The Tor Browser: gfx/layers/apz/util/ActiveElementManager.cpp@b8a032363ba2

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

     1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

     2 /* This Source Code Form is subject to the terms of the Mozilla Public

     3  * License, v. 2.0. If a copy of the MPL was not distributed with this

     4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

     6 #include "ActiveElementManager.h"

     7 #include "mozilla/EventStates.h"

     8 #include "mozilla/Preferences.h"

     9 #include "mozilla/Services.h"

    10 #include "inIDOMUtils.h"

    11 #include "nsIDOMDocument.h"

    12 #include "nsIDOMElement.h"

    13 #include "nsIDOMEventTarget.h"

    14 #include "base/message_loop.h"

    15 #include "base/task.h"

    17 namespace mozilla {

    18 namespace layers {

    20 static int32_t sActivationDelayMs = 100;

    21 static bool sActivationDelayMsSet = false;

    23 ActiveElementManager::ActiveElementManager()

    24   : mDomUtils(services::GetInDOMUtils()),

    25     mCanBePan(false),

    26     mCanBePanSet(false),

    27     mSetActiveTask(nullptr)

    28 {

    29   if (!sActivationDelayMsSet) {

    30     Preferences::AddIntVarCache(&sActivationDelayMs,

    31                                 "ui.touch_activation.delay_ms",

    32                                 sActivationDelayMs);

    33     sActivationDelayMsSet = true;

    34   }

    35 }

    37 ActiveElementManager::~ActiveElementManager() {}

    39 void

    40 ActiveElementManager::SetTargetElement(nsIDOMEventTarget* aTarget)

    41 {

    42   if (mTarget) {

    43     // Multiple fingers on screen (since HandleTouchEnd clears mTarget).

    44     CancelTask();

    45     ResetActive();

    46     mTarget = nullptr;

    47     return;

    48   }

    50   mTarget = do_QueryInterface(aTarget);

    51   TriggerElementActivation();

    52 }

    54 void

    55 ActiveElementManager::HandleTouchStart(bool aCanBePan)

    56 {

    57   mCanBePan = aCanBePan;

    58   mCanBePanSet = true;

    59   TriggerElementActivation();

    60 }

    62 void

    63 ActiveElementManager::TriggerElementActivation()

    64 {

    65   // Both HandleTouchStart() and SetTargetElement() call this. They can be

    66   // called in either order. One will set mCanBePanSet, and the other, mTarget.

    67   // We want to actually trigger the activation once both are set.

    68   if (!(mTarget && mCanBePanSet)) {

    69     return;

    70   }

    72   // If the touch cannot be a pan, make mTarget :active right away.

    73   // Otherwise, wait a bit to see if the user will pan or not.

    74   if (!mCanBePan) {

    75     SetActive(mTarget);

    76   } else {

    77     mSetActiveTask = NewRunnableMethod(

    78         this, &ActiveElementManager::SetActiveTask, mTarget);

    79     MessageLoop::current()->PostDelayedTask(

    80         FROM_HERE, mSetActiveTask, sActivationDelayMs);

    81   }

    82 }

    84 void

    85 ActiveElementManager::HandlePanStart()

    86 {

    87   // The user started to pan, so we don't want mTarget to be :active.

    88   // Make it not :active, and clear any pending task to make it :active.

    89   CancelTask();

    90   ResetActive();

    91 }

    93 void

    94 ActiveElementManager::HandleTouchEnd(bool aWasClick)

    95 {

    96   // If the touch was a click, make mTarget :active right away.

    97   // nsEventStateManager will reset the active element when processing

    98   // the mouse-down event generated by the click.

    99   CancelTask();

   100   if (aWasClick) {

   101     SetActive(mTarget);

   102   }

   104   // Clear mTarget for next touch.

   105   mTarget = nullptr;

   106 }

   108 void

   109 ActiveElementManager::SetActive(nsIDOMElement* aTarget)

   110 {

   111   if (mDomUtils) {

   112     mDomUtils->SetContentState(aTarget, NS_EVENT_STATE_ACTIVE.GetInternalValue());;

   113   }

   114 }

   116 void

   117 ActiveElementManager::ResetActive()

   118 {

   119   // Clear the :active flag from mTarget by setting it on the document root.

   120   if (mTarget) {

   121     nsCOMPtr<nsIDOMDocument> doc;

   122     mTarget->GetOwnerDocument(getter_AddRefs(doc));

   123     if (doc) {

   124       nsCOMPtr<nsIDOMElement> root;

   125       doc->GetDocumentElement(getter_AddRefs(root));

   126       if (root) {

   127         SetActive(root);

   128       }

   129     }

   130   }

   131 }

   133 void

   134 ActiveElementManager::SetActiveTask(nsIDOMElement* aTarget)

   135 {

   136   // This gets called from mSetActiveTask's Run() method. The message loop

   137   // deletes the task right after running it, so we need to null out

   138   // mSetActiveTask to make sure we're not left with a dangling pointer.

   139   mSetActiveTask = nullptr;

   140   SetActive(aTarget);

   141 }

   143 void

   144 ActiveElementManager::CancelTask()

   145 {

   146   if (mSetActiveTask) {

   147     mSetActiveTask->Cancel();

   148     mSetActiveTask = nullptr;

   149   }

   150 }

   152 }

   153 }

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