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// Copyright 2013 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef UI_EVENTS_EVENT_SOURCE_H_
#define UI_EVENTS_EVENT_SOURCE_H_
#include <list>
#include <memory>
#include <vector>
#include "base/scoped_observation_traits.h"
#include "ui/events/event_dispatcher.h"
#include "ui/events/event_rewriter.h"
#include "ui/events/events_export.h"
namespace ui {
class Event;
class EventSink;
// EventSource receives events from the native platform (e.g. X11, win32 etc.)
// and sends the events to an EventSink.
class EVENTS_EXPORT EventSource {
public:
EventSource();
EventSource(const EventSource&) = delete;
EventSource& operator=(const EventSource&) = delete;
virtual ~EventSource();
virtual EventSink* GetEventSink() = 0;
// Adds a rewriter to modify events before they are sent to the
// EventSink. The rewriter must be explicitly removed from the
// EventSource before the rewriter is destroyed. The EventSource
// does not take ownership of the rewriter.
void AddEventRewriter(EventRewriter* rewriter);
void RemoveEventRewriter(EventRewriter* rewriter);
// Sends the event through all rewriters and onto the source's EventSink.
EventDispatchDetails SendEventToSink(const Event* event);
// Send the event to the sink after rewriting; subclass overrides may queue
// events before delivery, i.e. for the WindowService.
virtual EventDispatchDetails DeliverEventToSink(Event* event);
protected:
// Sends the event through the rewriters and onto the source's EventSink.
// If |rewriter| is valid, |event| is only sent to the subsequent rewriters.
// This is used for asynchronous reposting of events processed by |rewriter|.
// TODO(kpschoedel): Remove along with old EventRewriter API.
EventDispatchDetails SendEventToSinkFromRewriter(
const Event* event,
const EventRewriter* rewriter);
private:
// Implementation of EventRewriterContinuation. No details need to be
// visible outside of event_source.cc.
class EventRewriterContinuationImpl;
// It's sufficient to have one EventRewriterContinuationImpl for each
// registered EventRewriter, so a list of them also serves as a list
// of registered rewriters.
typedef std::list<std::unique_ptr<EventRewriterContinuationImpl>>
EventRewriterList;
// Returns the EventRewriterContinuation for a given EventRewriter,
// or |rewriter_list_.end()| if the rewriter is not registered.
EventRewriterList::iterator FindContinuation(const EventRewriter* rewriter);
EventRewriterList rewriter_list_;
friend class EventRewriter; // TODO(kpschoedel): Remove along with old API.
friend class EventSourceTestApi;
};
} // namespace ui
namespace base {
template <>
struct ScopedObservationTraits<ui::EventSource, ui::EventRewriter> {
static void AddObserver(ui::EventSource* source,
ui::EventRewriter* observer) {
source->AddEventRewriter(observer);
}
static void RemoveObserver(ui::EventSource* source,
ui::EventRewriter* observer) {
source->RemoveEventRewriter(observer);
}
};
} // namespace base
#endif // UI_EVENTS_EVENT_SOURCE_H_