[InputEvent] Fire 'beforeinput' during typing, pressing hot keys and IME composition

third_party/WebKit/Source/core/events/InputEvent.cpp

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/events/InputEvent.h"
 
 #include "core/events/EventDispatcher.h"
+#include "public/platform/WebEditingCommandType.h"
 
 namespace blink {
 
+namespace {
+
+const struct {
+    InputEvent::InputType inputType;
+    const char* stringName;
+} kInputTypeStringNameMap[] = {
+    {InputEvent::InputType::None, ""},
+    {InputEvent::InputType::InsertText, "insertText"},
+    {InputEvent::InputType::ReplaceContent, "replaceContent"},
+    {InputEvent::InputType::DeleteContent, "deleteContent"},
+    {InputEvent::InputType::DeleteComposedCharacter, "deleteComposedCharacter"},
+    {InputEvent::InputType::Undo, "undo"},
+    {InputEvent::InputType::Redo, "redo"},
+};
+
+static_assert(arraysize(kInputTypeStringNameMap) == static_cast<size_t>(InputEvent::InputType::NumberOfInputTypes),
+    "must handle all InputEvent::InputType");
+
+String InputTypeToString(InputEvent::InputType inputType)
+{
+    const auto& it = std::begin(kInputTypeStringNameMap) + static_cast<size_t>(inputType);
+    if (it >= std::begin(kInputTypeStringNameMap) && it < std::end(kInputTypeStringNameMap))
+        return String(it->stringName);

[chongz, 2016/04/13 00:34:28]

Should I construct a local String table from |kInputTypeStringNameMap| so we
don't need to allocate every time? Or is there any cleaner way to do it?

[yosin_UTC9, 2016/04/13 06:13:09]

How about using AtomicString?

[chongz, 2016/04/13 23:53:09]

Done.

+    return "";

[yosin_UTC9, 2016/04/13 06:13:09]

s/""/emptyString()/

[chongz, 2016/04/13 23:53:09]

Done.

+}
+
+InputEvent::InputType InputTypeFromString(const String& stringName)

[yosin_UTC9, 2016/04/13 06:13:09]

s/InputTypeFromString/inputTypeFromString/ or |convertInputTypeToString()|
Functions in Blink should start with lower case letter.

[chongz, 2016/04/13 23:53:09]

Done.

+{
+    // TODO(chongz): Use binary search if the map goes larger.
+    for (const auto& entry : kInputTypeStringNameMap) {
+        if (codePointCompareIgnoringASCIICase(stringName, entry.stringName) == 0)
+            return entry.inputType;
+    }
+    return InputEvent::InputType::None;
+}
+
+} // anonymous namespace
+
 InputEvent::InputEvent()
 {
 }
 
 InputEvent::InputEvent(const AtomicString& type, const InputEventInit& initializer)
     : UIEvent(type, initializer)
 {
+    if (initializer.hasInputType())
+        m_inputType = InputTypeFromString(initializer.inputType());
+    if (initializer.hasData())
+        m_data = initializer.data();
+}
+
+/* static */
+InputEvent* InputEvent::createBeforeInputTyping(InputType inputType, const String& data)
+{
+    InputEventInit inputEventInit;
+
+    inputEventInit.setBubbles(true);
+    inputEventInit.setCancelable(true);
+    inputEventInit.setInputType(InputTypeToString(inputType));

[chongz, 2016/04/13 00:34:28]

I have to convert |inputType| to String here and then convert back to
|inputType| in |InputEvent::InputEvent(const AtomicString& type, const
InputEventInit& initializer)| since |InputEventInit.inputType| is String.

Adding another constructor that takes individual arguments instead of
|InputEventInit| looks ugly... Is there a better way to fix it? 

+    inputEventInit.setData(data);
+
+    return InputEvent::create(EventTypeNames::beforeinput, inputEventInit);
+}
+
+/* static */
+InputEvent* InputEvent::createBeforeInputFromComposition(InputType inputType, const String& data)
+{
+    InputEventInit inputEventInit;
+
+    inputEventInit.setBubbles(true);
+    inputEventInit.setCancelable(false);
+    inputEventInit.setInputType(InputTypeToString(inputType));
+    inputEventInit.setData(data);
+
+    return InputEvent::create(EventTypeNames::beforeinput, inputEventInit);
+}
+
+/* static */
+InputEvent* InputEvent::createBeforeInputEditorCommand(InputType inputType, const String& data)
+{
+    InputEventInit inputEventInit;
+
+    inputEventInit.setBubbles(true);
+    inputEventInit.setCancelable(true);
+    inputEventInit.setInputType(InputTypeToString(inputType));
+    inputEventInit.setData(data);
+
+    return InputEvent::create(EventTypeNames::beforeinput, inputEventInit);
+}
+
+String InputEvent::inputType() const
+{
+    return InputTypeToString(m_inputType);
 }
 
 bool InputEvent::isInputEvent() const
 {
     return true;
 }
 
 DEFINE_TRACE(InputEvent)
 {
     UIEvent::trace(visitor);
 }
 
 } // namespace blink