1 files changed, 175 insertions, 0 deletions
diff --git a/dom/base/SelectionChangeEventDispatcher.cpp b/dom/base/SelectionChangeEventDispatcher.cpp
new file mode 100644
index 0000000000..a669c45d53
--- /dev/null
+++ b/dom/base/SelectionChangeEventDispatcher.cpp
@@ -0,0 +1,175 @@
+/* -*- 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/. */
+
+/*
+ * Implementation of mozilla::SelectionChangeEventDispatcher
+ */
+
+#include "SelectionChangeEventDispatcher.h"
+
+#include "mozilla/AsyncEventDispatcher.h"
+#include "mozilla/BasePrincipal.h"
+#include "mozilla/IntegerRange.h"
+#include "mozilla/StaticPrefs_dom.h"
+#include "mozilla/dom/Document.h"
+#include "mozilla/dom/Selection.h"
+#include "nsCOMPtr.h"
+#include "nsContentUtils.h"
+#include "nsFrameSelection.h"
+#include "nsRange.h"
+
+namespace mozilla {
+
+using namespace dom;
+
+SelectionChangeEventDispatcher::RawRangeData::RawRangeData(
+    const nsRange* aRange) {
+  if (aRange->IsPositioned()) {
+    mStartContainer = aRange->GetStartContainer();
+    mEndContainer = aRange->GetEndContainer();
+    mStartOffset = aRange->StartOffset();
+    mEndOffset = aRange->EndOffset();
+  } else {
+    mStartContainer = nullptr;
+    mEndContainer = nullptr;
+    mStartOffset = 0;
+    mEndOffset = 0;
+  }
+}
+
+bool SelectionChangeEventDispatcher::RawRangeData::Equals(
+    const nsRange* aRange) {
+  if (!aRange->IsPositioned()) {
+    return !mStartContainer;
+  }
+  return mStartContainer == aRange->GetStartContainer() &&
+         mEndContainer == aRange->GetEndContainer() &&
+         mStartOffset == aRange->StartOffset() &&
+         mEndOffset == aRange->EndOffset();
+}
+
+inline void ImplCycleCollectionTraverse(
+    nsCycleCollectionTraversalCallback& aCallback,
+    SelectionChangeEventDispatcher::RawRangeData& aField, const char* aName,
+    uint32_t aFlags = 0) {
+  ImplCycleCollectionTraverse(aCallback, aField.mStartContainer,
+                              "mStartContainer", aFlags);
+  ImplCycleCollectionTraverse(aCallback, aField.mEndContainer, "mEndContainer",
+                              aFlags);
+}
+
+NS_IMPL_CYCLE_COLLECTION_CLASS(SelectionChangeEventDispatcher)
+
+NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(SelectionChangeEventDispatcher)
+  tmp->mOldRanges.Clear();
+NS_IMPL_CYCLE_COLLECTION_UNLINK_END
+
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(SelectionChangeEventDispatcher)
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mOldRanges);
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
+
+void SelectionChangeEventDispatcher::OnSelectionChange(Document* aDoc,
+                                                       Selection* aSel,
+                                                       int16_t aReason) {
+  // Check if the ranges have actually changed
+  // Don't bother checking this if we are hiding changes.
+  if (mOldRanges.Length() == aSel->RangeCount() &&
+      !aSel->IsBlockingSelectionChangeEvents()) {
+    bool changed = mOldDirection != aSel->GetDirection();
+    if (!changed) {
+      for (const uint32_t i : IntegerRange(mOldRanges.Length())) {
+        if (!mOldRanges[i].Equals(aSel->GetRangeAt(i))) {
+          changed = true;
+          break;
+        }
+      }
+    }
+
+    if (!changed) {
+      return;
+    }
+  }
+
+  // The ranges have actually changed, update the mOldRanges array
+  mOldRanges.ClearAndRetainStorage();
+  for (const uint32_t i : IntegerRange(aSel->RangeCount())) {
+    mOldRanges.AppendElement(RawRangeData(aSel->GetRangeAt(i)));
+  }
+  mOldDirection = aSel->GetDirection();
+
+  // If we are hiding changes, then don't do anything else. We do this after we
+  // update mOldRanges so that changes after the changes stop being hidden don't
+  // incorrectly trigger a change, even though they didn't change anything
+  if (aSel->IsBlockingSelectionChangeEvents()) {
+    return;
+  }
+
+  const Document* doc = aSel->GetParentObject();
+  if (MOZ_UNLIKELY(!doc)) {
+    return;
+  }
+  const nsPIDOMWindowInner* inner = doc->GetInnerWindow();
+  if (MOZ_UNLIKELY(!inner)) {
+    return;
+  }
+  const bool maybeHasSelectionChangeEventListeners =
+      !inner || inner->HasSelectionChangeEventListeners();
+  const bool maybeHasFormSelectEventListeners =
+      !inner || inner->HasFormSelectEventListeners();
+  if (!maybeHasSelectionChangeEventListeners &&
+      !maybeHasFormSelectEventListeners) {
+    return;
+  }
+
+  // Be aware, don't call GetTextControlFromSelectionLimiter once you might
+  // run script because selection limit may have already been changed by it.
+  nsCOMPtr<nsIContent> textControl;
+  if ((maybeHasFormSelectEventListeners &&
+       (aReason & nsISelectionListener::JS_REASON)) ||
+      maybeHasSelectionChangeEventListeners) {
+    if (const nsFrameSelection* fs = aSel->GetFrameSelection()) {
+      if (nsCOMPtr<nsIContent> root = fs->GetLimiter()) {
+        textControl = root->GetClosestNativeAnonymousSubtreeRootParentOrHost();
+        MOZ_ASSERT_IF(textControl,
+                      textControl->IsTextControlElement() &&
+                          !textControl->IsInNativeAnonymousSubtree());
+      }
+    }
+  };
+
+  // Selection changes with non-JS reason only cares about whether the new
+  // selection is collapsed or not. See TextInputListener::OnSelectionChange.
+  if (textControl && maybeHasFormSelectEventListeners &&
+      (aReason & nsISelectionListener::JS_REASON)) {
+    RefPtr<AsyncEventDispatcher> asyncDispatcher =
+        new AsyncEventDispatcher(textControl, eFormSelect, CanBubble::eYes);
+    asyncDispatcher->PostDOMEvent();
+  }
+
+  if (!maybeHasSelectionChangeEventListeners) {
+    return;
+  }
+
+  // The spec currently doesn't say that we should dispatch this event on text
+  // controls, so for now we only support doing that under a pref, disabled by
+  // default.
+  // See https://github.com/w3c/selection-api/issues/53.
+  if (textControl &&
+      !StaticPrefs::dom_select_events_textcontrols_selectionchange_enabled()) {
+    return;
+  }
+
+  nsINode* target =
+      textControl ? static_cast<nsINode*>(textControl.get()) : aDoc;
+  if (target) {
+    CanBubble canBubble = textControl ? CanBubble::eYes : CanBubble::eNo;
+    RefPtr<AsyncEventDispatcher> asyncDispatcher =
+        new AsyncEventDispatcher(target, eSelectionChange, canBubble);
+    asyncDispatcher->PostDOMEvent();
+  }
+}
+
+}  // namespace mozilla