dom/base/SelectionChangeEventDispatcher.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 /*
   8  * Implementation of mozilla::SelectionChangeEventDispatcher
   9  */
  10
  11 #include "SelectionChangeEventDispatcher.h"
  12
  13 #include "mozilla/AsyncEventDispatcher.h"
  14 #include "mozilla/BasePrincipal.h"
  15 #include "mozilla/IntegerRange.h"
  16 #include "mozilla/StaticPrefs_dom.h"
  17 #include "mozilla/dom/Document.h"
  18 #include "mozilla/dom/Selection.h"
  19 #include "nsCOMPtr.h"
  20 #include "nsContentUtils.h"
  21 #include "nsFrameSelection.h"
  22 #include "nsRange.h"
  23
  24 namespace mozilla {
  25
  26 using namespace dom;
  27
  28 SelectionChangeEventDispatcher::RawRangeData::RawRangeData(
  29     const nsRange* aRange) {
  30   if (aRange->IsPositioned()) {
  31     mStartContainer = aRange->GetStartContainer();
  32     mEndContainer = aRange->GetEndContainer();
  33     mStartOffset = aRange->StartOffset();
  34     mEndOffset = aRange->EndOffset();
  35   } else {
  36     mStartContainer = nullptr;
  37     mEndContainer = nullptr;
  38     mStartOffset = 0;
  39     mEndOffset = 0;
  40   }
  41 }
  42
  43 bool SelectionChangeEventDispatcher::RawRangeData::Equals(
  44     const nsRange* aRange) {
  45   if (!aRange->IsPositioned()) {
  46     return !mStartContainer;
  47   }
  48   return mStartContainer == aRange->GetStartContainer() &&
  49          mEndContainer == aRange->GetEndContainer() &&
  50          mStartOffset == aRange->StartOffset() &&
  51          mEndOffset == aRange->EndOffset();
  52 }
  53
  54 inline void ImplCycleCollectionTraverse(
  55     nsCycleCollectionTraversalCallback& aCallback,
  56     SelectionChangeEventDispatcher::RawRangeData& aField, const char* aName,
  57     uint32_t aFlags = 0) {
  58   ImplCycleCollectionTraverse(aCallback, aField.mStartContainer,
  59                               "mStartContainer", aFlags);
  60   ImplCycleCollectionTraverse(aCallback, aField.mEndContainer, "mEndContainer",
  61                               aFlags);
  62 }
  63
  64 NS_IMPL_CYCLE_COLLECTION_CLASS(SelectionChangeEventDispatcher)
  65
  66 NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(SelectionChangeEventDispatcher)
  67   tmp->mOldRanges.Clear();
  68 NS_IMPL_CYCLE_COLLECTION_UNLINK_END
  69
  70 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(SelectionChangeEventDispatcher)
  71   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mOldRanges);
  72 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
  73
  74 void SelectionChangeEventDispatcher::OnSelectionChange(Document* aDoc,
  75                                                        Selection* aSel,
  76                                                        int16_t aReason) {
  77   // Check if the ranges have actually changed
  78   // Don't bother checking this if we are hiding changes.
  79   if (mOldRanges.Length() == aSel->RangeCount() &&
  80       !aSel->IsBlockingSelectionChangeEvents()) {
  81     bool changed = mOldDirection != aSel->GetDirection();
  82     if (!changed) {
  83       for (const uint32_t i : IntegerRange(mOldRanges.Length())) {
  84         if (!mOldRanges[i].Equals(aSel->GetRangeAt(i))) {
  85           changed = true;
  86           break;
  87         }
  88       }
  89     }
  90
  91     if (!changed) {
  92       return;
  93     }
  94   }
  95
  96   // The ranges have actually changed, update the mOldRanges array
  97   mOldRanges.ClearAndRetainStorage();
  98   for (const uint32_t i : IntegerRange(aSel->RangeCount())) {
  99     mOldRanges.AppendElement(RawRangeData(aSel->GetRangeAt(i)));
 100   }
 101   mOldDirection = aSel->GetDirection();
 102
 103   // If we are hiding changes, then don't do anything else. We do this after we
 104   // update mOldRanges so that changes after the changes stop being hidden don't
 105   // incorrectly trigger a change, even though they didn't change anything
 106   if (aSel->IsBlockingSelectionChangeEvents()) {
 107     return;
 108   }
 109
 110   const Document* doc = aSel->GetParentObject();
 111   if (MOZ_UNLIKELY(!doc)) {
 112     return;
 113   }
 114   const nsPIDOMWindowInner* inner = doc->GetInnerWindow();
 115   if (MOZ_UNLIKELY(!inner)) {
 116     return;
 117   }
 118   const bool maybeHasSelectionChangeEventListeners =
 119       !inner || inner->HasSelectionChangeEventListeners();
 120   const bool maybeHasFormSelectEventListeners =
 121       !inner || inner->HasFormSelectEventListeners();
 122   if (!maybeHasSelectionChangeEventListeners &&
 123       !maybeHasFormSelectEventListeners) {
 124     return;
 125   }
 126
 127   // Be aware, don't call GetTextControlFromSelectionLimiter once you might
 128   // run script because selection limit may have already been changed by it.
 129   nsCOMPtr<nsIContent> textControl;
 130   if ((maybeHasFormSelectEventListeners &&
 131        (aReason & nsISelectionListener::JS_REASON)) ||
 132       maybeHasSelectionChangeEventListeners) {
 133     if (const nsFrameSelection* fs = aSel->GetFrameSelection()) {
 134       if (nsCOMPtr<nsIContent> root = fs->GetLimiter()) {
 135         textControl = root->GetClosestNativeAnonymousSubtreeRootParentOrHost();
 136         MOZ_ASSERT_IF(textControl,
 137                       textControl->IsTextControlElement() &&
 138                           !textControl->IsInNativeAnonymousSubtree());
 139       }
 140     }
 141   };
 142
 143   // Selection changes with non-JS reason only cares about whether the new
 144   // selection is collapsed or not. See TextInputListener::OnSelectionChange.
 145   if (textControl && maybeHasFormSelectEventListeners &&
 146       (aReason & nsISelectionListener::JS_REASON)) {
 147     RefPtr<AsyncEventDispatcher> asyncDispatcher =
 148         new AsyncEventDispatcher(textControl, eFormSelect, CanBubble::eYes);
 149     asyncDispatcher->PostDOMEvent();
 150   }
 151
 152   if (!maybeHasSelectionChangeEventListeners) {
 153     return;
 154   }
 155
 156   // The spec currently doesn't say that we should dispatch this event on text
 157   // controls, so for now we only support doing that under a pref, disabled by
 158   // default.
 159   // See https://github.com/w3c/selection-api/issues/53.
 160   if (textControl &&
 161       !StaticPrefs::dom_select_events_textcontrols_selectionchange_enabled()) {
 162     return;
 163   }
 164
 165   nsINode* target =
 166       textControl ? static_cast<nsINode*>(textControl.get()) : aDoc;
 167   if (!target) {
 168     return;
 169   }
 170
 171   if (target->HasScheduledSelectionChangeEvent()) {
 172     return;
 173   }
 174
 175   target->SetHasScheduledSelectionChangeEvent();
 176
 177   CanBubble canBubble = textControl ? CanBubble::eYes : CanBubble::eNo;
 178   RefPtr<AsyncEventDispatcher> asyncDispatcher =
 179       new AsyncSelectionChangeEventDispatcher(target, eSelectionChange,
 180                                               canBubble);
 181   asyncDispatcher->PostDOMEvent();
 182 }
 183
 184 }  // namespace mozilla