Bug 1722300 - patch 4 - Implement internal destinations when generating PDF output through cairo. r=mattwoodrow

Differential Revision: https://phabricator.services.mozilla.com/D120960

gfx/2d/2D.h

@@ -1081,6 +1081,7 @@ class DrawTarget : public external::AtomicRefCounted<DrawTarget> {
    * Method to generate hyperlink in PDF output (with appropriate backend).
    */
   virtual void Link(const char* aDestination, const Rect& aRect) {}
+  virtual void Destination(const char* aDestination, const Point& aPoint) {}
 
   /**
    * Returns a SourceSurface which is a snapshot of the current contents of the

gfx/2d/DrawTargetCairo.cpp

@@ -678,8 +678,13 @@ void DrawTargetCairo::Link(const char* aDestination, const Rect& aRect) {
   cairo_user_to_device(mContext, &x, &y);
   cairo_user_to_device_distance(mContext, &w, &h);
 
-  nsPrintfCString attributes("rect=[%f %f %f %f] uri='%s'", x, y, w, h,
-                             dest.get());
+  nsPrintfCString attributes("rect=[%f %f %f %f] ", x, y, w, h);
+  if (dest[0] == '#') {
+    // The actual destination does not have a leading '#'.
+    attributes.AppendPrintf("dest='%s'", dest.get() + 1);
+  } else {
+    attributes.AppendPrintf("uri='%s'", dest.get());
+  }
 
   // We generate a begin/end pair with no content in between, because we are
   // using the rect attribute of the begin tag to specify the link region
@@ -688,6 +693,29 @@ void DrawTargetCairo::Link(const char* aDestination, const Rect& aRect) {
   cairo_tag_end(mContext, CAIRO_TAG_LINK);
 }
 
+void DrawTargetCairo::Destination(const char* aDestination,
+                                  const Point& aPoint) {
+  if (!aDestination || !*aDestination) {
+    // No destination? Just bail out.
+    return;
+  }
+
+  nsAutoCString dest(aDestination);
+  for (size_t i = dest.Length(); i > 0;) {
+    --i;
+    if (dest[i] == '\'') {
+      dest.ReplaceLiteral(i, 1, "\\'");
+    }
+  }
+
+  double x = aPoint.x, y = aPoint.y;
+  cairo_user_to_device(mContext, &x, &y);
+
+  nsPrintfCString attributes("name='%s' x=%f y=%f internal", dest.get(), x, y);
+  cairo_tag_begin(mContext, CAIRO_TAG_DEST, attributes.get());
+  cairo_tag_end(mContext, CAIRO_TAG_DEST);
+}
+
 already_AddRefed<SourceSurface> DrawTargetCairo::Snapshot() {
   if (!IsValid()) {
     gfxCriticalNote << "DrawTargetCairo::Snapshot with bad surface "

gfx/2d/DrawTargetCairo.h

@@ -61,6 +61,8 @@ class DrawTargetCairo final : public DrawTarget {
   }
 
   virtual void Link(const char* aDestination, const Rect& aRect) override;
+  virtual void Destination(const char* aDestination,
+                           const Point& aPoint) override;
 
   virtual already_AddRefed<SourceSurface> Snapshot() override;
   virtual IntSize GetSize() const override;

gfx/2d/DrawTargetRecording.cpp

@@ -202,6 +202,11 @@ void DrawTargetRecording::Link(const char* aDestination, const Rect& aRect) {
   mRecorder->RecordEvent(RecordedLink(this, aDestination, aRect));
 }
 
+void DrawTargetRecording::Destination(const char* aDestination,
+                                      const Point& aPoint) {
+  mRecorder->RecordEvent(RecordedDestination(this, aDestination, aPoint));
+}
+
 void DrawTargetRecording::FillRect(const Rect& aRect, const Pattern& aPattern,
                                    const DrawOptions& aOptions) {
   EnsurePatternDependenciesStored(aPattern);

gfx/2d/DrawTargetRecording.h

@@ -30,6 +30,8 @@ class DrawTargetRecording : public DrawTarget {
   virtual bool IsRecording() const override { return true; }
 
   virtual void Link(const char* aDestination, const Rect& aRect) override;
+  virtual void Destination(const char* aDestination,
+                           const Point& aPoint) override;
 
   virtual already_AddRefed<SourceSurface> Snapshot() override;
   virtual already_AddRefed<SourceSurface> IntoLuminanceSource(

gfx/2d/RecordedEvent.cpp

@@ -117,6 +117,8 @@ std::string RecordedEvent::GetEventName(EventType aType) {
       return "ExternalSourceSurfaceCreation";
     case LINK:
       return "Link";
+    case DESTINATION:
+      return "Destination";
     default:
       return "Unknown";
   }

gfx/2d/RecordedEvent.h

@@ -30,7 +30,7 @@ const uint32_t kMagicInt = 0xc001feed;
 const uint16_t kMajorRevision = 10;
 // A change in minor revision means additions of new events. New streams will
 // not play in older players.
-const uint16_t kMinorRevision = 2;
+const uint16_t kMinorRevision = 3;
 
 struct ReferencePtr {
   ReferencePtr() : mLongPtr(0) {}
@@ -392,6 +392,7 @@ class RecordedEvent {
     DETACHALLSNAPSHOTS,
     OPTIMIZESOURCESURFACE,
     LINK,
+    DESTINATION,
     LAST,
   };
 

gfx/2d/RecordedEventImpl.h

@@ -1553,6 +1553,31 @@ class RecordedLink : public RecordedDrawingEvent<RecordedLink> {
   MOZ_IMPLICIT RecordedLink(S& aStream);
 };
 
+class RecordedDestination : public RecordedDrawingEvent<RecordedDestination> {
+ public:
+  RecordedDestination(DrawTarget* aDT, const char* aDestination,
+                      const Point& aPoint)
+      : RecordedDrawingEvent(DESTINATION, aDT),
+        mDestination(aDestination),
+        mPoint(aPoint) {}
+
+  bool PlayEvent(Translator* aTranslator) const override;
+  template <class S>
+  void Record(S& aStream) const;
+  void OutputSimpleEventInfo(std::stringstream& aStringStream) const override;
+
+  std::string GetName() const override { return "Destination"; }
+
+ private:
+  friend class RecordedEvent;
+
+  std::string mDestination;
+  Point mPoint;
+
+  template <class S>
+  MOZ_IMPLICIT RecordedDestination(S& aStream);
+};
+
 static std::string NameFromBackend(BackendType aType) {
   switch (aType) {
     case BackendType::NONE:
@@ -3923,6 +3948,43 @@ inline void RecordedLink::OutputSimpleEventInfo(
   aStringStream << "Link [" << mDestination << " @ " << mRect << "]";
 }
 
+inline bool RecordedDestination::PlayEvent(Translator* aTranslator) const {
+  DrawTarget* dt = aTranslator->LookupDrawTarget(mDT);
+  if (!dt) {
+    return false;
+  }
+  dt->Destination(mDestination.c_str(), mPoint);
+  return true;
+}
+
+template <class S>
+void RecordedDestination::Record(S& aStream) const {
+  RecordedDrawingEvent::Record(aStream);
+  WriteElement(aStream, mPoint);
+  uint32_t len = mDestination.length();
+  WriteElement(aStream, len);
+  if (len) {
+    aStream.write(mDestination.data(), len);
+  }
+}
+
+template <class S>
+RecordedDestination::RecordedDestination(S& aStream)
+    : RecordedDrawingEvent(DESTINATION, aStream) {
+  ReadElement(aStream, mPoint);
+  uint32_t len;
+  ReadElement(aStream, len);
+  mDestination.resize(size_t(len));
+  if (len && aStream.good()) {
+    aStream.read(&mDestination.front(), len);
+  }
+}
+
+inline void RecordedDestination::OutputSimpleEventInfo(
+    std::stringstream& aStringStream) const {
+  aStringStream << "Destination [" << mDestination << " @ " << mPoint << "]";
+}
+
 #define FOR_EACH_EVENT(f)                                          \
   f(DRAWTARGETCREATION, RecordedDrawTargetCreation);               \
   f(DRAWTARGETDESTRUCTION, RecordedDrawTargetDestruction);         \
@@ -3972,7 +4034,8 @@ inline void RecordedLink::OutputSimpleEventInfo(
   f(FLUSH, RecordedFlush);                                         \
   f(DETACHALLSNAPSHOTS, RecordedDetachAllSnapshots);               \
   f(OPTIMIZESOURCESURFACE, RecordedOptimizeSourceSurface);         \
-  f(LINK, RecordedLink);
+  f(LINK, RecordedLink);                                           \
+  f(DESTINATION, RecordedDestination);
 
 #define DO_WITH_EVENT_TYPE(_typeenum, _class) \
   case _typeenum: {                           \

layout/generic/nsIFrame.cpp

@@ -4004,8 +4004,8 @@ void nsIFrame::BuildDisplayListForChild(nsDisplayListBuilder* aBuilder,
   Maybe<nsDisplayListBuilder::Linkifier> linkifier;
   if (StaticPrefs::print_save_as_pdf_links_enabled() &&
       aBuilder->IsForPrinting()) {
-    linkifier.emplace(aBuilder, aChild);
-    linkifier->MaybeAppendLink(aBuilder, aChild, aLists.Content());
+    linkifier.emplace(aBuilder, aChild, aLists.Content());
+    linkifier->MaybeAppendLink(aBuilder, aChild);
   }
 
   nsIFrame* child = aChild;

layout/painting/nsDisplayItemTypesList.h

@@ -37,6 +37,7 @@ DECLARE_DISPLAY_ITEM_TYPE(COLUMN_RULE, TYPE_RENDERS_NO_IMAGES)
 DECLARE_DISPLAY_ITEM_TYPE(COMBOBOX_FOCUS, TYPE_RENDERS_NO_IMAGES)
 DECLARE_DISPLAY_ITEM_TYPE(COMPOSITOR_HITTEST_INFO, TYPE_RENDERS_NO_IMAGES)
 DECLARE_DISPLAY_ITEM_TYPE(CONTAINER, TYPE_RENDERS_NO_IMAGES | TYPE_IS_CONTAINER)
+DECLARE_DISPLAY_ITEM_TYPE(DESTINATION, TYPE_RENDERS_NO_IMAGES)
 DECLARE_DISPLAY_ITEM_TYPE(EVENT_RECEIVER, TYPE_RENDERS_NO_IMAGES)
 DECLARE_DISPLAY_ITEM_TYPE(FIELDSET_BORDER_BACKGROUND, 0)
 DECLARE_DISPLAY_ITEM_TYPE(FILTER, TYPE_RENDERS_NO_IMAGES | TYPE_IS_CONTAINER)

layout/painting/nsDisplayList.cpp

@@ -552,13 +552,9 @@ nsRect nsDisplayListBuilder::OutOfFlowDisplayData::ComputeVisibleRectForFrame(
 }
 
 nsDisplayListBuilder::Linkifier::Linkifier(nsDisplayListBuilder* aBuilder,
-                                           nsIFrame* aFrame) {
-  // Links don't nest, so if the builder already has a destination, no need to
-  // check for a link element here.
-  if (!aBuilder->mLinkSpec.IsEmpty()) {
-    return;
-  }
-
+                                           nsIFrame* aFrame,
+                                           nsDisplayList* aList)
+    : mList(aList) {
   // Find the element that we need to check for link-ness, bailing out if
   // we can't find one.
   Element* elem = Element::FromNodeOrNull(aFrame->GetContent());
@@ -566,29 +562,80 @@ nsDisplayListBuilder::Linkifier::Linkifier(nsDisplayListBuilder* aBuilder,
     return;
   }
 
-  // Check if we have actually found a link and it has a usable spec.
-  nsCOMPtr<nsIURI> linkURI;
-  if (!elem->IsLink(getter_AddRefs(linkURI))) {
+  // If the element has an id and/or name attribute, generate a destination
+  // for possible internal linking.
+  auto maybeGenerateDest = [&](const nsAtom* aAttr) {
+    nsAutoString attrValue;
+    elem->GetAttr(aAttr, attrValue);
+    if (!attrValue.IsEmpty()) {
+      NS_ConvertUTF16toUTF8 dest(attrValue);
+      // Ensure that we only emit a given destination once, although there may
+      // be multiple frames associated with a given element; we'll simply use
+      // the first of them as the target of any links to it.
+      // XXX(jfkthame) This prevents emitting duplicate destinations *on the
+      // same page*, but does not prevent duplicates on subsequent pages, as
+      // each new page is handled by a new temporary DisplayListBuilder. This
+      // seems to be harmless in practice, though a bit wasteful of space. To
+      // fix, we need to maintain the set of already-seen destinations globally
+      // for the print job, rather than attached to the (per-page) builder.
+      if (aBuilder->mDestinations.EnsureInserted(dest)) {
+        auto* destination = MakeDisplayItem<nsDisplayDestination>(
+            aBuilder, aFrame, dest.get(), aFrame->GetRect().TopLeft());
+        mList->AppendToTop(destination);
+      }
+    }
+  };
+  if (elem->HasID()) {
+    maybeGenerateDest(nsGkAtoms::id);
+  }
+  if (elem->HasName()) {
+    maybeGenerateDest(nsGkAtoms::name);
+  }
+
+  // Links don't nest, so if the builder already has a destination, no need to
+  // check for a link element here.
+  if (!aBuilder->mLinkSpec.IsEmpty()) {
     return;
   }
-  if (NS_FAILED(linkURI->GetSpec(aBuilder->mLinkSpec)) ||
-      aBuilder->mLinkSpec.IsEmpty()) {
+
+  // Check if we have actually found a link.
+  nsCOMPtr<nsIURI> uri;
+  if (!elem->IsLink(getter_AddRefs(uri))) {
     return;
   }
 
+  // Is it a local (in-page) destination?
+  bool hasRef, eqExRef;
+  nsIURI* docURI;
+  if (NS_SUCCEEDED(uri->GetHasRef(&hasRef)) && hasRef &&
+      (docURI = aFrame->PresContext()->Document()->GetDocumentURI()) &&
+      NS_SUCCEEDED(uri->EqualsExceptRef(docURI, &eqExRef)) && eqExRef) {
+    if (NS_FAILED(uri->GetRef(aBuilder->mLinkSpec)) ||
+        aBuilder->mLinkSpec.IsEmpty()) {
+      return;
+    }
+    // Mark the link spec as being an internal destination
+    aBuilder->mLinkSpec.Insert('#', 0);
+  } else {
+    if (NS_FAILED(uri->GetSpec(aBuilder->mLinkSpec)) ||
+        aBuilder->mLinkSpec.IsEmpty()) {
+      return;
+    }
+  }
+
   // Record that we need to reset the builder's state on destruction.
   mBuilderToReset = aBuilder;
 }
 
 void nsDisplayListBuilder::Linkifier::MaybeAppendLink(
-    nsDisplayListBuilder* aBuilder, nsIFrame* aFrame, nsDisplayList* aList) {
+    nsDisplayListBuilder* aBuilder, nsIFrame* aFrame) {
   // Note that we may generate a link here even if the constructor bailed out
   // without updating aBuilder->LinkSpec(), because it may have been set by
   // an ancestor that was associated with a link element.
   if (!aBuilder->mLinkSpec.IsEmpty()) {
     auto* link = MakeDisplayItem<nsDisplayLink>(
         aBuilder, aFrame, aBuilder->mLinkSpec.get(), aFrame->GetRect());
-    aList->AppendToTop(link);
+    mList->AppendToTop(link);
   }
 }
 
@@ -8323,7 +8370,9 @@ void nsDisplayTransform::Paint(nsDisplayListBuilder* aBuilder, gfxContext* aCtx,
   }
 
   gfxContextMatrixAutoSaveRestore saveMatrix(aCtx);
-  Matrix4x4 trans = ShouldSkipTransform(aBuilder) ? Matrix4x4() : GetAccumulatedPreserved3DTransform(aBuilder);
+  Matrix4x4 trans = ShouldSkipTransform(aBuilder)
+                        ? Matrix4x4()
+                        : GetAccumulatedPreserved3DTransform(aBuilder);
   if (!IsFrameVisible(mFrame, trans)) {
     return;
   }
@@ -10347,6 +10396,14 @@ void nsDisplayLink::Paint(nsDisplayListBuilder* aBuilder, gfxContext* aCtx) {
                               NSRectToRect(GetPaintRect(), appPerDev));
 }
 
+void nsDisplayDestination::Paint(nsDisplayListBuilder* aBuilder,
+                                 gfxContext* aCtx) {
+  auto appPerDev = mFrame->PresContext()->AppUnitsPerDevPixel();
+  aCtx->GetDrawTarget()->Destination(
+      mDestinationName.get(),
+      NSPointToPoint(GetPaintRect().TopLeft(), appPerDev));
+}
+
 void nsDisplayListCollection::SerializeWithCorrectZOrder(
     nsDisplayList* aOutResultList, nsIContent* aContent) {
   // Sort PositionedDescendants() in CSS 'z-order' order.  The list is already

layout/painting/nsDisplayList.h

@@ -1787,9 +1787,12 @@ class nsDisplayListBuilder {
 
   // Helper class to find what link spec (if any) to associate with a frame,
   // recording it in the builder, and generate the corresponding DisplayItem.
+  // This also takes care of generating a named destination for internal links
+  // if the element has an id or name attribute.
   class Linkifier {
    public:
-    Linkifier(nsDisplayListBuilder* aBuilder, nsIFrame* aFrame);
+    Linkifier(nsDisplayListBuilder* aBuilder, nsIFrame* aFrame,
+              nsDisplayList* aList);
 
     ~Linkifier() {
       if (mBuilderToReset) {
@@ -1797,11 +1800,11 @@ class nsDisplayListBuilder {
       }
     }
 
-    void MaybeAppendLink(nsDisplayListBuilder* aBuilder, nsIFrame* aFrame,
-                         nsDisplayList* aList);
+    void MaybeAppendLink(nsDisplayListBuilder* aBuilder, nsIFrame* aFrame);
 
    private:
     nsDisplayListBuilder* mBuilderToReset = nullptr;
+    nsDisplayList* mList;
   };
 
  private:
@@ -1984,6 +1987,7 @@ class nsDisplayListBuilder {
   const ActiveScrolledRoot* mFilterASR;
   std::unordered_set<nsIScrollableFrame*> mScrollFramesToNotify;
   nsCString mLinkSpec;  // Destination of link currently being emitted, if any.
+  nsTHashSet<nsCString> mDestinations;  // Destination names emitted.
   bool mContainsBlendMode;
   bool mIsBuildingScrollbar;
   bool mCurrentScrollbarWillHaveLayer;
@@ -7307,6 +7311,26 @@ class nsDisplayLink : public nsPaintedDisplayItem {
   nsRect mRect;
 };
 
+/**
+ * A display item to represent a destination within the document.
+ */
+class nsDisplayDestination : public nsPaintedDisplayItem {
+ public:
+  nsDisplayDestination(nsDisplayListBuilder* aBuilder, nsIFrame* aFrame,
+                       const char* aDestinationName, const nsPoint& aPosition)
+      : nsPaintedDisplayItem(aBuilder, aFrame),
+        mDestinationName(aDestinationName),
+        mPosition(aPosition) {}
+
+  NS_DISPLAY_DECL_NAME("Destination", TYPE_DESTINATION)
+
+  void Paint(nsDisplayListBuilder* aBuilder, gfxContext* aCtx) override;
+
+ private:
+  nsCString mDestinationName;
+  nsPoint mPosition;
+};
+
 class FlattenedDisplayListIterator {
  public:
   FlattenedDisplayListIterator(nsDisplayListBuilder* aBuilder,