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// Copyright 2015 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.
#ifndef REMOTING_CLIENT_NORMALIZING_INPUT_FILTER_MAC_H_
#define REMOTING_CLIENT_NORMALIZING_INPUT_FILTER_MAC_H_
#include <map>
#include "base/macros.h"
#include "remoting/protocol/input_filter.h"
namespace remoting {
// NormalizingInputFilterMac is designed to solve the problem of missing keyup
// events on Mac.
//
// PROBLEM
//
// On Mac if user presses CMD and then C key there is no keyup event generated
// for C when user releases the C key before the CMD key.
// The cause is that CMD + C triggers a system action and Chrome injects only a
// keydown event for the C key. Safari shares the same behavior.
//
// SOLUTION
//
// When a keyup event for CMD key happens we will check all prior keydown
// events received and inject corresponding keyup events artificially, with
// the exception of:
//
// SHIFT, CONTROL, OPTION, LEFT CMD, RIGHT CMD and CAPS LOCK
//
// because they are reported by Chrome correctly.
//
// There are a couple cases that this solution doesn't work perfectly, one
// of them leads to duplicated keyup events.
//
// User performs this sequence of actions:
//
// CMD DOWN, C DOWN, CMD UP, C UP
//
// In this case the algorithm will generate:
//
// CMD DOWN, C DOWN, C UP, CMD UP, C UP
//
// Because we artificially generate keyup events the C UP event is duplicated
// as user releases the key after CMD key. This would not be a problem as the
// receiver end will drop this duplicated keyup event.
class NormalizingInputFilterMac : public protocol::InputFilter {
public:
explicit NormalizingInputFilterMac(protocol::InputStub* input_stub);
~NormalizingInputFilterMac() override;
// InputFilter overrides.
void InjectKeyEvent(const protocol::KeyEvent& event) override;
private:
typedef std::map<int, protocol::KeyEvent> KeyPressedMap;
// Generate keyup events for any keys pressed with CMD.
void GenerateKeyupEvents();
// A map that stores pressed keycodes and the corresponding key event.
KeyPressedMap key_pressed_map_;
DISALLOW_COPY_AND_ASSIGN(NormalizingInputFilterMac);
};
} // namespace remoting
#endif // REMOTING_CLIENT_NORMALIZING_INPUT_FILTER_MAC_H_
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