gecko-dev/dom/svg/SVGNumberList.h

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6.2 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 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);
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_