gecko-dev/dom/svg/SVGPointList.h

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6.6 KiB
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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_SVGPOINTLIST_H__
#define MOZILLA_SVGPOINTLIST_H__
#include "nsCOMPtr.h"
#include "nsDebug.h"
#include "nsIContent.h"
#include "nsINode.h"
#include "nsIWeakReferenceUtils.h"
#include "SVGElement.h"
#include "nsTArray.h"
#include "SVGPoint.h"
#include <string.h>
namespace mozilla {
class nsISVGPoint;
/**
* 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 DOMSVGPointList.
*/
class SVGPointList {
friend class mozilla::nsISVGPoint;
friend class SVGAnimatedPointList;
friend class DOMSVGPointList;
friend class DOMSVGPoint;
public:
SVGPointList() {}
~SVGPointList() {}
// 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 mItems.IsEmpty(); }
uint32_t Length() const { return mItems.Length(); }
const SVGPoint& operator[](uint32_t aIndex) const { return mItems[aIndex]; }
bool operator==(const SVGPointList& rhs) const {
// memcmp can be faster than |mItems == rhs.mItems|
return mItems.Length() == rhs.mItems.Length() &&
memcmp(mItems.Elements(), rhs.mItems.Elements(),
mItems.Length() * sizeof(SVGPoint)) == 0;
}
bool SetCapacity(uint32_t aSize) {
return mItems.SetCapacity(aSize, fallible);
}
void Compact() { mItems.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
// SVGAnimatedPointList 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 SVGPointList& rhs);
SVGPoint& operator[](uint32_t aIndex) { return mItems[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 mItems.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() { mItems.Clear(); }
bool InsertItem(uint32_t aIndex, const SVGPoint& aPoint) {
if (aIndex >= mItems.Length()) {
aIndex = mItems.Length();
}
return !!mItems.InsertElementAt(aIndex, aPoint, fallible);
}
void ReplaceItem(uint32_t aIndex, const SVGPoint& aPoint) {
MOZ_ASSERT(aIndex < mItems.Length(),
"DOM wrapper caller should have raised INDEX_SIZE_ERR");
mItems[aIndex] = aPoint;
}
void RemoveItem(uint32_t aIndex) {
MOZ_ASSERT(aIndex < mItems.Length(),
"DOM wrapper caller should have raised INDEX_SIZE_ERR");
mItems.RemoveElementAt(aIndex);
}
bool AppendItem(SVGPoint aPoint) {
return !!mItems.AppendElement(aPoint, fallible);
}
protected:
/* See SVGLengthList for the rationale for using FallibleTArray<SVGPoint>
* instead of FallibleTArray<SVGPoint, 1>.
*/
FallibleTArray<SVGPoint> mItems;
};
/**
* This SVGPointList subclass is for SVGPointListSMILType which needs a
* mutable version of SVGPointList. Instances of this class do not have
* DOM wrappers that need to be kept in sync, so we can safely expose any
* protected base class methods required by the SMIL code.
*
* This class contains a strong reference to the element that instances of
* this class are being used to animate. This is because the SMIL code stores
* instances of this class in SMILValue objects, some of which are cached.
* Holding a strong reference to the element here prevents the element from
* disappearing out from under the SMIL code unexpectedly.
*/
class SVGPointListAndInfo : public SVGPointList {
public:
explicit SVGPointListAndInfo(dom::SVGElement* aElement = nullptr)
: 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());
}
/**
* Returns true if this object is an "identity" value, from the perspective
* of SMIL. In other words, returns true until the initial value set up in
* SVGPointListSMILType::Init() has been changed with a SetInfo() call.
*/
bool IsIdentity() const {
if (!mElement) {
MOZ_ASSERT(IsEmpty(), "target element propagation failure");
return true;
}
return false;
}
nsresult CopyFrom(const SVGPointListAndInfo& rhs) {
mElement = rhs.mElement;
return SVGPointList::CopyFrom(rhs);
}
/**
* Exposed so that SVGPointList baseVals can be copied to
* SVGPointListAndInfo objects. Note that callers should also call
* SetElement() when using this method!
*/
nsresult CopyFrom(const SVGPointList& rhs) {
return SVGPointList::CopyFrom(rhs);
}
const SVGPoint& operator[](uint32_t aIndex) const {
return SVGPointList::operator[](aIndex);
}
SVGPoint& operator[](uint32_t aIndex) {
return SVGPointList::operator[](aIndex);
}
bool SetLength(uint32_t aNumberOfItems) {
return SVGPointList::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 // MOZILLA_SVGPOINTLIST_H__