content/common/input/gesture_event_stream_validator.cc

   1 // Copyright 2014 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 "content/common/input/gesture_event_stream_validator.h"
   6
   7 #include "base/logging.h"
   8 #include "third_party/WebKit/public/web/WebInputEvent.h"
   9
  10 using blink::WebInputEvent;
  11
  12 namespace content {
  13
  14 GestureEventStreamValidator::GestureEventStreamValidator()
  15     : scrolling_(false), pinching_(false), waiting_for_tap_end_(false) {
  16 }
  17
  18 GestureEventStreamValidator::~GestureEventStreamValidator() {
  19 }
  20
  21 bool GestureEventStreamValidator::Validate(const blink::WebGestureEvent& event,
  22                                            std::string* error_msg) {
  23   DCHECK(error_msg);
  24   error_msg->clear();
  25   switch (event.type) {
  26     case WebInputEvent::GestureScrollBegin:
  27       if (scrolling_ || pinching_)
  28         error_msg->append("Scroll begin during scroll\n");
  29       scrolling_ = true;
  30       break;
  31     case WebInputEvent::GestureScrollUpdate:
  32     case WebInputEvent::GestureScrollUpdateWithoutPropagation:
  33       if (!scrolling_)
  34         error_msg->append("Scroll update outside of scroll\n");
  35       break;
  36     case WebInputEvent::GestureScrollEnd:
  37     case WebInputEvent::GestureFlingStart:
  38       if (!scrolling_)
  39         error_msg->append("Scroll end outside of scroll\n");
  40       if (pinching_)
  41         error_msg->append("Ending scroll while pinching\n");
  42       scrolling_ = false;
  43       break;
  44     case WebInputEvent::GesturePinchBegin:
  45       if (!scrolling_)
  46         error_msg->append("Pinch begin outside of scroll\n");
  47       if (pinching_)
  48         error_msg->append("Pinch begin during pinch\n");
  49       pinching_ = true;
  50       break;
  51     case WebInputEvent::GesturePinchUpdate:
  52       if (!pinching_ || !scrolling_)
  53         error_msg->append("Pinch update outside of pinch\n");
  54       break;
  55     case WebInputEvent::GesturePinchEnd:
  56       if (!pinching_ || !scrolling_)
  57         error_msg->append("Pinch end outside of pinch\n");
  58       pinching_ = false;
  59       break;
  60     case WebInputEvent::GestureTapDown:
  61       if (waiting_for_tap_end_)
  62         error_msg->append("Missing tap end event\n");
  63       waiting_for_tap_end_ = true;
  64       break;
  65     case WebInputEvent::GestureTap:
  66     case WebInputEvent::GestureTapCancel:
  67     case WebInputEvent::GestureDoubleTap:
  68       if (!waiting_for_tap_end_)
  69         error_msg->append("Missing GestureTapDown event\n");
  70       waiting_for_tap_end_ = false;
  71       break;
  72     default:
  73       break;
  74   }
  75   return error_msg->empty();
  76 }
  77
  78 }  // namespace content