1 files changed, 198 insertions, 0 deletions
diff --git a/dom/svg/SVGNumberList.h b/dom/svg/SVGNumberList.h
new file mode 100644
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+++ b/dom/svg/SVGNumberList.h
@@ -0,0 +1,198 @@
+/* -*- 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 DOM_SVG_SVGNUMBERLIST_H_
+#define DOM_SVG_SVGNUMBERLIST_H_
+
+#include "nsCOMPtr.h"
+#include "nsDebug.h"
+#include "nsIContent.h"
+#include "nsINode.h"
+#include "nsIWeakReferenceUtils.h"
+#include "SVGElement.h"
+#include "nsTArray.h"
+
+namespace mozilla {
+
+namespace dom {
+class DOMSVGNumber;
+class DOMSVGNumberList;
+}  // namespace dom
+
+/**
+ * ATTENTION! WARNING! WATCH OUT!!
+ *
+ * Consumers that modify objects of this type absolutely MUST keep the DOM
+ * wrappers for those lists (if any) in sync!! That's why this class is so
+ * locked down.
+ *
+ * The DOM wrapper class for this class is DOMSVGNumberList.
+ */
+class SVGNumberList {
+  friend class dom::DOMSVGNumber;
+  friend class dom::DOMSVGNumberList;
+  friend class SVGAnimatedNumberList;
+
+ public:
+  SVGNumberList() = default;
+  ~SVGNumberList() = default;
+
+  SVGNumberList& operator=(const SVGNumberList& aOther) {
+    mNumbers.ClearAndRetainStorage();
+    // Best-effort, really.
+    Unused << mNumbers.AppendElements(aOther.mNumbers, fallible);
+    return *this;
+  }
+
+  SVGNumberList(const SVGNumberList& aOther) { *this = aOther; }
+
+  // Only methods that don't make/permit modification to this list are public.
+  // Only our friend classes can access methods that may change us.
+
+  /// This may return an incomplete string on OOM, but that's acceptable.
+  void GetValueAsString(nsAString& aValue) const;
+
+  bool IsEmpty() const { return mNumbers.IsEmpty(); }
+
+  uint32_t Length() const { return mNumbers.Length(); }
+
+  const float& operator[](uint32_t aIndex) const { return mNumbers[aIndex]; }
+
+  bool operator==(const SVGNumberList& rhs) const {
+    return mNumbers == rhs.mNumbers;
+  }
+
+  bool SetCapacity(uint32_t size) {
+    return mNumbers.SetCapacity(size, fallible);
+  }
+
+  void Compact() { mNumbers.Compact(); }
+
+  // Access to methods that can modify objects of this type is deliberately
+  // limited. This is to reduce the chances of someone modifying objects of
+  // this type without taking the necessary steps to keep DOM wrappers in sync.
+  // If you need wider access to these methods, consider adding a method to
+  // SVGAnimatedNumberList and having that class act as an intermediary so it
+  // can take care of keeping DOM wrappers in sync.
+
+ protected:
+  /**
+   * This may fail on OOM if the internal capacity needs to be increased, in
+   * which case the list will be left unmodified.
+   */
+  nsresult CopyFrom(const SVGNumberList& rhs);
+  void SwapWith(SVGNumberList& aRhs) { mNumbers.SwapElements(aRhs.mNumbers); }
+
+  float& operator[](uint32_t aIndex) { return mNumbers[aIndex]; }
+
+  /**
+   * This may fail (return false) on OOM if the internal capacity is being
+   * increased, in which case the list will be left unmodified.
+   */
+  bool SetLength(uint32_t aNumberOfItems) {
+    return mNumbers.SetLength(aNumberOfItems, fallible);
+  }
+
+ private:
+  // Marking the following private only serves to show which methods are only
+  // used by our friend classes (as opposed to our subclasses) - it doesn't
+  // really provide additional safety.
+
+  nsresult SetValueFromString(const nsAString& aValue);
+
+  void Clear() { mNumbers.Clear(); }
+
+  bool InsertItem(uint32_t aIndex, const float& aNumber) {
+    if (aIndex >= mNumbers.Length()) {
+      aIndex = mNumbers.Length();
+    }
+    return !!mNumbers.InsertElementAt(aIndex, aNumber, fallible);
+  }
+
+  void ReplaceItem(uint32_t aIndex, const float& aNumber) {
+    MOZ_ASSERT(aIndex < mNumbers.Length(),
+               "DOM wrapper caller should have raised INDEX_SIZE_ERR");
+    mNumbers[aIndex] = aNumber;
+  }
+
+  void RemoveItem(uint32_t aIndex) {
+    MOZ_ASSERT(aIndex < mNumbers.Length(),
+               "DOM wrapper caller should have raised INDEX_SIZE_ERR");
+    mNumbers.RemoveElementAt(aIndex);
+  }
+
+  bool AppendItem(float aNumber) {
+    return !!mNumbers.AppendElement(aNumber, fallible);
+  }
+
+ protected:
+  /* See SVGLengthList for the rationale for using FallibleTArray<float> instead
+   * of FallibleTArray<float, 1>.
+   */
+  FallibleTArray<float> mNumbers;
+};
+
+/**
+ * This SVGNumberList subclass is used by the SMIL code when a number list
+ * is to be stored in a SMILValue instance. Since SMILValue objects may
+ * be cached, it is necessary for us to hold a strong reference to our element
+ * so that it doesn't disappear out from under us if, say, the element is
+ * removed from the DOM tree.
+ */
+class SVGNumberListAndInfo : public SVGNumberList {
+ public:
+  SVGNumberListAndInfo() : mElement(nullptr) {}
+
+  explicit SVGNumberListAndInfo(dom::SVGElement* aElement)
+      : mElement(do_GetWeakReference(static_cast<nsINode*>(aElement))) {}
+
+  void SetInfo(dom::SVGElement* aElement) {
+    mElement = do_GetWeakReference(static_cast<nsINode*>(aElement));
+  }
+
+  dom::SVGElement* Element() const {
+    nsCOMPtr<nsIContent> e = do_QueryReferent(mElement);
+    return static_cast<dom::SVGElement*>(e.get());
+  }
+
+  nsresult CopyFrom(const SVGNumberListAndInfo& rhs) {
+    mElement = rhs.mElement;
+    return SVGNumberList::CopyFrom(rhs);
+  }
+
+  // Instances of this special subclass do not have DOM wrappers that we need
+  // to worry about keeping in sync, so it's safe to expose any hidden base
+  // class methods required by the SMIL code, as we do below.
+
+  /**
+   * Exposed so that SVGNumberList baseVals can be copied to
+   * SVGNumberListAndInfo objects. Note that callers should also call
+   * SetInfo() when using this method!
+   */
+  nsresult CopyFrom(const SVGNumberList& rhs) {
+    return SVGNumberList::CopyFrom(rhs);
+  }
+  const float& operator[](uint32_t aIndex) const {
+    return SVGNumberList::operator[](aIndex);
+  }
+  float& operator[](uint32_t aIndex) {
+    return SVGNumberList::operator[](aIndex);
+  }
+  bool SetLength(uint32_t aNumberOfItems) {
+    return SVGNumberList::SetLength(aNumberOfItems);
+  }
+
+ private:
+  // We must keep a weak reference to our element because we may belong to a
+  // cached baseVal SMILValue. See the comments starting at:
+  // https://bugzilla.mozilla.org/show_bug.cgi?id=515116#c15
+  // See also https://bugzilla.mozilla.org/show_bug.cgi?id=653497
+  nsWeakPtr mElement;
+};
+
+}  // namespace mozilla
+
+#endif  // DOM_SVG_SVGNUMBERLIST_H_