dom/html/HTMLImageElement.h
author Nicholas Nethercote <nnethercote@mozilla.com>
Fri, 03 Mar 2017 15:32:11 +1100
changeset 374836 4e196d802c7be7f3a3c147cc6c5b6406656584b1
parent 370542 7870b72807809a9ce4fb0165f9b10fdcb1f78aba
permissions -rw-r--r--
Bug 1344118 - Fix the profiler's sleeping threads optimization. r=jseward. When ProfilerBuffer::reset() is called, DuplicateLastSample() will start failing for all sleeping threads because there will be no prior thread data in the buffer to duplicate. But the sampling loop doesn't detect such failure. This causes two problems: - Missing samples. - CPU usage goes through the roof, because each time around the sampling loop the length of the failing search increases. The fix is simple: detect failure in the sampling loop and do a normal sample in that case. The patch also removes ThreadInfo::DuplicateLastSample(), because it just calls onto ProfileBuffer::DuplicateLastSample().

/* -*- 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/. */

#ifndef mozilla_dom_HTMLImageElement_h
#define mozilla_dom_HTMLImageElement_h

#include "mozilla/Attributes.h"
#include "nsGenericHTMLElement.h"
#include "nsImageLoadingContent.h"
#include "nsIDOMHTMLImageElement.h"
#include "imgRequestProxy.h"
#include "Units.h"
#include "nsCycleCollectionParticipant.h"

namespace mozilla {
class EventChainPreVisitor;
namespace dom {

class ImageLoadTask;

class ResponsiveImageSelector;
class HTMLImageElement final : public nsGenericHTMLElement,
                               public nsImageLoadingContent,
                               public nsIDOMHTMLImageElement
{
  friend class HTMLSourceElement;
  friend class HTMLPictureElement;
  friend class ImageLoadTask;
public:
  explicit HTMLImageElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo);

  static already_AddRefed<HTMLImageElement>
    Image(const GlobalObject& aGlobal,
          const Optional<uint32_t>& aWidth,
          const Optional<uint32_t>& aHeight,
          ErrorResult& aError);

  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(HTMLImageElement,
                                           nsGenericHTMLElement)

  // nsISupports
  NS_DECL_ISUPPORTS_INHERITED

  virtual bool Draggable() const override;

  // Element
  virtual bool IsInteractiveHTMLContent(bool aIgnoreTabindex) const override;

  // EventTarget
  virtual void AsyncEventRunning(AsyncEventDispatcher* aEvent) override;

  // nsIDOMHTMLImageElement
  NS_DECL_NSIDOMHTMLIMAGEELEMENT

  NS_IMPL_FROMCONTENT_HTML_WITH_TAG(HTMLImageElement, img)

  // override from nsImageLoadingContent
  CORSMode GetCORSMode() override;

  // nsIContent
  virtual bool ParseAttribute(int32_t aNamespaceID,
                                nsIAtom* aAttribute,
                                const nsAString& aValue,
                                nsAttrValue& aResult) override;
  virtual nsChangeHint GetAttributeChangeHint(const nsIAtom* aAttribute,
                                              int32_t aModType) const override;
  NS_IMETHOD_(bool) IsAttributeMapped(const nsIAtom* aAttribute) const override;
  virtual nsMapRuleToAttributesFunc GetAttributeMappingFunction() const override;

  virtual nsresult GetEventTargetParent(
                     EventChainPreVisitor& aVisitor) override;

  bool IsHTMLFocusable(bool aWithMouse, bool *aIsFocusable, int32_t *aTabIndex) override;

  // SetAttr override.  C++ is stupid, so have to override both
  // overloaded methods.
  nsresult SetAttr(int32_t aNameSpaceID, nsIAtom* aName,
                   const nsAString& aValue, bool aNotify)
  {
    return SetAttr(aNameSpaceID, aName, nullptr, aValue, aNotify);
  }
  virtual nsresult SetAttr(int32_t aNameSpaceID, nsIAtom* aName,
                           nsIAtom* aPrefix, const nsAString& aValue,
                           bool aNotify) override;

  virtual nsresult BindToTree(nsIDocument* aDocument, nsIContent* aParent,
                              nsIContent* aBindingParent,
                              bool aCompileEventHandlers) override;
  virtual void UnbindFromTree(bool aDeep, bool aNullParent) override;

  virtual EventStates IntrinsicState() const override;
  virtual nsresult Clone(mozilla::dom::NodeInfo *aNodeInfo, nsINode **aResult) const override;

  virtual void NodeInfoChanged() override;

  nsresult CopyInnerTo(Element* aDest);

  void MaybeLoadImage();

  bool IsMap()
  {
    return GetBoolAttr(nsGkAtoms::ismap);
  }
  void SetIsMap(bool aIsMap, ErrorResult& aError)
  {
    SetHTMLBoolAttr(nsGkAtoms::ismap, aIsMap, aError);
  }
  uint32_t Width()
  {
    return GetWidthHeightForImage(mCurrentRequest).width;
  }
  void SetWidth(uint32_t aWidth, ErrorResult& aError)
  {
    SetUnsignedIntAttr(nsGkAtoms::width, aWidth, 0, aError);
  }
  uint32_t Height()
  {
    return GetWidthHeightForImage(mCurrentRequest).height;
  }
  void SetHeight(uint32_t aHeight, ErrorResult& aError)
  {
    SetUnsignedIntAttr(nsGkAtoms::height, aHeight, 0, aError);
  }
  uint32_t NaturalWidth();
  uint32_t NaturalHeight();
  bool Complete();
  uint32_t Hspace()
  {
    return GetUnsignedIntAttr(nsGkAtoms::hspace, 0);
  }
  void SetHspace(uint32_t aHspace, ErrorResult& aError)
  {
    SetUnsignedIntAttr(nsGkAtoms::hspace, aHspace, 0, aError);
  }
  uint32_t Vspace()
  {
    return GetUnsignedIntAttr(nsGkAtoms::vspace, 0);
  }
  void SetVspace(uint32_t aVspace, ErrorResult& aError)
  {
    SetUnsignedIntAttr(nsGkAtoms::vspace, aVspace, 0, aError);
  }

  // The XPCOM versions of the following getters work for Web IDL bindings as well
  void SetAlt(const nsAString& aAlt, ErrorResult& aError)
  {
    SetHTMLAttr(nsGkAtoms::alt, aAlt, aError);
  }
  void SetSrc(const nsAString& aSrc, ErrorResult& aError)
  {
    SetHTMLAttr(nsGkAtoms::src, aSrc, aError);
  }
  void SetSrcset(const nsAString& aSrcset, ErrorResult& aError)
  {
    SetHTMLAttr(nsGkAtoms::srcset, aSrcset, aError);
  }
  void GetCrossOrigin(nsAString& aResult)
  {
    // Null for both missing and invalid defaults is ok, since we
    // always parse to an enum value, so we don't need an invalid
    // default, and we _want_ the missing default to be null.
    GetEnumAttr(nsGkAtoms::crossorigin, nullptr, aResult);
  }
  void SetCrossOrigin(const nsAString& aCrossOrigin, ErrorResult& aError)
  {
    SetOrRemoveNullableStringAttr(nsGkAtoms::crossorigin, aCrossOrigin, aError);
  }
  void SetUseMap(const nsAString& aUseMap, ErrorResult& aError)
  {
    SetHTMLAttr(nsGkAtoms::usemap, aUseMap, aError);
  }
  void SetName(const nsAString& aName, ErrorResult& aError)
  {
    SetHTMLAttr(nsGkAtoms::name, aName, aError);
  }
  void SetAlign(const nsAString& aAlign, ErrorResult& aError)
  {
    SetHTMLAttr(nsGkAtoms::align, aAlign, aError);
  }
  void SetLongDesc(const nsAString& aLongDesc, ErrorResult& aError)
  {
    SetHTMLAttr(nsGkAtoms::longdesc, aLongDesc, aError);
  }
  void SetSizes(const nsAString& aSizes, ErrorResult& aError)
  {
    SetHTMLAttr(nsGkAtoms::sizes, aSizes, aError);
  }
  void SetBorder(const nsAString& aBorder, ErrorResult& aError)
  {
    SetHTMLAttr(nsGkAtoms::border, aBorder, aError);
  }
  void SetReferrerPolicy(const nsAString& aReferrer, ErrorResult& aError)
  {
    SetHTMLAttr(nsGkAtoms::referrerpolicy, aReferrer, aError);
  }
  void GetReferrerPolicy(nsAString& aReferrer)
  {
    GetEnumAttr(nsGkAtoms::referrerpolicy, EmptyCString().get(), aReferrer);
  }

  net::ReferrerPolicy
  GetImageReferrerPolicy() override
  {
    return GetReferrerPolicyAsEnum();
  }

  int32_t X();
  int32_t Y();
  // Uses XPCOM GetLowsrc.
  void SetLowsrc(const nsAString& aLowsrc, ErrorResult& aError)
  {
    SetHTMLAttr(nsGkAtoms::lowsrc, aLowsrc, aError);
  }

#ifdef DEBUG
  nsIDOMHTMLFormElement* GetForm() const;
#endif
  void SetForm(nsIDOMHTMLFormElement* aForm);
  void ClearForm(bool aRemoveFromForm);

  virtual void DestroyContent() override;

  void MediaFeatureValuesChanged();

  /**
   * Given a hypothetical <img> or <source> tag with the given parameters,
   * return what URI we would attempt to use, if any.  Used by the preloader to
   * resolve sources prior to DOM creation.
   *
   * @param aDocument The document this image would be for, for referencing
   *        viewport width and DPI/zoom
   * @param aIsSourceTag If these parameters are for a <source> tag (as in a
   *        <picture>) rather than an <img> tag. Note that some attrs are unused
   *        when this is true an vice versa
   * @param aSrcAttr [ignored if aIsSourceTag] The src attr for this image.
   * @param aSrcsetAttr The srcset attr for this image/source
   * @param aSizesAttr The sizes attr for this image/source
   * @param aTypeAttr [ignored if !aIsSourceTag] The type attr for this source.
   *                  Should be a void string to differentiate no type attribute
   *                  from an empty one.
   * @param aMediaAttr [ignored if !aIsSourceTag] The media attr for this
   *                   source.  Should be a void string to differentiate no
   *                   media attribute from an empty one.
   * @param aResult A reference to store the resulting URL spec in if we
   *                selected a source.  This value is not guaranteed to parse to
   *                a valid URL, merely the URL that the tag would attempt to
   *                resolve and load (which may be the empty string).  This
   *                parameter is not modified if return value is false.
   * @return True if we were able to select a final source, false if further
   *         sources would be considered.  It follows that this always returns
   *         true if !aIsSourceTag.
   *
   * Note that the return value may be true with an empty string as the result,
   * which implies that the parameters provided describe a tag that would select
   * no source.  This is distinct from a return of false which implies that
   * further <source> or <img> tags would be considered.
   */
  static bool
    SelectSourceForTagWithAttrs(nsIDocument *aDocument,
                                bool aIsSourceTag,
                                const nsAString& aSrcAttr,
                                const nsAString& aSrcsetAttr,
                                const nsAString& aSizesAttr,
                                const nsAString& aTypeAttr,
                                const nsAString& aMediaAttr,
                                nsAString& aResult);

  /**
   * If this image's src pointers to an SVG document, flush the SVG document's
   * use counters to telemetry.  Only used for testing purposes.
   */
  void FlushUseCounters();

protected:
  virtual ~HTMLImageElement();

  // Queues a task to run LoadSelectedImage pending stable state.
  //
  // Pending Bug 1076583 this is only used by the responsive image
  // algorithm (InResponsiveMode()) -- synchronous actions when just
  // using img.src will bypass this, and update source and kick off
  // image load synchronously.
  void QueueImageLoadTask(bool aAlwaysLoad);

  // True if we have a srcset attribute or a <picture> parent, regardless of if
  // any valid responsive sources were parsed from either.
  bool HaveSrcsetOrInPicture();

  // True if we are using the newer image loading algorithm. This will be the
  // only mode after Bug 1076583
  bool InResponsiveMode();

  // True if the given URL and density equal the last URL and density that was loaded by this element.
  bool SelectedSourceMatchesLast(nsIURI* aSelectedSource, double aSelectedDensity);

  // Resolve and load the current mResponsiveSelector (responsive mode) or src
  // attr image.
  nsresult LoadSelectedImage(bool aForce, bool aNotify, bool aAlwaysLoad);

  // True if this string represents a type we would support on <source type>
  static bool SupportedPictureSourceType(const nsAString& aType);

  // Update/create/destroy mResponsiveSelector
  void PictureSourceSrcsetChanged(nsIContent *aSourceNode,
                                  const nsAString& aNewValue, bool aNotify);
  void PictureSourceSizesChanged(nsIContent *aSourceNode,
                                 const nsAString& aNewValue, bool aNotify);
  // As we re-run the source selection on these mutations regardless,
  // we don't actually care which changed or to what
  void PictureSourceMediaOrTypeChanged(nsIContent *aSourceNode, bool aNotify);

  void PictureSourceAdded(nsIContent *aSourceNode);
  // This should be called prior to the unbind, such that nextsibling works
  void PictureSourceRemoved(nsIContent *aSourceNode);

  // Re-evaluates all source nodes (picture <source>,<img>) and finds
  // the best source set for mResponsiveSelector. If a better source
  // is found, creates a new selector and feeds the source to it. If
  // the current ResponsiveSelector is not changed, runs
  // SelectImage(true) to re-evaluate its candidates.
  //
  // Because keeping the existing selector is the common case (and we
  // often do no-op reselections), this does not re-parse values for
  // the existing mResponsiveSelector, meaning you need to update its
  // parameters as appropriate before calling (or null it out to force
  // recreation)
  //
  // Returns true if the source has changed, and false otherwise.
  bool UpdateResponsiveSource();

  // Given a <source> node that is a previous sibling *or* ourselves, try to
  // create a ResponsiveSelector.

  // If the node's srcset/sizes make for an invalid selector, returns
  // false. This does not guarantee the resulting selector matches an image,
  // only that it is valid.
  bool TryCreateResponsiveSelector(nsIContent *aSourceNode);

  CSSIntPoint GetXY();
  virtual JSObject* WrapNode(JSContext *aCx, JS::Handle<JSObject*> aGivenProto) override;
  void UpdateFormOwner();

  virtual nsresult BeforeSetAttr(int32_t aNameSpaceID, nsIAtom* aName,
                                 nsAttrValueOrString* aValue,
                                 bool aNotify) override;

  virtual nsresult AfterSetAttr(int32_t aNameSpaceID, nsIAtom* aName,
                                const nsAttrValue* aValue, bool aNotify) override;

  // This is a weak reference that this element and the HTMLFormElement
  // cooperate in maintaining.
  HTMLFormElement* mForm;

  // Created when we're tracking responsive image state
  RefPtr<ResponsiveImageSelector> mResponsiveSelector;

private:
  bool SourceElementMatches(nsIContent* aSourceNode);

  static void MapAttributesIntoRule(const nsMappedAttributes* aAttributes,
                                    GenericSpecifiedValues* aGenericData);

  bool mInDocResponsiveContent;
  RefPtr<ImageLoadTask> mPendingImageLoadTask;

  // Last URL that was attempted to load by this element.
  nsCOMPtr<nsIURI> mLastSelectedSource;
  // Last pixel density that was selected.
  double mCurrentDensity;
};

} // namespace dom
} // namespace mozilla

#endif /* mozilla_dom_HTMLImageElement_h */