Handle newCursorPosition correctly for Android's commitText()

third_party/WebKit/Source/core/editing/InputMethodController.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 167 matching lines @@
 
     // The composition can start inside a composed character sequence, so we have to override checks.
     // See <http://bugs.webkit.org/show_bug.cgi?id=15781>
     VisibleSelection selection;
     selection.setWithoutValidation(range.startPosition(), range.endPosition());
     frame().selection().setSelection(selection, 0);
 }
 
 bool InputMethodController::confirmComposition()
 {
-    return confirmComposition(composingText());
+    return replaceComposition(composingText(), KeepSelection);
 }
 
-bool InputMethodController::confirmComposition(const String& text, ConfirmCompositionBehavior confirmBehavior)
+bool InputMethodController::replaceComposition(const String& text, ConfirmCompositionBehavior confirmBehavior)
 {
     if (!hasComposition())
         return false;
 
     Optional<Editor::RevealSelectionScope> revealSelectionScope;
     if (confirmBehavior == KeepSelection)
         revealSelectionScope.emplace(&editor());
 
     // If the composition was set from existing text and didn't change, then
     // there's nothing to do here (and we should avoid doing anything as that
@@ skipping 23 matching lines @@
     insertTextDuringCompositionWithEvents(frame(), text, 0, TypingCommand::TextCompositionType::TextCompositionConfirm);
     // Event handler might destroy document.
     if (!frame().document())
         return false;
 
     // No DOM update after 'compositionend'.
     dispatchCompositionEndEvent(frame(), text);
 
     return true;
 }
 

[yabinh, 2016/08/29 08:44:01]

Move the comments here.

-bool InputMethodController::confirmCompositionOrInsertText(const String& text, ConfirmCompositionBehavior confirmBehavior)
+// If > 0, relativeCaretPosition is relative to the end of the text - 1;
+// if <= 0, its' relative to the start of the text.
+// This is to match Android behavior. See
+// https://developer.android.com/reference/android/view/inputmethod/InputConnection.html#commitText(java.lang.CharSequence, int)

[tkent, 2016/08/30 07:47:11]

Even though this follows an Android standard API, the current specification of
|relativeCaretPosition| is hard to understand and not acceptable.  Adding ", 1"
to many places looks very weird.

How about changing it to simply 'relative to the end of the text'?  i.e. this
function is just |return textStart + textLength + relativeCaretPosition|.

Conversion from Java's commitText(text, pos) would be
  if (pos > 0)
    Blink's confirmComposition(text, 1 - pos);
  else
    Blink's confirmComposition(text, pos - text.length());

[yabinh, 2016/08/30 12:33:05]

Done.

+static int computeAbsoluteCaretPosition(size_t textStart, size_t textLength, int relativeCaretPosition)
 {
-    if (!hasComposition()) {
-        if (!text.length())
-            return false;
+    if (relativeCaretPosition > 0)
+        relativeCaretPosition += textLength - 1;
+    return textStart + relativeCaretPosition;
+}
 
-        if (dispatchBeforeInputInsertText(frame().document()->focusedElement(), text) != DispatchEventResult::NotCanceled)
-            return false;
+bool InputMethodController::replaceCompositionAndMoveCaret(const String& text, int relativeCaretPosition)
+{
+    Element* rootEditableElement = frame().selection().rootEditableElement();
+    if (!rootEditableElement)
+        return false;
+    PlainTextRange compositionRange = PlainTextRange::create(*rootEditableElement, *m_compositionRange);
+    if (compositionRange.isNull())
+        return false;
+    int textStart = compositionRange.start();
 
-        editor().insertText(text, 0);
+    if (!replaceComposition(text, DoNotKeepSelection))
+        return false;
+
+    int absoluteCaretPosition = computeAbsoluteCaretPosition(textStart, text.length(), relativeCaretPosition);
+    return moveCaret(absoluteCaretPosition);
+}
+
+bool InputMethodController::commitComposition(const String& text)
+{
+    if (!hasComposition())
+        return insertText(text);
+
+    if (text.length()) {
+        replaceComposition(text, KeepSelection);
         return true;
     }
 
-    if (text.length()) {
-        confirmComposition(text);
-        return true;
-    }
-
-    if (confirmBehavior == DoNotKeepSelection)
-        return confirmComposition(composingText(), DoNotKeepSelection);
-
     SelectionOffsetsScope selectionOffsetsScope(this);
     return confirmComposition();
 }
 
+bool InputMethodController::commitCompositionAndMoveCaret(const String& text, int relativeCaretPosition)
+{
+    if (!hasComposition())
+        return insertTextAndMoveCaret(text, relativeCaretPosition);
+    if (text.length())
+        return replaceCompositionAndMoveCaret(text, relativeCaretPosition);
+    return replaceCompositionAndMoveCaret(composingText(), relativeCaretPosition);
+}
+
+bool InputMethodController::insertText(const String& text)
+{
+    if (!text.length())
+        return false;
+    if (dispatchBeforeInputInsertText(frame().document()->focusedElement(), text) != DispatchEventResult::NotCanceled)
+        return false;
+    editor().insertText(text, 0);
+    return true;
+}
+
+bool InputMethodController::insertTextAndMoveCaret(const String& text, int relativeCaretPosition)
+{
+    PlainTextRange selectionRange = getSelectionOffsets();
+    if (selectionRange.isNull())
+        return false;
+    int textStart = selectionRange.start();
+
+    if (!insertText(text))
+        return false;
+
+    int absoluteCaretPosition = computeAbsoluteCaretPosition(textStart, text.length(), relativeCaretPosition);
+    return moveCaret(absoluteCaretPosition);
+}
+
 void InputMethodController::cancelComposition()
 {
     if (!hasComposition())
         return;
 
     Editor::RevealSelectionScope revealSelectionScope(&editor());
 
     if (frame().selection().isNone())
         return;
 
@@ skipping 65 matching lines @@
     //    Sending a compositionupdate event at this time ensures that at least one
     //    compositionupdate event is dispatched.
     // 2. Updating the existing composition node.
     //    Send a compositionupdate event when this function updates the existing composition
     //    node, i.e. hasComposition() && !text.isEmpty().
     // 3. Canceling the ongoing composition.
     //    Send a compositionend event when function deletes the existing composition node, i.e.
     //    !hasComposition() && test.isEmpty().
     if (text.isEmpty()) {
         if (hasComposition()) {
-            confirmComposition(emptyString());
+            replaceComposition(emptyString(), KeepSelection);
         } else {
             // It's weird to call |setComposition()| with empty text outside composition, however some IME
             // (e.g. Japanese IBus-Anthy) did this, so we simply delete selection without sending extra events.
             TypingCommand::deleteSelection(*frame().document(), TypingCommand::PreventSpellChecking);
         }
 
         setEditableSelectionOffsets(selectedRange);
         return;
     }
 
@@ skipping 179 matching lines @@
 
     rightBoundary += textLength;
 
     // In case of exceeding the right boundary.
     start = std::min(start, rightBoundary);
     end = std::min(end, rightBoundary);
 
     return PlainTextRange(start, end);
 }
 
+bool InputMethodController::moveCaret(int newCaretPosition)
+{
+    frame().document()->updateStyleAndLayoutIgnorePendingStylesheets();
+
+    PlainTextRange selectedRange = createRangeForSelection(newCaretPosition, newCaretPosition, 0);
+    if (selectedRange.isNull())
+        return false;
+    return setEditableSelectionOffsets(selectedRange);
+}
+
 void InputMethodController::extendSelectionAndDelete(int before, int after)
 {
     if (!editor().canEdit())
         return;
     PlainTextRange selectionOffsets(getSelectionOffsets());
     if (selectionOffsets.isNull())
         return;
 
     // A common call of before=1 and after=0 will fail if the last character
     // is multi-code-word UTF-16, including both multi-16bit code-points and
@@ skipping 19 matching lines @@
     TypingCommand::deleteSelection(*frame().document());
 }
 
 DEFINE_TRACE(InputMethodController)
 {
     visitor->trace(m_frame);
     visitor->trace(m_compositionRange);
 }
 
 } // namespace blink