1 files changed, 111 insertions, 0 deletions
diff --git a/layout/svg/SVGViewFrame.cpp b/layout/svg/SVGViewFrame.cpp
new file mode 100644
index 0000000000..fbef5d3569
--- /dev/null
+++ b/layout/svg/SVGViewFrame.cpp
@@ -0,0 +1,111 @@
+/* -*- 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/. */
+
+// Keep in (case-insensitive) order:
+#include "mozilla/PresShell.h"
+#include "mozilla/SVGOuterSVGFrame.h"
+#include "mozilla/SVGUtils.h"
+#include "mozilla/dom/SVGSVGElement.h"
+#include "mozilla/dom/SVGViewElement.h"
+#include "nsIFrame.h"
+#include "nsGkAtoms.h"
+
+using namespace mozilla::dom;
+
+nsIFrame* NS_NewSVGViewFrame(mozilla::PresShell* aPresShell,
+                             mozilla::ComputedStyle* aStyle);
+
+namespace mozilla {
+
+/**
+ * While views are not directly rendered in SVG they can be linked to
+ * and thereby override attributes of an <svg> element via a fragment
+ * identifier. The SVGViewFrame class passes on any attribute changes
+ * the view receives to the overridden <svg> element (if there is one).
+ **/
+class SVGViewFrame final : public nsIFrame {
+  friend nsIFrame* ::NS_NewSVGViewFrame(mozilla::PresShell* aPresShell,
+                                        ComputedStyle* aStyle);
+
+ protected:
+  explicit SVGViewFrame(ComputedStyle* aStyle, nsPresContext* aPresContext)
+      : nsIFrame(aStyle, aPresContext, kClassID) {
+    AddStateBits(NS_FRAME_SVG_LAYOUT | NS_FRAME_IS_NONDISPLAY);
+  }
+
+ public:
+  NS_DECL_FRAMEARENA_HELPERS(SVGViewFrame)
+
+#ifdef DEBUG
+  void Init(nsIContent* aContent, nsContainerFrame* aParent,
+            nsIFrame* aPrevInFlow) override;
+#endif
+
+#ifdef DEBUG_FRAME_DUMP
+  nsresult GetFrameName(nsAString& aResult) const override {
+    return MakeFrameName(u"SVGView"_ns, aResult);
+  }
+#endif
+
+  nsresult AttributeChanged(int32_t aNameSpaceID, nsAtom* aAttribute,
+                            int32_t aModType) override;
+
+  bool ComputeCustomOverflow(OverflowAreas& aOverflowAreas) override {
+    // We don't maintain a ink overflow rect
+    return false;
+  }
+};
+
+}  // namespace mozilla
+
+nsIFrame* NS_NewSVGViewFrame(mozilla::PresShell* aPresShell,
+                             mozilla::ComputedStyle* aStyle) {
+  return new (aPresShell)
+      mozilla::SVGViewFrame(aStyle, aPresShell->GetPresContext());
+}
+
+namespace mozilla {
+
+NS_IMPL_FRAMEARENA_HELPERS(SVGViewFrame)
+
+#ifdef DEBUG
+void SVGViewFrame::Init(nsIContent* aContent, nsContainerFrame* aParent,
+                        nsIFrame* aPrevInFlow) {
+  NS_ASSERTION(aContent->IsSVGElement(nsGkAtoms::view),
+               "Content is not an SVG view");
+
+  nsIFrame::Init(aContent, aParent, aPrevInFlow);
+}
+#endif /* DEBUG */
+
+nsresult SVGViewFrame::AttributeChanged(int32_t aNameSpaceID,
+                                        nsAtom* aAttribute, int32_t aModType) {
+  // Ignore zoomAndPan as it does not cause the <svg> element to re-render
+
+  if (aNameSpaceID == kNameSpaceID_None &&
+      (aAttribute == nsGkAtoms::preserveAspectRatio ||
+       aAttribute == nsGkAtoms::viewBox)) {
+    SVGOuterSVGFrame* outerSVGFrame = SVGUtils::GetOuterSVGFrame(this);
+    NS_ASSERTION(outerSVGFrame->GetContent()->IsSVGElement(nsGkAtoms::svg),
+                 "Expecting an <svg> element");
+
+    SVGSVGElement* svgElement =
+        static_cast<SVGSVGElement*>(outerSVGFrame->GetContent());
+
+    nsAutoString viewID;
+    mContent->AsElement()->GetAttr(nsGkAtoms::id, viewID);
+
+    if (svgElement->IsOverriddenBy(viewID)) {
+      // We're the view that's providing overrides, so pretend that the frame
+      // we're overriding was updated.
+      outerSVGFrame->AttributeChanged(aNameSpaceID, aAttribute, aModType);
+    }
+  }
+
+  return nsIFrame::AttributeChanged(aNameSpaceID, aAttribute, aModType);
+}
+
+}  // namespace mozilla