accessible/generic/ImageAccessible.cpp

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #include "ImageAccessible.h"
   7
   8 #include "DocAccessible-inl.h"
   9 #include "LocalAccessible-inl.h"
  10 #include "nsAccUtils.h"
  11 #include "Role.h"
  12 #include "AccAttributes.h"
  13 #include "AccIterator.h"
  14 #include "CacheConstants.h"
  15 #include "States.h"
  16
  17 #include "imgIContainer.h"
  18 #include "imgIRequest.h"
  19 #include "nsGenericHTMLElement.h"
  20 #include "mozilla/dom/BrowsingContext.h"
  21 #include "mozilla/dom/Document.h"
  22 #include "mozilla/dom/MutationEventBinding.h"
  23 #include "nsContentUtils.h"
  24 #include "nsIImageLoadingContent.h"
  25 #include "nsPIDOMWindow.h"
  26 #include "nsIURI.h"
  27
  28 namespace mozilla::a11y {
  29
  30 NS_IMPL_ISUPPORTS_INHERITED(ImageAccessible, LinkableAccessible,
  31                             imgINotificationObserver)
  32
  33 ////////////////////////////////////////////////////////////////////////////////
  34 // ImageAccessible
  35 ////////////////////////////////////////////////////////////////////////////////
  36
  37 ImageAccessible::ImageAccessible(nsIContent* aContent, DocAccessible* aDoc)
  38     : LinkableAccessible(aContent, aDoc),
  39       mImageRequestStatus(imgIRequest::STATUS_NONE) {
  40   mType = eImageType;
  41   nsCOMPtr<nsIImageLoadingContent> content(do_QueryInterface(mContent));
  42   if (content) {
  43     content->AddNativeObserver(this);
  44     nsCOMPtr<imgIRequest> imageRequest;
  45     content->GetRequest(nsIImageLoadingContent::CURRENT_REQUEST,
  46                         getter_AddRefs(imageRequest));
  47     if (imageRequest) {
  48       imageRequest->GetImageStatus(&mImageRequestStatus);
  49     }
  50   }
  51 }
  52
  53 ImageAccessible::~ImageAccessible() {}
  54
  55 ////////////////////////////////////////////////////////////////////////////////
  56 // LocalAccessible public
  57
  58 void ImageAccessible::Shutdown() {
  59   nsCOMPtr<nsIImageLoadingContent> content(do_QueryInterface(mContent));
  60   if (content) {
  61     content->RemoveNativeObserver(this);
  62   }
  63
  64   LinkableAccessible::Shutdown();
  65 }
  66
  67 uint64_t ImageAccessible::NativeState() const {
  68   // The state is a bitfield, get our inherited state, then logically OR it with
  69   // states::ANIMATED if this is an animated image.
  70
  71   uint64_t state = LinkableAccessible::NativeState();
  72
  73   if (mImageRequestStatus & imgIRequest::STATUS_IS_ANIMATED) {
  74     state |= states::ANIMATED;
  75   }
  76
  77   if (!(mImageRequestStatus & imgIRequest::STATUS_SIZE_AVAILABLE)) {
  78     nsIFrame* frame = GetFrame();
  79     MOZ_ASSERT(!frame || frame->AccessibleType() == eImageType ||
  80                frame->AccessibleType() == a11y::eHTMLImageMapType ||
  81                frame->IsImageBoxFrame());
  82     if (frame && !(frame->GetStateBits() & IMAGE_SIZECONSTRAINED)) {
  83       // The size of this image hasn't been constrained and we haven't loaded
  84       // enough of the image to know its size yet. This means it currently
  85       // has 0 width and height.
  86       state |= states::INVISIBLE;
  87     }
  88   }
  89
  90   return state;
  91 }
  92
  93 ENameValueFlag ImageAccessible::NativeName(nsString& aName) const {
  94   bool hasAltAttrib =
  95       mContent->AsElement()->GetAttr(kNameSpaceID_None, nsGkAtoms::alt, aName);
  96   if (!aName.IsEmpty()) return eNameOK;
  97
  98   ENameValueFlag nameFlag = LocalAccessible::NativeName(aName);
  99   if (!aName.IsEmpty()) return nameFlag;
 100
 101   // No accessible name but empty 'alt' attribute is present. If further name
 102   // computation algorithm doesn't provide non empty name then it means
 103   // an empty 'alt' attribute was used to indicate a decorative image (see
 104   // LocalAccessible::Name() method for details).
 105   return hasAltAttrib ? eNoNameOnPurpose : eNameOK;
 106 }
 107
 108 role ImageAccessible::NativeRole() const { return roles::GRAPHIC; }
 109
 110 void ImageAccessible::DOMAttributeChanged(int32_t aNameSpaceID,
 111                                           nsAtom* aAttribute, int32_t aModType,
 112                                           const nsAttrValue* aOldValue,
 113                                           uint64_t aOldState) {
 114   LinkableAccessible::DOMAttributeChanged(aNameSpaceID, aAttribute, aModType,
 115                                           aOldValue, aOldState);
 116
 117   if (aAttribute == nsGkAtoms::longdesc &&
 118       (aModType == dom::MutationEvent_Binding::ADDITION ||
 119        aModType == dom::MutationEvent_Binding::REMOVAL)) {
 120     SendCache(CacheDomain::Actions, CacheUpdateType::Update);
 121   }
 122 }
 123
 124 ////////////////////////////////////////////////////////////////////////////////
 125 // LocalAccessible
 126
 127 uint8_t ImageAccessible::ActionCount() const {
 128   uint8_t actionCount = LinkableAccessible::ActionCount();
 129   return HasLongDesc() ? actionCount + 1 : actionCount;
 130 }
 131
 132 void ImageAccessible::ActionNameAt(uint8_t aIndex, nsAString& aName) {
 133   aName.Truncate();
 134   if (IsLongDescIndex(aIndex) && HasLongDesc()) {
 135     aName.AssignLiteral("showlongdesc");
 136   } else {
 137     LinkableAccessible::ActionNameAt(aIndex, aName);
 138   }
 139 }
 140
 141 bool ImageAccessible::DoAction(uint8_t aIndex) const {
 142   // Get the long description uri and open in a new window.
 143   if (!IsLongDescIndex(aIndex)) return LinkableAccessible::DoAction(aIndex);
 144
 145   nsCOMPtr<nsIURI> uri = GetLongDescURI();
 146   if (!uri) return false;
 147
 148   nsAutoCString utf8spec;
 149   uri->GetSpec(utf8spec);
 150   NS_ConvertUTF8toUTF16 spec(utf8spec);
 151
 152   dom::Document* document = mContent->OwnerDoc();
 153   nsCOMPtr<nsPIDOMWindowOuter> piWindow = document->GetWindow();
 154   if (!piWindow) return false;
 155
 156   RefPtr<dom::BrowsingContext> tmp;
 157   return NS_SUCCEEDED(piWindow->Open(spec, u""_ns, u""_ns,
 158                                      /* aLoadInfo = */ nullptr,
 159                                      /* aForceNoOpener = */ false,
 160                                      getter_AddRefs(tmp)));
 161 }
 162
 163 ////////////////////////////////////////////////////////////////////////////////
 164 // ImageAccessible
 165
 166 LayoutDeviceIntPoint ImageAccessible::Position(uint32_t aCoordType) {
 167   LayoutDeviceIntPoint point = Bounds().TopLeft();
 168   nsAccUtils::ConvertScreenCoordsTo(&point.x, &point.y, aCoordType, this);
 169   return point;
 170 }
 171
 172 LayoutDeviceIntSize ImageAccessible::Size() { return Bounds().Size(); }
 173
 174 // LocalAccessible
 175 already_AddRefed<AccAttributes> ImageAccessible::NativeAttributes() {
 176   RefPtr<AccAttributes> attributes = LinkableAccessible::NativeAttributes();
 177
 178   nsString src;
 179   mContent->AsElement()->GetAttr(kNameSpaceID_None, nsGkAtoms::src, src);
 180   if (!src.IsEmpty()) attributes->SetAttribute(nsGkAtoms::src, std::move(src));
 181
 182   return attributes.forget();
 183 }
 184
 185 ////////////////////////////////////////////////////////////////////////////////
 186 // Private methods
 187
 188 already_AddRefed<nsIURI> ImageAccessible::GetLongDescURI() const {
 189   if (mContent->AsElement()->HasAttr(kNameSpaceID_None, nsGkAtoms::longdesc)) {
 190     // To check if longdesc contains an invalid url.
 191     nsAutoString longdesc;
 192     mContent->AsElement()->GetAttr(kNameSpaceID_None, nsGkAtoms::longdesc,
 193                                    longdesc);
 194     if (longdesc.FindChar(' ') != -1 || longdesc.FindChar('\t') != -1 ||
 195         longdesc.FindChar('\r') != -1 || longdesc.FindChar('\n') != -1) {
 196       return nullptr;
 197     }
 198     nsCOMPtr<nsIURI> uri;
 199     nsContentUtils::NewURIWithDocumentCharset(getter_AddRefs(uri), longdesc,
 200                                               mContent->OwnerDoc(),
 201                                               mContent->GetBaseURI());
 202     return uri.forget();
 203   }
 204
 205   DocAccessible* document = Document();
 206   if (document) {
 207     IDRefsIterator iter(document, mContent, nsGkAtoms::aria_describedby);
 208     while (nsIContent* target = iter.NextElem()) {
 209       if ((target->IsHTMLElement(nsGkAtoms::a) ||
 210            target->IsHTMLElement(nsGkAtoms::area)) &&
 211           target->AsElement()->HasAttr(kNameSpaceID_None, nsGkAtoms::href)) {
 212         nsGenericHTMLElement* element = nsGenericHTMLElement::FromNode(target);
 213
 214         nsCOMPtr<nsIURI> uri;
 215         element->GetURIAttr(nsGkAtoms::href, nullptr, getter_AddRefs(uri));
 216         return uri.forget();
 217       }
 218     }
 219   }
 220
 221   return nullptr;
 222 }
 223
 224 bool ImageAccessible::IsLongDescIndex(uint8_t aIndex) const {
 225   return aIndex == LinkableAccessible::ActionCount();
 226 }
 227
 228 ////////////////////////////////////////////////////////////////////////////////
 229 // imgINotificationObserver
 230
 231 void ImageAccessible::Notify(imgIRequest* aRequest, int32_t aType,
 232                              const nsIntRect* aData) {
 233   if (aType != imgINotificationObserver::FRAME_COMPLETE &&
 234       aType != imgINotificationObserver::LOAD_COMPLETE &&
 235       aType != imgINotificationObserver::DECODE_COMPLETE) {
 236     // We should update our state if the whole image was decoded,
 237     // or the first frame in the case of a gif.
 238     return;
 239   }
 240
 241   if (IsDefunct() || !mParent) {
 242     return;
 243   }
 244
 245   uint32_t status = imgIRequest::STATUS_NONE;
 246   aRequest->GetImageStatus(&status);
 247
 248   if ((status ^ mImageRequestStatus) & imgIRequest::STATUS_SIZE_AVAILABLE) {
 249     nsIFrame* frame = GetFrame();
 250     if (frame && !(frame->GetStateBits() & IMAGE_SIZECONSTRAINED)) {
 251       RefPtr<AccEvent> event = new AccStateChangeEvent(
 252           this, states::INVISIBLE,
 253           !(status & imgIRequest::STATUS_SIZE_AVAILABLE));
 254       mDoc->FireDelayedEvent(event);
 255     }
 256   }
 257
 258   if ((status ^ mImageRequestStatus) & imgIRequest::STATUS_IS_ANIMATED) {
 259     RefPtr<AccEvent> event = new AccStateChangeEvent(
 260         this, states::ANIMATED, (status & imgIRequest::STATUS_IS_ANIMATED));
 261     mDoc->FireDelayedEvent(event);
 262   }
 263
 264   mImageRequestStatus = status;
 265 }
 266
 267 }  // namespace mozilla::a11y