Bug 870022 - Part 7 - HTMLImageElement - Make <picture> aware, react to <source> tag and sizes attr changes. r=jst

content/base/src/ResponsiveImageSelector.cpp

@@ -151,6 +151,21 @@ ResponsiveImageSelector::SetDefaultSource(const nsAString & aSpec)
   return NS_OK;
 }
 
+uint32_t
+ResponsiveImageSelector::NumCandidates(bool aIncludeDefault)
+{
+  uint32_t candidates = mCandidates.Length();
+
+  // If present, the default candidate is the last item
+  if (!aIncludeDefault && candidates &&
+      (mCandidates[candidates - 1].Type() ==
+       ResponsiveImageCandidate::eCandidateType_Default)) {
+    candidates--;
+  }
+
+  return candidates;
+}
+
 void
 ResponsiveImageSelector::SetDefaultSource(nsIURI *aURL)
 {

content/base/src/ResponsiveImageSelector.h

@@ -37,6 +37,10 @@ public:
   nsresult SetDefaultSource(const nsAString & aSpec);
   void SetDefaultSource(nsIURI *aURL);
 
+  uint32_t NumCandidates(bool aIncludeDefault = true);
+
+  nsIContent *Content() { return mContent; }
+
   // Get the URL for the selected best candidate
   already_AddRefed<nsIURI> GetSelectedImageURL();
   double GetSelectedImageDensity();

content/html/content/src/HTMLImageElement.cpp

@@ -26,6 +26,10 @@
 #include "nsFocusManager.h"
 #include "mozilla/dom/HTMLFormElement.h"
 
+// Responsive images!
+#include "mozilla/dom/HTMLSourceElement.h"
+#include "mozilla/dom/ResponsiveImageSelector.h"
+
 #include "imgIContainer.h"
 #include "imgILoader.h"
 #include "imgINotificationObserver.h"
@@ -46,6 +50,21 @@ static const char *kPrefSrcsetEnabled = "dom.image.srcset.enabled";
 
 NS_IMPL_NS_NEW_HTML_ELEMENT(Image)
 
+// 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;
+}
+
 namespace mozilla {
 namespace dom {
 
@@ -351,6 +370,8 @@ HTMLImageElement::AfterSetAttr(int32_t aNameSpaceID, nsIAtom* aName,
   // Handle src/srcset/crossorigin 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.
+
+  nsCOMPtr<nsIContent> thisContent = AsContent();
   if (aName == nsGkAtoms::src &&
       aNameSpaceID == kNameSpaceID_None) {
     // SetAttr handles setting src in the non-responsive case, so only handle it
@@ -368,8 +389,14 @@ HTMLImageElement::AfterSetAttr(int32_t aNameSpaceID, nsIAtom* aName,
              AsContent()->IsInDoc() &&
              IsSrcsetEnabled()) {
     // We currently don't handle responsive mode until BindToTree
-    UpdateSourceSet(aValue->GetStringValue());
-    LoadSelectedImage(false, aNotify);
+    PictureSourceSrcsetChanged(thisContent,
+                               aValue ? aValue->GetStringValue() : EmptyString(),
+                               aNotify);
+  } else if (aName == nsGkAtoms::sizes &&
+             aNameSpaceID == kNameSpaceID_None &&
+             thisContent->IsInDoc() &&
+             HTMLPictureElement::IsPictureEnabled()) {
+    PictureSourceSizesChanged(thisContent, aValue->GetStringValue(), aNotify);
   } else if (aName == nsGkAtoms::crossorigin &&
              aNameSpaceID == kNameSpaceID_None &&
              aNotify) {
@@ -502,9 +529,12 @@ HTMLImageElement::BindToTree(nsIDocument* aDocument, nsIContent* aParent,
     UpdateFormOwner();
   }
 
+  bool addedToPicture = aParent && aParent->Tag() == nsGkAtoms::picture &&
+                        HTMLPictureElement::IsPictureEnabled();
   bool haveSrcset = IsSrcsetEnabled() &&
                     HasAttr(kNameSpaceID_None, nsGkAtoms::srcset);
-  if (haveSrcset || HasAttr(kNameSpaceID_None, nsGkAtoms::src)) {
+  if (addedToPicture || haveSrcset ||
+      HasAttr(kNameSpaceID_None, nsGkAtoms::src)) {
     // FIXME: Bug 660963 it would be nice if we could just have
     // ClearBrokenState update our state and do it fast...
     ClearBrokenState();
@@ -512,15 +542,8 @@ HTMLImageElement::BindToTree(nsIDocument* aDocument, nsIContent* aParent,
 
     // We don't handle responsive changes when not bound to a tree, update them
     // now if necessary
-    if (haveSrcset) {
-      nsAutoString srcset;
-      GetAttr(kNameSpaceID_None, nsGkAtoms::srcset, srcset);
-      UpdateSourceSet(srcset);
-      if (mResponsiveSelector) {
-        nsAutoString src;
-        GetAttr(kNameSpaceID_None, nsGkAtoms::src, src);
-        mResponsiveSelector->SetDefaultSource(src);
-      }
+    if (addedToPicture || haveSrcset) {
+      MaybeUpdateResponsiveSelector();
     }
 
     // If loading is temporarily disabled, don't even launch MaybeLoadImage.
@@ -796,37 +819,224 @@ HTMLImageElement::LoadSelectedImage(bool aForce, bool aNotify)
   return rv;
 }
 
+void
+HTMLImageElement::PictureSourceSrcsetChanged(nsIContent *aSourceNode,
+                                             const nsAString& aNewValue,
+                                             bool aNotify)
+{
+  if (aSourceNode != AsContent() && !HTMLPictureElement::IsPictureEnabled()) {
+    // Don't consider <source> nodes if picture is pref'd off
+    return;
+  }
+
+  nsIContent *currentSrc = mResponsiveSelector ? mResponsiveSelector->Content()
+                                               : nullptr;
+
+  if (aSourceNode == currentSrc) {
+    // We're currently using this node as our responsive selector source.
+    mResponsiveSelector->SetCandidatesFromSourceSet(aNewValue);
+    // Search for a new source if we are no longer valid.
+    MaybeUpdateResponsiveSelector(currentSrc);
+
+    LoadSelectedImage(false, aNotify);
+  } else if (currentSrc && IsPreviousSibling(currentSrc, aSourceNode)) {
+      // If we have a source and it is previous to the one being updated, ignore
+      return;
+  } else {
+    // This is previous to our current source or we don't have a current source,
+    // use it if valid.
+    if (TryCreateResponsiveSelector(aSourceNode, &aNewValue, nullptr)) {
+      LoadSelectedImage(false, aNotify);
+    }
+  }
+}
+
+void
+HTMLImageElement::PictureSourceSizesChanged(nsIContent *aSourceNode,
+                                            const nsAString& aNewValue,
+                                            bool aNotify)
+{
+  if (!HTMLPictureElement::IsPictureEnabled()) {
+    // Don't consider sizes at all if picture support is disabled
+    return;
+  }
+
+  nsIContent *currentSrc = mResponsiveSelector ? mResponsiveSelector->Content()
+                                               : nullptr;
+
+  if (aSourceNode == currentSrc) {
+    // We're currently using this node as our responsive selector source.
+    mResponsiveSelector->SetSizesFromDescriptor(aNewValue);
+    LoadSelectedImage(false, aNotify);
+  }
+}
+
+void
+HTMLImageElement::PictureSourceAdded(nsIContent *aSourceNode)
+{
+  // If the source node is previous to our current one, or ourselves if we have
+  // no responsive source, try to use it as a responsive source.
+  nsIContent *currentSrc = mResponsiveSelector ? mResponsiveSelector->Content()
+                                               : AsContent();
+
+  if (HTMLPictureElement::IsPictureEnabled() &&
+      IsPreviousSibling(aSourceNode, currentSrc) &&
+      TryCreateResponsiveSelector(aSourceNode, nullptr, nullptr)) {
+    LoadSelectedImage(false, true);
+  }
+}
+
+void
+HTMLImageElement::PictureSourceRemoved(nsIContent *aSourceNode)
+{
+  // If this is our current source, we'll need to find another one or leave
+  // responsive mode.
+  if (mResponsiveSelector && mResponsiveSelector->Content() == aSourceNode) {
+    MaybeUpdateResponsiveSelector(aSourceNode, true);
+    LoadSelectedImage(false, true);
+  }
+}
+
+bool
+HTMLImageElement::MaybeUpdateResponsiveSelector(nsIContent *aCurrentSource,
+                                                bool aSourceRemoved)
+{
+  nsIContent *thisContent = AsContent();
+
+  if (!aCurrentSource && mResponsiveSelector) {
+    aCurrentSource = mResponsiveSelector->Content();
+  }
+
+  // If we have a source with candidates, no update is needed unless it is being
+  // removed
+  if (aCurrentSource && !aSourceRemoved &&
+      mResponsiveSelector->NumCandidates()) {
+    return false;
+  }
+
+  // Otherwise, invalidate
+  bool hadSelector = !!mResponsiveSelector;
+  mResponsiveSelector = nullptr;
+
+  if (!IsSrcsetEnabled()) {
+    return hadSelector;
+  }
+
+  // See if there's another source node we could use.
+  bool pictureEnabled = HTMLPictureElement::IsPictureEnabled();
+  nsIContent *nextSource = nullptr;
+  if (pictureEnabled && aCurrentSource && aCurrentSource != thisContent) {
+    // If current source is the <img> tag, there is no next candidate. Otherwise,
+    // it's the next sibling of the current source.
+    MOZ_ASSERT(IsPreviousSibling(aCurrentSource, thisContent) &&
+               thisContent->GetParentNode()->Tag() == nsGkAtoms::picture);
+    nextSource = aCurrentSource->GetNextSibling();
+  } else if (!aCurrentSource) {
+    // If no current source at all, start from the first possible source, which
+    // is the first node of the <picture> element or ourselves if we're not a
+    // picture
+    nsINode *parent = pictureEnabled ? thisContent->GetParentNode() : nullptr;
+    if (parent && parent->Tag() == nsGkAtoms::picture) {
+      nextSource = parent->GetFirstChild();
+    } else {
+      nextSource = thisContent;
+    }
+  }
+
+  while (nextSource) {
+    if (nextSource == thisContent) {
+      // We are the last possible source, so stop searching if we match or
+      // not
+      TryCreateResponsiveSelector(nextSource);
+      break;
+    } else if (nextSource->Tag() == nsGkAtoms::source &&
+               TryCreateResponsiveSelector(nextSource)) {
+      // If this led to a valid source, stop
+      break;
+    }
+
+    nextSource = nextSource->GetNextSibling();
+  }
+
+  // State changed unless we didn't make a selector and didn't start with one
+  return mResponsiveSelector || hadSelector;
+}
+
+bool
+HTMLImageElement::TryCreateResponsiveSelector(nsIContent *aSourceNode,
+                                              const nsAString *aSrcset,
+                                              const nsAString *aSizes)
+{
+  if (!IsSrcsetEnabled()) {
+    return false;
+  }
+
+  bool pictureEnabled = HTMLPictureElement::IsPictureEnabled();
+  // Skip if this is not a <source> with matching media query
+  bool isSourceTag = aSourceNode->Tag() == nsGkAtoms::source;
+  if (isSourceTag) {
+    DebugOnly<nsINode *> parent(nsINode::GetParentNode());
+    MOZ_ASSERT(parent && parent->Tag() == nsGkAtoms::picture);
+    MOZ_ASSERT(IsPreviousSibling(aSourceNode, AsContent()));
+    MOZ_ASSERT(pictureEnabled);
+
+    HTMLSourceElement *src = static_cast<HTMLSourceElement*>(aSourceNode);
+    if (!src->MatchesCurrentMedia()) {
+      return false;
+    }
+  } else if (aSourceNode->Tag() == nsGkAtoms::img) {
+    // Otherwise this is the <img> tag itself
+    MOZ_ASSERT(aSourceNode == AsContent());
+  }
+
+  // Skip if has no srcset or an empty srcset
+  nsString srcset;
+  if (aSrcset) {
+    srcset = *aSrcset;
+  } else if (!aSourceNode->GetAttr(kNameSpaceID_None, nsGkAtoms::srcset,
+                                   srcset)) {
+    return false;
+  }
+
+  if (srcset.IsEmpty()) {
+    return false;
+  }
+
+
+  // Try to parse
+  nsRefPtr<ResponsiveImageSelector> sel = new ResponsiveImageSelector(this);
+  if (!sel->SetCandidatesFromSourceSet(srcset)) {
+    // No possible candidates, don't need to bother parsing sizes
+    return false;
+  }
+
+  if (pictureEnabled && aSizes) {
+    sel->SetSizesFromDescriptor(*aSizes);
+  } else if (pictureEnabled) {
+    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 == AsContent());
+    nsAutoString src;
+    if (GetAttr(kNameSpaceID_None, nsGkAtoms::src, src) && !src.IsEmpty()) {
+      sel->SetDefaultSource(src);
+    }
+  }
+
+  mResponsiveSelector = sel;
+  return true;
+}
+
 void
 HTMLImageElement::DestroyContent()
 {
   mResponsiveSelector = nullptr;
 }
 
-void
-HTMLImageElement::UpdateSourceSet(const nsAString & aSrcset)
-{
-  MOZ_ASSERT(IsSrcsetEnabled());
-
-  bool haveSrcset = !aSrcset.IsEmpty();
-
-  if (haveSrcset && !mResponsiveSelector) {
-    mResponsiveSelector = new ResponsiveImageSelector(this);
-    mResponsiveSelector->SetCandidatesFromSourceSet(aSrcset);
-
-    // src may have been set before we decided we were responsive
-    nsAutoString src;
-    if (GetAttr(kNameSpaceID_None, nsGkAtoms::src, src) && src.Length()) {
-      mResponsiveSelector->SetDefaultSource(src);
-    }
-
-  } else if (haveSrcset) {
-    mResponsiveSelector->SetCandidatesFromSourceSet(aSrcset);
-  } else if (mResponsiveSelector) {
-    // Clearing srcset, don't need responsive selector anymore
-    mResponsiveSelector = nullptr;
-  }
-}
-
 } // namespace dom
 } // namespace mozilla
 

content/html/content/src/HTMLImageElement.h

@@ -12,16 +12,20 @@
 #include "nsIDOMHTMLImageElement.h"
 #include "imgRequestProxy.h"
 #include "Units.h"
-#include "mozilla/dom/ResponsiveImageSelector.h"
+
+// Only needed for IsPictureEnabled()
+#include "mozilla/dom/HTMLPictureElement.h"
 
 namespace mozilla {
 class EventChainPreVisitor;
 namespace dom {
 
+class ResponsiveImageSelector;
 class HTMLImageElement MOZ_FINAL : public nsGenericHTMLElement,
                                    public nsImageLoadingContent,
                                    public nsIDOMHTMLImageElement
 {
+  friend class HTMLSourceElement;
 public:
   explicit HTMLImageElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo);
   virtual ~HTMLImageElement();
@@ -190,7 +194,27 @@ protected:
   nsresult LoadSelectedImage(bool aForce, bool aNotify);
 
   // Update/create/destroy mResponsiveSelector
-  void UpdateSourceSet(const nsAString & aSrcset);
+  void PictureSourceSrcsetChanged(nsIContent *aSourceNode,
+                                  const nsAString& aNewValue, bool aNotify);
+  void PictureSourceSizesChanged(nsIContent *aSourceNode,
+                                 const nsAString& aNewValue, bool aNotify);
+
+  void PictureSourceAdded(nsIContent *aSourceNode);
+  // This should be called prior to the unbind, such that nextsibling works
+  void PictureSourceRemoved(nsIContent *aSourceNode);
+
+  bool MaybeUpdateResponsiveSelector(nsIContent *aCurrentSource = nullptr,
+                                     bool aSourceRemoved = false);
+
+  // 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,
+                                   const nsAString *aSrcset = nullptr,
+                                   const nsAString *aSizes = nullptr);
 
   CSSIntPoint GetXY();
   virtual void GetItemValueText(nsAString& text) MOZ_OVERRIDE;

content/html/content/src/HTMLSourceElement.cpp

@@ -7,9 +7,16 @@
 #include "mozilla/dom/HTMLSourceElement.h"
 #include "mozilla/dom/HTMLSourceElementBinding.h"
 
+#include "mozilla/dom/HTMLImageElement.h"
+#include "mozilla/dom/ResponsiveImageSelector.h"
+
+#include "nsGkAtoms.h"
+
 #include "nsIMediaList.h"
 #include "nsCSSParser.h"
 
+#include "mozilla/Preferences.h"
+
 NS_IMPL_NS_NEW_HTML_ELEMENT(Source)
 
 namespace mozilla {
@@ -52,7 +59,28 @@ nsresult
 HTMLSourceElement::AfterSetAttr(int32_t aNameSpaceID, nsIAtom* aName,
                                 const nsAttrValue* aValue, bool aNotify)
 {
-  if (aName == nsGkAtoms::media) {
+  // If we are associated with a <picture> with a valid <img>, notify it of
+  // responsive parameter changes
+  nsINode *parent = nsINode::GetParentNode();
+  if (aNameSpaceID == kNameSpaceID_None &&
+      (aName == nsGkAtoms::srcset || aName == nsGkAtoms::sizes) &&
+      parent && parent->Tag() == nsGkAtoms::picture && MatchesCurrentMedia()) {
+
+    nsString strVal = aValue ? aValue->GetStringValue() : EmptyString();
+    // Find all img siblings after this <source> and notify them of the change
+    nsCOMPtr<nsINode> sibling = AsContent();
+    while ( (sibling = sibling->GetNextSibling()) ) {
+      if (sibling->Tag() == nsGkAtoms::img) {
+        HTMLImageElement *img = static_cast<HTMLImageElement*>(sibling.get());
+        if (aName == nsGkAtoms::srcset) {
+          img->PictureSourceSrcsetChanged(AsContent(), strVal, aNotify);
+        } else if (aName == nsGkAtoms::sizes) {
+          img->PictureSourceSizesChanged(AsContent(), strVal, aNotify);
+        }
+      }
+    }
+
+  } else if (aNameSpaceID == kNameSpaceID_None && aName == nsGkAtoms::media) {
     mMediaList = nullptr;
     if (aValue) {
       nsString mediaStr = aValue->GetStringValue();
@@ -92,15 +120,41 @@ HTMLSourceElement::BindToTree(nsIDocument *aDocument,
                                                  aCompileEventHandlers);
   NS_ENSURE_SUCCESS(rv, rv);
 
-  if (!aParent || !aParent->IsNodeOfType(nsINode::eMEDIA))
-    return NS_OK;
-
-  HTMLMediaElement* media = static_cast<HTMLMediaElement*>(aParent);
-  media->NotifyAddedSource();
+  if (aParent && aParent->IsNodeOfType(nsINode::eMEDIA)) {
+    HTMLMediaElement* media = static_cast<HTMLMediaElement*>(aParent);
+    media->NotifyAddedSource();
+  } else if (aParent && aParent->Tag() == nsGkAtoms::picture) {
+    // Find any img siblings after this <source> and notify them
+    nsCOMPtr<nsINode> sibling = AsContent();
+    while ( (sibling = sibling->GetNextSibling()) ) {
+      if (sibling->Tag() == nsGkAtoms::img) {
+        HTMLImageElement *img = static_cast<HTMLImageElement*>(sibling.get());
+        img->PictureSourceAdded(AsContent());
+      }
+    }
+  }
 
   return NS_OK;
 }
 
+void
+HTMLSourceElement::UnbindFromTree(bool aDeep, bool aNullParent)
+{
+  nsINode *parent = nsINode::GetParentNode();
+  if (parent && parent->Tag() == nsGkAtoms::picture) {
+    // Find all img siblings after this <source> and notify them of our demise
+    nsCOMPtr<nsINode> sibling = AsContent();
+    while ( (sibling = sibling->GetNextSibling()) ) {
+      if (sibling->Tag() == nsGkAtoms::img) {
+        HTMLImageElement *img = static_cast<HTMLImageElement*>(sibling.get());
+        img->PictureSourceRemoved(AsContent());
+      }
+    }
+  }
+
+  nsGenericHTMLElement::UnbindFromTree(aDeep, aNullParent);
+}
+
 JSObject*
 HTMLSourceElement::WrapNode(JSContext* aCx)
 {

content/html/content/src/HTMLSourceElement.h

@@ -17,6 +17,7 @@ class nsMediaList;
 namespace mozilla {
 namespace dom {
 
+class ResponsiveImageSelector;
 class HTMLSourceElement MOZ_FINAL : public nsGenericHTMLElement,
                                     public nsIDOMHTMLSourceElement
 {
@@ -39,6 +40,7 @@ public:
   virtual nsresult BindToTree(nsIDocument* aDocument, nsIContent* aParent,
                               nsIContent* aBindingParent,
                               bool aCompileEventHandlers) MOZ_OVERRIDE;
+  virtual void UnbindFromTree(bool aDeep, bool aNullParent) MOZ_OVERRIDE;
 
   // If this element's media attr matches for its owner document.  Returns true
   // if no media attr was set.