker event. So there's
// no need to reset it on return here.
do {
MSG msg = { 0 };
// Don't get wrapped up in here if the child connection dies.
{
MonitorAutoLock lock(*mMonitor);
if (!Connected()) {
return;
}
}
// Retrieve window or thread messages
if (PeekMessageW(&msg, nullptr, 0, 0, PM_REMOVE)) {
// The child UI should have been destroyed before the app is closed, in
// which case, we should never get this here.
if (msg.message == WM_QUIT) {
NS_ERROR("WM_QUIT received in SpinInternalEventLoop!");
} else {
TranslateMessage(&msg);
::DispatchMessageW(&msg);
return;
}
}
// Note, give dispatching windows events priority over checking if
// mEvent is signaled, otherwise heavy ipc traffic can cause jittery
// playback of video. We'll exit out on each disaptch above, so ipc
// won't get starved.
// Wait for UI events or a signal from the io thread.
DWORD result = MsgWaitForMultipleObjects(1, &mEvent, FALSE, INFINITE,
QS_ALLINPUT);
if (result == WAIT_OBJECT_0) {
// Our NotifyWorkerThread event was signaled
return;
}
} while (true);
}
bool
MessageChannel::WaitForSyncNotify()
{
mMonitor->AssertCurrentThreadOwns();
// Initialize global objects used in deferred messaging.
Init();
NS_ASSERTION(mTopFrame && !mTopFrame->mInterrupt,
"Top frame is not a sync frame!");
MonitorAutoUnlock unlock(*mMonitor);
bool timedout = false;
UINT_PTR timerId = 0;
TimeoutData timeoutData = { 0 };
if (mTimeoutMs != kNoTimeout) {
InitTimeoutData(&timeoutData, mTimeoutMs);
// We only do this to ensure that we won't get stuck in
// MsgWaitForMultipleObjects below.
timerId = SetTimer(nullptr, 0, mTimeoutMs, nullptr);
NS_ASSERTION(timerId, "SetTimer failed!");
}
// Setup deferred processing of native events while we wait for a response.
NS_ASSERTION(!MessageChannel::IsPumpingMessages(),
"Shouldn't be pumping already!");
MessageChannel::SetIsPumpingMessages(true);
HHOOK windowHook = SetWindowsHookEx(WH_CALLWNDPROC, CallWindowProcedureHook,
nullptr, gUIThreadId);
NS_ASSERTION(windowHook, "Failed to set hook!");
{
while (1) {
MSG msg = { 0 };
// Don't get wrapped up in here if the child connection dies.
{
MonitorAutoLock lock(*mMonitor);
if (!Connected()) {
break;
}
}
// Wait until we have a message in the queue. MSDN docs are a bit unclear
// but it seems that windows from two different threads (and it should be
// noted that a thread in another process counts as a "different thread")
// will implicitly have their message queues attached if they are parented
// to one another. This wait call, then, will return for a message
// delivered to *either* thread.
DWORD result = MsgWaitForMultipleObjects(1, &mEvent, FALSE, INFINITE,
QS_ALLINPUT);
if (result == WAIT_OBJECT_0) {
// Our NotifyWorkerThread event was signaled
ResetEvent(mEvent);
break;
} else
if (result != (WAIT_OBJECT_0 + 1)) {
NS_ERROR("Wait failed!");
break;
}
if (TimeoutHasExpired(timeoutData)) {
// A timeout was specified and we've passed it. Break out.
timedout = true;
break;
}
// The only way to know on which thread the message was delivered is to
// use some logic on the return values of GetQueueStatus and PeekMessage.
// PeekMessage will return false if there are no "queued" messages, but it
// will run all "nonqueued" messages before returning. So if PeekMessage
// returns false and there are no "nonqueued" messages that were run then
// we know that the message we woke for was intended for a window on
// another thread.
bool haveSentMessagesPending =
(HIWORD(GetQueueStatus(QS_SENDMESSAGE)) & QS_SENDMESSAGE) != 0;
// This PeekMessage call will actually process all "nonqueued" messages
// that are pending before returning. If we have "nonqueued" messages
// pending then we should have switched out all the window procedures
// above. In that case this PeekMessage call won't actually cause any
// mozilla code (or plugin code) to run.
// If the following PeekMessage call fails to return a message for us (and
// returns false) and we didn't run any "nonqueued" messages then we must
// have woken up for a message designated for a window in another thread.
// If we loop immediately then we could enter a tight loop, so we'll give
// up our time slice here to let the child process its message.
if (!PeekMessageW(&msg, nullptr, 0, 0, PM_NOREMOVE) &&
!haveSentMessagesPending) {
// Message was for child, we should wait a bit.
SwitchToThread();
}
}
}
// Unhook the neutered window procedure hook.
UnhookWindowsHookEx(windowHook);
// Unhook any neutered windows procedures so messages can be delivered
// normally.
UnhookNeuteredWindows();
// Before returning we need to set a hook to run any deferred messages that
// we received during the IPC call. The hook will unset itself as soon as
// someone else calls GetMessage, PeekMessage, or runs code that generates
// a "nonqueued" message.
ScheduleDeferredMessageRun();
if (timerId) {
KillTimer(nullptr, timerId);
}
MessageChannel::SetIsPumpingMessages(false);
return WaitResponse(timedout);
}
bool
MessageChannel::WaitForInterruptNotify()
{
mMonitor->AssertCurrentThreadOwns();
if (!InterruptStackDepth()) {
// There is currently no way to recover from this condition.
NS_RUNTIMEABORT("StackDepth() is 0 in call to MessageChannel::WaitForNotify!");
}
// Initialize global objects used in deferred messaging.
Init();
NS_ASSERTION(mTopFrame && mTopFrame->mInterrupt,
"Top frame is not a sync frame!");
MonitorAutoUnlock unlock(*mMonitor);
bool timedout = false;
UINT_PTR timerId = 0;
TimeoutData timeoutData = { 0 };
// windowHook is used as a flag variable for the loop below: if it is set
// and we start to spin a nested event loop, we need to clear the hook and
// process deferred/pending messages.
// If windowHook is nullptr, MessageChannel::IsPumpingMessages should be false.
HHOOK windowHook = nullptr;
while (1) {
NS_ASSERTION((!!windowHook) == MessageChannel::IsPumpingMessages(),
"windowHook out of sync with reality");
if (mTopFrame->mSpinNestedEvents) {
if (windowHook) {
UnhookWindowsHookEx(windowHook);
windowHook = nullptr;
if (timerId) {
KillTimer(nullptr, timerId);
timerId = 0;
}
// Used by widget to assert on incoming native events
MessageChannel::SetIsPumpingMessages(false);
// Unhook any neutered windows procedures so messages can be delievered
// normally.
UnhookNeuteredWindows();
// Send all deferred "nonqueued" message to the intended receiver.
// We're dropping into SpinInternalEventLoop so we should be fairly
// certain these will get delivered soohn.
ScheduleDeferredMessageRun();
}
SpinInternalEventLoop();
ResetEvent(mEvent);
return true;
}
if (!windowHook) {
MessageChannel::SetIsPumpingMessages(true);
windowHook = SetWindowsHookEx(WH_CALLWNDPROC, CallWindowProcedureHook,
nullptr, gUIThreadId);
NS_ASSERTION(windowHook, "Failed to set hook!");
NS_ASSERTION(!timerId, "Timer already initialized?");
if (mTimeoutMs != kNoTimeout) {
InitTimeoutData(&timeoutData, mTimeoutMs);
timerId = SetTimer(nullptr, 0, mTimeoutMs, nullptr);
NS_ASSERTION(timerId, "SetTimer failed!");
}
}
MSG msg = { 0 };
// Don't get wrapped up in here if the child connection dies.
{
MonitorAutoLock lock(*mMonitor);
if (!Connected()) {
break;
}
}
DWORD result = MsgWaitForMultipleObjects(1, &mEvent, FALSE, INFINITE,
QS_ALLINPUT);
if (result == WAIT_OBJECT_0) {
// Our NotifyWorkerThread event was signaled
ResetEvent(mEvent);
break;
} else
if (result != (WAIT_OBJECT_0 + 1)) {
NS_ERROR("Wait failed!");
break;
}
if (TimeoutHasExpired(timeoutData)) {
// A timeout was specified and we've passed it. Break out.
timedout = true;
break;
}
// See MessageChannel's WaitFor*Notify for details.
bool haveSentMessagesPending =
(HIWORD(GetQueueStatus(QS_SENDMESSAGE)) & QS_SENDMESSAGE) != 0;
// PeekMessage markes the messages as "old" so that they don't wake up
// MsgWaitForMultipleObjects every time.
if (!PeekMessageW(&msg, nullptr, 0, 0, PM_NOREMOVE) &&
!haveSentMessagesPending) {
// Message was for child, we should wait a bit.
SwitchToThread();
}
}
if (windowHook) {
// Unhook the neutered window procedure hook.
UnhookWindowsHookEx(windowHook);
// Unhook any neutered windows procedures so messages can be delivered
// normally.
UnhookNeuteredWindows();
// Before returning we need to set a hook to run any deferred messages that
// we received during the IPC call. The hook will unset itself as soon as
// someone else calls GetMessage, PeekMessage, or runs code that generates
// a "nonqueued" message.
ScheduleDeferredMessageRun();
if (timerId) {
KillTimer(nullptr, timerId);
}
}
MessageChannel::SetIsPumpingMessages(false);
return WaitResponse(timedout);
}
void
MessageChannel::NotifyWorkerThread()
{
mMonitor->AssertCurrentThreadOwns();
NS_ASSERTION(mEvent, "No signal event to set, this is really bad!");
if (!SetEvent(mEvent)) {
NS_WARNING("Failed to set NotifyWorkerThread event!");
}
}
void
DeferredSendMessage::Run()
{
AssertWindowIsNotNeutered(hWnd);
if (!IsWindow(hWnd)) {
NS_ERROR("Invalid window!");
return;
}
WNDPROC wndproc =
reinterpret_cast<WNDPROC>(GetWindowLongPtr(hWnd, GWLP_WNDPROC));
if (!wndproc) {
NS_ERROR("Invalid window procedure!");
return;
}
CallWindowProc(wndproc, hWnd, message, wParam, lParam);
}
void
DeferredRedrawMessage::Run()
{
AssertWindowIsNotNeutered(hWnd);
if (!IsWindow(hWnd)) {
NS_ERROR("Invalid window!");
return;
}
#ifdef DEBUG
BOOL ret =
#endif
RedrawWindow(hWnd, nullptr, nullptr, flags);
NS_ASSERTION(ret, "RedrawWindow failed!");
}
DeferredUpdateMessage::DeferredUpdateMessage(HWND aHWnd)
{
mWnd = aHWnd;
if (!GetUpdateRect(mWnd, &mUpdateRect, FALSE)) {
memset(&mUpdateRect, 0, sizeof(RECT));
return;
}
ValidateRect(mWnd, &mUpdateRect);
}
void
DeferredUpdateMessage::Run()
{
AssertWindowIsNotNeutered(mWnd);
if (!IsWindow(mWnd)) {
NS_ERROR("Invalid window!");
return;
}
InvalidateRect(mWnd, &mUpdateRect, FALSE);
#ifdef DEBUG
BOOL ret =
#endif
UpdateWindow(mWnd);
NS_ASSERTION(ret, "UpdateWindow failed!");
}
DeferredSettingChangeMessage::DeferredSettingChangeMessage(HWND aHWnd,
UINT aMessage,
WPARAM aWParam,
LPARAM aLParam)
: DeferredSendMessage(aHWnd, aMessage, aWParam, aLParam)
{
NS_ASSERTION(aMessage == WM_SETTINGCHANGE, "Wrong message type!");
if (aLParam) {
lParamString = _wcsdup(reinterpret_cast<const wchar_t*>(aLParam));
lParam = reinterpret_cast<LPARAM>(lParamString);
}
else {
lParamString = nullptr;
lParam = 0;
}
}
DeferredSettingChangeMessage::~DeferredSettingChangeMessage()
{
free(lParamString);
}
DeferredWindowPosMessage::DeferredWindowPosMessage(HWND aHWnd,
LPARAM aLParam,
bool aForCalcSize,
WPARAM aWParam)
{
if (aForCalcSize) {
if (aWParam) {
NCCALCSIZE_PARAMS* arg = reinterpret_cast<NCCALCSIZE_PARAMS*>(aLParam);
memcpy(&windowPos, arg->lppos, sizeof(windowPos));
NS_ASSERTION(aHWnd == windowPos.hwnd, "Mismatched hwnds!");
}
else {
RECT* arg = reinterpret_cast<RECT*>(aLParam);
windowPos.hwnd = aHWnd;
windowPos.hwndInsertAfter = nullptr;
windowPos.x = arg->left;
windowPos.y = arg->top;
windowPos.cx = arg->right - arg->left;
windowPos.cy = arg->bottom - arg->top;
NS_ASSERTION(arg->right >= arg->left && arg->bottom >= arg->top,
"Negative width or height!");
}
windowPos.flags = SWP_FRAMECHANGED | SWP_NOACTIVATE | SWP_NOOWNERZORDER |
SWP_NOZORDER | SWP_DEFERERASE | SWP_NOSENDCHANGING;
}
else {
// Not for WM_NCCALCSIZE
WINDOWPOS* arg = reinterpret_cast<WINDOWPOS*>(aLParam);
memcpy(&windowPos, arg, sizeof(windowPos));
NS_ASSERTION(aHWnd == windowPos.hwnd, "Mismatched hwnds!");
// Windows sends in some private flags sometimes that we can't simply copy.
// Filter here.
UINT mask = SWP_ASYNCWINDOWPOS | SWP_DEFERERASE | SWP_DRAWFRAME |
SWP_FRAMECHANGED | SWP_HIDEWINDOW | SWP_NOACTIVATE |
SWP_NOCOPYBITS | SWP_NOMOVE | SWP_NOOWNERZORDER | SWP_NOREDRAW |
SWP_NOREPOSITION | SWP_NOSENDCHANGING | SWP_NOSIZE |
SWP_NOZORDER | SWP_SHOWWINDOW;
windowPos.flags &= mask;
}
}
void
DeferredWindowPosMessage::Run()
{
AssertWindowIsNotNeutered(windowPos.hwnd);
if (!IsWindow(windowPos.hwnd)) {
NS_ERROR("Invalid window!");
return;
}
if (!IsWindow(windowPos.hwndInsertAfter)) {
NS_WARNING("ZOrder change cannot be honored");
windowPos.hwndInsertAfter = 0;
windowPos.flags |= SWP_NOZORDER;
}
#ifdef DEBUG
BOOL ret =
#endif
SetWindowPos(windowPos.hwnd, windowPos.hwndInsertAfter, windowPos.x,
windowPos.y, windowPos.cx, windowPos.cy, windowPos.flags);
NS_ASSERTION(ret, "SetWindowPos failed!");
}
DeferredCopyDataMessage::DeferredCopyDataMessage(HWND aHWnd,
UINT aMessage,
WPARAM aWParam,
LPARAM aLParam)
: DeferredSendMessage(aHWnd, aMessage, aWParam, aLParam)
{
NS_ASSERTION(IsWindow(reinterpret_cast<HWND>(aWParam)), "Bad window!");
COPYDATASTRUCT* source = reinterpret_cast<COPYDATASTRUCT*>(aLParam);
NS_ASSERTION(source, "Should never be null!");
copyData.dwData = source->dwData;
copyData.cbData = source->cbData;
if (source->cbData) {
copyData.lpData = malloc(source->cbData);
if (copyData.lpData) {
memcpy(copyData.lpData, source->lpData, source->cbData);
}
else {
NS_ERROR("Out of memory?!");
copyData.cbData = 0;
}
}
else {
copyData.lpData = nullptr;
}
lParam = reinterpret_cast<LPARAM>(©Data);
}
DeferredCopyDataMessage::~DeferredCopyDataMessage()
{
free(copyData.lpData);
}
DeferredStyleChangeMessage::DeferredStyleChangeMessage(HWND aHWnd,
WPARAM aWParam,
LPARAM aLParam)
: hWnd(aHWnd)
{
index = static_cast<int>(aWParam);
style = reinterpret_cast<STYLESTRUCT*>(aLParam)->styleNew;
}
void
DeferredStyleChangeMessage::Run()
{
SetWindowLongPtr(hWnd, index, style);
}
DeferredSetIconMessage::DeferredSetIconMessage(HWND aHWnd,
UINT aMessage,
WPARAM aWParam,
LPARAM aLParam)
: DeferredSendMessage(aHWnd, aMessage, aWParam, aLParam)
{
NS_ASSERTION(aMessage == WM_SETICON, "Wrong message type!");
}
void
DeferredSetIconMessage::Run()
{
AssertWindowIsNotNeutered(hWnd);
if (!IsWindow(hWnd)) {
NS_ERROR("Invalid window!");
return;
}
WNDPROC wndproc =
reinterpret_cast<WNDPROC>(GetWindowLongPtr(hWnd, GWLP_WNDPROC));
if (!wndproc) {
NS_ERROR("Invalid window procedure!");
return;
}
HICON hOld = reinterpret_cast<HICON>(
CallWindowProc(wndproc, hWnd, message, wParam, lParam));
if (hOld) {
DestroyIcon(hOld);
}
}
