dom/html/HTMLImageElement.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_HTMLImageElement_h
   8 #define mozilla_dom_HTMLImageElement_h
   9
  10 #include "mozilla/Attributes.h"
  11 #include "nsGenericHTMLElement.h"
  12 #include "nsImageLoadingContent.h"
  13 #include "Units.h"
  14 #include "nsCycleCollectionParticipant.h"
  15
  16 namespace mozilla {
  17 class EventChainPreVisitor;
  18 namespace dom {
  19
  20 class ImageLoadTask;
  21
  22 class ResponsiveImageSelector;
  23 class HTMLImageElement final : public nsGenericHTMLElement,
  24                                public nsImageLoadingContent {
  25   friend class HTMLSourceElement;
  26   friend class HTMLPictureElement;
  27   friend class ImageLoadTask;
  28
  29  public:
  30   explicit HTMLImageElement(
  31       already_AddRefed<mozilla::dom::NodeInfo>&& aNodeInfo);
  32
  33   static already_AddRefed<HTMLImageElement> Image(
  34       const GlobalObject& aGlobal, const Optional<uint32_t>& aWidth,
  35       const Optional<uint32_t>& aHeight, ErrorResult& aError);
  36
  37   NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(HTMLImageElement,
  38                                            nsGenericHTMLElement)
  39
  40   // nsISupports
  41   NS_DECL_ISUPPORTS_INHERITED
  42
  43   bool Draggable() const override;
  44
  45   ResponsiveImageSelector* GetResponsiveImageSelector() {
  46     return mResponsiveSelector.get();
  47   }
  48
  49   // Element
  50   bool IsInteractiveHTMLContent() const override;
  51
  52   // EventTarget
  53   void AsyncEventRunning(AsyncEventDispatcher* aEvent) override;
  54
  55   NS_IMPL_FROMNODE_HTML_WITH_TAG(HTMLImageElement, img)
  56
  57   // override from nsImageLoadingContent
  58   CORSMode GetCORSMode() override;
  59
  60   // nsIContent
  61   bool ParseAttribute(int32_t aNamespaceID, nsAtom* aAttribute,
  62                       const nsAString& aValue,
  63                       nsIPrincipal* aMaybeScriptedPrincipal,
  64                       nsAttrValue& aResult) override;
  65   nsChangeHint GetAttributeChangeHint(const nsAtom* aAttribute,
  66                                       int32_t aModType) const override;
  67   NS_IMETHOD_(bool) IsAttributeMapped(const nsAtom* aAttribute) const override;
  68   nsMapRuleToAttributesFunc GetAttributeMappingFunction() const override;
  69
  70   void GetEventTargetParent(EventChainPreVisitor& aVisitor) override;
  71   nsINode* GetScopeChainParent() const override;
  72
  73   bool IsHTMLFocusable(bool aWithMouse, bool* aIsFocusable,
  74                        int32_t* aTabIndex) override;
  75
  76   nsresult BindToTree(BindContext&, nsINode& aParent) override;
  77   void UnbindFromTree(UnbindContext&) override;
  78
  79   nsresult Clone(dom::NodeInfo*, nsINode** aResult) const override;
  80
  81   void NodeInfoChanged(Document* aOldDoc) override;
  82
  83   nsresult CopyInnerTo(HTMLImageElement* aDest);
  84
  85   void MaybeLoadImage(bool aAlwaysForceLoad);
  86
  87   bool IsMap() { return GetBoolAttr(nsGkAtoms::ismap); }
  88   void SetIsMap(bool aIsMap, ErrorResult& aError) {
  89     SetHTMLBoolAttr(nsGkAtoms::ismap, aIsMap, aError);
  90   }
  91   MOZ_CAN_RUN_SCRIPT uint32_t Width();
  92   void SetWidth(uint32_t aWidth, ErrorResult& aError) {
  93     SetUnsignedIntAttr(nsGkAtoms::width, aWidth, 0, aError);
  94   }
  95   MOZ_CAN_RUN_SCRIPT uint32_t Height();
  96   void SetHeight(uint32_t aHeight, ErrorResult& aError) {
  97     SetUnsignedIntAttr(nsGkAtoms::height, aHeight, 0, aError);
  98   }
  99
 100   nsIntSize NaturalSize();
 101   uint32_t NaturalHeight() { return NaturalSize().height; }
 102   uint32_t NaturalWidth() { return NaturalSize().width; }
 103
 104   bool Complete();
 105   uint32_t Hspace() {
 106     return GetDimensionAttrAsUnsignedInt(nsGkAtoms::hspace, 0);
 107   }
 108   void SetHspace(uint32_t aHspace, ErrorResult& aError) {
 109     SetUnsignedIntAttr(nsGkAtoms::hspace, aHspace, 0, aError);
 110   }
 111   uint32_t Vspace() {
 112     return GetDimensionAttrAsUnsignedInt(nsGkAtoms::vspace, 0);
 113   }
 114   void SetVspace(uint32_t aVspace, ErrorResult& aError) {
 115     SetUnsignedIntAttr(nsGkAtoms::vspace, aVspace, 0, aError);
 116   }
 117
 118   void GetAlt(nsAString& aAlt) { GetHTMLAttr(nsGkAtoms::alt, aAlt); }
 119   void SetAlt(const nsAString& aAlt, ErrorResult& aError) {
 120     SetHTMLAttr(nsGkAtoms::alt, aAlt, aError);
 121   }
 122   void GetSrc(nsAString& aSrc) { GetURIAttr(nsGkAtoms::src, nullptr, aSrc); }
 123   void SetSrc(const nsAString& aSrc, ErrorResult& aError) {
 124     SetHTMLAttr(nsGkAtoms::src, aSrc, aError);
 125   }
 126   void SetSrc(const nsAString& aSrc, nsIPrincipal* aTriggeringPrincipal,
 127               ErrorResult& aError) {
 128     SetHTMLAttr(nsGkAtoms::src, aSrc, aTriggeringPrincipal, aError);
 129   }
 130   void GetSrcset(nsAString& aSrcset) {
 131     GetHTMLAttr(nsGkAtoms::srcset, aSrcset);
 132   }
 133   void SetSrcset(const nsAString& aSrcset, nsIPrincipal* aTriggeringPrincipal,
 134                  ErrorResult& aError) {
 135     SetHTMLAttr(nsGkAtoms::srcset, aSrcset, aTriggeringPrincipal, aError);
 136   }
 137   void GetCrossOrigin(nsAString& aResult) {
 138     // Null for both missing and invalid defaults is ok, since we
 139     // always parse to an enum value, so we don't need an invalid
 140     // default, and we _want_ the missing default to be null.
 141     GetEnumAttr(nsGkAtoms::crossorigin, nullptr, aResult);
 142   }
 143   void SetCrossOrigin(const nsAString& aCrossOrigin, ErrorResult& aError) {
 144     SetOrRemoveNullableStringAttr(nsGkAtoms::crossorigin, aCrossOrigin, aError);
 145   }
 146   void GetUseMap(nsAString& aUseMap) {
 147     GetHTMLAttr(nsGkAtoms::usemap, aUseMap);
 148   }
 149   void SetUseMap(const nsAString& aUseMap, ErrorResult& aError) {
 150     SetHTMLAttr(nsGkAtoms::usemap, aUseMap, aError);
 151   }
 152   void GetName(nsAString& aName) { GetHTMLAttr(nsGkAtoms::name, aName); }
 153   void SetName(const nsAString& aName, ErrorResult& aError) {
 154     SetHTMLAttr(nsGkAtoms::name, aName, aError);
 155   }
 156   void GetAlign(nsAString& aAlign) { GetHTMLAttr(nsGkAtoms::align, aAlign); }
 157   void SetAlign(const nsAString& aAlign, ErrorResult& aError) {
 158     SetHTMLAttr(nsGkAtoms::align, aAlign, aError);
 159   }
 160   void GetLongDesc(nsAString& aLongDesc) {
 161     GetURIAttr(nsGkAtoms::longdesc, nullptr, aLongDesc);
 162   }
 163   void SetLongDesc(const nsAString& aLongDesc, ErrorResult& aError) {
 164     SetHTMLAttr(nsGkAtoms::longdesc, aLongDesc, aError);
 165   }
 166   void GetSizes(nsAString& aSizes) { GetHTMLAttr(nsGkAtoms::sizes, aSizes); }
 167   void SetSizes(const nsAString& aSizes, ErrorResult& aError) {
 168     SetHTMLAttr(nsGkAtoms::sizes, aSizes, aError);
 169   }
 170   void GetCurrentSrc(nsAString& aValue);
 171   void GetBorder(nsAString& aBorder) {
 172     GetHTMLAttr(nsGkAtoms::border, aBorder);
 173   }
 174   void SetBorder(const nsAString& aBorder, ErrorResult& aError) {
 175     SetHTMLAttr(nsGkAtoms::border, aBorder, aError);
 176   }
 177   void SetReferrerPolicy(const nsAString& aReferrer, ErrorResult& aError) {
 178     SetHTMLAttr(nsGkAtoms::referrerpolicy, aReferrer, aError);
 179   }
 180   void GetReferrerPolicy(nsAString& aReferrer) {
 181     GetEnumAttr(nsGkAtoms::referrerpolicy, "", aReferrer);
 182   }
 183   void SetDecoding(const nsAString& aDecoding, ErrorResult& aError) {
 184     SetHTMLAttr(nsGkAtoms::decoding, aDecoding, aError);
 185   }
 186   void GetDecoding(nsAString& aValue);
 187
 188   void SetLoading(const nsAString& aLoading, ErrorResult& aError) {
 189     SetHTMLAttr(nsGkAtoms::loading, aLoading, aError);
 190   }
 191
 192   bool IsAwaitingLoadOrLazyLoading() const {
 193     return mLazyLoading || mPendingImageLoadTask;
 194   }
 195
 196   bool IsLazyLoading() const { return mLazyLoading; }
 197
 198   already_AddRefed<Promise> Decode(ErrorResult& aRv);
 199
 200   MOZ_CAN_RUN_SCRIPT int32_t X();
 201   MOZ_CAN_RUN_SCRIPT int32_t Y();
 202   void GetLowsrc(nsAString& aLowsrc) {
 203     GetURIAttr(nsGkAtoms::lowsrc, nullptr, aLowsrc);
 204   }
 205   void SetLowsrc(const nsAString& aLowsrc, ErrorResult& aError) {
 206     SetHTMLAttr(nsGkAtoms::lowsrc, aLowsrc, aError);
 207   }
 208
 209 #ifdef DEBUG
 210   HTMLFormElement* GetForm() const;
 211 #endif
 212   void SetForm(HTMLFormElement* aForm);
 213   void ClearForm(bool aRemoveFromForm);
 214
 215   void DestroyContent() override;
 216
 217   void MediaFeatureValuesChanged();
 218
 219   /**
 220    * Given a hypothetical <img> or <source> tag with the given parameters,
 221    * return what URI we would attempt to use, if any.  Used by the preloader to
 222    * resolve sources prior to DOM creation.
 223    *
 224    * @param aDocument The document this image would be for, for referencing
 225    *        viewport width and DPI/zoom
 226    * @param aIsSourceTag If these parameters are for a <source> tag (as in a
 227    *        <picture>) rather than an <img> tag. Note that some attrs are unused
 228    *        when this is true an vice versa
 229    * @param aSrcAttr [ignored if aIsSourceTag] The src attr for this image.
 230    * @param aSrcsetAttr The srcset attr for this image/source
 231    * @param aSizesAttr The sizes attr for this image/source
 232    * @param aTypeAttr [ignored if !aIsSourceTag] The type attr for this source.
 233    *                  Should be a void string to differentiate no type attribute
 234    *                  from an empty one.
 235    * @param aMediaAttr [ignored if !aIsSourceTag] The media attr for this
 236    *                   source.  Should be a void string to differentiate no
 237    *                   media attribute from an empty one.
 238    * @param aResult A reference to store the resulting URL spec in if we
 239    *                selected a source.  This value is not guaranteed to parse to
 240    *                a valid URL, merely the URL that the tag would attempt to
 241    *                resolve and load (which may be the empty string).  This
 242    *                parameter is not modified if return value is false.
 243    * @return True if we were able to select a final source, false if further
 244    *         sources would be considered.  It follows that this always returns
 245    *         true if !aIsSourceTag.
 246    *
 247    * Note that the return value may be true with an empty string as the result,
 248    * which implies that the parameters provided describe a tag that would select
 249    * no source.  This is distinct from a return of false which implies that
 250    * further <source> or <img> tags would be considered.
 251    */
 252   static bool SelectSourceForTagWithAttrs(
 253       Document* aDocument, bool aIsSourceTag, const nsAString& aSrcAttr,
 254       const nsAString& aSrcsetAttr, const nsAString& aSizesAttr,
 255       const nsAString& aTypeAttr, const nsAString& aMediaAttr,
 256       nsAString& aResult);
 257
 258   enum class FromIntersectionObserver : bool { No, Yes };
 259   enum class StartLoading : bool { No, Yes };
 260   void StopLazyLoading(StartLoading);
 261
 262   // This is used when restyling, for retrieving the extra style from the source
 263   // element.
 264   const StyleLockedDeclarationBlock* GetMappedAttributesFromSource() const;
 265
 266   FetchPriority GetFetchPriorityForImage() const override;
 267
 268  protected:
 269   virtual ~HTMLImageElement();
 270
 271   // Update the responsive source synchronously and queues a task to run
 272   // LoadSelectedImage pending stable state.
 273   //
 274   // Pending Bug 1076583 this is only used by the responsive image
 275   // algorithm (InResponsiveMode()) -- synchronous actions when just
 276   // using img.src will bypass this, and update source and kick off
 277   // image load synchronously.
 278   void UpdateSourceSyncAndQueueImageTask(
 279       bool aAlwaysLoad, const HTMLSourceElement* aSkippedSource = nullptr);
 280
 281   // True if we have a srcset attribute or a <picture> parent, regardless of if
 282   // any valid responsive sources were parsed from either.
 283   bool HaveSrcsetOrInPicture();
 284
 285   // True if we are using the newer image loading algorithm. This will be the
 286   // only mode after Bug 1076583
 287   bool InResponsiveMode();
 288
 289   // True if the given URL equals the last URL that was loaded by this element.
 290   bool SelectedSourceMatchesLast(nsIURI* aSelectedSource);
 291
 292   // Load the current mResponsiveSelector (responsive mode) or src attr image.
 293   // Note: This doesn't run the full selection for the responsive selector.
 294   nsresult LoadSelectedImage(bool aForce, bool aNotify, bool aAlwaysLoad);
 295
 296   // True if this string represents a type we would support on <source type>
 297   static bool SupportedPictureSourceType(const nsAString& aType);
 298
 299   // Update/create/destroy mResponsiveSelector
 300   void PictureSourceSrcsetChanged(nsIContent* aSourceNode,
 301                                   const nsAString& aNewValue, bool aNotify);
 302   void PictureSourceSizesChanged(nsIContent* aSourceNode,
 303                                  const nsAString& aNewValue, bool aNotify);
 304   // As we re-run the source selection on these mutations regardless,
 305   // we don't actually care which changed or to what
 306   void PictureSourceMediaOrTypeChanged(nsIContent* aSourceNode, bool aNotify);
 307
 308   // This is called when we update "width" or "height" attribute of source
 309   // element.
 310   void PictureSourceDimensionChanged(HTMLSourceElement* aSourceNode,
 311                                      bool aNotify);
 312
 313   void PictureSourceAdded(HTMLSourceElement* aSourceNode = nullptr);
 314   // This should be called prior to the unbind, such that nextsibling works
 315   void PictureSourceRemoved(HTMLSourceElement* aSourceNode = nullptr);
 316
 317   // Re-evaluates all source nodes (picture <source>,<img>) and finds
 318   // the best source set for mResponsiveSelector. If a better source
 319   // is found, creates a new selector and feeds the source to it. If
 320   // the current ResponsiveSelector is not changed, runs
 321   // SelectImage(true) to re-evaluate its candidates.
 322   //
 323   // Because keeping the existing selector is the common case (and we
 324   // often do no-op reselections), this does not re-parse values for
 325   // the existing mResponsiveSelector, meaning you need to update its
 326   // parameters as appropriate before calling (or null it out to force
 327   // recreation)
 328   //
 329   // if |aSkippedSource| is non-null, we will skip it when running the
 330   // algorithm. This is used when we need to update the source when we are
 331   // removing the source element.
 332   //
 333   // Returns true if the source has changed, and false otherwise.
 334   bool UpdateResponsiveSource(
 335       const HTMLSourceElement* aSkippedSource = nullptr);
 336
 337   // Given a <source> node that is a previous sibling *or* ourselves, try to
 338   // create a ResponsiveSelector.
 339
 340   // If the node's srcset/sizes make for an invalid selector, returns
 341   // nullptr. This does not guarantee the resulting selector matches an image,
 342   // only that it is valid.
 343   already_AddRefed<ResponsiveImageSelector> TryCreateResponsiveSelector(
 344       Element* aSourceElement);
 345
 346   MOZ_CAN_RUN_SCRIPT CSSIntPoint GetXY();
 347   JSObject* WrapNode(JSContext*, JS::Handle<JSObject*> aGivenProto) override;
 348   void UpdateFormOwner();
 349
 350   void BeforeSetAttr(int32_t aNameSpaceID, nsAtom* aName,
 351                      const nsAttrValue* aValue, bool aNotify) override;
 352
 353   void AfterSetAttr(int32_t aNameSpaceID, nsAtom* aName,
 354                     const nsAttrValue* aValue, const nsAttrValue* aOldValue,
 355                     nsIPrincipal* aMaybeScriptedPrincipal,
 356                     bool aNotify) override;
 357   void OnAttrSetButNotChanged(int32_t aNamespaceID, nsAtom* aName,
 358                               const nsAttrValueOrString& aValue,
 359                               bool aNotify) override;
 360
 361   // Override for nsImageLoadingContent.
 362   nsIContent* AsContent() override { return this; }
 363
 364   // Created when we're tracking responsive image state
 365   RefPtr<ResponsiveImageSelector> mResponsiveSelector;
 366
 367   // This is a weak reference that this element and the HTMLFormElement
 368   // cooperate in maintaining.
 369   HTMLFormElement* mForm = nullptr;
 370
 371  private:
 372   bool SourceElementMatches(Element* aSourceElement);
 373
 374   static void MapAttributesIntoRule(MappedDeclarationsBuilder&);
 375   /**
 376    * This function is called by AfterSetAttr and OnAttrSetButNotChanged.
 377    * It will not be called if the value is being unset.
 378    *
 379    * @param aNamespaceID the namespace of the attr being set
 380    * @param aName the localname of the attribute being set
 381    * @param aValue the value it's being set to represented as either a string or
 382    *        a parsed nsAttrValue.
 383    * @param aOldValue the value previously set. Will be null if no value was
 384    *        previously set. This value should only be used when
 385    *        aValueMaybeChanged is true; when aValueMaybeChanged is false,
 386    *        aOldValue should be considered unreliable.
 387    * @param aNotify Whether we plan to notify document observers.
 388    */
 389   void AfterMaybeChangeAttr(int32_t aNamespaceID, nsAtom* aName,
 390                             const nsAttrValueOrString& aValue,
 391                             const nsAttrValue* aOldValue,
 392                             nsIPrincipal* aMaybeScriptedPrincipal,
 393                             bool aNotify);
 394
 395   bool ShouldLoadImage() const;
 396
 397   // Set this image as a lazy load image due to loading="lazy".
 398   void SetLazyLoading();
 399
 400   void StartLoadingIfNeeded();
 401
 402   bool IsInPicture() const {
 403     return GetParentElement() &&
 404            GetParentElement()->IsHTMLElement(nsGkAtoms::picture);
 405   }
 406
 407   void InvalidateAttributeMapping();
 408
 409   void SetResponsiveSelector(RefPtr<ResponsiveImageSelector>&& aSource);
 410   void SetDensity(double aDensity);
 411
 412   // Queue an image load task (via microtask).
 413   void QueueImageLoadTask(bool aAlwaysLoad);
 414
 415   RefPtr<ImageLoadTask> mPendingImageLoadTask;
 416   nsCOMPtr<nsIURI> mSrcURI;
 417   nsCOMPtr<nsIPrincipal> mSrcTriggeringPrincipal;
 418   nsCOMPtr<nsIPrincipal> mSrcsetTriggeringPrincipal;
 419
 420   // Last URL that was attempted to load by this element.
 421   nsCOMPtr<nsIURI> mLastSelectedSource;
 422   // Last pixel density that was selected.
 423   double mCurrentDensity = 1.0;
 424   bool mInDocResponsiveContent = false;
 425 };
 426
 427 }  // namespace dom
 428 }  // namespace mozilla
 429
 430 #endif /* mozilla_dom_HTMLImageElement_h */