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// Copyright 2016 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 THIRD_PARTY_BLINK_RENDERER_CORE_INPUT_TOUCH_EVENT_MANAGER_H_
#define THIRD_PARTY_BLINK_RENDERER_CORE_INPUT_TOUCH_EVENT_MANAGER_H_
#include "base/macros.h"
#include "third_party/blink/public/platform/web_coalesced_input_event.h"
#include "third_party/blink/public/platform/web_input_event_result.h"
#include "third_party/blink/public/platform/web_pointer_event.h"
#include "third_party/blink/public/platform/web_touch_event.h"
#include "third_party/blink/renderer/core/core_export.h"
#include "third_party/blink/renderer/core/events/pointer_event_factory.h"
#include "third_party/blink/renderer/core/input/event_handling_util.h"
#include "third_party/blink/renderer/platform/graphics/touch_action.h"
#include "third_party/blink/renderer/platform/wtf/allocator/allocator.h"
#include "third_party/blink/renderer/platform/wtf/hash_map.h"
#include "third_party/blink/renderer/platform/wtf/vector.h"
namespace blink {
class LocalFrame;
class Document;
class Touch;
// This class takes care of dispatching all touch events and
// maintaining related states.
class CORE_EXPORT TouchEventManager final
: public GarbageCollected<TouchEventManager> {
public:
explicit TouchEventManager(LocalFrame&);
void Trace(blink::Visitor*);
void HandleTouchPoint(const WebPointerEvent&,
const Vector<WebPointerEvent>&,
const event_handling_util::PointerEventTarget&);
WebInputEventResult FlushEvents();
// Resets the internal state of this object.
void Clear();
// Returns whether there is any touch on the screen.
bool IsAnyTouchActive() const;
private:
// Class represending one touch point event with its coalesced events and
// related attributes.
class TouchPointAttributes final
: public GarbageCollected<TouchPointAttributes> {
public:
void Trace(blink::Visitor* visitor) { visitor->Trace(target_); }
TouchPointAttributes() = default;
explicit TouchPointAttributes(WebPointerEvent event)
: event_(event), stale_(false) {}
// Last state of the touch point.
WebPointerEvent event_;
// The list of coalesced events of the touch point represented by this class
// if there is any. Note that at the end of each frame this list gets
// cleared and the touch point |stale_| flag will be true for the next frame
// unless more new events arrives for this touch point.
Vector<WebPointerEvent> coalesced_events_;
Member<Node> target_; // The target of each active touch point.
String region_; // // The region of each active touch point.
bool stale_;
};
WebCoalescedInputEvent GenerateWebCoalescedInputEvent();
Touch* CreateDomTouch(const TouchPointAttributes*, bool* known_target);
void AllTouchesReleasedCleanup();
// Keeps track of attributes of the touch point in the
// |touch_points_attributes_| map and does the hit-testing if the original hit
// test result was not inside capturing frame |touch_sequence_document_| for
// touch events.
void UpdateTouchAttributeMapsForPointerDown(
const WebPointerEvent&,
const event_handling_util::PointerEventTarget&);
// This is triggered either by VSync signal to send one touch event per frame
// accumulating all move events or by discrete events pointerdown/up/cancel.
WebInputEventResult DispatchTouchEventFromAccumulatdTouchPoints();
// Used only if |should_enforce_vertical_scroll_| is set.
WebInputEventResult EnsureVerticalScrollIsPossible(WebInputEventResult);
// NOTE: If adding a new field to this class please ensure that it is
// cleared in |TouchEventManager::clear()|.
const Member<LocalFrame> frame_;
// The attributes of each active touch point indexed by the touch ID.
using TouchAttributeMap =
HeapHashMap<int,
Member<TouchPointAttributes>,
WTF::IntHash<int>,
WTF::UnsignedWithZeroKeyHashTraits<int>>;
TouchAttributeMap touch_attribute_map_;
// If set, the document of the active touch sequence. Unset if no touch
// sequence active.
Member<Document> touch_sequence_document_;
bool suppressing_touchmoves_within_slop_;
// This is used to created a consistent sequence of coalesced events compared
// to the last frame.
WebTouchEvent last_coalesced_touch_event_;
// The current touch action, computed on each touch start and is
// a union of all touches. Reset when all touches are released.
TouchAction current_touch_action_;
// TODO(ekaramad): Send the update after 'touchmove' to make sure we are only
// enforcing vertical scroll.
// When true, the current touch sequence should be handled such that vertical
// scrolling is always possible. To this end, the output of event handlers for
// 'touchstart' and 'touchmove' is overwritten to not handled so that
// scrolling cannot be blocked. However, to ensure only vertical scrolling is
// possible, the update for effective 'touch-action' is postponed to after
// handling 'touchstart' handlers and potentially overwritten to 'pan-y' so
// that only horizontal scrolling is blocked.
bool should_enforce_vertical_scroll_ = false;
// When set to a value, the effective touch-action is sent to the browser
// after all 'touchstart' handlers have been invoked. This is used by feature
// policy to enforce specific directions of scroll in spite of scroll-blocking
// events being prevent defaulted. When multiple pointer down events occur
// during the same touch sequence, the value of effective touch action which
// is sent to the browser after handling each dispatched 'touchstart' is the
// intersection of all the previously calculated effective touch action values
// during the sequence.
base::Optional<TouchAction> delayed_effective_touch_action_;
DISALLOW_COPY_AND_ASSIGN(TouchEventManager);
};
} // namespace blink
#endif // THIRD_PARTY_BLINK_RENDERER_CORE_INPUT_TOUCH_EVENT_MANAGER_H_
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