tor-browser

SVGNumberList.h (6661B)

---

/* -*- 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 "SVGElement.h"
#include "nsCOMPtr.h"
#include "nsDebug.h"
#include "nsIContent.h"
#include "nsINode.h"
#include "nsIWeakReferenceUtils.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.
   (void)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]; }

 [[nodiscard]] FallibleTArray<float>::const_iterator begin() const {
   return mNumbers.begin();
 }
 [[nodiscard]] FallibleTArray<float>::const_iterator end() const {
   return mNumbers.end();
 }

 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_