/* -*- 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_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