dom/html/HTMLImageElement.cpp
author Nicholas Nethercote <nnethercote@mozilla.com>
Fri, 03 Mar 2017 15:32:11 +1100
changeset 374836 4e196d802c7be7f3a3c147cc6c5b6406656584b1
parent 370552 530f32f163161128bb62f0ae9f545d7dac1018fb
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/. */

#include "mozilla/dom/HTMLImageElement.h"
#include "mozilla/dom/HTMLImageElementBinding.h"
#include "nsGkAtoms.h"
#include "nsStyleConsts.h"
#include "nsPresContext.h"
#include "nsMappedAttributes.h"
#include "nsSize.h"
#include "nsDocument.h"
#include "nsIDocument.h"
#include "nsIDOMMutationEvent.h"
#include "nsIScriptContext.h"
#include "nsIURL.h"
#include "nsIIOService.h"
#include "nsIServiceManager.h"
#include "nsContentUtils.h"
#include "nsContainerFrame.h"
#include "nsNodeInfoManager.h"
#include "mozilla/MouseEvents.h"
#include "nsContentPolicyUtils.h"
#include "nsIDOMWindow.h"
#include "nsFocusManager.h"
#include "mozilla/dom/HTMLFormElement.h"
#include "nsAttrValueOrString.h"
#include "imgLoader.h"
#include "Image.h"

// Responsive images!
#include "mozilla/dom/HTMLSourceElement.h"
#include "mozilla/dom/ResponsiveImageSelector.h"

#include "imgIContainer.h"
#include "imgILoader.h"
#include "imgINotificationObserver.h"
#include "imgRequestProxy.h"

#include "nsILoadGroup.h"

#include "nsIDOMHTMLMapElement.h"
#include "mozilla/EventDispatcher.h"
#include "mozilla/EventStates.h"
#include "mozilla/GenericSpecifiedValuesInlines.h"
#include "mozilla/net/ReferrerPolicy.h"

#include "nsLayoutUtils.h"

using namespace mozilla::net;

NS_IMPL_NS_NEW_HTML_ELEMENT(Image)

#ifdef DEBUG
// Is aSubject a previous sibling of aNode.
static bool IsPreviousSibling(nsINode *aSubject, nsINode *aNode)
{
  if (aSubject == aNode) {
    return false;
  }

  nsINode *parent = aSubject->GetParentNode();
  if (parent && parent == aNode->GetParentNode()) {
    return parent->IndexOf(aSubject) < parent->IndexOf(aNode);
  }

  return false;
}
#endif

namespace mozilla {
namespace dom {

// Calls LoadSelectedImage on host element unless it has been superseded or
// canceled -- this is the synchronous section of "update the image data".
// https://html.spec.whatwg.org/multipage/embedded-content.html#update-the-image-data
class ImageLoadTask : public Runnable
{
public:
  ImageLoadTask(HTMLImageElement *aElement, bool aAlwaysLoad)
    : mElement(aElement)
    , mAlwaysLoad(aAlwaysLoad)
  {
    mDocument = aElement->OwnerDoc();
    mDocument->BlockOnload();
  }

  NS_IMETHOD Run() override
  {
    if (mElement->mPendingImageLoadTask == this) {
      mElement->mPendingImageLoadTask = nullptr;
      mElement->LoadSelectedImage(true, true, mAlwaysLoad);
    }
    mDocument->UnblockOnload(false);
    return NS_OK;
  }

  bool AlwaysLoad() {
    return mAlwaysLoad;
  }

private:
  ~ImageLoadTask() {}
  RefPtr<HTMLImageElement> mElement;
  nsCOMPtr<nsIDocument> mDocument;
  bool mAlwaysLoad;
};

HTMLImageElement::HTMLImageElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo)
  : nsGenericHTMLElement(aNodeInfo)
  , mForm(nullptr)
  , mInDocResponsiveContent(false)
  , mCurrentDensity(1.0)
{
  // We start out broken
  AddStatesSilently(NS_EVENT_STATE_BROKEN);
}

HTMLImageElement::~HTMLImageElement()
{
  DestroyImageLoadingContent();
}


NS_IMPL_ADDREF_INHERITED(HTMLImageElement, Element)
NS_IMPL_RELEASE_INHERITED(HTMLImageElement, Element)

NS_IMPL_CYCLE_COLLECTION_INHERITED(HTMLImageElement,
                                   nsGenericHTMLElement,
                                   mResponsiveSelector)

// QueryInterface implementation for HTMLImageElement
NS_INTERFACE_TABLE_HEAD_CYCLE_COLLECTION_INHERITED(HTMLImageElement)
  NS_INTERFACE_TABLE_INHERITED(HTMLImageElement,
                               nsIDOMHTMLImageElement,
                               nsIImageLoadingContent,
                               imgIOnloadBlocker,
                               imgINotificationObserver)
NS_INTERFACE_TABLE_TAIL_INHERITING(nsGenericHTMLElement)


NS_IMPL_ELEMENT_CLONE(HTMLImageElement)


NS_IMPL_STRING_ATTR(HTMLImageElement, Name, name)
NS_IMPL_STRING_ATTR(HTMLImageElement, Align, align)
NS_IMPL_STRING_ATTR(HTMLImageElement, Alt, alt)
NS_IMPL_STRING_ATTR(HTMLImageElement, Border, border)
NS_IMPL_INT_ATTR(HTMLImageElement, Hspace, hspace)
NS_IMPL_BOOL_ATTR(HTMLImageElement, IsMap, ismap)
NS_IMPL_URI_ATTR(HTMLImageElement, LongDesc, longdesc)
NS_IMPL_STRING_ATTR(HTMLImageElement, Sizes, sizes)
NS_IMPL_URI_ATTR(HTMLImageElement, Lowsrc, lowsrc)
NS_IMPL_URI_ATTR(HTMLImageElement, Src, src)
NS_IMPL_STRING_ATTR(HTMLImageElement, Srcset, srcset)
NS_IMPL_STRING_ATTR(HTMLImageElement, UseMap, usemap)
NS_IMPL_INT_ATTR(HTMLImageElement, Vspace, vspace)

bool
HTMLImageElement::IsInteractiveHTMLContent(bool aIgnoreTabindex) const
{
  return HasAttr(kNameSpaceID_None, nsGkAtoms::usemap) ||
          nsGenericHTMLElement::IsInteractiveHTMLContent(aIgnoreTabindex);
}

void
HTMLImageElement::AsyncEventRunning(AsyncEventDispatcher* aEvent)
{
  nsImageLoadingContent::AsyncEventRunning(aEvent);
}

nsresult
HTMLImageElement::GetCurrentSrc(nsAString& aValue)
{
  nsCOMPtr<nsIURI> currentURI;
  GetCurrentURI(getter_AddRefs(currentURI));
  if (currentURI) {
    nsAutoCString spec;
    currentURI->GetSpec(spec);
    CopyUTF8toUTF16(spec, aValue);
  } else {
    SetDOMStringToNull(aValue);
  }

  return NS_OK;
}

bool
HTMLImageElement::Draggable() const
{
  // images may be dragged unless the draggable attribute is false
  return !AttrValueIs(kNameSpaceID_None, nsGkAtoms::draggable,
                      nsGkAtoms::_false, eIgnoreCase);
}

bool
HTMLImageElement::Complete()
{
  if (!mCurrentRequest) {
    return true;
  }

  if (mPendingRequest) {
    return false;
  }

  uint32_t status;
  mCurrentRequest->GetImageStatus(&status);
  return
    (status &
     (imgIRequest::STATUS_LOAD_COMPLETE | imgIRequest::STATUS_ERROR)) != 0;
}

NS_IMETHODIMP
HTMLImageElement::GetComplete(bool* aComplete)
{
  NS_PRECONDITION(aComplete, "Null out param!");

  *aComplete = Complete();

  return NS_OK;
}

CSSIntPoint
HTMLImageElement::GetXY()
{
  nsIFrame* frame = GetPrimaryFrame(FlushType::Layout);
  if (!frame) {
    return CSSIntPoint(0, 0);
  }

  nsIFrame* layer = nsLayoutUtils::GetClosestLayer(frame->GetParent());
  return CSSIntPoint::FromAppUnitsRounded(frame->GetOffsetTo(layer));
}

int32_t
HTMLImageElement::X()
{
  return GetXY().x;
}

int32_t
HTMLImageElement::Y()
{
  return GetXY().y;
}

NS_IMETHODIMP
HTMLImageElement::GetX(int32_t* aX)
{
  *aX = X();
  return NS_OK;
}

NS_IMETHODIMP
HTMLImageElement::GetY(int32_t* aY)
{
  *aY = Y();
  return NS_OK;
}

NS_IMETHODIMP
HTMLImageElement::GetHeight(uint32_t* aHeight)
{
  *aHeight = Height();

  return NS_OK;
}

NS_IMETHODIMP
HTMLImageElement::SetHeight(uint32_t aHeight)
{
  ErrorResult rv;
  SetHeight(aHeight, rv);
  return rv.StealNSResult();
}

NS_IMETHODIMP
HTMLImageElement::GetWidth(uint32_t* aWidth)
{
  *aWidth = Width();

  return NS_OK;
}

NS_IMETHODIMP
HTMLImageElement::SetWidth(uint32_t aWidth)
{
  ErrorResult rv;
  SetWidth(aWidth, rv);
  return rv.StealNSResult();
}

bool
HTMLImageElement::ParseAttribute(int32_t aNamespaceID,
                                 nsIAtom* aAttribute,
                                 const nsAString& aValue,
                                 nsAttrValue& aResult)
{
  if (aNamespaceID == kNameSpaceID_None) {
    if (aAttribute == nsGkAtoms::align) {
      return ParseAlignValue(aValue, aResult);
    }
    if (aAttribute == nsGkAtoms::crossorigin) {
      ParseCORSValue(aValue, aResult);
      return true;
    }
    if (ParseImageAttribute(aAttribute, aValue, aResult)) {
      return true;
    }
  }

  return nsGenericHTMLElement::ParseAttribute(aNamespaceID, aAttribute, aValue,
                                              aResult);
}

void
HTMLImageElement::MapAttributesIntoRule(const nsMappedAttributes* aAttributes,
                                        GenericSpecifiedValues* aData)
{
  nsGenericHTMLElement::MapImageAlignAttributeInto(aAttributes, aData);
  nsGenericHTMLElement::MapImageBorderAttributeInto(aAttributes, aData);
  nsGenericHTMLElement::MapImageMarginAttributeInto(aAttributes, aData);
  nsGenericHTMLElement::MapImageSizeAttributesInto(aAttributes, aData);
  nsGenericHTMLElement::MapCommonAttributesInto(aAttributes, aData);
}

nsChangeHint
HTMLImageElement::GetAttributeChangeHint(const nsIAtom* aAttribute,
                                         int32_t aModType) const
{
  nsChangeHint retval =
    nsGenericHTMLElement::GetAttributeChangeHint(aAttribute, aModType);
  if (aAttribute == nsGkAtoms::usemap ||
      aAttribute == nsGkAtoms::ismap) {
    retval |= nsChangeHint_ReconstructFrame;
  } else if (aAttribute == nsGkAtoms::alt) {
    if (aModType == nsIDOMMutationEvent::ADDITION ||
        aModType == nsIDOMMutationEvent::REMOVAL) {
      retval |= nsChangeHint_ReconstructFrame;
    }
  }
  return retval;
}

NS_IMETHODIMP_(bool)
HTMLImageElement::IsAttributeMapped(const nsIAtom* aAttribute) const
{
  static const MappedAttributeEntry* const map[] = {
    sCommonAttributeMap,
    sImageMarginSizeAttributeMap,
    sImageBorderAttributeMap,
    sImageAlignAttributeMap
  };

  return FindAttributeDependence(aAttribute, map);
}


nsMapRuleToAttributesFunc
HTMLImageElement::GetAttributeMappingFunction() const
{
  return &MapAttributesIntoRule;
}


nsresult
HTMLImageElement::BeforeSetAttr(int32_t aNameSpaceID, nsIAtom* aName,
                                nsAttrValueOrString* aValue,
                                bool aNotify)
{

  if (aNameSpaceID == kNameSpaceID_None && mForm &&
      (aName == nsGkAtoms::name || aName == nsGkAtoms::id)) {
    // remove the image from the hashtable as needed
    nsAutoString tmp;
    GetAttr(kNameSpaceID_None, aName, tmp);

    if (!tmp.IsEmpty()) {
      mForm->RemoveImageElementFromTable(this, tmp);
    }
  }

  return nsGenericHTMLElement::BeforeSetAttr(aNameSpaceID, aName,
                                             aValue, aNotify);
}

nsresult
HTMLImageElement::AfterSetAttr(int32_t aNameSpaceID, nsIAtom* aName,
                               const nsAttrValue* aValue, bool aNotify)
{
  if (aNameSpaceID == kNameSpaceID_None && mForm &&
      (aName == nsGkAtoms::name || aName == nsGkAtoms::id) &&
      aValue && !aValue->IsEmptyString()) {
    // add the image to the hashtable as needed
    MOZ_ASSERT(aValue->Type() == nsAttrValue::eAtom,
               "Expected atom value for name/id");
    mForm->AddImageElementToTable(this,
      nsDependentAtomString(aValue->GetAtomValue()));
  }

  // Handle src/srcset updates. If aNotify is false, we are coming from the
  // parser or some such place; we'll get bound after all the attributes have
  // been set, so we'll do the image load from BindToTree.

  nsAttrValueOrString attrVal(aValue);

  if (aName == nsGkAtoms::src &&
      aNameSpaceID == kNameSpaceID_None &&
      !aValue) {
    // SetAttr handles setting src since it needs to catch img.src =
    // img.src, so we only need to handle the unset case
    if (InResponsiveMode()) {
      if (mResponsiveSelector &&
          mResponsiveSelector->Content() == this) {
        mResponsiveSelector->SetDefaultSource(NullString());
      }
      QueueImageLoadTask(true);
    } else {
      // Bug 1076583 - We still behave synchronously in the non-responsive case
      CancelImageRequests(aNotify);
    }
  } else if (aName == nsGkAtoms::srcset &&
             aNameSpaceID == kNameSpaceID_None) {
    PictureSourceSrcsetChanged(this, attrVal.String(), aNotify);
  } else if (aName == nsGkAtoms::sizes &&
             aNameSpaceID == kNameSpaceID_None) {
    PictureSourceSizesChanged(this, attrVal.String(), aNotify);
  }

  return nsGenericHTMLElement::AfterSetAttr(aNameSpaceID, aName,
                                            aValue, aNotify);
}

nsresult
HTMLImageElement::GetEventTargetParent(EventChainPreVisitor& aVisitor)
{
  // We handle image element with attribute ismap in its corresponding frame
  // element. Set mMultipleActionsPrevented here to prevent the click event
  // trigger the behaviors in Element::PostHandleEventForLinks
  WidgetMouseEvent* mouseEvent = aVisitor.mEvent->AsMouseEvent();
  if (mouseEvent && mouseEvent->IsLeftClickEvent() && IsMap()) {
    mouseEvent->mFlags.mMultipleActionsPrevented = true;
  }
  return nsGenericHTMLElement::GetEventTargetParent(aVisitor);
}

bool
HTMLImageElement::IsHTMLFocusable(bool aWithMouse,
                                  bool *aIsFocusable, int32_t *aTabIndex)
{
  int32_t tabIndex = TabIndex();

  if (IsInUncomposedDoc()) {
    nsAutoString usemap;
    GetUseMap(usemap);
    // XXXbz which document should this be using?  sXBL/XBL2 issue!  I
    // think that OwnerDoc() is right, since we don't want to
    // assume stuff about the document we're bound to.
    if (OwnerDoc()->FindImageMap(usemap)) {
      if (aTabIndex) {
        // Use tab index on individual map areas
        *aTabIndex = (sTabFocusModel & eTabFocus_linksMask)? 0 : -1;
      }
      // Image map is not focusable itself, but flag as tabbable
      // so that image map areas get walked into.
      *aIsFocusable = false;

      return false;
    }
  }

  if (aTabIndex) {
    // Can be in tab order if tabindex >=0 and form controls are tabbable.
    *aTabIndex = (sTabFocusModel & eTabFocus_formElementsMask)? tabIndex : -1;
  }

  *aIsFocusable =
#ifdef XP_MACOSX
    (!aWithMouse || nsFocusManager::sMouseFocusesFormControl) &&
#endif
    (tabIndex >= 0 || HasAttr(kNameSpaceID_None, nsGkAtoms::tabindex));

  return false;
}

nsresult
HTMLImageElement::SetAttr(int32_t aNameSpaceID, nsIAtom* aName,
                          nsIAtom* aPrefix, const nsAString& aValue,
                          bool aNotify)
{
  bool forceReload = false;
  // We need to force our image to reload.  This must be done here, not in
  // AfterSetAttr or BeforeSetAttr, because we want to do it even if the attr is
  // being set to its existing value, which is normally optimized away as a
  // no-op.
  //
  // If we are in responsive mode, we drop the forced reload behavior,
  // but still trigger a image load task for img.src = img.src per
  // spec.
  //
  // Both cases handle unsetting src in AfterSetAttr
  if (aNameSpaceID == kNameSpaceID_None &&
      aName == nsGkAtoms::src) {

    if (InResponsiveMode()) {
      if (mResponsiveSelector &&
          mResponsiveSelector->Content() == this) {
        mResponsiveSelector->SetDefaultSource(aValue);
      }
      QueueImageLoadTask(true);
    } else if (aNotify) {
      // If aNotify is false, we are coming from the parser or some such place;
      // we'll get bound after all the attributes have been set, so we'll do the
      // sync image load from BindToTree. Skip the LoadImage call in that case.

      // Note that this sync behavior is partially removed from the spec, bug 1076583

      // A hack to get animations to reset. See bug 594771.
      mNewRequestsWillNeedAnimationReset = true;

      // Force image loading here, so that we'll try to load the image from
      // network if it's set to be not cacheable...  If we change things so that
      // the state gets in Element's attr-setting happen around this
      // LoadImage call, we could start passing false instead of aNotify
      // here.
      LoadImage(aValue, true, aNotify, eImageLoadType_Normal);

      mNewRequestsWillNeedAnimationReset = false;
    }
  } else if (aNameSpaceID == kNameSpaceID_None &&
             aName == nsGkAtoms::crossorigin &&
             aNotify) {
    nsAttrValue attrValue;
    ParseCORSValue(aValue, attrValue);
    if (GetCORSMode() != AttrValueToCORSMode(&attrValue)) {
      // Force a new load of the image with the new cross origin policy.
      forceReload = true;
    }
  } else if (aName == nsGkAtoms::referrerpolicy &&
      aNameSpaceID == kNameSpaceID_None &&
      aNotify) {
    ReferrerPolicy referrerPolicy = AttributeReferrerPolicyFromString(aValue);
    if (!InResponsiveMode() &&
        referrerPolicy != RP_Unset &&
        referrerPolicy != GetImageReferrerPolicy()) {
      // XXX: Bug 1076583 - We still use the older synchronous algorithm
      // Because referrerPolicy is not treated as relevant mutations, setting
      // the attribute will neither trigger a reload nor update the referrer
      // policy of the loading channel (whether it has previously completed or
      // not). Force a new load of the image with the new referrerpolicy.
      forceReload = true;
    }
  }

  nsresult rv = nsGenericHTMLElement::SetAttr(aNameSpaceID, aName, aPrefix,
                                              aValue, aNotify);

  // Because we load image synchronously in non-responsive-mode, we need to do
  // reload after the attribute has been set if the reload is triggerred by
  // cross origin changing.
  if (forceReload) {
    if (InResponsiveMode()) {
      // per spec, full selection runs when this changes, even though
      // it doesn't directly affect the source selection
      QueueImageLoadTask(true);
    } else {
      // Bug 1076583 - We still use the older synchronous algorithm in
      // non-responsive mode. Force a new load of the image with the
      // new cross origin policy
      ForceReload(aNotify);
    }
  }

  return rv;
}

nsresult
HTMLImageElement::BindToTree(nsIDocument* aDocument, nsIContent* aParent,
                             nsIContent* aBindingParent,
                             bool aCompileEventHandlers)
{
  nsresult rv = nsGenericHTMLElement::BindToTree(aDocument, aParent,
                                                 aBindingParent,
                                                 aCompileEventHandlers);
  NS_ENSURE_SUCCESS(rv, rv);

  nsImageLoadingContent::BindToTree(aDocument, aParent, aBindingParent,
                                    aCompileEventHandlers);

  if (aParent) {
    UpdateFormOwner();
  }

  if (HaveSrcsetOrInPicture()) {
    if (aDocument && !mInDocResponsiveContent) {
      aDocument->AddResponsiveContent(this);
      mInDocResponsiveContent = true;
    }

    // Run selection algorithm when an img element is inserted into a document
    // in order to react to changes in the environment. See note of
    // https://html.spec.whatwg.org/multipage/embedded-content.html#img-environment-changes
    QueueImageLoadTask(false);
  } else if (!InResponsiveMode() &&
             HasAttr(kNameSpaceID_None, nsGkAtoms::src)) {
    // We skip loading when our attributes were set from parser land,
    // so trigger a aForce=false load now to check if things changed.
    // This isn't necessary for responsive mode, since creating the
    // image load task is asynchronous we don't need to take special
    // care to avoid doing so when being filled by the parser.

    // FIXME: Bug 660963 it would be nice if we could just have
    // ClearBrokenState update our state and do it fast...
    ClearBrokenState();
    RemoveStatesSilently(NS_EVENT_STATE_BROKEN);

    // We still act synchronously for the non-responsive case (Bug
    // 1076583), but still need to delay if it is unsafe to run
    // script.

    // If loading is temporarily disabled, don't even launch MaybeLoadImage.
    // Otherwise MaybeLoadImage may run later when someone has reenabled
    // loading.
    if (LoadingEnabled()) {
      nsContentUtils::AddScriptRunner(
          NewRunnableMethod(this, &HTMLImageElement::MaybeLoadImage));
    }
  }

  return rv;
}

void
HTMLImageElement::UnbindFromTree(bool aDeep, bool aNullParent)
{
  if (mForm) {
    if (aNullParent || !FindAncestorForm(mForm)) {
      ClearForm(true);
    } else {
      UnsetFlags(MAYBE_ORPHAN_FORM_ELEMENT);
    }
  }

  if (mInDocResponsiveContent) {
    nsIDocument* doc = GetOurOwnerDoc();
    MOZ_ASSERT(doc);
    if (doc) {
      doc->RemoveResponsiveContent(this);
      mInDocResponsiveContent = false;
    }
  }

  mLastSelectedSource = nullptr;

  nsImageLoadingContent::UnbindFromTree(aDeep, aNullParent);
  nsGenericHTMLElement::UnbindFromTree(aDeep, aNullParent);
}

void
HTMLImageElement::UpdateFormOwner()
{
  if (!mForm) {
    mForm = FindAncestorForm();
  }

  if (mForm && !HasFlag(ADDED_TO_FORM)) {
    // Now we need to add ourselves to the form
    nsAutoString nameVal, idVal;
    GetAttr(kNameSpaceID_None, nsGkAtoms::name, nameVal);
    GetAttr(kNameSpaceID_None, nsGkAtoms::id, idVal);

    SetFlags(ADDED_TO_FORM);

    mForm->AddImageElement(this);

    if (!nameVal.IsEmpty()) {
      mForm->AddImageElementToTable(this, nameVal);
    }

    if (!idVal.IsEmpty()) {
      mForm->AddImageElementToTable(this, idVal);
    }
  }
}

void
HTMLImageElement::MaybeLoadImage()
{
  // Our base URI may have changed, or we may have had responsive parameters
  // change while not bound to the tree. Re-parse src/srcset and call LoadImage,
  // which is a no-op if it resolves to the same effective URI without aForce.

  // Note, check LoadingEnabled() after LoadImage call.

  LoadSelectedImage(false, true, false);

  if (!LoadingEnabled()) {
    CancelImageRequests(true);
  }
}

EventStates
HTMLImageElement::IntrinsicState() const
{
  return nsGenericHTMLElement::IntrinsicState() |
    nsImageLoadingContent::ImageState();
}

void
HTMLImageElement::NodeInfoChanged()
{
  // Resetting the last selected source if adoption steps are run.
  mLastSelectedSource = nullptr;
}

// static
already_AddRefed<HTMLImageElement>
HTMLImageElement::Image(const GlobalObject& aGlobal,
                        const Optional<uint32_t>& aWidth,
                        const Optional<uint32_t>& aHeight,
                        ErrorResult& aError)
{
  nsCOMPtr<nsPIDOMWindowInner> win = do_QueryInterface(aGlobal.GetAsSupports());
  nsIDocument* doc;
  if (!win || !(doc = win->GetExtantDoc())) {
    aError.Throw(NS_ERROR_FAILURE);
    return nullptr;
  }

  already_AddRefed<mozilla::dom::NodeInfo> nodeInfo =
    doc->NodeInfoManager()->GetNodeInfo(nsGkAtoms::img, nullptr,
                                        kNameSpaceID_XHTML,
                                        nsIDOMNode::ELEMENT_NODE);

  RefPtr<HTMLImageElement> img = new HTMLImageElement(nodeInfo);

  if (aWidth.WasPassed()) {
    img->SetWidth(aWidth.Value(), aError);
    if (aError.Failed()) {
      return nullptr;
    }

    if (aHeight.WasPassed()) {
      img->SetHeight(aHeight.Value(), aError);
      if (aError.Failed()) {
        return nullptr;
      }
    }
  }

  return img.forget();
}

uint32_t
HTMLImageElement::NaturalHeight()
{
  uint32_t height;
  nsresult rv = nsImageLoadingContent::GetNaturalHeight(&height);

  if (NS_FAILED(rv)) {
    MOZ_ASSERT(false, "GetNaturalHeight should not fail");
    return 0;
  }

  if (mResponsiveSelector) {
    double density = mResponsiveSelector->GetSelectedImageDensity();
    MOZ_ASSERT(density >= 0.0);
    height = NSToIntRound(double(height) / density);
  }

  return height;
}

NS_IMETHODIMP
HTMLImageElement::GetNaturalHeight(uint32_t* aNaturalHeight)
{
  *aNaturalHeight = NaturalHeight();
  return NS_OK;
}

uint32_t
HTMLImageElement::NaturalWidth()
{
  uint32_t width;
  nsresult rv = nsImageLoadingContent::GetNaturalWidth(&width);

  if (NS_FAILED(rv)) {
    MOZ_ASSERT(false, "GetNaturalWidth should not fail");
    return 0;
  }

  if (mResponsiveSelector) {
    double density = mResponsiveSelector->GetSelectedImageDensity();
    MOZ_ASSERT(density >= 0.0);
    width = NSToIntRound(double(width) / density);
  }

  return width;
}

NS_IMETHODIMP
HTMLImageElement::GetNaturalWidth(uint32_t* aNaturalWidth)
{
  *aNaturalWidth = NaturalWidth();
  return NS_OK;
}

nsresult
HTMLImageElement::CopyInnerTo(Element* aDest)
{
  bool destIsStatic = aDest->OwnerDoc()->IsStaticDocument();
  auto dest = static_cast<HTMLImageElement*>(aDest);
  if (destIsStatic) {
    CreateStaticImageClone(dest);
  }

  nsresult rv = nsGenericHTMLElement::CopyInnerTo(aDest);
  if (NS_FAILED(rv)) {
    return rv;
  }

  if (!destIsStatic) {
    // In SetAttr (called from nsGenericHTMLElement::CopyInnerTo), dest skipped
    // doing the image load because we passed in false for aNotify.  But we
    // really do want it to do the load, so set it up to happen once the cloning
    // reaches a stable state.
    if (!dest->InResponsiveMode() &&
        dest->HasAttr(kNameSpaceID_None, nsGkAtoms::src)) {
      nsContentUtils::AddScriptRunner(
        NewRunnableMethod(dest, &HTMLImageElement::MaybeLoadImage));
    }
  }

  return NS_OK;
}

CORSMode
HTMLImageElement::GetCORSMode()
{
  return AttrValueToCORSMode(GetParsedAttr(nsGkAtoms::crossorigin));
}

JSObject*
HTMLImageElement::WrapNode(JSContext* aCx, JS::Handle<JSObject*> aGivenProto)
{
  return HTMLImageElementBinding::Wrap(aCx, this, aGivenProto);
}

#ifdef DEBUG
nsIDOMHTMLFormElement*
HTMLImageElement::GetForm() const
{
  return mForm;
}
#endif

void
HTMLImageElement::SetForm(nsIDOMHTMLFormElement* aForm)
{
  NS_PRECONDITION(aForm, "Don't pass null here");
  NS_ASSERTION(!mForm,
               "We don't support switching from one non-null form to another.");

  mForm = static_cast<HTMLFormElement*>(aForm);
}

void
HTMLImageElement::ClearForm(bool aRemoveFromForm)
{
  NS_ASSERTION((mForm != nullptr) == HasFlag(ADDED_TO_FORM),
               "Form control should have had flag set correctly");

  if (!mForm) {
    return;
  }

  if (aRemoveFromForm) {
    nsAutoString nameVal, idVal;
    GetAttr(kNameSpaceID_None, nsGkAtoms::name, nameVal);
    GetAttr(kNameSpaceID_None, nsGkAtoms::id, idVal);

    mForm->RemoveImageElement(this);

    if (!nameVal.IsEmpty()) {
      mForm->RemoveImageElementFromTable(this, nameVal);
    }

    if (!idVal.IsEmpty()) {
      mForm->RemoveImageElementFromTable(this, idVal);
    }
  }

  UnsetFlags(ADDED_TO_FORM);
  mForm = nullptr;
}

void
HTMLImageElement::QueueImageLoadTask(bool aAlwaysLoad)
{
  // If loading is temporarily disabled, we don't want to queue tasks
  // that may then run when loading is re-enabled.
  if (!LoadingEnabled() || !this->OwnerDoc()->IsCurrentActiveDocument()) {
    return;
  }

  // Ensure that we don't overwrite a previous load request that requires
  // a complete load to occur.
  bool alwaysLoad = aAlwaysLoad;
  if (mPendingImageLoadTask) {
    alwaysLoad = alwaysLoad || mPendingImageLoadTask->AlwaysLoad();
  }
  RefPtr<ImageLoadTask> task = new ImageLoadTask(this, alwaysLoad);
  // The task checks this to determine if it was the last
  // queued event, and so earlier tasks are implicitly canceled.
  mPendingImageLoadTask = task;
  nsContentUtils::RunInStableState(task.forget());
}

bool
HTMLImageElement::HaveSrcsetOrInPicture()
{
  if (HasAttr(kNameSpaceID_None, nsGkAtoms::srcset)) {
    return true;
  }

  Element *parent = nsINode::GetParentElement();
  return (parent && parent->IsHTMLElement(nsGkAtoms::picture));
}

bool
HTMLImageElement::InResponsiveMode()
{
  // When we lose srcset or leave a <picture> element, the fallback to img.src
  // will happen from the microtask, and we should behave responsively in the
  // interim
  return mResponsiveSelector ||
         mPendingImageLoadTask ||
         HaveSrcsetOrInPicture();
}

bool
HTMLImageElement::SelectedSourceMatchesLast(nsIURI* aSelectedSource, double aSelectedDensity)
{
  // If there was no selected source previously, we don't want to short-circuit the load.
  // Similarly for if there is no newly selected source.
  if (!mLastSelectedSource || !aSelectedSource) {
    return false;
  }
  bool equal = false;
  return NS_SUCCEEDED(mLastSelectedSource->Equals(aSelectedSource, &equal)) && equal &&
      aSelectedDensity == mCurrentDensity;
}

nsresult
HTMLImageElement::LoadSelectedImage(bool aForce, bool aNotify, bool aAlwaysLoad)
{
  nsresult rv = NS_ERROR_FAILURE;

  if (aForce) {
    // In responsive mode we generally want to re-run the full
    // selection algorithm whenever starting a new load, per
    // spec. This also causes us to re-resolve the URI as appropriate.
    if (!UpdateResponsiveSource() && !aAlwaysLoad) {
      return NS_OK;
    }
  }

  nsCOMPtr<nsIURI> selectedSource;
  double currentDensity = 1.0; // default to 1.0 for the src attribute case
  if (mResponsiveSelector) {
    nsCOMPtr<nsIURI> url = mResponsiveSelector->GetSelectedImageURL();
    selectedSource = url;
    currentDensity = mResponsiveSelector->GetSelectedImageDensity();
    if (!aAlwaysLoad && SelectedSourceMatchesLast(selectedSource, currentDensity)) {
      return NS_OK;
    }
    if (url) {
      rv = LoadImage(url, aForce, aNotify, eImageLoadType_Imageset);
    }
  } else {
    nsAutoString src;
    if (!GetAttr(kNameSpaceID_None, nsGkAtoms::src, src)) {
      CancelImageRequests(aNotify);
      rv = NS_OK;
    } else {
      nsIDocument* doc = GetOurOwnerDoc();
      if (doc) {
        StringToURI(src, doc, getter_AddRefs(selectedSource));
        if (!aAlwaysLoad && SelectedSourceMatchesLast(selectedSource, currentDensity)) {
          return NS_OK;
        }
      }

      // If we have a srcset attribute or are in a <picture> element,
      // we always use the Imageset load type, even if we parsed no
      // valid responsive sources from either, per spec.
      rv = LoadImage(src, aForce, aNotify,
                     HaveSrcsetOrInPicture() ? eImageLoadType_Imageset
                                             : eImageLoadType_Normal);
    }
  }
  mLastSelectedSource = selectedSource;
  mCurrentDensity = currentDensity;

  if (NS_FAILED(rv)) {
    CancelImageRequests(aNotify);
  }
  return rv;
}

void
HTMLImageElement::PictureSourceSrcsetChanged(nsIContent *aSourceNode,
                                             const nsAString& aNewValue,
                                             bool aNotify)
{
  MOZ_ASSERT(aSourceNode == this ||
             IsPreviousSibling(aSourceNode, this),
             "Should not be getting notifications for non-previous-siblings");

  nsIContent *currentSrc =
    mResponsiveSelector ? mResponsiveSelector->Content() : nullptr;

  if (aSourceNode == currentSrc) {
    // We're currently using this node as our responsive selector
    // source.
    mResponsiveSelector->SetCandidatesFromSourceSet(aNewValue);
  }

  if (!mInDocResponsiveContent && IsInComposedDoc()) {
    nsIDocument* doc = GetOurOwnerDoc();
    if (doc) {
      doc->AddResponsiveContent(this);
      mInDocResponsiveContent = true;
    }
  }

  // This always triggers the image update steps per the spec, even if
  // we are not using this source.
  QueueImageLoadTask(true);
}

void
HTMLImageElement::PictureSourceSizesChanged(nsIContent *aSourceNode,
                                            const nsAString& aNewValue,
                                            bool aNotify)
{
  MOZ_ASSERT(aSourceNode == this ||
             IsPreviousSibling(aSourceNode, this),
             "Should not be getting notifications for non-previous-siblings");

  nsIContent *currentSrc =
    mResponsiveSelector ? mResponsiveSelector->Content() : nullptr;

  if (aSourceNode == currentSrc) {
    // We're currently using this node as our responsive selector
    // source.
    mResponsiveSelector->SetSizesFromDescriptor(aNewValue);
  }

  // This always triggers the image update steps per the spec, even if
  // we are not using this source.
  QueueImageLoadTask(true);
}

void
HTMLImageElement::PictureSourceMediaOrTypeChanged(nsIContent *aSourceNode,
                                                  bool aNotify)
{
  MOZ_ASSERT(IsPreviousSibling(aSourceNode, this),
             "Should not be getting notifications for non-previous-siblings");

  // This always triggers the image update steps per the spec, even if
  // we are not switching to/from this source
  QueueImageLoadTask(true);
}

void
HTMLImageElement::PictureSourceAdded(nsIContent *aSourceNode)
{
  MOZ_ASSERT(aSourceNode == this ||
             IsPreviousSibling(aSourceNode, this),
             "Should not be getting notifications for non-previous-siblings");

  QueueImageLoadTask(true);
}

void
HTMLImageElement::PictureSourceRemoved(nsIContent *aSourceNode)
{
  MOZ_ASSERT(aSourceNode == this ||
             IsPreviousSibling(aSourceNode, this),
             "Should not be getting notifications for non-previous-siblings");

  QueueImageLoadTask(true);
}

bool
HTMLImageElement::UpdateResponsiveSource()
{
  bool hadSelector = !!mResponsiveSelector;

  nsIContent *currentSource =
    mResponsiveSelector ? mResponsiveSelector->Content() : nullptr;
  Element *parent = nsINode::GetParentElement();

  nsINode *candidateSource = nullptr;
  if (parent && parent->IsHTMLElement(nsGkAtoms::picture)) {
    // Walk source nodes previous to ourselves
    candidateSource = parent->GetFirstChild();
  } else {
    candidateSource = this;
  }

  while (candidateSource) {
    if (candidateSource == currentSource) {
      // found no better source before current, re-run selection on
      // that and keep it if it's still usable.
      bool changed = mResponsiveSelector->SelectImage(true);
      if (mResponsiveSelector->NumCandidates()) {
        bool isUsableCandidate = true;

        // an otherwise-usable source element may still have a media query that may not
        // match any more.
        if (candidateSource->IsHTMLElement(nsGkAtoms::source) &&
            !SourceElementMatches(candidateSource->AsContent())) {
          isUsableCandidate = false;
        }

        if (isUsableCandidate) {
          return changed;
        }
      }

      // no longer valid
      mResponsiveSelector = nullptr;
      if (candidateSource == this) {
        // No further possibilities
        break;
      }
    } else if (candidateSource == this) {
      // We are the last possible source
      if (!TryCreateResponsiveSelector(candidateSource->AsContent())) {
        // Failed to find any source
        mResponsiveSelector = nullptr;
      }
      break;
    } else if (candidateSource->IsHTMLElement(nsGkAtoms::source) &&
               TryCreateResponsiveSelector(candidateSource->AsContent())) {
      // This led to a valid source, stop
      break;
    }
    candidateSource = candidateSource->GetNextSibling();
  }

  if (!candidateSource) {
    // Ran out of siblings without finding ourself, e.g. XBL magic.
    mResponsiveSelector = nullptr;
  }

  // If we reach this point, either:
  // - there was no selector originally, and there is not one now
  // - there was no selector originally, and there is one now
  // - there was a selector, and there is a different one now
  // - there was a selector, and there is not one now
  return hadSelector || mResponsiveSelector;
}

/*static */ bool
HTMLImageElement::SupportedPictureSourceType(const nsAString& aType)
{
  nsAutoString type;
  nsAutoString params;

  nsContentUtils::SplitMimeType(aType, type, params);
  if (type.IsEmpty()) {
    return true;
  }

  return
    imgLoader::SupportImageWithMimeType(NS_ConvertUTF16toUTF8(type).get(),
                                        AcceptedMimeTypes::IMAGES_AND_DOCUMENTS);
}

bool
HTMLImageElement::SourceElementMatches(nsIContent* aSourceNode)
{
  MOZ_ASSERT(aSourceNode->IsHTMLElement(nsGkAtoms::source));

  DebugOnly<Element *> parent(nsINode::GetParentElement());
  MOZ_ASSERT(parent && parent->IsHTMLElement(nsGkAtoms::picture));
  MOZ_ASSERT(IsPreviousSibling(aSourceNode, this));

  // Check media and type
  HTMLSourceElement *src = static_cast<HTMLSourceElement*>(aSourceNode);
  if (!src->MatchesCurrentMedia()) {
    return false;
  }

  nsAutoString type;
  if (aSourceNode->GetAttr(kNameSpaceID_None, nsGkAtoms::type, type) &&
      !SupportedPictureSourceType(type)) {
    return false;
  }

  return true;
}

bool
HTMLImageElement::TryCreateResponsiveSelector(nsIContent *aSourceNode)
{
  // Skip if this is not a <source> with matching media query
  bool isSourceTag = aSourceNode->IsHTMLElement(nsGkAtoms::source);
  if (isSourceTag) {
    if (!SourceElementMatches(aSourceNode)) {
      return false;
    }
  } else if (aSourceNode->IsHTMLElement(nsGkAtoms::img)) {
    // Otherwise this is the <img> tag itself
    MOZ_ASSERT(aSourceNode == this);
  }

  // Skip if has no srcset or an empty srcset
  nsString srcset;
  if (!aSourceNode->GetAttr(kNameSpaceID_None, nsGkAtoms::srcset, srcset)) {
    return false;
  }

  if (srcset.IsEmpty()) {
    return false;
  }


  // Try to parse
  RefPtr<ResponsiveImageSelector> sel = new ResponsiveImageSelector(aSourceNode);
  if (!sel->SetCandidatesFromSourceSet(srcset)) {
    // No possible candidates, don't need to bother parsing sizes
    return false;
  }

  nsAutoString sizes;
  aSourceNode->GetAttr(kNameSpaceID_None, nsGkAtoms::sizes, sizes);
  sel->SetSizesFromDescriptor(sizes);

  // If this is the <img> tag, also pull in src as the default source
  if (!isSourceTag) {
    MOZ_ASSERT(aSourceNode == this);
    nsAutoString src;
    if (GetAttr(kNameSpaceID_None, nsGkAtoms::src, src) && !src.IsEmpty()) {
      sel->SetDefaultSource(src);
    }
  }

  mResponsiveSelector = sel;
  return true;
}

/* static */ bool
HTMLImageElement::SelectSourceForTagWithAttrs(nsIDocument *aDocument,
                                              bool aIsSourceTag,
                                              const nsAString& aSrcAttr,
                                              const nsAString& aSrcsetAttr,
                                              const nsAString& aSizesAttr,
                                              const nsAString& aTypeAttr,
                                              const nsAString& aMediaAttr,
                                              nsAString& aResult)
{
  MOZ_ASSERT(aIsSourceTag || (aTypeAttr.IsEmpty() && aMediaAttr.IsEmpty()),
             "Passing type or media attrs makes no sense without aIsSourceTag");
  MOZ_ASSERT(!aIsSourceTag || aSrcAttr.IsEmpty(),
             "Passing aSrcAttr makes no sense with aIsSourceTag set");

  if (aSrcsetAttr.IsEmpty()) {
    if (!aIsSourceTag) {
      // For an <img> with no srcset, we would always select the src attr.
      aResult.Assign(aSrcAttr);
      return true;
    }
    // Otherwise, a <source> without srcset is never selected
    return false;
  }

  // Would not consider source tags with unsupported media or type
  if (aIsSourceTag &&
      ((!aMediaAttr.IsVoid() &&
       !HTMLSourceElement::WouldMatchMediaForDocument(aMediaAttr, aDocument)) ||
      (!aTypeAttr.IsVoid() &&
       !SupportedPictureSourceType(aTypeAttr)))) {
    return false;
  }

  // Using srcset or picture <source>, build a responsive selector for this tag.
  RefPtr<ResponsiveImageSelector> sel =
    new ResponsiveImageSelector(aDocument);

  sel->SetCandidatesFromSourceSet(aSrcsetAttr);
  if (!aSizesAttr.IsEmpty()) {
    sel->SetSizesFromDescriptor(aSizesAttr);
  }
  if (!aIsSourceTag) {
    sel->SetDefaultSource(aSrcAttr);
  }

  if (sel->GetSelectedImageURLSpec(aResult)) {
    return true;
  }

  if (!aIsSourceTag) {
    // <img> tag with no match would definitively load nothing.
    aResult.Truncate();
    return true;
  }

  // <source> tags with no match would leave source yet-undetermined.
  return false;
}

void
HTMLImageElement::DestroyContent()
{
  mResponsiveSelector = nullptr;

  nsGenericHTMLElement::DestroyContent();
}

void
HTMLImageElement::MediaFeatureValuesChanged()
{
  QueueImageLoadTask(false);
}

void
HTMLImageElement::FlushUseCounters()
{
  nsCOMPtr<imgIRequest> request;
  GetRequest(CURRENT_REQUEST, getter_AddRefs(request));

  nsCOMPtr<imgIContainer> container;
  request->GetImage(getter_AddRefs(container));

  static_cast<image::Image*>(container.get())->ReportUseCounters();
}

} // namespace dom
} // namespace mozilla