1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include "remoting/host/remote_input_filter.h"
6
7 #include <stdint.h>
8
9 #include "base/logging.h"
10 #include "remoting/proto/event.pb.h"
11
12 namespace {
13
14 // The number of remote mouse events to record for the purpose of eliminating
15 // "echoes" detected by the local input detector. The value should be large
16 // enough to cope with the fact that multiple events might be injected before
17 // any echoes are detected.
18 const unsigned int kNumRemoteMousePositions = 50;
19
20 // The number of remote keypress events to record for the purpose of eliminating
21 // "echoes" detected by the local input detector. The value should be large
22 // enough to cope with the fact that multiple events might be injected before
23 // any echoes are detected.
24 const unsigned int kNumRemoteKeyPresses = 20;
25
26 // The number of milliseconds for which to block remote input when local input
27 // is received.
28 const int64_t kRemoteBlockTimeoutMillis = 2000;
29
30 } // namespace
31
32 namespace remoting {
33
RemoteInputFilter(protocol::InputEventTracker * event_tracker)34 RemoteInputFilter::RemoteInputFilter(protocol::InputEventTracker* event_tracker)
35 : event_tracker_(event_tracker),
36 expect_local_echo_(true) {
37 }
38
39 RemoteInputFilter::~RemoteInputFilter() = default;
40
LocalPointerMoved(const webrtc::DesktopVector & pos,ui::EventType type)41 bool RemoteInputFilter::LocalPointerMoved(const webrtc::DesktopVector& pos,
42 ui::EventType type) {
43 // If this is a genuine local input event (rather than an echo of a remote
44 // input event that we've just injected), then ignore remote inputs for a
45 // short time.
46 //
47 // Note that no platforms both inject and monitor for touch events, so echo
48 // suppression is only applied to mouse input.
49 if (expect_local_echo_ && type == ui::ET_MOUSE_MOVED) {
50 auto found_position = injected_mouse_positions_.begin();
51 while (found_position != injected_mouse_positions_.end() &&
52 !pos.equals(*found_position)) {
53 ++found_position;
54 }
55 if (found_position != injected_mouse_positions_.end()) {
56 // Remove it from the list, and any positions that were added before it,
57 // if any. This is because the local input monitor is assumed to receive
58 // injected mouse position events in the order in which they were injected
59 // (if at all). If the position is found somewhere other than the front
60 // of the queue, this would be because the earlier positions weren't
61 // successfully injected (or the local input monitor might have skipped
62 // over some positions), and not because the events were out-of-sequence.
63 // These spurious positions should therefore be discarded.
64 injected_mouse_positions_.erase(injected_mouse_positions_.begin(),
65 ++found_position);
66 return false;
67 }
68 }
69
70 LocalInputDetected();
71 return true;
72 }
73
LocalKeyPressed(uint32_t usb_keycode)74 bool RemoteInputFilter::LocalKeyPressed(uint32_t usb_keycode) {
75 // If local echo is expected and |usb_keycode| is the oldest unechoed injected
76 // keypress, then ignore it.
77 if (expect_local_echo_ && !injected_key_presses_.empty() &&
78 injected_key_presses_.front() == usb_keycode) {
79 injected_key_presses_.pop_front();
80 return false;
81 }
82
83 LocalInputDetected();
84 return true;
85 }
86
LocalInputDetected()87 void RemoteInputFilter::LocalInputDetected() {
88 event_tracker_->ReleaseAll();
89 latest_local_input_time_ = base::TimeTicks::Now();
90 }
91
SetExpectLocalEcho(bool expect_local_echo)92 void RemoteInputFilter::SetExpectLocalEcho(bool expect_local_echo) {
93 expect_local_echo_ = expect_local_echo;
94 if (!expect_local_echo_)
95 injected_mouse_positions_.clear();
96 }
97
InjectKeyEvent(const protocol::KeyEvent & event)98 void RemoteInputFilter::InjectKeyEvent(const protocol::KeyEvent& event) {
99 if (ShouldIgnoreInput())
100 return;
101 if (expect_local_echo_ && event.pressed() && event.has_usb_keycode()) {
102 injected_key_presses_.push_back(event.usb_keycode());
103 if (injected_key_presses_.size() > kNumRemoteKeyPresses) {
104 VLOG(1) << "Injected key press queue full.";
105 injected_key_presses_.clear();
106 }
107 }
108 event_tracker_->InjectKeyEvent(event);
109 }
110
InjectTextEvent(const protocol::TextEvent & event)111 void RemoteInputFilter::InjectTextEvent(const protocol::TextEvent& event) {
112 if (ShouldIgnoreInput())
113 return;
114 event_tracker_->InjectTextEvent(event);
115 }
116
InjectMouseEvent(const protocol::MouseEvent & event)117 void RemoteInputFilter::InjectMouseEvent(const protocol::MouseEvent& event) {
118 if (ShouldIgnoreInput())
119 return;
120 if (expect_local_echo_ && event.has_x() && event.has_y()) {
121 injected_mouse_positions_.push_back(
122 webrtc::DesktopVector(event.x(), event.y()));
123 if (injected_mouse_positions_.size() > kNumRemoteMousePositions) {
124 VLOG(1) << "Injected mouse positions queue full.";
125 injected_mouse_positions_.pop_front();
126 }
127 }
128 event_tracker_->InjectMouseEvent(event);
129 }
130
InjectTouchEvent(const protocol::TouchEvent & event)131 void RemoteInputFilter::InjectTouchEvent(const protocol::TouchEvent& event) {
132 if (ShouldIgnoreInput())
133 return;
134 event_tracker_->InjectTouchEvent(event);
135 }
136
ShouldIgnoreInput() const137 bool RemoteInputFilter::ShouldIgnoreInput() const {
138 // Ignore remote events if the local mouse moved recently.
139 int64_t millis =
140 (base::TimeTicks::Now() - latest_local_input_time_).InMilliseconds();
141 if (millis < kRemoteBlockTimeoutMillis)
142 return true;
143 return false;
144 }
145
146 } // namespace remoting
147