1 files changed, 131 insertions, 0 deletions
diff --git a/dom/svg/SVGAnimatedTransformList.h b/dom/svg/SVGAnimatedTransformList.h
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+++ b/dom/svg/SVGAnimatedTransformList.h
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+/* -*- 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/. */
+
+#ifndef mozilla_dom_SVGAnimatedTransformList_h
+#define mozilla_dom_SVGAnimatedTransformList_h
+
+#include "nsAutoPtr.h"
+#include "nsCOMPtr.h"
+#include "nsCycleCollectionParticipant.h"
+#include "nsSVGElement.h"
+#include "nsWrapperCache.h"
+#include "mozilla/Attributes.h"
+
+namespace mozilla {
+
+class DOMSVGTransformList;
+class nsSVGAnimatedTransformList;
+
+namespace dom {
+
+/**
+ * Class SVGAnimatedTransformList
+ *
+ * This class is used to create the DOM tearoff objects that wrap internal
+ * nsSVGAnimatedTransformList objects.
+ *
+ * See the architecture comment in DOMSVGAnimatedLengthList.h (that's
+ * LENGTH list). The comment for that class largly applies to this one too
+ * and will go a long way to helping you understand the architecture here.
+ *
+ * This class is strongly intertwined with DOMSVGTransformList and
+ * DOMSVGTransform.
+ * Our DOMSVGTransformList base and anim vals are friends and take care of
+ * nulling out our pointers to them when they die (making our pointers to them
+ * true weak refs).
+ */
+class SVGAnimatedTransformList final : public nsWrapperCache
+{
+  friend class mozilla::DOMSVGTransformList;
+
+public:
+  NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING(SVGAnimatedTransformList)
+  NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_NATIVE_CLASS(SVGAnimatedTransformList)
+
+  /**
+   * Factory method to create and return a SVGAnimatedTransformList wrapper
+   * for a given internal nsSVGAnimatedTransformList object. The factory takes
+   * care of caching the object that it returns so that the same object can be
+   * returned for the given nsSVGAnimatedTransformList each time it is requested.
+   * The cached object is only removed from the cache when it is destroyed due
+   * to there being no more references to it or to any of its descendant
+   * objects. If that happens, any subsequent call requesting the DOM wrapper
+   * for the nsSVGAnimatedTransformList will naturally result in a new
+   * SVGAnimatedTransformList being returned.
+   */
+  static already_AddRefed<SVGAnimatedTransformList>
+    GetDOMWrapper(nsSVGAnimatedTransformList *aList, nsSVGElement *aElement);
+
+  /**
+   * This method returns the SVGAnimatedTransformList wrapper for an internal
+   * nsSVGAnimatedTransformList object if it currently has a wrapper. If it does
+   * not, then nullptr is returned.
+   */
+  static SVGAnimatedTransformList*
+    GetDOMWrapperIfExists(nsSVGAnimatedTransformList *aList);
+
+  /**
+   * Called by internal code to notify us when we need to sync the length of
+   * our baseVal DOM list with its internal list. This is called just prior to
+   * the length of the internal baseVal list being changed so that any DOM list
+   * items that need to be removed from the DOM list can first get their values
+   * from their internal counterpart.
+   *
+   * The only time this method could fail is on OOM when trying to increase the
+   * length of the DOM list. If that happens then this method simply clears the
+   * list and returns. Callers just proceed as normal, and we simply accept
+   * that the DOM list will be empty (until successfully set to a new value).
+   */
+  void InternalBaseValListWillChangeLengthTo(uint32_t aNewLength);
+  void InternalAnimValListWillChangeLengthTo(uint32_t aNewLength);
+
+  /**
+   * Returns true if our attribute is animating (in which case our animVal is
+   * not simply a mirror of our baseVal).
+   */
+  bool IsAnimating() const;
+
+  // WebIDL
+  nsSVGElement* GetParentObject() const { return mElement; }
+  virtual JSObject* WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override;
+  // These aren't weak refs because mBaseVal and mAnimVal are weak
+  already_AddRefed<DOMSVGTransformList> BaseVal();
+  already_AddRefed<DOMSVGTransformList> AnimVal();
+
+private:
+
+  /**
+   * Only our static GetDOMWrapper() factory method may create objects of our
+   * type.
+   */
+  explicit SVGAnimatedTransformList(nsSVGElement *aElement)
+    : mBaseVal(nullptr)
+    , mAnimVal(nullptr)
+    , mElement(aElement)
+  {
+  }
+
+  ~SVGAnimatedTransformList();
+
+  /// Get a reference to this DOM wrapper object's internal counterpart.
+  nsSVGAnimatedTransformList& InternalAList();
+  const nsSVGAnimatedTransformList& InternalAList() const;
+
+  // Weak refs to our DOMSVGTransformList baseVal/animVal objects. These objects
+  // are friends and take care of clearing these pointers when they die, making
+  // these true weak references.
+  DOMSVGTransformList *mBaseVal;
+  DOMSVGTransformList *mAnimVal;
+
+  // Strong ref to our element to keep it alive. We hold this not only for
+  // ourself, but also for our base/animVal and all of their items.
+  RefPtr<nsSVGElement> mElement;
+};
+
+} // namespace dom
+} // namespace mozilla
+
+#endif // mozilla_dom_SVGAnimatedTransformList_h