blob: b5e70902792435e36d8bb58c6cff5c46c3b462e5 [file] [log] [blame]
// Copyright 2014 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.
#include "content/common/input/touch_event_stream_validator.h"
#include "base/logging.h"
#include "base/strings/stringprintf.h"
#include "content/common/input/web_touch_event_traits.h"
#include "third_party/WebKit/public/platform/WebTouchEvent.h"
#include "ui/events/blink/web_input_event_traits.h"
using base::StringPrintf;
using blink::WebInputEvent;
using blink::WebTouchEvent;
using blink::WebTouchPoint;
namespace content {
namespace {
const WebTouchPoint* FindTouchPoint(const WebTouchEvent& event, int id) {
for (unsigned i = 0; i < event.touches_length; ++i) {
if (event.touches[i].id == id)
return &event.touches[i];
}
return NULL;
}
std::string TouchPointIdsToString(const WebTouchEvent& event) {
std::stringstream ss;
for (unsigned i = 0; i < event.touches_length; ++i) {
if (i)
ss << ",";
ss << event.touches[i].id;
}
return ss.str();
}
} // namespace
TouchEventStreamValidator::TouchEventStreamValidator() {
}
TouchEventStreamValidator::~TouchEventStreamValidator() {
}
bool TouchEventStreamValidator::Validate(const WebTouchEvent& event,
std::string* error_msg) {
DCHECK(error_msg);
error_msg->clear();
// TouchScrollStarted is not part of a regular touch event stream.
if (event.GetType() == WebInputEvent::kTouchScrollStarted)
return true;
WebTouchEvent previous_event = previous_event_;
previous_event_ = event;
if (!event.touches_length) {
error_msg->append("Touch event is empty.\n");
return false;
}
if (!WebInputEvent::IsTouchEventType(event.GetType())) {
error_msg->append(StringPrintf("Touch event has invalid type: %s\n",
WebInputEvent::GetName(event.GetType())));
}
// Allow "hard" restarting of touch stream validation. This is necessary
// in cases where touch event forwarding ceases in response to the event ack
// or removal of touch handlers.
if (WebTouchEventTraits::IsTouchSequenceStart(event))
previous_event = WebTouchEvent();
// Unreleased points from the previous event should exist in the latest event.
for (unsigned i = 0; i < previous_event.touches_length; ++i) {
const WebTouchPoint& previous_point = previous_event.touches[i];
if (previous_point.state == WebTouchPoint::kStateCancelled ||
previous_point.state == WebTouchPoint::kStateReleased)
continue;
const WebTouchPoint* point = FindTouchPoint(event, previous_point.id);
if (!point) {
error_msg->append(StringPrintf(
"Previously active touch point (id=%d) not in new event (ids=%s).\n",
previous_point.id, TouchPointIdsToString(event).c_str()));
}
}
bool found_valid_state_for_type = false;
for (unsigned i = 0; i < event.touches_length; ++i) {
const WebTouchPoint& point = event.touches[i];
const WebTouchPoint* previous_point =
FindTouchPoint(previous_event, point.id);
// The point should exist in the previous event if it is not a new point.
if (!previous_point) {
if (point.state != WebTouchPoint::kStatePressed)
error_msg->append(StringPrintf(
"Active touch point (id=%d) not in previous event (ids=%s).\n",
point.id, TouchPointIdsToString(previous_event).c_str()));
} else {
if (point.state == WebTouchPoint::kStatePressed &&
previous_point->state != WebTouchPoint::kStateCancelled &&
previous_point->state != WebTouchPoint::kStateReleased) {
error_msg->append(StringPrintf(
"Pressed touch point (id=%d) already exists in previous event "
"(ids=%s).\n",
point.id, TouchPointIdsToString(previous_event).c_str()));
}
}
switch (point.state) {
case WebTouchPoint::kStateUndefined:
error_msg->append(
StringPrintf("Undefined touch point state (id=%d).\n", point.id));
break;
case WebTouchPoint::kStateReleased:
if (event.GetType() != WebInputEvent::kTouchEnd) {
error_msg->append(StringPrintf(
"Released touch point (id=%d) outside touchend.\n", point.id));
} else {
found_valid_state_for_type = true;
}
break;
case WebTouchPoint::kStatePressed:
if (event.GetType() != WebInputEvent::kTouchStart) {
error_msg->append(StringPrintf(
"Pressed touch point (id=%d) outside touchstart.\n", point.id));
} else {
found_valid_state_for_type = true;
}
break;
case WebTouchPoint::kStateMoved:
if (event.GetType() != WebInputEvent::kTouchMove) {
error_msg->append(StringPrintf(
"Moved touch point (id=%d) outside touchmove.\n", point.id));
} else {
found_valid_state_for_type = true;
}
break;
case WebTouchPoint::kStateStationary:
break;
case WebTouchPoint::kStateCancelled:
if (event.GetType() != WebInputEvent::kTouchCancel) {
error_msg->append(StringPrintf(
"Cancelled touch point (id=%d) outside touchcancel.\n",
point.id));
} else {
found_valid_state_for_type = true;
}
break;
}
}
if (!found_valid_state_for_type) {
error_msg->append(
StringPrintf("No valid touch point corresponding to event type: %s\n",
WebInputEvent::GetName(event.GetType())));
}
return error_msg->empty();
}
} // namespace content