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-rw-r--r--gfx/layers/apz/util/ActiveElementManager.cpp178
1 files changed, 178 insertions, 0 deletions
diff --git a/gfx/layers/apz/util/ActiveElementManager.cpp b/gfx/layers/apz/util/ActiveElementManager.cpp
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+++ b/gfx/layers/apz/util/ActiveElementManager.cpp
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "ActiveElementManager.h"
+#include "mozilla/EventStateManager.h"
+#include "mozilla/PresShell.h"
+#include "mozilla/StaticPrefs_ui.h"
+#include "mozilla/dom/Element.h"
+#include "mozilla/dom/Document.h"
+
+static mozilla::LazyLogModule sApzAemLog("apz.activeelement");
+#define AEM_LOG(...) MOZ_LOG(sApzAemLog, LogLevel::Debug, (__VA_ARGS__))
+
+namespace mozilla {
+namespace layers {
+
+ActiveElementManager::ActiveElementManager()
+ : mCanBePan(false), mCanBePanSet(false), mSetActiveTask(nullptr) {}
+
+ActiveElementManager::~ActiveElementManager() = default;
+
+void ActiveElementManager::SetTargetElement(dom::EventTarget* aTarget) {
+ if (mTarget) {
+ // Multiple fingers on screen (since HandleTouchEnd clears mTarget).
+ AEM_LOG("Multiple fingers on-screen, clearing target element\n");
+ CancelTask();
+ ResetActive();
+ ResetTouchBlockState();
+ return;
+ }
+
+ mTarget = dom::Element::FromEventTargetOrNull(aTarget);
+ AEM_LOG("Setting target element to %p\n", mTarget.get());
+ TriggerElementActivation();
+}
+
+void ActiveElementManager::HandleTouchStart(bool aCanBePan) {
+ AEM_LOG("Touch start, aCanBePan: %d\n", aCanBePan);
+ if (mCanBePanSet) {
+ // Multiple fingers on screen (since HandleTouchEnd clears mCanBePanSet).
+ AEM_LOG("Multiple fingers on-screen, clearing touch block state\n");
+ CancelTask();
+ ResetActive();
+ ResetTouchBlockState();
+ return;
+ }
+
+ mCanBePan = aCanBePan;
+ mCanBePanSet = true;
+ TriggerElementActivation();
+}
+
+void ActiveElementManager::TriggerElementActivation() {
+ // Both HandleTouchStart() and SetTargetElement() call this. They can be
+ // called in either order. One will set mCanBePanSet, and the other, mTarget.
+ // We want to actually trigger the activation once both are set.
+ if (!(mTarget && mCanBePanSet)) {
+ return;
+ }
+
+ // If the touch cannot be a pan, make mTarget :active right away.
+ // Otherwise, wait a bit to see if the user will pan or not.
+ if (!mCanBePan) {
+ SetActive(mTarget);
+ } else {
+ CancelTask(); // this is only needed because of bug 1169802. Fixing that
+ // bug properly should make this unnecessary.
+ MOZ_ASSERT(mSetActiveTask == nullptr);
+
+ RefPtr<CancelableRunnable> task =
+ NewCancelableRunnableMethod<nsCOMPtr<dom::Element>>(
+ "layers::ActiveElementManager::SetActiveTask", this,
+ &ActiveElementManager::SetActiveTask, mTarget);
+ mSetActiveTask = task;
+ NS_GetCurrentThread()->DelayedDispatch(
+ task.forget(), StaticPrefs::ui_touch_activation_delay_ms());
+ AEM_LOG("Scheduling mSetActiveTask %p\n", mSetActiveTask.get());
+ }
+}
+
+void ActiveElementManager::ClearActivation() {
+ AEM_LOG("Clearing element activation\n");
+ CancelTask();
+ ResetActive();
+}
+
+void ActiveElementManager::HandleTouchEndEvent(bool aWasClick) {
+ AEM_LOG("Touch end event, aWasClick: %d\n", aWasClick);
+
+ // If the touch was a click, make mTarget :active right away.
+ // nsEventStateManager will reset the active element when processing
+ // the mouse-down event generated by the click.
+ CancelTask();
+ if (aWasClick) {
+ // Scrollbar thumbs use a different mechanism for their active
+ // highlight (the "active" attribute), so don't set the active state
+ // on them because nothing will clear it.
+ if (!(mTarget && mTarget->IsXULElement(nsGkAtoms::thumb))) {
+ SetActive(mTarget);
+ }
+ } else {
+ // We might reach here if mCanBePan was false on touch-start and
+ // so we set the element active right away. Now it turns out the
+ // action was not a click so we need to reset the active element.
+ ResetActive();
+ }
+
+ ResetTouchBlockState();
+}
+
+void ActiveElementManager::HandleTouchEnd() {
+ AEM_LOG("Touch end, clearing pan state\n");
+ mCanBePanSet = false;
+}
+
+static nsPresContext* GetPresContextFor(nsIContent* aContent) {
+ if (!aContent) {
+ return nullptr;
+ }
+ PresShell* presShell = aContent->OwnerDoc()->GetPresShell();
+ if (!presShell) {
+ return nullptr;
+ }
+ return presShell->GetPresContext();
+}
+
+void ActiveElementManager::SetActive(dom::Element* aTarget) {
+ AEM_LOG("Setting active %p\n", aTarget);
+
+ if (nsPresContext* pc = GetPresContextFor(aTarget)) {
+ pc->EventStateManager()->SetContentState(aTarget,
+ dom::ElementState::ACTIVE);
+ }
+}
+
+void ActiveElementManager::ResetActive() {
+ AEM_LOG("Resetting active from %p\n", mTarget.get());
+
+ // Clear the :active flag from mTarget by setting it on the document root.
+ if (mTarget) {
+ dom::Element* root = mTarget->OwnerDoc()->GetDocumentElement();
+ if (root) {
+ AEM_LOG("Found root %p, making active\n", root);
+ SetActive(root);
+ }
+ }
+}
+
+void ActiveElementManager::ResetTouchBlockState() {
+ mTarget = nullptr;
+ mCanBePanSet = false;
+}
+
+void ActiveElementManager::SetActiveTask(
+ const nsCOMPtr<dom::Element>& aTarget) {
+ AEM_LOG("mSetActiveTask %p running\n", mSetActiveTask.get());
+
+ // This gets called from mSetActiveTask's Run() method. The message loop
+ // deletes the task right after running it, so we need to null out
+ // mSetActiveTask to make sure we're not left with a dangling pointer.
+ mSetActiveTask = nullptr;
+ SetActive(aTarget);
+}
+
+void ActiveElementManager::CancelTask() {
+ AEM_LOG("Cancelling task %p\n", mSetActiveTask.get());
+
+ if (mSetActiveTask) {
+ mSetActiveTask->Cancel();
+ mSetActiveTask = nullptr;
+ }
+}
+
+} // namespace layers
+} // namespace mozilla