Bug 436418, patch H: SVG/SMIL animateMotion - add support for <mpath> sub-element. r=roc

content/svg/content/src/Makefile.in

@@ -129,6 +129,7 @@ CPPSRCS += nsSVGAnimateElement.cpp \
            nsSVGAnimateTransformElement.cpp \
            nsSVGAnimateMotionElement.cpp \
            nsSVGAnimationElement.cpp \
+           nsSVGMpathElement.cpp \
            nsSVGSetElement.cpp \
            nsSVGTransformSMILType.cpp \
            nsSVGTransformSMILAttr.cpp \

content/svg/content/src/SVGMotionSMILAnimationFunction.cpp

@@ -43,6 +43,7 @@
 #include "nsSVGPathDataParser.h"
 #include "nsSVGPathSeg.h"
 #include "nsSVGPathElement.h" // for nsSVGPathList
+#include "nsSVGMpathElement.h"
 
 namespace mozilla {
 
@@ -150,6 +151,25 @@ SVGMotionSMILAnimationFunction::GetCalcMode() const
 //----------------------------------------------------------------------
 // Helpers for GetValues
 
+/*
+ * Returns the first <mpath> child of the given element
+ */
+
+static nsSVGMpathElement*
+GetFirstMpathChild(nsIContent* aElem)
+{
+  PRUint32 childCount = aElem->GetChildCount();
+  for (PRUint32 i = 0; i < childCount; ++i) {
+    nsIContent* child = aElem->GetChildAt(i);
+    if (child->Tag() == nsGkAtoms::mpath &&
+        child->GetNameSpaceID() == kNameSpaceID_SVG) {
+      return static_cast<nsSVGMpathElement*>(child);
+    }
+  }
+
+  return nsnull;
+}
+
 void
 SVGMotionSMILAnimationFunction::
   RebuildPathAndVerticesFromBasicAttrs(const nsIContent* aContextElem)
@@ -224,6 +244,27 @@ SVGMotionSMILAnimationFunction::
   }
 }
 
+void
+SVGMotionSMILAnimationFunction::
+  RebuildPathAndVerticesFromMpathElem(nsSVGMpathElement* aMpathElem)
+{
+  mPathSourceType = ePathSourceType_Mpath;
+
+  // Use the path that's the target of our chosen <mpath> child.
+  nsSVGPathElement* pathElem = aMpathElem->GetReferencedPath();
+  if (pathElem) {
+    if (pathElem->HasAttr(kNameSpaceID_None, nsGkAtoms::d)) {
+      const nsAString& pathSpec =
+        pathElem->GetParsedAttr(nsGkAtoms::d)->GetStringValue();
+      nsresult rv = SetPathVerticesFromPathString(pathSpec);
+      if (NS_SUCCEEDED(rv)) {
+        mPath = pathElem->GetFlattenedPath(
+          pathElem->PrependLocalTransformTo(gfxMatrix()));
+      }
+    }
+  }
+}
+
 void
 SVGMotionSMILAnimationFunction::RebuildPathAndVerticesFromPathAttr()
 {
@@ -304,9 +345,13 @@ SVGMotionSMILAnimationFunction::
 
   // Do we have a mpath child? if so, it trumps everything. Otherwise, we look
   // through our list of path-defining attributes, in order of priority.
-  // XXXdholbert This is where we should check for mpath, in <mpath> patch.
-  // ...else, if no mpath child:
-  if (HasAttr(nsGkAtoms::path)) {
+  nsSVGMpathElement* firstMpathChild =
+    GetFirstMpathChild(&mAnimationElement->Content());
+
+  if (firstMpathChild) {
+    RebuildPathAndVerticesFromMpathElem(firstMpathChild);
+    mValueNeedsReparsingEverySample = PR_FALSE;
+  } else if (HasAttr(nsGkAtoms::path)) {
     RebuildPathAndVerticesFromPathAttr();
     mValueNeedsReparsingEverySample = PR_FALSE;
   } else {

content/svg/content/src/SVGMotionSMILAnimationFunction.h

@@ -42,6 +42,8 @@
 #include "SVGMotionSMILType.h" // for RotateType
 #include "gfxPath.h"  // for gfxFlattenedPath
 
+class nsSVGMpathElement;
+
 namespace mozilla {
 
 //----------------------------------------------------------------------
@@ -60,6 +62,13 @@ public:
                                      nsresult* aParseResult = nsnull);
   NS_OVERRIDE virtual PRBool UnsetAttr(nsIAtom* aAttribute);
 
+  // Method to allow our owner-element to signal us when our <mpath>
+  // has changed or been added/removed.  When that happens, we need to
+  // mark ourselves as changed so we'll get recomposed, and mark our path data
+  // as stale so it'll get regenerated (regardless of mPathSourceType, since
+  // <mpath> trumps all the other sources of path data)
+  void MpathChanged() { mIsPathStale = mHasChanged = PR_TRUE; }
+
 protected:
   enum PathSourceType {
     // NOTE: Ordering matters here. Higher-priority path-descriptors should
@@ -88,6 +97,7 @@ protected:
   void     MarkStaleIfAttributeAffectsPath(nsIAtom* aAttribute);
   nsresult SetPathVerticesFromPathString(const nsAString& aPathSpec);
   void     RebuildPathAndVertices(const nsIContent* aContextElem);
+  void     RebuildPathAndVerticesFromMpathElem(nsSVGMpathElement* aMpathElem);
   void     RebuildPathAndVerticesFromPathAttr();
   void     RebuildPathAndVerticesFromBasicAttrs(const nsIContent* aContextElem);
   PRBool   GenerateValuesForPathAndPoints(gfxFlattenedPath* aPath,

content/svg/content/src/crashtests/436418-mpathRoot-1.svg

@@ -0,0 +1,4 @@
+<svg:mpath xmlns:svg="http://www.w3.org/2000/svg"
+           xmlns:xlink="http://www.w3.org/1999/xlink"
+           xlink:href="#foo">
+</svg:mpath>

content/svg/content/src/crashtests/crashtests.list

@@ -42,6 +42,7 @@ load 427325-1.svg
 load 428228-1.svg
 load 428841-1.svg
 load 435209-1.svg
+load 436418-mpathRoot-1.svg
 load 448244-1.svg
 load 466576-1.xhtml
 load 535691-1.svg

content/svg/content/src/nsSVGAnimateMotionElement.cpp

@@ -38,48 +38,7 @@
  *
  * ***** END LICENSE BLOCK ***** */
 
-#include "nsSVGAnimationElement.h"
-#include "nsIDOMSVGAnimateMotionElement.h"
-#include "nsSVGEnum.h"
-#include "SVGMotionSMILAnimationFunction.h"
-
-#include "nsCOMArray.h"
-#include "nsIDOMSVGPathSeg.h"
-#include "nsSVGPathSeg.h"
-#include "nsSVGPathDataParser.h"
-
-
-typedef nsSVGAnimationElement nsSVGAnimateMotionElementBase;
-
-class nsSVGAnimateMotionElement : public nsSVGAnimateMotionElementBase,
-                                  public nsIDOMSVGAnimateMotionElement
-{
-protected:
-  friend nsresult NS_NewSVGAnimateMotionElement(nsIContent **aResult,
-                                                   nsINodeInfo *aNodeInfo);
-  nsSVGAnimateMotionElement(nsINodeInfo* aNodeInfo);
-
-  mozilla::SVGMotionSMILAnimationFunction mAnimationFunction;
-
-public:
-  // interfaces:
-  NS_DECL_ISUPPORTS_INHERITED
-  NS_DECL_NSIDOMSVGANIMATEMOTIONELEMENT
-
-  NS_FORWARD_NSIDOMNODE(nsSVGAnimateMotionElementBase::)
-  NS_FORWARD_NSIDOMELEMENT(nsSVGAnimateMotionElementBase::)
-  NS_FORWARD_NSIDOMSVGELEMENT(nsSVGAnimateMotionElementBase::)
-  NS_FORWARD_NSIDOMSVGANIMATIONELEMENT(nsSVGAnimateMotionElementBase::)
-
-  // nsIDOMNode specializations
-  virtual nsresult Clone(nsINodeInfo *aNodeInfo, nsINode **aResult) const;
-
-  // nsISMILAnimationElement
-  virtual nsSMILAnimationFunction& AnimationFunction();
-  virtual nsIAtom* GetTargetAttributeName() const;
-  virtual nsSMILTargetAttrType GetTargetAttributeType() const;
-
-};
+#include "nsSVGAnimateMotionElement.h"
 
 NS_IMPL_NS_NEW_SVG_ELEMENT(AnimateMotion)
 

content/svg/content/src/nsSVGAnimateMotionElement.h

@@ -0,0 +1,81 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* ***** BEGIN LICENSE BLOCK *****
+ * Version: MPL 1.1/GPL 2.0/LGPL 2.1
+ *
+ * The contents of this file are subject to the Mozilla Public License Version
+ * 1.1 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * Software distributed under the License is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+ * for the specific language governing rights and limitations under the
+ * License.
+ *
+ * The Original Code is the Mozilla SVG project.
+ *
+ * The Initial Developer of the Original Code is the Mozilla Foundation.
+ * Portions created by the Initial Developer are Copyright (C) 2010
+ * the Initial Developer. All Rights Reserved.
+ *
+ * Contributor(s):
+ *   Daniel Holbert <dholbert@mozilla.com>
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * either of the GNU General Public License Version 2 or later (the "GPL"),
+ * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+ * in which case the provisions of the GPL or the LGPL are applicable instead
+ * of those above. If you wish to allow use of your version of this file only
+ * under the terms of either the GPL or the LGPL, and not to allow others to
+ * use your version of this file under the terms of the MPL, indicate your
+ * decision by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL or the LGPL. If you do not delete
+ * the provisions above, a recipient may use your version of this file under
+ * the terms of any one of the MPL, the GPL or the LGPL.
+ *
+ * ***** END LICENSE BLOCK ***** */
+
+#ifndef NS_SVGANIMATEMOTIONELEMENT_H_
+#define NS_SVGANIMATEMOTIONELEMENT_H_
+
+#include "nsSVGAnimationElement.h"
+#include "nsIDOMSVGAnimateMotionElement.h"
+#include "nsSVGEnum.h"
+#include "SVGMotionSMILAnimationFunction.h"
+
+typedef nsSVGAnimationElement nsSVGAnimateMotionElementBase;
+
+class nsSVGAnimateMotionElement : public nsSVGAnimateMotionElementBase,
+                                  public nsIDOMSVGAnimateMotionElement
+{
+protected:
+  friend nsresult NS_NewSVGAnimateMotionElement(nsIContent **aResult,
+                                                   nsINodeInfo *aNodeInfo);
+  nsSVGAnimateMotionElement(nsINodeInfo* aNodeInfo);
+
+  mozilla::SVGMotionSMILAnimationFunction mAnimationFunction;
+
+public:
+  // interfaces:
+  NS_DECL_ISUPPORTS_INHERITED
+  NS_DECL_NSIDOMSVGANIMATEMOTIONELEMENT
+
+  NS_FORWARD_NSIDOMNODE(nsSVGAnimateMotionElementBase::)
+  NS_FORWARD_NSIDOMELEMENT(nsSVGAnimateMotionElementBase::)
+  NS_FORWARD_NSIDOMSVGELEMENT(nsSVGAnimateMotionElementBase::)
+  NS_FORWARD_NSIDOMSVGANIMATIONELEMENT(nsSVGAnimateMotionElementBase::)
+
+  // nsIDOMNode specializations
+  virtual nsresult Clone(nsINodeInfo *aNodeInfo, nsINode **aResult) const;
+
+  // nsISMILAnimationElement
+  virtual nsSMILAnimationFunction& AnimationFunction();
+  virtual nsIAtom* GetTargetAttributeName() const;
+  virtual nsSMILTargetAttrType GetTargetAttributeType() const;
+
+  // Utility method to let our <mpath> children tell us when they've changed,
+  // so we can make sure our mAnimationFunction is marked as having changed.
+  void MpathChanged() { mAnimationFunction.MpathChanged(); }
+};
+
+#endif // NS_SVGANIMATEMOTIONELEMENT_H_

content/svg/content/src/nsSVGElementFactory.cpp

@@ -172,6 +172,8 @@ NS_NewSVGAnimateTransformElement(nsIContent **aResult, nsINodeInfo *aNodeInfo);
 nsresult
 NS_NewSVGAnimateMotionElement(nsIContent **aResult, nsINodeInfo *aNodeInfo);
 nsresult
+NS_NewSVGMpathElement(nsIContent **aResult, nsINodeInfo *aNodeInfo);
+nsresult
 NS_NewSVGSetElement(nsIContent **aResult, nsINodeInfo *aNodeInfo);
 #endif // MOZ_SMIL
 
@@ -313,6 +315,8 @@ NS_NewSVGElement(nsIContent** aResult, nsINodeInfo *aNodeInfo,
       return NS_NewSVGAnimateTransformElement(aResult, aNodeInfo);
     if (name == nsGkAtoms::animateMotion)
       return NS_NewSVGAnimateMotionElement(aResult, aNodeInfo);
+    if (name == nsGkAtoms::mpath)
+      return NS_NewSVGMpathElement(aResult, aNodeInfo);
     if (name == nsGkAtoms::set)
       return NS_NewSVGSetElement(aResult, aNodeInfo);
   }

content/svg/content/src/nsSVGMpathElement.cpp

@@ -0,0 +1,296 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* ***** BEGIN LICENSE BLOCK *****
+ * Version: MPL 1.1/GPL 2.0/LGPL 2.1
+ *
+ * The contents of this file are subject to the Mozilla Public License Version
+ * 1.1 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * Software distributed under the License is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+ * for the specific language governing rights and limitations under the
+ * License.
+ *
+ * The Original Code is the Mozilla SVG project.
+ *
+ * The Initial Developer of the Original Code is the Mozilla Foundation.
+ * Portions created by the Initial Developer are Copyright (C) 2010
+ * the Initial Developer. All Rights Reserved.
+ *
+ * Contributor(s):
+ *   Daniel Holbert <dholbert@mozilla.com>
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * either of the GNU General Public License Version 2 or later (the "GPL"),
+ * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+ * in which case the provisions of the GPL or the LGPL are applicable instead
+ * of those above. If you wish to allow use of your version of this file only
+ * under the terms of either the GPL or the LGPL, and not to allow others to
+ * use your version of this file under the terms of the MPL, indicate your
+ * decision by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL or the LGPL. If you do not delete
+ * the provisions above, a recipient may use your version of this file under
+ * the terms of any one of the MPL, the GPL or the LGPL.
+ *
+ * ***** END LICENSE BLOCK ***** */
+
+#include "nsSVGMpathElement.h"
+#include "nsAutoPtr.h"
+#include "nsDebug.h"
+#include "nsSVGPathElement.h"
+#include "nsSVGAnimateMotionElement.h"
+
+nsSVGElement::StringInfo nsSVGMpathElement::sStringInfo[1] =
+{
+  { &nsGkAtoms::href, kNameSpaceID_XLink },
+};
+
+NS_IMPL_NS_NEW_SVG_ELEMENT(Mpath)
+
+// Cycle collection magic -- based on nsSVGUseElement
+NS_IMPL_CYCLE_COLLECTION_CLASS(nsSVGMpathElement)
+NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN_INHERITED(nsSVGMpathElement,
+                                                nsSVGMpathElementBase)
+  tmp->UnlinkHrefTarget(PR_FALSE);
+NS_IMPL_CYCLE_COLLECTION_UNLINK_END
+
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(nsSVGMpathElement,
+                                                  nsSVGMpathElementBase)
+  tmp->mHrefTarget.Traverse(&cb);
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
+
+//----------------------------------------------------------------------
+// nsISupports methods
+
+NS_IMPL_ADDREF_INHERITED(nsSVGMpathElement,nsSVGMpathElementBase)
+NS_IMPL_RELEASE_INHERITED(nsSVGMpathElement,nsSVGMpathElementBase)
+
+DOMCI_DATA(SVGMpathElement, nsSVGMpathElement)
+
+NS_INTERFACE_TABLE_HEAD_CYCLE_COLLECTION_INHERITED(nsSVGMpathElement)
+  NS_NODE_INTERFACE_TABLE6(nsSVGMpathElement, nsIDOMNode, nsIDOMElement,
+                           nsIDOMSVGElement,  nsIDOMSVGURIReference,
+                           nsIDOMSVGMpathElement, nsIMutationObserver)
+  NS_DOM_INTERFACE_MAP_ENTRY_CLASSINFO(SVGMpathElement)
+NS_INTERFACE_MAP_END_INHERITING(nsSVGMpathElementBase)
+
+// Constructor
+#ifdef _MSC_VER
+// Disable "warning C4355: 'this' : used in base member initializer list".
+// We can ignore that warning because we know that mHrefTarget's constructor 
+// doesn't dereference the pointer passed to it.
+#pragma warning(push)
+#pragma warning(disable:4355)
+#endif
+nsSVGMpathElement::nsSVGMpathElement(nsINodeInfo* aNodeInfo)
+  : nsSVGMpathElementBase(aNodeInfo),
+    mHrefTarget(this)
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
+{
+}
+
+nsSVGMpathElement::~nsSVGMpathElement()
+{
+  UnlinkHrefTarget(PR_FALSE);
+}
+
+//----------------------------------------------------------------------
+// nsIDOMNode methods
+
+NS_IMPL_ELEMENT_CLONE_WITH_INIT(nsSVGMpathElement)
+
+//----------------------------------------------------------------------
+// nsIDOMSVGURIReference methods
+
+/* readonly attribute nsIDOMSVGAnimatedString href; */
+NS_IMETHODIMP
+nsSVGMpathElement::GetHref(nsIDOMSVGAnimatedString** aHref)
+{
+  return mStringAttributes[HREF].ToDOMAnimatedString(aHref, this);
+}
+
+//----------------------------------------------------------------------
+// nsIContent methods
+
+nsresult
+nsSVGMpathElement::BindToTree(nsIDocument* aDocument,
+                              nsIContent* aParent,
+                              nsIContent* aBindingParent,
+                              PRBool aCompileEventHandlers)
+{
+  NS_ABORT_IF_FALSE(!mHrefTarget.get(),
+                    "Shouldn't have href-target yet "
+                    "(or it should've been cleared)");
+  nsresult rv = nsSVGMpathElementBase::BindToTree(aDocument, aParent,
+                                                  aBindingParent,
+                                                  aCompileEventHandlers);
+  NS_ENSURE_SUCCESS(rv,rv);
+
+  if (aDocument) {
+    const nsAttrValue* hrefAttrValue =
+      mAttrsAndChildren.GetAttr(nsGkAtoms::href, kNameSpaceID_XLink);
+    if (hrefAttrValue) {
+      UpdateHrefTarget(aParent, hrefAttrValue->GetStringValue());
+    }
+  }
+
+  return NS_OK;
+}
+
+void
+nsSVGMpathElement::UnbindFromTree(PRBool aDeep, PRBool aNullParent)
+{
+  UnlinkHrefTarget(PR_TRUE);
+  nsSVGMpathElementBase::UnbindFromTree(aDeep, aNullParent);
+}
+
+PRBool
+nsSVGMpathElement::ParseAttribute(PRInt32 aNamespaceID,
+                                  nsIAtom* aAttribute,
+                                  const nsAString& aValue,
+                                  nsAttrValue& aResult)
+{
+  PRBool returnVal =
+    nsSVGMpathElementBase::ParseAttribute(aNamespaceID, aAttribute,
+                                          aValue, aResult);
+  if (aNamespaceID == kNameSpaceID_XLink &&
+      aAttribute == nsGkAtoms::href &&
+      IsInDoc()) {
+    // NOTE: If we fail the IsInDoc call, it's ok -- we'll update the target
+    // on next BindToTree call.
+    UpdateHrefTarget(GetParent(), aValue);
+  }
+  return returnVal;
+}
+
+nsresult
+nsSVGMpathElement::UnsetAttr(PRInt32 aNamespaceID,
+                             nsIAtom* aAttribute, PRBool aNotify)
+{
+  nsresult rv = nsSVGMpathElementBase::UnsetAttr(aNamespaceID, aAttribute,
+                                                 aNotify);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (aNamespaceID == kNameSpaceID_XLink &&
+      aAttribute == nsGkAtoms::href) {
+    UnlinkHrefTarget(PR_TRUE);
+  }
+
+  return NS_OK;
+}
+
+//----------------------------------------------------------------------
+// nsSVGElement methods
+
+nsSVGElement::StringAttributesInfo
+nsSVGMpathElement::GetStringInfo()
+{
+  return StringAttributesInfo(mStringAttributes, sStringInfo,
+                              NS_ARRAY_LENGTH(sStringInfo));
+}
+
+//----------------------------------------------------------------------
+// nsIMutationObserver methods
+
+void
+nsSVGMpathElement::AttributeChanged(nsIDocument *aDocument,
+                                    nsIContent *aContent,
+                                    PRInt32 aNameSpaceID,
+                                    nsIAtom *aAttribute,
+                                    PRInt32 aModType)
+{
+  if (aNameSpaceID == kNameSpaceID_None) {
+    if (aAttribute == nsGkAtoms::d) {
+      NotifyParentOfMpathChange(GetParent());
+    }
+  }
+}
+
+//----------------------------------------------------------------------
+// Public helper methods
+
+nsSVGPathElement*
+nsSVGMpathElement::GetReferencedPath()
+{
+  if (!HasAttr(kNameSpaceID_XLink, nsGkAtoms::href)) {
+    NS_ABORT_IF_FALSE(!mHrefTarget.get(),
+                      "We shouldn't have an xlink:href target "
+                      "if we don't have an xlink:href attribute");
+    return nsnull;
+  }
+
+  nsIContent* genericTarget = mHrefTarget.get();
+  if (genericTarget &&
+      genericTarget->Tag() == nsGkAtoms::path) {
+    return static_cast<nsSVGPathElement*>(genericTarget);
+  }
+  return nsnull;
+}
+
+//----------------------------------------------------------------------
+// Protected helper methods
+
+void
+nsSVGMpathElement::UpdateHrefTarget(nsIContent* aParent,
+                                    const nsAString& aHrefStr)
+{
+  nsCOMPtr<nsIURI> targetURI;
+  nsCOMPtr<nsIURI> baseURI = GetBaseURI();
+  nsContentUtils::NewURIWithDocumentCharset(getter_AddRefs(targetURI),
+                                            aHrefStr, GetOwnerDoc(), baseURI);
+
+  // Stop observing old target (if any)
+  if (mHrefTarget.get()) {
+    mHrefTarget.get()->RemoveMutationObserver(this);
+  }
+
+  if (aParent) {
+    // Pass in |aParent| instead of |this| -- first argument is only used
+    // for a call to GetCurrentDoc(), and |this| might not have a current
+    // document yet (if our caller is BindToTree).
+    mHrefTarget.Reset(aParent, targetURI);
+  } else {
+    // if we don't have a parent, then there's no animateMotion element
+    // depending on our target, so there's no point tracking it right now.
+    mHrefTarget.Unlink();
+  }
+
+  // Start observing new target (if any)
+  if (mHrefTarget.get()) {
+    mHrefTarget.get()->AddMutationObserver(this);
+  }
+
+  NotifyParentOfMpathChange(aParent);
+}
+
+void
+nsSVGMpathElement::UnlinkHrefTarget(PRBool aNotifyParent)
+{
+  // Stop observing old target (if any)
+  if (mHrefTarget.get()) {
+    mHrefTarget.get()->RemoveMutationObserver(this);
+  }
+  mHrefTarget.Unlink();
+
+  if (aNotifyParent) {
+    NotifyParentOfMpathChange(GetParent());
+  }
+}
+
+void
+nsSVGMpathElement::NotifyParentOfMpathChange(nsIContent* aParent)
+{
+  if (aParent &&
+      aParent->GetNameSpaceID() == kNameSpaceID_SVG &&
+      aParent->Tag() == nsGkAtoms::animateMotion) {
+
+    nsSVGAnimateMotionElement* animateMotionParent =
+      static_cast<nsSVGAnimateMotionElement*>(aParent);
+
+    animateMotionParent->MpathChanged();
+    AnimationNeedsResample();
+  }
+}

content/svg/content/src/nsSVGMpathElement.h

@@ -0,0 +1,139 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* ***** BEGIN LICENSE BLOCK *****
+ * Version: MPL 1.1/GPL 2.0/LGPL 2.1
+ *
+ * The contents of this file are subject to the Mozilla Public License Version
+ * 1.1 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * Software distributed under the License is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+ * for the specific language governing rights and limitations under the
+ * License.
+ *
+ * The Original Code is the Mozilla SVG project.
+ *
+ * The Initial Developer of the Original Code is the Mozilla Foundation.
+ * Portions created by the Initial Developer are Copyright (C) 2010
+ * the Initial Developer. All Rights Reserved.
+ *
+ * Contributor(s):
+ *   Daniel Holbert <dholbert@mozilla.com>
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * either of the GNU General Public License Version 2 or later (the "GPL"),
+ * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+ * in which case the provisions of the GPL or the LGPL are applicable instead
+ * of those above. If you wish to allow use of your version of this file only
+ * under the terms of either the GPL or the LGPL, and not to allow others to
+ * use your version of this file under the terms of the MPL, indicate your
+ * decision by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL or the LGPL. If you do not delete
+ * the provisions above, a recipient may use your version of this file under
+ * the terms of any one of the MPL, the GPL or the LGPL.
+ *
+ * ***** END LICENSE BLOCK ***** */
+
+#ifndef NS_SVGMPATHELEMENT_H_
+#define NS_SVGMPATHELEMENT_H_
+
+#include "nsIDOMSVGMpathElement.h"
+#include "nsIDOMSVGURIReference.h"
+#include "nsSVGElement.h"
+#include "nsStubMutationObserver.h"
+#include "nsSVGPathElement.h"
+#include "nsSVGString.h"
+#include "nsReferencedElement.h"
+
+
+typedef nsSVGElement nsSVGMpathElementBase;
+
+class nsSVGMpathElement : public nsSVGMpathElementBase,
+                          public nsIDOMSVGMpathElement,
+                          public nsIDOMSVGURIReference,
+                          public nsStubMutationObserver
+{
+protected:
+  friend nsresult NS_NewSVGMpathElement(nsIContent **aResult,
+                                        nsINodeInfo *aNodeInfo);
+  nsSVGMpathElement(nsINodeInfo* aNodeInfo);
+  ~nsSVGMpathElement();
+
+
+public:
+  // interfaces:
+  NS_DECL_ISUPPORTS_INHERITED
+  NS_DECL_NSIDOMSVGMPATHELEMENT
+  NS_DECL_NSIDOMSVGURIREFERENCE
+
+  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(nsSVGMpathElement,
+                                           nsSVGMpathElementBase)
+
+  NS_DECL_NSIMUTATIONOBSERVER_ATTRIBUTECHANGED
+
+  // Forward interface implementations to base class
+  NS_FORWARD_NSIDOMNODE(nsSVGMpathElementBase::)
+  NS_FORWARD_NSIDOMELEMENT(nsSVGMpathElementBase::)
+  NS_FORWARD_NSIDOMSVGELEMENT(nsSVGMpathElementBase::)
+
+  // nsIContent interface
+  virtual nsresult Clone(nsINodeInfo *aNodeInfo, nsINode **aResult) const;
+  virtual nsresult BindToTree(nsIDocument* aDocument, nsIContent* aParent,
+                              nsIContent* aBindingParent,
+                              PRBool aCompileEventHandlers);
+  virtual void UnbindFromTree(PRBool aDeep, PRBool aNullParent);
+
+  virtual nsresult UnsetAttr(PRInt32 aNamespaceID, nsIAtom* aAttribute,
+                             PRBool aNotify);
+  // nsGenericElement specializations
+  virtual PRBool ParseAttribute(PRInt32 aNamespaceID,
+                                nsIAtom* aAttribute,
+                                const nsAString& aValue,
+                                nsAttrValue& aResult);
+
+  // Public helper method: If our xlink:href attribute links to a <path>
+  // element, this method returns a pointer to that element. Otherwise,
+  // this returns nsnull.
+  nsSVGPathElement* GetReferencedPath();
+
+protected:
+  class PathReference : public nsReferencedElement {
+  public:
+    PathReference(nsSVGMpathElement* aMpathElement) :
+      mMpathElement(aMpathElement) {}
+  protected:
+    // We need to be notified when target changes, in order to request a sample
+    // (which will clear animation effects that used the old target-path
+    // and recompute the animation effects using the new target-path).
+    virtual void ContentChanged(nsIContent* aFrom, nsIContent* aTo) {
+      nsReferencedElement::ContentChanged(aFrom, aTo);
+      if (aFrom) {
+        aFrom->RemoveMutationObserver(mMpathElement);
+      }
+      if (aTo) {
+        aTo->AddMutationObserver(mMpathElement);
+      }
+      mMpathElement->NotifyParentOfMpathChange(mMpathElement->GetParent());
+    }
+
+    // We need to override IsPersistent to get persistent tracking (beyond the
+    // first time the target changes)
+    virtual PRBool IsPersistent() { return PR_TRUE; }
+  private:
+    nsSVGMpathElement* const mMpathElement;
+  };
+
+  virtual StringAttributesInfo GetStringInfo();
+
+  void UpdateHrefTarget(nsIContent* aParent, const nsAString& aHrefStr);
+  void UnlinkHrefTarget(PRBool aNotifyParent);
+  void NotifyParentOfMpathChange(nsIContent* aParent);
+
+  enum { HREF };
+  nsSVGString        mStringAttributes[1];
+  static StringInfo  sStringInfo[1];
+  PathReference      mHrefTarget;
+};
+
+#endif // NS_SVGMPATHELEMENT_H_

dom/base/nsDOMClassInfo.cpp

@@ -373,6 +373,7 @@
 #include "nsIDOMSVGAnimateElement.h"
 #include "nsIDOMSVGAnimateTransformElement.h"
 #include "nsIDOMSVGAnimateMotionElement.h"
+#include "nsIDOMSVGMpathElement.h"
 #include "nsIDOMSVGSetElement.h"
 #include "nsIDOMSVGAnimationElement.h"
 #include "nsIDOMElementTimeControl.h"
@@ -971,6 +972,8 @@ static nsDOMClassInfoData sClassInfoData[] = {
                            ELEMENT_SCRIPTABLE_FLAGS)
   NS_DEFINE_CLASSINFO_DATA(SVGAnimateMotionElement, nsElementSH,
                            ELEMENT_SCRIPTABLE_FLAGS)
+  NS_DEFINE_CLASSINFO_DATA(SVGMpathElement, nsElementSH,
+                           ELEMENT_SCRIPTABLE_FLAGS)
   NS_DEFINE_CLASSINFO_DATA(SVGSetElement, nsElementSH,
                            ELEMENT_SCRIPTABLE_FLAGS)
 #endif // MOZ_SMIL
@@ -2927,6 +2930,12 @@ nsDOMClassInfo::Init()
     DOM_CLASSINFO_MAP_ENTRY(nsIDOMElementTimeControl)
     DOM_CLASSINFO_SVG_ELEMENT_MAP_ENTRIES
   DOM_CLASSINFO_MAP_END
+
+  DOM_CLASSINFO_MAP_BEGIN(SVGMpathElement, nsIDOMSVGMpathElement)
+    DOM_CLASSINFO_MAP_ENTRY(nsIDOMSVGURIReference)
+    DOM_CLASSINFO_SVG_ELEMENT_MAP_ENTRIES
+  DOM_CLASSINFO_MAP_END
+
 #endif // MOZ_SMIL
 
   DOM_CLASSINFO_MAP_BEGIN(SVGCircleElement, nsIDOMSVGCircleElement)

dom/base/nsDOMClassInfoClasses.h

@@ -236,6 +236,7 @@ DOMCI_CLASS(SVGAltGlyphElement)
 DOMCI_CLASS(SVGAnimateElement)
 DOMCI_CLASS(SVGAnimateTransformElement)
 DOMCI_CLASS(SVGAnimateMotionElement)
+DOMCI_CLASS(SVGMpathElement)
 DOMCI_CLASS(SVGSetElement)
 #endif // MOZ_SMIL
 DOMCI_CLASS(SVGCircleElement)

dom/interfaces/svg/Makefile.in

@@ -135,6 +135,7 @@ XPIDLSRCS	+= \
 		nsIDOMSVGAnimateTransformElement.idl \
 		nsIDOMSVGAnimateMotionElement.idl \
 		nsIDOMSVGAnimationElement.idl \
+		nsIDOMSVGMpathElement.idl \
 		nsIDOMSVGSetElement.idl \
 		$(NULL)
 endif

dom/interfaces/svg/nsIDOMSVGMpathElement.idl

@@ -0,0 +1,60 @@
+/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* ***** BEGIN LICENSE BLOCK *****
+ * Version: MPL 1.1/GPL 2.0/LGPL 2.1
+ *
+ * The contents of this file are subject to the Mozilla Public License Version
+ * 1.1 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * Software distributed under the License is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+ * for the specific language governing rights and limitations under the
+ * License.
+ *
+ * The Original Code is the Mozilla SVG project.
+ *
+ * The Initial Developer of the Original Code is
+ * the Mozilla Foundation.
+ * Portions created by the Initial Developer are Copyright (C) 2010
+ * the Initial Developer. All Rights Reserved.
+ *
+ * Contributor(s):
+ *   Daniel Holbert <dholbert@mozilla.com>
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * either the GNU General Public License Version 2 or later (the "GPL"), or
+ * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+ * in which case the provisions of the GPL or the LGPL are applicable instead
+ * of those above. If you wish to allow use of your version of this file only
+ * under the terms of either the GPL or the LGPL, and not to allow others to
+ * use your version of this file under the terms of the MPL, indicate your
+ * decision by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL or the LGPL. If you do not delete
+ * the provisions above, a recipient may use your version of this file under
+ * the terms of any one of the MPL, the GPL or the LGPL.
+ *
+ * ***** END LICENSE BLOCK ***** */
+
+#include "nsIDOMSVGElement.idl"
+
+/**
+ * For more information on this interface please see
+ * http://www.w3.org/TR/SVG/animate.html#mpathElement
+ */
+
+[scriptable, uuid(752f5ec1-eaf6-4cfa-887b-96bc69ec36b8)]
+interface nsIDOMSVGMpathElement
+  : nsIDOMSVGElement
+/*
+  The SVG DOM makes use of multiple interface inheritance.
+  Since XPCOM only supports single interface inheritance,
+  the best thing that we can do is to promise that whenever
+  an object implements _this_ interface it will also
+  implement the following interfaces. (We then have to QI to
+  hop between them.)
+    nsIDOMSVGURIReference,
+    nsIDOMSVGExternalResourcesRequired,
+*/
+{
+};