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tenfourfox/dom/svg/DOMSVGPathSegList.cpp

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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/. */
#include "nsSVGElement.h"
#include "DOMSVGPathSegList.h"
#include "DOMSVGPathSeg.h"
#include "nsError.h"
#include "SVGAnimatedPathSegList.h"
#include "nsCOMPtr.h"
#include "nsSVGAttrTearoffTable.h"
#include "SVGPathSegUtils.h"
#include "mozilla/dom/SVGPathSegListBinding.h"
// See the comment in this file's header.
namespace mozilla {
static inline
nsSVGAttrTearoffTable<void, DOMSVGPathSegList>&
SVGPathSegListTearoffTable()
{
static nsSVGAttrTearoffTable<void, DOMSVGPathSegList>
sSVGPathSegListTearoffTable;
return sSVGPathSegListTearoffTable;
}
NS_IMPL_CYCLE_COLLECTION_CLASS(DOMSVGPathSegList)
NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(DOMSVGPathSegList)
// No unlinking of mElement, we'd need to null out the value pointer (the
// object it points to is held by the element) and null-check it everywhere.
NS_IMPL_CYCLE_COLLECTION_UNLINK_PRESERVED_WRAPPER
NS_IMPL_CYCLE_COLLECTION_UNLINK_END
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(DOMSVGPathSegList)
NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mElement)
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_SCRIPT_OBJECTS
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN(DOMSVGPathSegList)
NS_IMPL_CYCLE_COLLECTION_TRACE_PRESERVED_WRAPPER
NS_IMPL_CYCLE_COLLECTION_TRACE_END
NS_IMPL_CYCLE_COLLECTING_ADDREF(DOMSVGPathSegList)
NS_IMPL_CYCLE_COLLECTING_RELEASE(DOMSVGPathSegList)
NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(DOMSVGPathSegList)
NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY
NS_INTERFACE_MAP_ENTRY(nsISupports)
NS_INTERFACE_MAP_END
//----------------------------------------------------------------------
// Helper class: AutoChangePathSegListNotifier
// Stack-based helper class to pair calls to WillChangePathSegList and
// DidChangePathSegList.
class MOZ_RAII AutoChangePathSegListNotifier
{
public:
explicit AutoChangePathSegListNotifier(DOMSVGPathSegList* aPathSegList MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
: mPathSegList(aPathSegList)
{
MOZ_GUARD_OBJECT_NOTIFIER_INIT;
MOZ_ASSERT(mPathSegList, "Expecting non-null pathSegList");
mEmptyOrOldValue =
mPathSegList->Element()->WillChangePathSegList();
}
~AutoChangePathSegListNotifier()
{
mPathSegList->Element()->DidChangePathSegList(mEmptyOrOldValue);
if (mPathSegList->AttrIsAnimating()) {
mPathSegList->Element()->AnimationNeedsResample();
}
}
private:
DOMSVGPathSegList* const mPathSegList;
nsAttrValue mEmptyOrOldValue;
MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
};
/* static */ already_AddRefed<DOMSVGPathSegList>
DOMSVGPathSegList::GetDOMWrapper(void *aList,
nsSVGElement *aElement,
bool aIsAnimValList)
{
RefPtr<DOMSVGPathSegList> wrapper =
SVGPathSegListTearoffTable().GetTearoff(aList);
if (!wrapper) {
wrapper = new DOMSVGPathSegList(aElement, aIsAnimValList);
SVGPathSegListTearoffTable().AddTearoff(aList, wrapper);
}
return wrapper.forget();
}
/* static */ DOMSVGPathSegList*
DOMSVGPathSegList::GetDOMWrapperIfExists(void *aList)
{
return SVGPathSegListTearoffTable().GetTearoff(aList);
}
DOMSVGPathSegList::~DOMSVGPathSegList()
{
// There are now no longer any references to us held by script or list items.
// Note we must use GetAnimValKey/GetBaseValKey here, NOT InternalList()!
void *key = mIsAnimValList ?
InternalAList().GetAnimValKey() :
InternalAList().GetBaseValKey();
SVGPathSegListTearoffTable().RemoveTearoff(key);
}
JSObject*
DOMSVGPathSegList::WrapObject(JSContext *cx, JS::Handle<JSObject*> aGivenProto)
{
return mozilla::dom::SVGPathSegListBinding::Wrap(cx, this, aGivenProto);
}
void
DOMSVGPathSegList::InternalListWillChangeTo(const SVGPathData& aNewValue)
{
// When the number of items in our internal counterpart changes, we MUST stay
// in sync. Everything in the scary comment in
// DOMSVGLengthList::InternalBaseValListWillChangeTo applies here just as
// much, but we have the additional issue that failing to stay in sync would
// mean that - assuming we aren't reading bad memory - we would likely end up
// decoding command types from argument floats when looking in our
// SVGPathData's data array! Either way, we'll likely then go down
// NS_NOTREACHED code paths, or end up reading/setting more bad memory!!
// The only time that our other DOM list type implementations remove items is
// if those items become surplus items due to an attribute change or SMIL
// animation sample shortening the list. In general though, they try to keep
// their existing DOM items, even when things change. To be consistent, we'd
// really like to do the same thing. However, because different types of path
// segment correspond to different DOMSVGPathSeg subclasses, the type of
// items in our list are generally not the same, which makes this harder for
// us. We have to remove DOM segments if their type is not the same as the
// type of the new internal segment at their index.
//
// We also need to sync up mInternalDataIndex, but since we need to loop over
// all the items in the new list checking types anyway, that's almost
// insignificant in terms of overhead.
//
// Note that this method is called on every single SMIL animation resample
// and we have no way to short circuit the overhead since we don't have a
// way to tell if the call is due to a new animation, or a resample of an
// existing animation (when the number and type of items would be the same).
// (Note that a new animation could start overriding an existing animation at
// any time, so checking IsAnimating() wouldn't work.) Because we get called
// on every sample, it would not be acceptable alternative to throw away all
// our items and let them be recreated lazily, since that would break what
// script sees!
uint32_t length = mItems.Length();
uint32_t index = 0;
uint32_t dataLength = aNewValue.mData.Length();
uint32_t dataIndex = 0; // index into aNewValue's raw data array
uint32_t newSegType;
RefPtr<DOMSVGPathSegList> kungFuDeathGrip;
if (length) {
// RemovingFromList() might clear last reference to |this|.
// Retain a temporary reference to keep from dying before returning.
//
// NOTE: For path-seg lists (unlike other list types), we have to do this
// *whenever our list is nonempty* (even if we're growing in length).
// That's because the path-seg-type of any segment could differ between old
// list vs. new list, which will make us destroy & recreate that segment,
// which could remove the last reference to us.
//
// (We explicitly *don't* want to create a kungFuDeathGrip in the length=0
// case, though, because we do hit this code inside our constructor before
// any other owning references have been added, and at that point, the
// deathgrip-removal would make us die before we exit our constructor.)
kungFuDeathGrip = this;
}
while (index < length && dataIndex < dataLength) {
newSegType = SVGPathSegUtils::DecodeType(aNewValue.mData[dataIndex]);
if (ItemAt(index) && ItemAt(index)->Type() != newSegType) {
ItemAt(index)->RemovingFromList();
ItemAt(index) = nullptr;
}
// Only after the RemovingFromList() can we touch mInternalDataIndex!
mItems[index].mInternalDataIndex = dataIndex;
++index;
dataIndex += 1 + SVGPathSegUtils::ArgCountForType(newSegType);
}
MOZ_ASSERT((index == length && dataIndex <= dataLength) ||
(index <= length && dataIndex == dataLength),
"very bad - list corruption?");
if (index < length) {
// aNewValue has fewer items than our previous internal counterpart
uint32_t newLength = index;
// Remove excess items from the list:
for (; index < length; ++index) {
if (ItemAt(index)) {
ItemAt(index)->RemovingFromList();
ItemAt(index) = nullptr;
}
}
// Only now may we truncate mItems
mItems.TruncateLength(newLength);
} else if (dataIndex < dataLength) {
// aNewValue has more items than our previous internal counterpart
// Sync mItems:
while (dataIndex < dataLength) {
if (mItems.Length() &&
mItems.Length() - 1 > DOMSVGPathSeg::MaxListIndex()) {
// It's safe to get out of sync with our internal list as long as we
// have FEWER items than it does.
return;
}
if (!mItems.AppendElement(ItemProxy(nullptr, dataIndex), fallible)) {
// OOM
ErrorResult rv;
Clear(rv);
MOZ_ASSERT(!rv.Failed());
return;
}
dataIndex += 1 + SVGPathSegUtils::ArgCountForType(SVGPathSegUtils::DecodeType(aNewValue.mData[dataIndex]));
}
}
MOZ_ASSERT(dataIndex == dataLength, "Serious processing error");
MOZ_ASSERT(index == length, "Serious counting error");
}
bool
DOMSVGPathSegList::AttrIsAnimating() const
{
return InternalAList().IsAnimating();
}
bool
DOMSVGPathSegList::AnimListMirrorsBaseList() const
{
return GetDOMWrapperIfExists(InternalAList().GetAnimValKey()) &&
!AttrIsAnimating();
}
SVGPathData&
DOMSVGPathSegList::InternalList() const
{
SVGAnimatedPathSegList *alist = mElement->GetAnimPathSegList();
return mIsAnimValList && alist->IsAnimating() ? *alist->mAnimVal : alist->mBaseVal;
}
SVGAnimatedPathSegList&
DOMSVGPathSegList::InternalAList() const
{
MOZ_ASSERT(mElement->GetAnimPathSegList(), "Internal error");
return *mElement->GetAnimPathSegList();
}
// ----------------------------------------------------------------------------
// nsIDOMSVGPathSegList implementation:
void
DOMSVGPathSegList::Clear(ErrorResult& aError)
{
if (IsAnimValList()) {
aError.Throw(NS_ERROR_DOM_NO_MODIFICATION_ALLOWED_ERR);
return;
}
if (LengthNoFlush() > 0) {
AutoChangePathSegListNotifier notifier(this);
// DOM list items that are to be removed must be removed before we change
// the internal list, otherwise they wouldn't be able to copy their
// internal counterparts' values!
InternalListWillChangeTo(SVGPathData()); // clears mItems
if (!AttrIsAnimating()) {
// The anim val list is in sync with the base val list
DOMSVGPathSegList *animList =
GetDOMWrapperIfExists(InternalAList().GetAnimValKey());
if (animList) {
animList->InternalListWillChangeTo(SVGPathData()); // clears its mItems
}
}
InternalList().Clear();
}
}
already_AddRefed<DOMSVGPathSeg>
DOMSVGPathSegList::Initialize(DOMSVGPathSeg& aNewItem, ErrorResult& aError)
{
if (IsAnimValList()) {
aError.Throw(NS_ERROR_DOM_NO_MODIFICATION_ALLOWED_ERR);
return nullptr;
}
// If aNewItem is already in a list we should insert a clone of aNewItem,
// and for consistency, this should happen even if *this* is the list that
// aNewItem is currently in. Note that in the case of aNewItem being in this
// list, the Clear() call before the InsertItemBefore() call would remove it
// from this list, and so the InsertItemBefore() call would not insert a
// clone of aNewItem, it would actually insert aNewItem. To prevent that
// from happening we have to do the clone here, if necessary.
RefPtr<DOMSVGPathSeg> domItem = &aNewItem;
if (aNewItem.HasOwner()) {
domItem = aNewItem.Clone();
}
Clear(aError);
MOZ_ASSERT(!aError.Failed(), "How could this fail?");
return InsertItemBefore(*domItem, 0, aError);
}
already_AddRefed<DOMSVGPathSeg>
DOMSVGPathSegList::GetItem(uint32_t index, ErrorResult& error)
{
bool found;
RefPtr<DOMSVGPathSeg> item = IndexedGetter(index, found, error);
if (!found) {
error.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
}
return item.forget();
}
already_AddRefed<DOMSVGPathSeg>
DOMSVGPathSegList::IndexedGetter(uint32_t aIndex, bool& aFound,
ErrorResult& aError)
{
if (IsAnimValList()) {
Element()->FlushAnimations();
}
aFound = aIndex < LengthNoFlush();
if (aFound) {
return GetItemAt(aIndex);
}
return nullptr;
}
already_AddRefed<DOMSVGPathSeg>
DOMSVGPathSegList::InsertItemBefore(DOMSVGPathSeg& aNewItem,
uint32_t aIndex,
ErrorResult& aError)
{
if (IsAnimValList()) {
aError.Throw(NS_ERROR_DOM_NO_MODIFICATION_ALLOWED_ERR);
return nullptr;
}
uint32_t internalIndex;
if (aIndex < LengthNoFlush()) {
internalIndex = mItems[aIndex].mInternalDataIndex;
} else {
aIndex = LengthNoFlush();
internalIndex = InternalList().mData.Length();
}
if (aIndex >= DOMSVGPathSeg::MaxListIndex()) {
aError.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
return nullptr;
}
RefPtr<DOMSVGPathSeg> domItem = &aNewItem;
if (domItem->HasOwner()) {
domItem = domItem->Clone(); // must do this before changing anything!
}
uint32_t argCount = SVGPathSegUtils::ArgCountForType(domItem->Type());
// Ensure we have enough memory so we can avoid complex error handling below:
if (!mItems.SetCapacity(mItems.Length() + 1, fallible) ||
!InternalList().mData.SetCapacity(InternalList().mData.Length() + 1 + argCount,
fallible)) {
aError.Throw(NS_ERROR_OUT_OF_MEMORY);
return nullptr;
}
if (AnimListMirrorsBaseList()) {
DOMSVGPathSegList *animVal =
GetDOMWrapperIfExists(InternalAList().GetAnimValKey());
MOZ_ASSERT(animVal, "animVal should be a valid pointer");
if (!animVal->mItems.SetCapacity(
animVal->mItems.Length() + 1, fallible)) {
aError.Throw(NS_ERROR_OUT_OF_MEMORY);
return nullptr;
}
}
AutoChangePathSegListNotifier notifier(this);
// Now that we know we're inserting, keep animVal list in sync as necessary.
MaybeInsertNullInAnimValListAt(aIndex, internalIndex, argCount);
float segAsRaw[1 + NS_SVG_PATH_SEG_MAX_ARGS];
domItem->ToSVGPathSegEncodedData(segAsRaw);
MOZ_ALWAYS_TRUE(InternalList().mData.InsertElementsAt(internalIndex,
segAsRaw,
1 + argCount,
fallible));
MOZ_ALWAYS_TRUE(mItems.InsertElementAt(aIndex,
ItemProxy(domItem.get(),
internalIndex),
fallible));
// This MUST come after the insertion into InternalList(), or else under the
// insertion into InternalList() the values read from domItem would be bad
// data from InternalList() itself!:
domItem->InsertingIntoList(this, aIndex, IsAnimValList());
UpdateListIndicesFromIndex(aIndex + 1, argCount + 1);
return domItem.forget();
}
already_AddRefed<DOMSVGPathSeg>
DOMSVGPathSegList::ReplaceItem(DOMSVGPathSeg& aNewItem,
uint32_t aIndex,
ErrorResult& aError)
{
if (IsAnimValList()) {
aError.Throw(NS_ERROR_DOM_NO_MODIFICATION_ALLOWED_ERR);
return nullptr;
}
if (aIndex >= LengthNoFlush()) {
aError.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
return nullptr;
}
RefPtr<DOMSVGPathSeg> domItem = &aNewItem;
if (domItem->HasOwner()) {
domItem = domItem->Clone(); // must do this before changing anything!
}
AutoChangePathSegListNotifier notifier(this);
if (ItemAt(aIndex)) {
// Notify any existing DOM item of removal *before* modifying the lists so
// that the DOM item can copy the *old* value at its index:
ItemAt(aIndex)->RemovingFromList();
}
uint32_t internalIndex = mItems[aIndex].mInternalDataIndex;
// We use InternalList() to get oldArgCount since we may not have a DOM
// wrapper at the index being replaced.
uint32_t oldType = SVGPathSegUtils::DecodeType(InternalList().mData[internalIndex]);
// NOTE: ArgCountForType returns a (small) unsigned value, but we're
// intentionally putting it in a signed variable, because we're going to
// subtract these values and might produce something negative.
int32_t oldArgCount = SVGPathSegUtils::ArgCountForType(oldType);
int32_t newArgCount = SVGPathSegUtils::ArgCountForType(domItem->Type());
float segAsRaw[1 + NS_SVG_PATH_SEG_MAX_ARGS];
domItem->ToSVGPathSegEncodedData(segAsRaw);
if (AnimListMirrorsBaseList()) {
// The anim val list is in sync with the base val list - remove mirroring
// animVal item if necessary. We do this *before* touching InternalList()
// so the removed item can correctly store its internal value.
DOMSVGPathSegList* animVal =
GetDOMWrapperIfExists(InternalAList().GetAnimValKey());
if (animVal->ItemAt(aIndex)) {
animVal->ItemAt(aIndex)->RemovingFromList();
animVal->ItemAt(aIndex) = nullptr;
}
}
if (!InternalList().mData.ReplaceElementsAt(internalIndex, 1 + oldArgCount,
segAsRaw, 1 + newArgCount,
fallible)) {
aError.Throw(NS_ERROR_OUT_OF_MEMORY);
return nullptr;
}
ItemAt(aIndex) = domItem;
// This MUST come after the ToSVGPathSegEncodedData call, otherwise that call
// would end up reading bad data from InternalList()!
domItem->InsertingIntoList(this, aIndex, IsAnimValList());
int32_t delta = newArgCount - oldArgCount;
if (delta != 0) {
// Sync up the internal indexes of all ItemProxys that come after aIndex:
UpdateListIndicesFromIndex(aIndex + 1, delta);
if (AnimListMirrorsBaseList()) {
// The anim val list is in sync with the base val list
DOMSVGPathSegList* animVal =
GetDOMWrapperIfExists(InternalAList().GetAnimValKey());
animVal->UpdateListIndicesFromIndex(aIndex + 1, delta);
}
}
return domItem.forget();
}
already_AddRefed<DOMSVGPathSeg>
DOMSVGPathSegList::RemoveItem(uint32_t aIndex,
ErrorResult& aError)
{
if (IsAnimValList()) {
aError.Throw(NS_ERROR_DOM_NO_MODIFICATION_ALLOWED_ERR);
return nullptr;
}
if (aIndex >= LengthNoFlush()) {
aError.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
return nullptr;
}
// We have to return the removed item, so get it, creating it if necessary:
RefPtr<DOMSVGPathSeg> result = GetItemAt(aIndex);
AutoChangePathSegListNotifier notifier(this);
// Notify the DOM item of removal *before* modifying the lists so that the
// DOM item can copy its *old* value:
ItemAt(aIndex)->RemovingFromList();
uint32_t internalIndex = mItems[aIndex].mInternalDataIndex;
uint32_t segType = SVGPathSegUtils::DecodeType(InternalList().mData[internalIndex]);
// NOTE: ArgCountForType returns a (small) unsigned value, but we're
// intentionally putting it in a signed value, because we're going to
// negate it, and you can't negate an unsigned value.
int32_t argCount = SVGPathSegUtils::ArgCountForType(segType);
// Now that we know we're removing, keep animVal list in sync as necessary.
// Do this *before* touching InternalList() so the removed item can get its
// internal value.
MaybeRemoveItemFromAnimValListAt(aIndex, argCount);
InternalList().mData.RemoveElementsAt(internalIndex, 1 + argCount);
mItems.RemoveElementAt(aIndex);
UpdateListIndicesFromIndex(aIndex, -(argCount + 1));
return result.forget();
}
already_AddRefed<DOMSVGPathSeg>
DOMSVGPathSegList::GetItemAt(uint32_t aIndex)
{
MOZ_ASSERT(aIndex < mItems.Length());
if (!ItemAt(aIndex)) {
ItemAt(aIndex) = DOMSVGPathSeg::CreateFor(this, aIndex, IsAnimValList());
}
RefPtr<DOMSVGPathSeg> result = ItemAt(aIndex);
return result.forget();
}
void
DOMSVGPathSegList::
MaybeInsertNullInAnimValListAt(uint32_t aIndex,
uint32_t aInternalIndex,
uint32_t aArgCountForItem)
{
MOZ_ASSERT(!IsAnimValList(), "call from baseVal to animVal");
if (!AnimListMirrorsBaseList()) {
return;
}
// The anim val list is in sync with the base val list
DOMSVGPathSegList *animVal =
GetDOMWrapperIfExists(InternalAList().GetAnimValKey());
MOZ_ASSERT(animVal, "AnimListMirrorsBaseList() promised a non-null animVal");
MOZ_ASSERT(animVal->mItems.Length() == mItems.Length(),
"animVal list not in sync!");
MOZ_ALWAYS_TRUE(animVal->mItems.InsertElementAt(aIndex,
ItemProxy(nullptr,
aInternalIndex),
fallible));
animVal->UpdateListIndicesFromIndex(aIndex + 1, 1 + aArgCountForItem);
}
void
DOMSVGPathSegList::
MaybeRemoveItemFromAnimValListAt(uint32_t aIndex,
int32_t aArgCountForItem)
{
MOZ_ASSERT(!IsAnimValList(), "call from baseVal to animVal");
if (!AnimListMirrorsBaseList()) {
return;
}
// This needs to be a strong reference; otherwise, the RemovingFromList call
// below might drop the last reference to animVal before we're done with it.
RefPtr<DOMSVGPathSegList> animVal =
GetDOMWrapperIfExists(InternalAList().GetAnimValKey());
MOZ_ASSERT(animVal, "AnimListMirrorsBaseList() promised a non-null animVal");
MOZ_ASSERT(animVal->mItems.Length() == mItems.Length(),
"animVal list not in sync!");
if (animVal->ItemAt(aIndex)) {
animVal->ItemAt(aIndex)->RemovingFromList();
}
animVal->mItems.RemoveElementAt(aIndex);
animVal->UpdateListIndicesFromIndex(aIndex, -(1 + aArgCountForItem));
}
void
DOMSVGPathSegList::UpdateListIndicesFromIndex(uint32_t aStartingIndex,
int32_t aInternalDataIndexDelta)
{
uint32_t length = mItems.Length();
for (uint32_t i = aStartingIndex; i < length; ++i) {
mItems[i].mInternalDataIndex += aInternalDataIndexDelta;
if (ItemAt(i)) {
ItemAt(i)->UpdateListIndex(i);
}
}
}
} // namespace mozilla
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