Bug 1176950 nsTextStore should keep storing locked content until NOTIFY_IME_OF_COMPOSITION_UPDATE is notified r=emk

widget/windows/nsTextStore.cpp

@@ -1230,6 +1230,7 @@ nsTextStore::nsTextStore()
   , mPendingOnSelectionChange(false)
   , mPendingOnLayoutChange(false)
   , mPendingDestroy(false)
+  , mPendingClearLockedContent(false)
   , mNativeCaretIsCreated(false)
   , mDeferNotifyingTSF(false)
 {
@@ -1604,7 +1605,10 @@ nsTextStore::FlushPendingActions()
     return;
   }
 
-  mLockedContent.Clear();
+  // If dispatching event causes NOTIFY_IME_OF_COMPOSITION_UPDATE, we should
+  // wait to abandon mLockedContent until it's notified because the dispatched
+  // event may be handled asynchronously in e10s mode.
+  mPendingClearLockedContent = !mPendingActions.Length();
 
   nsRefPtr<nsWindowBase> kungFuDeathGrip(mWidget);
   for (uint32_t i = 0; i < mPendingActions.Length(); i++) {
@@ -1638,6 +1642,8 @@ nsTextStore::FlushPendingActions()
         WidgetCompositionEvent compositionStart(true, NS_COMPOSITION_START,
                                                 mWidget);
         mWidget->InitEvent(compositionStart);
+        // NS_COMPOSITION_START always causes NOTIFY_IME_OF_COMPOSITION_UPDATE.
+        mPendingClearLockedContent = true;
         DispatchEvent(compositionStart);
         if (!mWidget || mWidget->Destroyed()) {
           break;
@@ -1701,6 +1707,11 @@ nsTextStore::FlushPendingActions()
           action.mRanges->AppendElement(wholeRange);
         }
         compositionChange.mRanges = action.mRanges;
+        // When the NS_COMPOSITION_CHANGE causes a DOM text event,
+        // NOTIFY_IME_OF_COMPOSITION_UPDATE will be notified.
+        if (compositionChange.CausesDOMTextEvent()) {
+          mPendingClearLockedContent = true;
+        }
         DispatchEvent(compositionChange);
         // Be aware, the mWidget might already have been destroyed.
         break;
@@ -1721,6 +1732,11 @@ nsTextStore::FlushPendingActions()
                                                  mWidget);
         mWidget->InitEvent(compositionCommit);
         compositionCommit.mData = action.mData;
+        // When the NS_COMPOSITION_COMMIT causes a DOM text event,
+        // NOTIFY_IME_OF_COMPOSITION_UPDATE will be notified.
+        if (compositionCommit.CausesDOMTextEvent()) {
+          mPendingClearLockedContent = true;
+        }
         DispatchEvent(compositionCommit);
         if (!mWidget || mWidget->Destroyed()) {
           break;
@@ -1783,6 +1799,11 @@ nsTextStore::MaybeFlushPendingNotifications()
     return;
   }
 
+  if (mPendingClearLockedContent) {
+    mPendingClearLockedContent = false;
+    mLockedContent.Clear();
+  }
+
   if (mPendingOnLayoutChange) {
     MOZ_LOG(sTextStoreLog, LogLevel::Info,
            ("TSF: 0x%p   nsTextStore::MaybeFlushPendingNotifications(), "
@@ -1904,9 +1925,9 @@ nsTextStore::GetSelection(ULONG ulIndex,
 nsTextStore::Content&
 nsTextStore::LockedContent()
 {
-  MOZ_ASSERT(IsReadLocked(),
+  // This should be called when the document is locked or the content hasn't
-             "LockedContent must be called only during the document is locked");
+  // been abandoned yet.
-  if (!IsReadLocked()) {
+  if (NS_WARN_IF(!IsReadLocked() && !mLockedContent.IsInitialized())) {
     mLockedContent.Clear();
     return mLockedContent;
   }
@@ -4364,6 +4385,8 @@ nsTextStore::OnTextChangeInternal(const IMENotification& aIMENotification)
 void
 nsTextStore::NotifyTSFOfTextChange(const TS_TEXTCHANGE& aTextChange)
 {
+  // XXX We need to cache the text change ranges and notify TSF of that
+  //     the document is unlocked.
   if (NS_WARN_IF(IsReadLocked())) {
     return;
   }
@@ -4531,9 +4554,7 @@ nsTextStore::OnUpdateCompositionInternal()
      "mDeferNotifyingTSF=%s",
      this, GetBoolName(mDeferNotifyingTSF)));
 
-  if (!mDeferNotifyingTSF) {
+  mPendingClearLockedContent = true;
-    return NS_OK;
-  }
   mDeferNotifyingTSF = false;
   MaybeFlushPendingNotifications();
   return NS_OK;

widget/windows/nsTextStore.h

@@ -684,9 +684,9 @@ protected:
 
     bool mInitialized;
   };
-  // mLockedContent caches content of the document ONLY while the document
+  // mLockedContent starts to cache content of the document at first query of
-  // is locked.  I.e., the content is cleared at unlocking the document since
+  // the content during a document lock.  This is abandoned after document is
-  // we need to reduce the memory usage.  This is initialized by
+  // unlocked and dispatched events are handled.  This is initialized by
   // LockedContent() automatically.  So, don't access this member directly
   // except at calling Clear(), IsInitialized(), IsLayoutChangedAfter() or
   // IsLayoutChanged().
@@ -779,6 +779,9 @@ protected:
   // During the documet is locked, we shouldn't destroy the instance.
   // If this is true, the instance will be destroyed after unlocked.
   bool                         mPendingDestroy;
+  // If this is true, MaybeFlushPendingNotifications() will clear the
+  // mLockedContent.
+  bool                         mPendingClearLockedContent;
   // While there is native caret, this is true.  Otherwise, false.
   bool                         mNativeCaretIsCreated;
   // While the instance is dispatching events, the event may not be handled