Bug 555642 part.1 nsCaret should have a way to override the caret visible state for hiding caret temporarily and nsEditor should hide caret if composition string doesn't have caret information r=roc

editor/libeditor/IMETextTxn.cpp

@@ -223,7 +223,12 @@ IMETextTxn::SetIMESelection(nsEditor& aEditor,
                  static_cast<uint32_t>(caretOffset) <= maxOffset);
       rv = selection->Collapse(aTextNode, caretOffset);
       setCaret = setCaret || NS_SUCCEEDED(rv);
-      NS_ASSERTION(setCaret, "Failed to collapse normal selection");
+      if (NS_WARN_IF(!setCaret)) {
+        continue;
+      }
+      // If caret range is specified explicitly, we should show the caret if
+      // it should be so.
+      aEditor.HideCaret(false);
       continue;
     }
 
@@ -292,6 +297,8 @@ IMETextTxn::SetIMESelection(nsEditor& aEditor,
     rv = selection->Collapse(aTextNode, caretOffset);
     NS_ASSERTION(NS_SUCCEEDED(rv),
                  "Failed to set caret at the end of composition string");
+    // If caret range isn't specified explicitly, we should hide the caret.
+    aEditor.HideCaret(true);
   }
 
   rv = selection->EndBatchChanges();

editor/libeditor/nsEditor.cpp

@@ -147,6 +147,7 @@ nsEditor::nsEditor()
 ,  mDidPostCreate(false)
 ,  mDispatchInputEvent(true)
 ,  mIsInEditAction(false)
+,  mHidingCaret(false)
 {
 }
 
@@ -158,6 +159,8 @@ nsEditor::~nsEditor()
     mComposition->OnEditorDestroyed();
     mComposition = nullptr;
   }
+  // If this editor is still hiding the caret, we need to restore it.
+  HideCaret(false);
   mTxnMgr = nullptr;
 
   delete mPhonetic;
@@ -464,6 +467,8 @@ nsEditor::PreDestroy(bool aDestroyingFrames)
 
   // Unregister event listeners
   RemoveEventListeners();
+  // If this editor is still hiding the caret, we need to restore it.
+  HideCaret(false);
   mActionListeners.Clear();
   mEditorObservers.Clear();
   mDocStateListeners.Clear();
@@ -2065,6 +2070,10 @@ nsEditor::EndIMEComposition()
     }
   }
 
+  // Composition string may have hidden the caret.  Therefore, we need to
+  // cancel it here.
+  HideCaret(false);
+
   /* reset the data we need to construct a transaction */
   mIMETextNode = nullptr;
   mIMETextOffset = 0;
@@ -5258,3 +5267,23 @@ nsEditor::GetIMESelectionStartOffsetIn(nsINode* aTextNode)
   }
   return minOffset < INT32_MAX ? minOffset : -1;
 }
+
+void
+nsEditor::HideCaret(bool aHide)
+{
+  if (mHidingCaret == aHide) {
+    return;
+  }
+
+  nsCOMPtr<nsIPresShell> presShell = GetPresShell();
+  NS_ENSURE_TRUE_VOID(presShell);
+  nsRefPtr<nsCaret> caret = presShell->GetCaret();
+  NS_ENSURE_TRUE_VOID(caret);
+
+  mHidingCaret = aHide;
+  if (aHide) {
+    caret->AddForceHide();
+  } else {
+    caret->RemoveForceHide();
+  }
+}

editor/libeditor/nsEditor.h

@@ -824,6 +824,13 @@ public:
   void FindBetterInsertionPoint(nsCOMPtr<nsINode>& aNode,
                                 int32_t& aOffset);
 
+  /**
+   * HideCaret() hides caret with nsCaret::AddForceHide() or may show carent
+   * with nsCaret::RemoveForceHide().  This does NOT set visibility of
+   * nsCaret.  Therefore, this is stateless.
+   */
+  void HideCaret(bool aHide);
+
 protected:
   enum Tristate {
     eTriUnset,
@@ -883,6 +890,7 @@ protected:
   bool mDidPostCreate;    // whether PostCreate has been called
   bool mDispatchInputEvent;
   bool mIsInEditAction;   // true while the instance is handling an edit action
+  bool mHidingCaret;      // whether caret is hidden forcibly.
 
   friend bool NSCanUnload(nsISupports* serviceMgr);
   friend class nsAutoTxnsConserveSelection;

layout/base/nsCaret.cpp

@@ -127,8 +127,9 @@ IsKeyboardRTL()
 
 nsCaret::nsCaret()
 : mOverrideOffset(0)
-, mIsBlinkOn(false)
 , mBlinkCount(-1)
+, mHideCount(0)
+, mIsBlinkOn(false)
 , mVisible(false)
 , mReadOnly(false)
 , mShowDuringSelection(false)
@@ -266,7 +267,7 @@ void nsCaret::SetVisible(bool inMakeVisible)
 
 bool nsCaret::IsVisible()
 {
-  if (!mVisible) {
+  if (!mVisible || mHideCount) {
     return false;
   }
 
@@ -303,6 +304,25 @@ bool nsCaret::IsVisible()
   return true;
 }
 
+void nsCaret::AddForceHide()
+{
+  MOZ_ASSERT(mHideCount < UINT32_MAX);
+  if (++mHideCount > 1) {
+    return;
+  }
+  ResetBlinking();
+  SchedulePaint();
+}
+
+void nsCaret::RemoveForceHide()
+{
+  if (!mHideCount || --mHideCount) {
+    return;
+  }
+  ResetBlinking();
+  SchedulePaint();
+}
+
 void nsCaret::SetCaretReadOnly(bool inMakeReadonly)
 {
   mReadOnly = inMakeReadonly;
@@ -622,7 +642,7 @@ void nsCaret::ResetBlinking()
 {
   mIsBlinkOn = true;
 
-  if (mReadOnly || !mVisible) {
+  if (mReadOnly || !mVisible || mHideCount) {
     StopBlinking();
     return;
   }

layout/base/nsCaret.h

@@ -78,6 +78,21 @@ class nsCaret final : public nsISelectionListener
      *  because we're in non-editable/disabled content.
      */
     bool IsVisible();
+    /**
+     * AddForceHide() increases mHideCount and hide the caret even if
+     * SetVisible(true) has been or will be called.  This is useful when the
+     * caller wants to hide caret temporarily and it needs to cancel later.
+     * Especially, in the latter case, it's too difficult to decide if the
+     * caret should be actually visible or not because caret visible state
+     * is set from a lot of event handlers.  So, it's very stateful.
+     */
+    void AddForceHide();
+    /**
+     * RemoveForceHide() decreases mHideCount if it's over 0.
+     * If the value becomes 0, this may show the caret if SetVisible(true)
+     * has been called.
+     */
+    void RemoveForceHide();
     /** SetCaretReadOnly set the appearance of the caret
      *  @param inMakeReadonly true to show the caret in a 'read only' state,
      *         false to show the caret in normal, editing state
@@ -201,17 +216,22 @@ protected:
      * Ignored if mOverrideContent is null.
      */
     int32_t               mOverrideOffset;
-
-    /**
-     * mIsBlinkOn is true when we're in a blink cycle where the caret is on.
-     */
-    bool                  mIsBlinkOn;
     /**
      * mBlinkCount is used to control the number of times to blink the caret
      * before stopping the blink. This is reset each time we reset the
      * blinking.
      */
     int32_t               mBlinkCount;
+    /**
+     * mHideCount is not 0, it means that somebody doesn't want the caret
+     * to be visible.  See AddForceHide() and RemoveForceHide().
+     */
+    uint32_t              mHideCount;
+
+    /**
+     * mIsBlinkOn is true when we're in a blink cycle where the caret is on.
+     */
+    bool                  mIsBlinkOn;
     /**
      * mIsVisible is true when SetVisible was last called with 'true'.
      */