gecko-dev/widget/TextEventDispatcher.h

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8.4 KiB
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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef mozilla_textcompositionsynthesizer_h_
#define mozilla_textcompositionsynthesizer_h_
#include "nsAutoPtr.h"
#include "nsString.h"
#include "mozilla/Attributes.h"
#include "mozilla/EventForwards.h"
#include "mozilla/TextEventDispatcherListener.h"
#include "mozilla/TextRange.h"
class nsIWidget;
namespace mozilla {
namespace widget {
struct IMENotification;
/**
* TextEventDispatcher is a helper class for dispatching widget events defined
* in TextEvents.h. Currently, this is a helper for dispatching
* WidgetCompositionEvent. However, WidgetKeyboardEvent and/or
* WidgetQueryContentEvent may be supported by this class in the future.
* An instance of this class is created by nsIWidget instance and owned by it.
* This is typically created only by the top level widgets because only they
* handle IME.
*/
class TextEventDispatcher MOZ_FINAL
{
~TextEventDispatcher()
{
}
NS_INLINE_DECL_REFCOUNTING(TextEventDispatcher)
public:
explicit TextEventDispatcher(nsIWidget* aWidget);
/**
* Initializes the instance for IME or automated test. Either IME or tests
* need to call one of them before starting composition. If they return
* NS_ERROR_ALREADY_INITIALIZED, it means that the listener already listens
* notifications from TextEventDispatcher for same purpose (for IME or tests).
* If this returns another error, the caller shouldn't keep starting
* composition.
*
* @param aListener Specify the listener to listen notifications and
* requests. This must not be null.
* NOTE: aListener is stored as weak reference in
* TextEventDispatcher. See mListener
* definition below.
*/
nsresult BeginInputTransaction(TextEventDispatcherListener* aListener);
nsresult BeginInputTransactionForTests(
TextEventDispatcherListener* aListener);
/**
* OnDestroyWidget() is called when mWidget is being destroyed.
*/
void OnDestroyWidget();
/**
* GetState() returns current state of this class.
*
* @return NS_OK: Fine to compose text.
* NS_ERROR_NOT_INITIALIZED: BeginInputTransaction() or
* BeginInputTransactionForTests()
* should be called.
* NS_ERROR_NOT_AVAILABLE: The widget isn't available for
* composition.
*/
nsresult GetState() const;
/**
* IsComposing() returns true after calling StartComposition() and before
* calling CommitComposition().
*/
bool IsComposing() const { return mIsComposing; }
/**
* StartComposition() starts composition explicitly.
*/
nsresult StartComposition(nsEventStatus& aStatus);
/**
* CommitComposition() commits composition.
*
* @param aCommitString If this is null, commits with the last composition
* string. Otherwise, commits the composition with
* this value.
*/
nsresult CommitComposition(nsEventStatus& aStatus,
const nsAString* aCommitString = nullptr);
/**
* SetPendingCompositionString() sets new composition string which will be
* dispatched with NS_COMPOSITION_CHANGE event by calling Flush().
*
* @param aString New composition string.
*/
nsresult SetPendingCompositionString(const nsAString& aString)
{
return mPendingComposition.SetString(aString);
}
/**
* AppendClauseToPendingComposition() appends a clause information to
* the pending composition string.
*
* @param aLength Length of the clause.
* @param aAttribute One of NS_TEXTRANGE_RAWINPUT,
* NS_TEXTRANGE_SELECTEDRAWTEXT,
* NS_TEXTRANGE_CONVERTEDTEXT or
* NS_TEXTRANGE_SELECTEDCONVERTEDTEXT.
*/
nsresult AppendClauseToPendingComposition(uint32_t aLength,
uint32_t aAttribute)
{
return mPendingComposition.AppendClause(aLength, aAttribute);
}
/**
* SetCaretInPendingComposition() sets caret position in the pending
* composition string and its length. This is optional. If IME doesn't
* want to show caret, it shouldn't need to call this.
*
* @param aOffset Offset of the caret in the pending composition
* string. This should not be larger than the length
* of the pending composition string.
* @param aLength Caret width. If this is 0, caret will be collapsed.
* Note that Gecko doesn't supported wide caret yet,
* therefore, this is ignored for now.
*/
nsresult SetCaretInPendingComposition(uint32_t aOffset,
uint32_t aLength)
{
return mPendingComposition.SetCaret(aOffset, aLength);
}
/**
* FlushPendingComposition() sends the pending composition string
* to the widget of the store DOM window. Before calling this, IME needs to
* set pending composition string with SetPendingCompositionString(),
* AppendClauseToPendingComposition() and/or
* SetCaretInPendingComposition().
*/
nsresult FlushPendingComposition(nsEventStatus& aStatus)
{
return mPendingComposition.Flush(this, aStatus);
}
/**
* @see nsIWidget::NotifyIME()
*/
nsresult NotifyIME(const IMENotification& aIMENotification);
private:
// mWidget is owner of the instance. When this is created, this is set.
// And when mWidget is released, this is cleared by OnDestroyWidget().
// Note that mWidget may be destroyed already (i.e., mWidget->Destroyed() may
// return true).
nsIWidget* mWidget;
// mListener is a weak reference to TextEventDispatcherListener. That might
// be referred by JS. Therefore, the listener might be difficult to release
// itself if this is a strong reference. Additionally, it's difficult to
// check if a method to uninstall the listener is called by valid instance.
// So, using weak reference is the best way in this case.
nsWeakPtr mListener;
// mPendingComposition stores new composition string temporarily.
// These values will be used for dispatching NS_COMPOSITION_CHANGE event
// in Flush(). When Flush() is called, the members will be cleared
// automatically.
class PendingComposition
{
public:
PendingComposition();
nsresult SetString(const nsAString& aString);
nsresult AppendClause(uint32_t aLength, uint32_t aAttribute);
nsresult SetCaret(uint32_t aOffset, uint32_t aLength);
nsresult Flush(TextEventDispatcher* aDispatcher, nsEventStatus& aStatus);
void Clear();
private:
nsAutoString mString;
nsRefPtr<TextRangeArray> mClauses;
TextRange mCaret;
void EnsureClauseArray();
};
PendingComposition mPendingComposition;
bool mForTests;
// See IsComposing().
bool mIsComposing;
nsresult BeginInputTransactionInternal(
TextEventDispatcherListener* aListener,
bool aForTests);
/**
* InitEvent() initializes aEvent. This must be called before dispatching
* the event.
*/
void InitEvent(WidgetCompositionEvent& aEvent) const;
/**
* StartCompositionAutomaticallyIfNecessary() starts composition if it hasn't
* been started it yet.
*
* @param aStatus If it succeeded to start composition normally, this
* returns nsEventStatus_eIgnore. Otherwise, e.g.,
* the composition is canceled during dispatching
* compositionstart event, this returns
* nsEventStatus_eConsumeNoDefault. In this case,
* the caller shouldn't keep doing its job.
* @return Only when something unexpected occurs, this returns
* an error. Otherwise, returns NS_OK even if aStatus
* is nsEventStatus_eConsumeNoDefault.
*/
nsresult StartCompositionAutomaticallyIfNecessary(nsEventStatus& aStatus);
};
} // namespace widget
} // namespace mozilla
#endif // #ifndef mozilla_widget_textcompositionsynthesizer_h_