dom/base/DocumentOrShadowRoot.h

   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 #ifndef mozilla_dom_DocumentOrShadowRoot_h__
   8 #define mozilla_dom_DocumentOrShadowRoot_h__
   9
  10 #include "mozilla/dom/NameSpaceConstants.h"
  11 #include "mozilla/IdentifierMapEntry.h"
  12 #include "mozilla/RelativeTo.h"
  13 #include "mozilla/ReverseIterator.h"
  14 #include "nsClassHashtable.h"
  15 #include "nsContentListDeclarations.h"
  16 #include "nsTArray.h"
  17 #include "nsTHashSet.h"
  18
  19 class nsContentList;
  20 class nsCycleCollectionTraversalCallback;
  21 class nsINode;
  22 class nsINodeList;
  23 class nsWindowSizes;
  24
  25 namespace mozilla {
  26 class ErrorResult;
  27 class StyleSheet;
  28 class ErrorResult;
  29
  30 namespace dom {
  31
  32 class Animation;
  33 class Element;
  34 class Document;
  35 class DocumentOrShadowRoot;
  36 class HTMLInputElement;
  37 class StyleSheetList;
  38 class ShadowRoot;
  39 template <typename T>
  40 class Sequence;
  41
  42 /**
  43  * A class meant to be shared by ShadowRoot and Document, that holds a list of
  44  * stylesheets.
  45  *
  46  * TODO(emilio, bug 1418159): In the future this should hold most of the
  47  * relevant style state, this should allow us to fix bug 548397.
  48  */
  49 class DocumentOrShadowRoot {
  50   enum class Kind {
  51     Document,
  52     ShadowRoot,
  53   };
  54
  55  public:
  56   // These should always be non-null, but can't use a reference because
  57   // dereferencing `this` on initializer lists is UB, apparently, see
  58   // bug 1596499.
  59   explicit DocumentOrShadowRoot(Document*);
  60   explicit DocumentOrShadowRoot(ShadowRoot*);
  61
  62   // Unusual argument naming is because of cycle collection macros.
  63   static void Traverse(DocumentOrShadowRoot* tmp,
  64                        nsCycleCollectionTraversalCallback& cb);
  65   static void Unlink(DocumentOrShadowRoot* tmp);
  66
  67   nsINode& AsNode() { return *mAsNode; }
  68
  69   const nsINode& AsNode() const { return *mAsNode; }
  70
  71   StyleSheet* SheetAt(size_t aIndex) const {
  72     return mStyleSheets.SafeElementAt(aIndex);
  73   }
  74
  75   size_t SheetCount() const { return mStyleSheets.Length(); }
  76
  77   const nsTArray<RefPtr<StyleSheet>>& AdoptedStyleSheets() const {
  78     return mAdoptedStyleSheets;
  79   }
  80
  81   /**
  82    * Returns an index for the sheet in relative style order.
  83    * If there are non-applicable sheets, then this index may
  84    * not match 1:1 with the sheet's actual index in the style set.
  85    *
  86    * Handles sheets from both mStyleSheets and mAdoptedStyleSheets
  87    */
  88   int32_t StyleOrderIndexOfSheet(const StyleSheet& aSheet) const;
  89
  90   StyleSheetList* StyleSheets();
  91
  92   void RemoveStyleSheet(StyleSheet&);
  93
  94   Element* GetElementById(const nsAString& aElementId) const;
  95   Element* GetElementById(nsAtom* aElementId) const;
  96
  97   /**
  98    * This method returns _all_ the elements in this scope which have id
  99    * aElementId, if there are any.  Otherwise it returns null.
 100    *
 101    * This is useful for stuff like QuerySelector optimization and such.
 102    */
 103   const nsTArray<Element*>* GetAllElementsForId(
 104       const IdentifierMapEntry::DependentAtomOrString& aElementId) const {
 105     IdentifierMapEntry* entry = mIdentifierMap.GetEntry(aElementId);
 106     return entry ? &entry->GetIdElements() : nullptr;
 107   }
 108
 109   already_AddRefed<nsContentList> GetElementsByTagName(
 110       const nsAString& aTagName) {
 111     return NS_GetContentList(&AsNode(), kNameSpaceID_Unknown, aTagName);
 112   }
 113
 114   already_AddRefed<nsContentList> GetElementsByTagNameNS(
 115       const nsAString& aNamespaceURI, const nsAString& aLocalName);
 116
 117   already_AddRefed<nsContentList> GetElementsByTagNameNS(
 118       const nsAString& aNamespaceURI, const nsAString& aLocalName,
 119       mozilla::ErrorResult&);
 120
 121   already_AddRefed<nsContentList> GetElementsByClassName(
 122       const nsAString& aClasses);
 123
 124   ~DocumentOrShadowRoot();
 125
 126   Element* GetPointerLockElement();
 127   Element* GetFullscreenElement() const;
 128
 129   Element* ElementFromPoint(float aX, float aY);
 130   nsINode* NodeFromPoint(float aX, float aY);
 131
 132   void ElementsFromPoint(float aX, float aY, nsTArray<RefPtr<Element>>&);
 133   void NodesFromPoint(float aX, float aY, nsTArray<RefPtr<nsINode>>&);
 134
 135   /**
 136    * Helper for elementFromPoint implementation that allows
 137    * ignoring the scroll frame and/or avoiding layout flushes.
 138    *
 139    * @see nsIDOMWindowUtils::elementFromPoint
 140    */
 141   Element* ElementFromPointHelper(float aX, float aY,
 142                                   bool aIgnoreRootScrollFrame,
 143                                   bool aFlushLayout,
 144                                   ViewportType aViewportType);
 145
 146   void NodesFromRect(float aX, float aY, float aTopSize, float aRightSize,
 147                      float aBottomSize, float aLeftSize,
 148                      bool aIgnoreRootScrollFrame, bool aFlushLayout,
 149                      bool aOnlyVisible, float aVisibleThreshold,
 150                      nsTArray<RefPtr<nsINode>>&);
 151
 152   /**
 153    * This gets fired when the element that an id refers to changes.
 154    * This fires at difficult times. It is generally not safe to do anything
 155    * which could modify the DOM in any way. Use
 156    * nsContentUtils::AddScriptRunner.
 157    * @return true to keep the callback in the callback set, false
 158    * to remove it.
 159    */
 160   typedef bool (*IDTargetObserver)(Element* aOldElement, Element* aNewelement,
 161                                    void* aData);
 162
 163   /**
 164    * Add an IDTargetObserver for a specific ID. The IDTargetObserver
 165    * will be fired whenever the content associated with the ID changes
 166    * in the future. If aForImage is true, mozSetImageElement can override
 167    * what content is associated with the ID. In that case the IDTargetObserver
 168    * will be notified at those times when the result of LookupImageElement
 169    * changes.
 170    * At most one (aObserver, aData, aForImage) triple can be
 171    * registered for each ID.
 172    * @return the content currently associated with the ID.
 173    */
 174   Element* AddIDTargetObserver(nsAtom* aID, IDTargetObserver aObserver,
 175                                void* aData, bool aForImage);
 176
 177   /**
 178    * Remove the (aObserver, aData, aForImage) triple for a specific ID, if
 179    * registered.
 180    */
 181   void RemoveIDTargetObserver(nsAtom* aID, IDTargetObserver aObserver,
 182                               void* aData, bool aForImage);
 183
 184   /**
 185    * Lookup an image element using its associated ID, which is usually provided
 186    * by |-moz-element()|. Similar to GetElementById, with the difference that
 187    * elements set using mozSetImageElement have higher priority.
 188    * @param aId the ID associated the element we want to lookup
 189    * @return the element associated with |aId|
 190    */
 191   Element* LookupImageElement(const nsAString& aElementId);
 192
 193   /**
 194    * Check that aId is not empty and log a message to the console
 195    * service if it is.
 196    * @returns true if aId looks correct, false otherwise.
 197    */
 198   inline bool CheckGetElementByIdArg(const nsAString& aId) {
 199     if (aId.IsEmpty()) {
 200       ReportEmptyGetElementByIdArg();
 201       return false;
 202     }
 203     return true;
 204   }
 205
 206   void ReportEmptyGetElementByIdArg() const;
 207
 208   // Web Animations
 209   MOZ_CAN_RUN_SCRIPT
 210   void GetAnimations(nsTArray<RefPtr<Animation>>& aAnimations);
 211
 212   nsINode* Retarget(nsINode*) const;
 213
 214   void OnSetAdoptedStyleSheets(StyleSheet&, uint32_t aIndex, ErrorResult&);
 215   void OnDeleteAdoptedStyleSheets(StyleSheet&, uint32_t aIndex, ErrorResult&);
 216
 217   // This is needed because ServoStyleSet / ServoAuthorData don't deal with
 218   // duplicate stylesheets (and it's unclear we'd want to support that as it'd
 219   // be a bunch of duplicate work), while adopted stylesheets do need to deal
 220   // with them.
 221   template <typename Callback>
 222   void EnumerateUniqueAdoptedStyleSheetsBackToFront(Callback aCallback) {
 223     StyleSheetSet set(mAdoptedStyleSheets.Length());
 224     for (StyleSheet* sheet : Reversed(mAdoptedStyleSheets)) {
 225       if (MOZ_UNLIKELY(!set.EnsureInserted(sheet))) {
 226         continue;
 227       }
 228       aCallback(*sheet);
 229     }
 230   }
 231
 232  protected:
 233   // Cycle collection helper functions
 234   void TraverseSheetRefInStylesIfApplicable(
 235       StyleSheet&, nsCycleCollectionTraversalCallback&);
 236   void TraverseStyleSheets(nsTArray<RefPtr<StyleSheet>>&, const char*,
 237                            nsCycleCollectionTraversalCallback&);
 238   void UnlinkStyleSheets(nsTArray<RefPtr<StyleSheet>>&);
 239
 240   using StyleSheetSet = nsTHashSet<const StyleSheet*>;
 241   void RemoveSheetFromStylesIfApplicable(StyleSheet&);
 242   void ClearAdoptedStyleSheets();
 243
 244   /**
 245    * Clone's the argument's adopted style sheets into this.
 246    * This should only be used when cloning a static document for printing.
 247    */
 248   void CloneAdoptedSheetsFrom(const DocumentOrShadowRoot&);
 249
 250   void InsertSheetAt(size_t aIndex, StyleSheet& aSheet);
 251
 252   void AddSizeOfExcludingThis(nsWindowSizes&) const;
 253   void AddSizeOfOwnedSheetArrayExcludingThis(
 254       nsWindowSizes&, const nsTArray<RefPtr<StyleSheet>>&) const;
 255
 256   /**
 257    * If focused element's subtree root is this document or shadow root, return
 258    * focused element, otherwise, get the shadow host recursively until the
 259    * shadow host's subtree root is this document or shadow root.
 260    */
 261   Element* GetRetargetedFocusedElement();
 262
 263   nsTArray<RefPtr<StyleSheet>> mStyleSheets;
 264   RefPtr<StyleSheetList> mDOMStyleSheets;
 265
 266   /**
 267    * Style sheets that are adopted by assinging to the `adoptedStyleSheets`
 268    * WebIDL atribute. These can only be constructed stylesheets.
 269    */
 270   nsTArray<RefPtr<StyleSheet>> mAdoptedStyleSheets;
 271
 272   /*
 273    * mIdentifierMap works as follows for IDs:
 274    * 1) Attribute changes affect the table immediately (removing and adding
 275    *    entries as needed).
 276    * 2) Removals from the DOM affect the table immediately
 277    * 3) Additions to the DOM always update existing entries for names, and add
 278    *    new ones for IDs.
 279    */
 280   nsTHashtable<IdentifierMapEntry> mIdentifierMap;
 281
 282   // Always non-null, see comment in the constructor as to why a pointer instead
 283   // of a reference.
 284   nsINode* mAsNode;
 285   const Kind mKind;
 286 };
 287
 288 }  // namespace dom
 289
 290 }  // namespace mozilla
 291
 292 #endif