remoting/host/remote_input_filter.cc

   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 "base/logging.h"
   8 #include "remoting/proto/event.pb.h"
   9
  10 namespace {
  11
  12 // The number of remote mouse events to record for the purpose of eliminating
  13 // "echoes" detected by the local input detector. The value should be large
  14 // enough to cope with the fact that multiple events might be injected before
  15 // any echoes are detected.
  16 const unsigned int kNumRemoteMousePositions = 50;
  17
  18 // The number of milliseconds for which to block remote input when local input
  19 // is received.
  20 const int64 kRemoteBlockTimeoutMillis = 2000;
  21
  22 } // namespace
  23
  24 namespace remoting {
  25
  26 RemoteInputFilter::RemoteInputFilter(protocol::InputEventTracker* event_tracker)
  27     : event_tracker_(event_tracker),
  28       expect_local_echo_(true) {
  29 }
  30
  31 RemoteInputFilter::~RemoteInputFilter() {
  32 }
  33
  34 void RemoteInputFilter::LocalMouseMoved(
  35     const webrtc::DesktopVector& mouse_pos) {
  36   // If this is a genuine local input event (rather than an echo of a remote
  37   // input event that we've just injected), then ignore remote inputs for a
  38   // short time.
  39   if (expect_local_echo_) {
  40     std::list<webrtc::DesktopVector>::iterator found_position =
  41         injected_mouse_positions_.begin();
  42     while (found_position != injected_mouse_positions_.end() &&
  43            !mouse_pos.equals(*found_position)) {
  44       ++found_position;
  45     }
  46     if (found_position != injected_mouse_positions_.end()) {
  47       // Remove it from the list, and any positions that were added before it,
  48       // if any.  This is because the local input monitor is assumed to receive
  49       // injected mouse position events in the order in which they were injected
  50       // (if at all).  If the position is found somewhere other than the front
  51       // of the queue, this would be because the earlier positions weren't
  52       // successfully injected (or the local input monitor might have skipped
  53       // over some positions), and not because the events were out-of-sequence.
  54       // These spurious positions should therefore be discarded.
  55       injected_mouse_positions_.erase(injected_mouse_positions_.begin(),
  56                                       ++found_position);
  57       return;
  58     }
  59   }
  60
  61   // Release all pressed buttons or keys, disable inputs, and note the time.
  62   event_tracker_->ReleaseAll();
  63   latest_local_input_time_ = base::TimeTicks::Now();
  64 }
  65
  66 void RemoteInputFilter::SetExpectLocalEcho(bool expect_local_echo) {
  67   expect_local_echo_ = expect_local_echo;
  68   if (!expect_local_echo_)
  69     injected_mouse_positions_.clear();
  70 }
  71
  72 void RemoteInputFilter::InjectKeyEvent(const protocol::KeyEvent& event) {
  73   if (ShouldIgnoreInput())
  74     return;
  75   event_tracker_->InjectKeyEvent(event);
  76 }
  77
  78 void RemoteInputFilter::InjectTextEvent(const protocol::TextEvent& event) {
  79   if (ShouldIgnoreInput())
  80     return;
  81   event_tracker_->InjectTextEvent(event);
  82 }
  83
  84 void RemoteInputFilter::InjectMouseEvent(const protocol::MouseEvent& event) {
  85   if (ShouldIgnoreInput())
  86     return;
  87   if (expect_local_echo_ && event.has_x() && event.has_y()) {
  88     injected_mouse_positions_.push_back(
  89         webrtc::DesktopVector(event.x(), event.y()));
  90     if (injected_mouse_positions_.size() > kNumRemoteMousePositions) {
  91       VLOG(1) << "Injected mouse positions queue full.";
  92       injected_mouse_positions_.pop_front();
  93     }
  94   }
  95   event_tracker_->InjectMouseEvent(event);
  96 }
  97
  98 bool RemoteInputFilter::ShouldIgnoreInput() const {
  99   // Ignore remote events if the local mouse moved recently.
 100   int64 millis =
 101       (base::TimeTicks::Now() - latest_local_input_time_).InMilliseconds();
 102   if (millis < kRemoteBlockTimeoutMillis)
 103     return true;
 104   return false;
 105 }
 106
 107 }  // namespace remoting