Bug 697981 - Prevent reloading of spelling dictionary on unfocused editors; r=roc

editor/libeditor/nsEditor.cpp

@@ -148,6 +148,7 @@ nsEditor::nsEditor()
 ,  mDispatchInputEvent(true)
 ,  mIsInEditAction(false)
 ,  mHidingCaret(false)
+,  mObservingDictionaryUpdates(false)
 {
 }
 
@@ -307,7 +308,7 @@ nsEditor::PostCreate()
     nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService();
     if (obs) {
       obs->AddObserver(this,
-                       SPELLCHECK_DICTIONARY_UPDATE_NOTIFICATION,
+                       SPELLCHECK_DICTIONARY_REMOVE_NOTIFICATION,
                        false);
     }
   }
@@ -451,6 +452,8 @@ nsEditor::PreDestroy(bool aDestroyingFrames)
   if (obs) {
     obs->RemoveObserver(this,
                         SPELLCHECK_DICTIONARY_UPDATE_NOTIFICATION);
+    obs->RemoveObserver(this,
+                        SPELLCHECK_DICTIONARY_REMOVE_NOTIFICATION);
   }
 
   // Let spellchecker clean up its observers etc. It is important not to
@@ -1315,7 +1318,9 @@ NS_IMETHODIMP nsEditor::Observe(nsISupports* aSubj, const char *aTopic,
                                 const char16_t *aData)
 {
   NS_ASSERTION(!strcmp(aTopic,
-                       SPELLCHECK_DICTIONARY_UPDATE_NOTIFICATION),
+                       SPELLCHECK_DICTIONARY_UPDATE_NOTIFICATION) ||
+               !strcmp(aTopic,
+                       SPELLCHECK_DICTIONARY_REMOVE_NOTIFICATION),
                "Unexpected observer topic");
 
   // When mozInlineSpellChecker::CanEnableInlineSpellChecking changes
@@ -5202,6 +5207,29 @@ nsEditor::OnFocus(nsIDOMEventTarget* aFocusEventTarget)
   }
 }
 
+void
+nsEditor::StartWatchingDictionaryChanges()
+{
+  if (!mObservingDictionaryUpdates) {
+    nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService();
+    if (obs) {
+      obs->AddObserver(this, SPELLCHECK_DICTIONARY_UPDATE_NOTIFICATION, false);
+    }
+    mObservingDictionaryUpdates = true;
+  }
+}
+
+void
+nsEditor::StopWatchingDictionaryChanges()
+{
+  // Removing an observer that wasn't added doesn't cause any harm.
+  nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService();
+  if (obs) {
+    obs->RemoveObserver(this, SPELLCHECK_DICTIONARY_UPDATE_NOTIFICATION);
+  }
+  mObservingDictionaryUpdates = false;
+}
+
 NS_IMETHODIMP
 nsEditor::GetSuppressDispatchingInputEvent(bool *aSuppressed)
 {

editor/libeditor/nsEditor.h

@@ -249,6 +249,9 @@ public:
 
   void SwitchTextDirectionTo(uint32_t aDirection);
 
+  void StartWatchingDictionaryChanges();
+  void StopWatchingDictionaryChanges();
+
 protected:
   nsresult DetermineCurrentDirection();
   void FireInputEvent();
@@ -891,6 +894,7 @@ protected:
   bool mDispatchInputEvent;
   bool mIsInEditAction;   // true while the instance is handling an edit action
   bool mHidingCaret;      // whether caret is hidden forcibly.
+  bool mObservingDictionaryUpdates;  // whether the editor is observing dictionary changes.
 
   friend bool NSCanUnload(nsISupports* serviceMgr);
   friend class nsAutoTxnsConserveSelection;

editor/libeditor/nsEditorEventListener.cpp

@@ -1114,6 +1114,8 @@ nsEditorEventListener::Focus(nsIDOMEvent* aEvent)
     }
   }
 
+  mEditor->StartWatchingDictionaryChanges();
+
   mEditor->OnFocus(target);
 
   nsCOMPtr<nsIPresShell> ps = GetPresShell();
@@ -1130,6 +1132,8 @@ nsEditorEventListener::Blur(nsIDOMEvent* aEvent)
 {
   NS_ENSURE_TRUE(aEvent, NS_OK);
 
+  mEditor->StopWatchingDictionaryChanges();
+
   // check if something else is focused. If another element is focused, then
   // we should not change the selection.
   nsIFocusManager* fm = nsFocusManager::GetFocusManager();

extensions/spellcheck/hunspell/src/mozHunspell.cpp

@@ -604,5 +604,11 @@ NS_IMETHODIMP mozHunspell::RemoveDirectory(nsIFile *aDir)
 {
   mDynamicDirectories.RemoveObject(aDir);
   LoadDictionaryList(true);
+  nsCOMPtr<nsIObserverService> obs = mozilla::services::GetObserverService();
+  if (obs) {
+    obs->NotifyObservers(nullptr,
+                         SPELLCHECK_DICTIONARY_REMOVE_NOTIFICATION,
+                         nullptr);
+  }
   return NS_OK;
 }

extensions/spellcheck/idl/mozISpellCheckingEngine.idl

@@ -104,4 +104,6 @@ interface mozISpellCheckingEngine : nsISupports {
 
 #define SPELLCHECK_DICTIONARY_UPDATE_NOTIFICATION \
   "spellcheck-dictionary-update"
+#define SPELLCHECK_DICTIONARY_REMOVE_NOTIFICATION \
+  "spellcheck-dictionary-remove"
 %}