Bug 1343037 part 14. Implement nsTextEditorState::SetSelectionDirection. r=ehsan

This introduces two behavior changes:

1)  In cached mode, we used to treat unknown selection directions as "none".
    Now we treat it like "forward", consistently with the "have an editor" mode.
2)  Before this change, in cached mode, we did not fire "select" events on
    selectionDirection changes.

MozReview-Commit-ID: 4nBCAm3mAiz

dom/html/HTMLInputElement.cpp

@@ -6539,22 +6539,8 @@ HTMLInputElement::SetSelectionDirection(const nsAString& aDirection, ErrorResult
   }
 
   nsTextEditorState* state = GetEditorState();
-  if (state && state->IsSelectionCached()) {
-    nsITextControlFrame::SelectionDirection dir = nsITextControlFrame::eNone;
-    if (aDirection.EqualsLiteral("forward")) {
-      dir = nsITextControlFrame::eForward;
-    } else if (aDirection.EqualsLiteral("backward")) {
-      dir = nsITextControlFrame::eBackward;
-    }
-    state->GetSelectionProperties().SetDirection(dir);
-    return;
-  }
-
-  int32_t start, end;
-  GetSelectionRange(&start, &end, aRv);
-  if (!aRv.Failed()) {
-    aRv = SetSelectionRange(start, end, aDirection);
-  }
+  MOZ_ASSERT(state, "SupportsTextSelection came back true!");
+  state->SetSelectionDirection(aDirection, aRv);
 }
 
 NS_IMETHODIMP

dom/html/HTMLTextAreaElement.cpp

@@ -765,27 +765,7 @@ void
 HTMLTextAreaElement::SetSelectionDirection(const nsAString& aDirection,
                                            ErrorResult& aError)
 {
-  if (mState.IsSelectionCached()) {
-    nsITextControlFrame::SelectionDirection dir = nsITextControlFrame::eNone;
-    if (aDirection.EqualsLiteral("forward")) {
-      dir = nsITextControlFrame::eForward;
-    } else if (aDirection.EqualsLiteral("backward")) {
-      dir = nsITextControlFrame::eBackward;
-    }
-    mState.GetSelectionProperties().SetDirection(dir);
-    return;
-  }
-
-  int32_t start, end;
-  GetSelectionRange(&start, &end, aError);
-  if (aError.Failed()) {
-    return;
-  }
-
-  nsresult rv = SetSelectionRange(start, end, aDirection);
-  if (NS_FAILED(rv)) {
-    aError.Throw(rv);
-  }
+  mState.SetSelectionDirection(aDirection, aError);
 }
 
 NS_IMETHODIMP

dom/html/nsTextEditorState.cpp

@@ -1762,6 +1762,38 @@ nsTextEditorState::SetSelectionEnd(const mozilla::dom::Nullable<uint32_t>& aEnd,
   SetSelectionRange(start, end, dir, aRv);
 }
 
+static nsITextControlFrame::SelectionDirection
+DirectionStringToSelectionDirection(const nsAString& aDirection)
+{
+  if (aDirection.EqualsLiteral("backward")) {
+    return nsITextControlFrame::eBackward;
+  }
+
+  // We don't support directionless selections.
+  return nsITextControlFrame::eForward;
+}
+
+void
+nsTextEditorState::SetSelectionDirection(const nsAString& aDirection,
+                                         ErrorResult& aRv)
+{
+  nsITextControlFrame::SelectionDirection dir =
+    DirectionStringToSelectionDirection(aDirection);
+
+  if (IsSelectionCached()) {
+    GetSelectionProperties().SetDirection(dir);
+    return;
+  }
+
+  int32_t start, end;
+  GetSelectionRange(&start, &end, aRv);
+  if (aRv.Failed()) {
+    return;
+  }
+
+  SetSelectionRange(start, end, dir, aRv);
+}
+
 HTMLInputElement*
 nsTextEditorState::GetParentNumberControl(nsFrame* aFrame) const
 {

dom/html/nsTextEditorState.h

@@ -310,6 +310,12 @@ public:
   void SetSelectionEnd(const mozilla::dom::Nullable<uint32_t>& aEnd,
                        mozilla::ErrorResult& aRv);
 
+  // Set the selection direction.  This basically implements the
+  // https://html.spec.whatwg.org/multipage/forms.html#dom-textarea/input-selectiondirection
+  // setter.
+  void SetSelectionDirection(const nsAString& aDirection,
+                             mozilla::ErrorResult& aRv);
+
   void UpdateEditableState(bool aNotify) {
     if (mRootNode) {
       mRootNode->UpdateEditableState(aNotify);