Adding upstream version 86.0.1.upstream/86.0.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 305 insertions, 0 deletions

diff --git a/widget/nsBaseAppShell.cpp b/widget/nsBaseAppShell.cpp
new file mode 100644
index 0000000000..648096b8c2
--- /dev/null
+++ b/widget/nsBaseAppShell.cpp
@@ -0,0 +1,305 @@
+/* -*- Mode: c++; tab-width: 2; indent-tabs-mode: nil; -*- */
+/* 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 "base/message_loop.h"
+
+#include "nsBaseAppShell.h"
+#include "nsExceptionHandler.h"
+#include "nsThreadUtils.h"
+#include "nsIObserverService.h"
+#include "nsServiceManagerUtils.h"
+#include "mozilla/Services.h"
+#include "nsXULAppAPI.h"
+
+// When processing the next thread event, the appshell may process native
+// events (if not in performance mode), which can result in suppressing the
+// next thread event for at most this many ticks:
+#define THREAD_EVENT_STARVATION_LIMIT PR_MillisecondsToInterval(10)
+
+NS_IMPL_ISUPPORTS(nsBaseAppShell, nsIAppShell, nsIThreadObserver, nsIObserver)
+
+nsBaseAppShell::nsBaseAppShell()
+    : mSuspendNativeCount(0),
+      mEventloopNestingLevel(0),
+      mBlockedWait(nullptr),
+      mFavorPerf(0),
+      mNativeEventPending(false),
+      mStarvationDelay(0),
+      mSwitchTime(0),
+      mLastNativeEventTime(0),
+      mEventloopNestingState(eEventloopNone),
+      mRunning(false),
+      mExiting(false),
+      mBlockNativeEvent(false),
+      mProcessedGeckoEvents(false) {}
+
+nsBaseAppShell::~nsBaseAppShell() = default;
+
+nsresult nsBaseAppShell::Init() {
+  // Configure ourselves as an observer for the current thread:
+
+  if (XRE_UseNativeEventProcessing()) {
+    nsCOMPtr<nsIThreadInternal> threadInt =
+        do_QueryInterface(NS_GetCurrentThread());
+    NS_ENSURE_STATE(threadInt);
+
+    threadInt->SetObserver(this);
+  }
+
+  nsCOMPtr<nsIObserverService> obsSvc = mozilla::services::GetObserverService();
+  if (obsSvc) obsSvc->AddObserver(this, NS_XPCOM_SHUTDOWN_OBSERVER_ID, false);
+  return NS_OK;
+}
+
+// Called by nsAppShell's native event callback
+void nsBaseAppShell::NativeEventCallback() {
+  if (!mNativeEventPending.exchange(false)) return;
+
+  // If DoProcessNextNativeEvent is on the stack, then we assume that we can
+  // just unwind and let nsThread::ProcessNextEvent process the next event.
+  // However, if we are called from a nested native event loop (maybe via some
+  // plug-in or library function), then go ahead and process Gecko events now.
+  if (mEventloopNestingState == eEventloopXPCOM) {
+    mEventloopNestingState = eEventloopOther;
+    // XXX there is a tiny risk we will never get a new NativeEventCallback,
+    // XXX see discussion in bug 389931.
+    return;
+  }
+
+  // nsBaseAppShell::Run is not being used to pump events, so this may be
+  // our only opportunity to process pending gecko events.
+
+  nsIThread* thread = NS_GetCurrentThread();
+  bool prevBlockNativeEvent = mBlockNativeEvent;
+  if (mEventloopNestingState == eEventloopOther) {
+    if (!NS_HasPendingEvents(thread)) return;
+    // We're in a nested native event loop and have some gecko events to
+    // process.  While doing that we block processing native events from the
+    // appshell - instead, we want to get back to the nested native event
+    // loop ASAP (bug 420148).
+    mBlockNativeEvent = true;
+  }
+
+  IncrementEventloopNestingLevel();
+  EventloopNestingState prevVal = mEventloopNestingState;
+  NS_ProcessPendingEvents(thread, THREAD_EVENT_STARVATION_LIMIT);
+  mProcessedGeckoEvents = true;
+  mEventloopNestingState = prevVal;
+  mBlockNativeEvent = prevBlockNativeEvent;
+
+  // Continue processing pending events later (we don't want to starve the
+  // embedders event loop).
+  if (NS_HasPendingEvents(thread)) DoProcessMoreGeckoEvents();
+
+  DecrementEventloopNestingLevel();
+}
+
+// Note, this is currently overidden on windows, see comments in nsAppShell for
+// details.
+void nsBaseAppShell::DoProcessMoreGeckoEvents() { OnDispatchedEvent(); }
+
+// Main thread via OnProcessNextEvent below
+bool nsBaseAppShell::DoProcessNextNativeEvent(bool mayWait) {
+  // The next native event to be processed may trigger our NativeEventCallback,
+  // in which case we do not want it to process any thread events since we'll
+  // do that when this function returns.
+  //
+  // If the next native event is not our NativeEventCallback, then we may end
+  // up recursing into this function.
+  //
+  // However, if the next native event is not our NativeEventCallback, but it
+  // results in another native event loop, then our NativeEventCallback could
+  // fire and it will see mEventloopNestingState as eEventloopOther.
+  //
+  EventloopNestingState prevVal = mEventloopNestingState;
+  mEventloopNestingState = eEventloopXPCOM;
+
+  IncrementEventloopNestingLevel();
+  bool result = ProcessNextNativeEvent(mayWait);
+  DecrementEventloopNestingLevel();
+
+  mEventloopNestingState = prevVal;
+  return result;
+}
+
+//-------------------------------------------------------------------------
+// nsIAppShell methods:
+
+NS_IMETHODIMP
+nsBaseAppShell::Run(void) {
+  NS_ENSURE_STATE(!mRunning);  // should not call Run twice
+  mRunning = true;
+
+  nsIThread* thread = NS_GetCurrentThread();
+
+  MessageLoop::current()->Run();
+
+  NS_ProcessPendingEvents(thread);
+
+  mRunning = false;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBaseAppShell::Exit(void) {
+  if (mRunning && !mExiting) {
+    MessageLoop::current()->Quit();
+  }
+  mExiting = true;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBaseAppShell::FavorPerformanceHint(bool favorPerfOverStarvation,
+                                     uint32_t starvationDelay) {
+  mStarvationDelay = PR_MillisecondsToInterval(starvationDelay);
+  if (favorPerfOverStarvation) {
+    ++mFavorPerf;
+  } else {
+    --mFavorPerf;
+    mSwitchTime = PR_IntervalNow();
+  }
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBaseAppShell::SuspendNative() {
+  ++mSuspendNativeCount;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBaseAppShell::ResumeNative() {
+  --mSuspendNativeCount;
+  NS_ASSERTION(mSuspendNativeCount >= 0,
+               "Unbalanced call to nsBaseAppShell::ResumeNative!");
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBaseAppShell::GetEventloopNestingLevel(uint32_t* aNestingLevelResult) {
+  NS_ENSURE_ARG_POINTER(aNestingLevelResult);
+
+  *aNestingLevelResult = mEventloopNestingLevel;
+
+  return NS_OK;
+}
+
+//-------------------------------------------------------------------------
+// nsIThreadObserver methods:
+
+// Called from any thread
+NS_IMETHODIMP
+nsBaseAppShell::OnDispatchedEvent() {
+  if (mBlockNativeEvent) return NS_OK;
+
+  if (mNativeEventPending.exchange(true)) return NS_OK;
+
+  // Returns on the main thread in NativeEventCallback above
+  ScheduleNativeEventCallback();
+  return NS_OK;
+}
+
+// Called from the main thread
+NS_IMETHODIMP
+nsBaseAppShell::OnProcessNextEvent(nsIThreadInternal* thr, bool mayWait) {
+  if (mBlockNativeEvent) {
+    if (!mayWait) return NS_OK;
+    // Hmm, we're in a nested native event loop and would like to get
+    // back to it ASAP, but it seems a gecko event has caused us to
+    // spin up a nested XPCOM event loop (eg. modal window), so we
+    // really must start processing native events here again.
+    mBlockNativeEvent = false;
+    if (NS_HasPendingEvents(thr))
+      OnDispatchedEvent();  // in case we blocked it earlier
+  }
+
+  PRIntervalTime start = PR_IntervalNow();
+  PRIntervalTime limit = THREAD_EVENT_STARVATION_LIMIT;
+
+  // Unblock outer nested wait loop (below).
+  if (mBlockedWait) *mBlockedWait = false;
+
+  bool* oldBlockedWait = mBlockedWait;
+  mBlockedWait = &mayWait;
+
+  // When mayWait is true, we need to make sure that there is an event in the
+  // thread's event queue before we return.  Otherwise, the thread will block
+  // on its event queue waiting for an event.
+  bool needEvent = mayWait;
+  // Reset prior to invoking DoProcessNextNativeEvent which might cause
+  // NativeEventCallback to process gecko events.
+  mProcessedGeckoEvents = false;
+
+  if (mFavorPerf <= 0 && start > mSwitchTime + mStarvationDelay) {
+    // Favor pending native events
+    PRIntervalTime now = start;
+    bool keepGoing;
+    do {
+      mLastNativeEventTime = now;
+      keepGoing = DoProcessNextNativeEvent(false);
+    } while (keepGoing && ((now = PR_IntervalNow()) - start) < limit);
+  } else {
+    // Avoid starving native events completely when in performance mode
+    if (start - mLastNativeEventTime > limit) {
+      mLastNativeEventTime = start;
+      DoProcessNextNativeEvent(false);
+    }
+  }
+
+  while (!NS_HasPendingEvents(thr) && !mProcessedGeckoEvents) {
+    // If we have been asked to exit from Run, then we should not wait for
+    // events to process.  Note that an inner nested event loop causes
+    // 'mayWait' to become false too, through 'mBlockedWait'.
+    if (mExiting) mayWait = false;
+
+    mLastNativeEventTime = PR_IntervalNow();
+    if (!DoProcessNextNativeEvent(mayWait) || !mayWait) break;
+  }
+
+  mBlockedWait = oldBlockedWait;
+
+  // Make sure that the thread event queue does not block on its monitor, as
+  // it normally would do if it did not have any pending events.  To avoid
+  // that, we simply insert a dummy event into its queue during shutdown.
+  if (needEvent && !mExiting && !NS_HasPendingEvents(thr)) {
+    DispatchDummyEvent(thr);
+  }
+
+  return NS_OK;
+}
+
+bool nsBaseAppShell::DispatchDummyEvent(nsIThread* aTarget) {
+  NS_ASSERTION(NS_IsMainThread(), "Wrong thread!");
+
+  if (!mDummyEvent) mDummyEvent = new mozilla::Runnable("DummyEvent");
+
+  return NS_SUCCEEDED(aTarget->Dispatch(mDummyEvent, NS_DISPATCH_NORMAL));
+}
+
+void nsBaseAppShell::IncrementEventloopNestingLevel() {
+  ++mEventloopNestingLevel;
+  CrashReporter::SetEventloopNestingLevel(mEventloopNestingLevel);
+}
+
+void nsBaseAppShell::DecrementEventloopNestingLevel() {
+  --mEventloopNestingLevel;
+  CrashReporter::SetEventloopNestingLevel(mEventloopNestingLevel);
+}
+
+// Called from the main thread
+NS_IMETHODIMP
+nsBaseAppShell::AfterProcessNextEvent(nsIThreadInternal* thr,
+                                      bool eventWasProcessed) {
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsBaseAppShell::Observe(nsISupports* subject, const char* topic,
+                        const char16_t* data) {
+  NS_ASSERTION(!strcmp(topic, NS_XPCOM_SHUTDOWN_OBSERVER_ID), "oops");
+  Exit();
+  return NS_OK;
+}