dom/svg/DOMSVGPointList.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "DOMSVGPointList.h"
   8
   9 #include "nsContentUtils.h"
  10 #include "DOMSVGPoint.h"
  11 #include "nsError.h"
  12 #include "SVGAnimatedPointList.h"
  13 #include "SVGAttrTearoffTable.h"
  14 #include "mozilla/dom/SVGElement.h"
  15 #include "mozilla/dom/SVGPointListBinding.h"
  16 #include <algorithm>
  17
  18 // See the comment in this file's header.
  19
  20 // local helper functions
  21 namespace {
  22
  23 void UpdateListIndicesFromIndex(
  24     FallibleTArray<mozilla::dom::DOMSVGPoint*>& aItemsArray,
  25     uint32_t aStartingIndex) {
  26   uint32_t length = aItemsArray.Length();
  27
  28   for (uint32_t i = aStartingIndex; i < length; ++i) {
  29     if (aItemsArray[i]) {
  30       aItemsArray[i]->UpdateListIndex(i);
  31     }
  32   }
  33 }
  34
  35 }  // namespace
  36
  37 namespace mozilla::dom {
  38
  39 static inline SVGAttrTearoffTable<void, DOMSVGPointList>&
  40 SVGPointListTearoffTable() {
  41   static SVGAttrTearoffTable<void, DOMSVGPointList> sSVGPointListTearoffTable;
  42   return sSVGPointListTearoffTable;
  43 }
  44
  45 NS_IMPL_CYCLE_COLLECTION_CLASS(DOMSVGPointList)
  46
  47 NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(DOMSVGPointList)
  48   // No unlinking of mElement, we'd need to null out the value pointer (the
  49   // object it points to is held by the element) and null-check it everywhere.
  50   tmp->RemoveFromTearoffTable();
  51   NS_IMPL_CYCLE_COLLECTION_UNLINK_PRESERVED_WRAPPER
  52 NS_IMPL_CYCLE_COLLECTION_UNLINK_END
  53 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(DOMSVGPointList)
  54   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mElement)
  55 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
  56 NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN(DOMSVGPointList)
  57   NS_IMPL_CYCLE_COLLECTION_TRACE_PRESERVED_WRAPPER
  58 NS_IMPL_CYCLE_COLLECTION_TRACE_END
  59
  60 NS_IMPL_CYCLE_COLLECTING_ADDREF(DOMSVGPointList)
  61 NS_IMPL_CYCLE_COLLECTING_RELEASE(DOMSVGPointList)
  62
  63 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(DOMSVGPointList)
  64   NS_INTERFACE_MAP_ENTRY_CONCRETE(DOMSVGPointList)
  65   NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY
  66   NS_INTERFACE_MAP_ENTRY(nsISupports)
  67 NS_INTERFACE_MAP_END
  68
  69 /* static */
  70 already_AddRefed<DOMSVGPointList> DOMSVGPointList::GetDOMWrapper(
  71     void* aList, SVGElement* aElement, bool aIsAnimValList) {
  72   RefPtr<DOMSVGPointList> wrapper =
  73       SVGPointListTearoffTable().GetTearoff(aList);
  74   if (!wrapper) {
  75     wrapper = new DOMSVGPointList(aElement, aIsAnimValList);
  76     SVGPointListTearoffTable().AddTearoff(aList, wrapper);
  77   }
  78   return wrapper.forget();
  79 }
  80
  81 /* static */
  82 DOMSVGPointList* DOMSVGPointList::GetDOMWrapperIfExists(void* aList) {
  83   return SVGPointListTearoffTable().GetTearoff(aList);
  84 }
  85
  86 void DOMSVGPointList::RemoveFromTearoffTable() {
  87   // Called from Unlink and the destructor.
  88   //
  89   // There are now no longer any references to us held by script or list items.
  90   // Note we must use GetAnimValKey/GetBaseValKey here, NOT InternalList()!
  91   void* key = mIsAnimValList ? InternalAList().GetAnimValKey()
  92                              : InternalAList().GetBaseValKey();
  93   SVGPointListTearoffTable().RemoveTearoff(key);
  94 }
  95
  96 DOMSVGPointList::~DOMSVGPointList() { RemoveFromTearoffTable(); }
  97
  98 JSObject* DOMSVGPointList::WrapObject(JSContext* cx,
  99                                       JS::Handle<JSObject*> aGivenProto) {
 100   return mozilla::dom::SVGPointList_Binding::Wrap(cx, this, aGivenProto);
 101 }
 102
 103 void DOMSVGPointList::InternalListWillChangeTo(const SVGPointList& aNewValue) {
 104   // When the number of items in our internal counterpart changes, we MUST stay
 105   // in sync. Everything in the scary comment in
 106   // DOMSVGLengthList::InternalBaseValListWillChangeTo applies here too!
 107
 108   uint32_t oldLength = mItems.Length();
 109
 110   uint32_t newLength = aNewValue.Length();
 111   if (newLength > DOMSVGPoint::MaxListIndex()) {
 112     // It's safe to get out of sync with our internal list as long as we have
 113     // FEWER items than it does.
 114     newLength = DOMSVGPoint::MaxListIndex();
 115   }
 116
 117   RefPtr<DOMSVGPointList> kungFuDeathGrip;
 118   if (newLength < oldLength) {
 119     // RemovingFromList() might clear last reference to |this|.
 120     // Retain a temporary reference to keep from dying before returning.
 121     kungFuDeathGrip = this;
 122   }
 123
 124   // If our length will decrease, notify the items that will be removed:
 125   for (uint32_t i = newLength; i < oldLength; ++i) {
 126     if (mItems[i]) {
 127       mItems[i]->RemovingFromList();
 128     }
 129   }
 130
 131   if (!mItems.SetLength(newLength, fallible)) {
 132     // We silently ignore SetLength OOM failure since being out of sync is safe
 133     // so long as we have *fewer* items than our internal list.
 134     mItems.Clear();
 135     return;
 136   }
 137
 138   // If our length has increased, null out the new pointers:
 139   for (uint32_t i = oldLength; i < newLength; ++i) {
 140     mItems[i] = nullptr;
 141   }
 142 }
 143
 144 bool DOMSVGPointList::AttrIsAnimating() const {
 145   return InternalAList().IsAnimating();
 146 }
 147
 148 bool DOMSVGPointList::AnimListMirrorsBaseList() const {
 149   return GetDOMWrapperIfExists(InternalAList().GetAnimValKey()) &&
 150          !AttrIsAnimating();
 151 }
 152
 153 SVGPointList& DOMSVGPointList::InternalList() const {
 154   SVGAnimatedPointList* alist = mElement->GetAnimatedPointList();
 155   return mIsAnimValList && alist->IsAnimating() ? *alist->mAnimVal
 156                                                 : alist->mBaseVal;
 157 }
 158
 159 SVGAnimatedPointList& DOMSVGPointList::InternalAList() const {
 160   MOZ_ASSERT(mElement->GetAnimatedPointList(), "Internal error");
 161   return *mElement->GetAnimatedPointList();
 162 }
 163
 164 // ----------------------------------------------------------------------------
 165 // nsIDOMSVGPointList implementation:
 166
 167 void DOMSVGPointList::Clear(ErrorResult& aError) {
 168   if (IsAnimValList()) {
 169     aError.Throw(NS_ERROR_DOM_NO_MODIFICATION_ALLOWED_ERR);
 170     return;
 171   }
 172
 173   if (LengthNoFlush() > 0) {
 174     AutoChangePointListNotifier notifier(this);
 175     // DOM list items that are to be removed must be removed before we change
 176     // the internal list, otherwise they wouldn't be able to copy their
 177     // internal counterparts' values!
 178
 179     InternalListWillChangeTo(SVGPointList());  // clears mItems
 180
 181     if (!AttrIsAnimating()) {
 182       // The anim val list is in sync with the base val list
 183       DOMSVGPointList* animList =
 184           GetDOMWrapperIfExists(InternalAList().GetAnimValKey());
 185       if (animList) {
 186         animList->InternalListWillChangeTo(
 187             SVGPointList());  // clears its mItems
 188       }
 189     }
 190
 191     InternalList().Clear();
 192   }
 193 }
 194
 195 already_AddRefed<DOMSVGPoint> DOMSVGPointList::Initialize(DOMSVGPoint& aNewItem,
 196                                                           ErrorResult& aError) {
 197   if (IsAnimValList()) {
 198     aError.Throw(NS_ERROR_DOM_NO_MODIFICATION_ALLOWED_ERR);
 199     return nullptr;
 200   }
 201
 202   // If aNewItem is already in a list we should insert a clone of aNewItem,
 203   // and for consistency, this should happen even if *this* is the list that
 204   // aNewItem is currently in. Note that in the case of aNewItem being in this
 205   // list, the Clear() call before the InsertItemBefore() call would remove it
 206   // from this list, and so the InsertItemBefore() call would not insert a
 207   // clone of aNewItem, it would actually insert aNewItem. To prevent that
 208   // from happening we have to do the clone here, if necessary.
 209
 210   RefPtr<DOMSVGPoint> domItem = &aNewItem;
 211   if (domItem->HasOwner()) {
 212     domItem = domItem->Copy();  // must do this before changing anything!
 213   }
 214
 215   ErrorResult rv;
 216   Clear(rv);
 217   MOZ_ASSERT(!rv.Failed());
 218   return InsertItemBefore(*domItem, 0, aError);
 219 }
 220
 221 already_AddRefed<DOMSVGPoint> DOMSVGPointList::GetItem(uint32_t index,
 222                                                        ErrorResult& error) {
 223   bool found;
 224   RefPtr<DOMSVGPoint> item = IndexedGetter(index, found, error);
 225   if (!found) {
 226     error.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
 227   }
 228   return item.forget();
 229 }
 230
 231 already_AddRefed<DOMSVGPoint> DOMSVGPointList::IndexedGetter(
 232     uint32_t aIndex, bool& aFound, ErrorResult& aError) {
 233   if (IsAnimValList()) {
 234     Element()->FlushAnimations();
 235   }
 236   aFound = aIndex < LengthNoFlush();
 237   if (aFound) {
 238     return GetItemAt(aIndex);
 239   }
 240   return nullptr;
 241 }
 242
 243 already_AddRefed<DOMSVGPoint> DOMSVGPointList::InsertItemBefore(
 244     DOMSVGPoint& aNewItem, uint32_t aIndex, ErrorResult& aError) {
 245   if (IsAnimValList()) {
 246     aError.Throw(NS_ERROR_DOM_NO_MODIFICATION_ALLOWED_ERR);
 247     return nullptr;
 248   }
 249
 250   aIndex = std::min(aIndex, LengthNoFlush());
 251   if (aIndex >= DOMSVGPoint::MaxListIndex()) {
 252     aError.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
 253     return nullptr;
 254   }
 255
 256   RefPtr<DOMSVGPoint> domItem = &aNewItem;
 257   if (domItem->HasOwner()) {
 258     domItem = domItem->Copy();  // must do this before changing anything!
 259   }
 260
 261   // Ensure we have enough memory so we can avoid complex error handling below:
 262   if (!mItems.SetCapacity(mItems.Length() + 1, fallible) ||
 263       !InternalList().SetCapacity(InternalList().Length() + 1)) {
 264     aError.Throw(NS_ERROR_OUT_OF_MEMORY);
 265     return nullptr;
 266   }
 267   if (AnimListMirrorsBaseList()) {
 268     DOMSVGPointList* animVal =
 269         GetDOMWrapperIfExists(InternalAList().GetAnimValKey());
 270     MOZ_ASSERT(animVal, "animVal must be a valid pointer");
 271     if (!animVal->mItems.SetCapacity(animVal->mItems.Length() + 1, fallible)) {
 272       aError.Throw(NS_ERROR_OUT_OF_MEMORY);
 273       return nullptr;
 274     }
 275   }
 276
 277   AutoChangePointListNotifier notifier(this);
 278   // Now that we know we're inserting, keep animVal list in sync as necessary.
 279   MaybeInsertNullInAnimValListAt(aIndex);
 280
 281   InternalList().InsertItem(aIndex, domItem->ToSVGPoint());
 282   MOZ_ALWAYS_TRUE(mItems.InsertElementAt(aIndex, domItem, fallible));
 283
 284   // This MUST come after the insertion into InternalList(), or else under the
 285   // insertion into InternalList() the values read from domItem would be bad
 286   // data from InternalList() itself!:
 287   domItem->InsertingIntoList(this, aIndex, IsAnimValList());
 288
 289   UpdateListIndicesFromIndex(mItems, aIndex + 1);
 290
 291   return domItem.forget();
 292 }
 293
 294 already_AddRefed<DOMSVGPoint> DOMSVGPointList::ReplaceItem(
 295     DOMSVGPoint& aNewItem, uint32_t aIndex, ErrorResult& aError) {
 296   if (IsAnimValList()) {
 297     aError.Throw(NS_ERROR_DOM_NO_MODIFICATION_ALLOWED_ERR);
 298     return nullptr;
 299   }
 300
 301   if (aIndex >= LengthNoFlush()) {
 302     aError.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
 303     return nullptr;
 304   }
 305
 306   RefPtr<DOMSVGPoint> domItem = &aNewItem;
 307   if (domItem->HasOwner()) {
 308     domItem = domItem->Copy();  // must do this before changing anything!
 309   }
 310
 311   AutoChangePointListNotifier notifier(this);
 312   if (mItems[aIndex]) {
 313     // Notify any existing DOM item of removal *before* modifying the lists so
 314     // that the DOM item can copy the *old* value at its index:
 315     mItems[aIndex]->RemovingFromList();
 316   }
 317
 318   InternalList()[aIndex] = domItem->ToSVGPoint();
 319   mItems[aIndex] = domItem;
 320
 321   // This MUST come after the ToSVGPoint() call, otherwise that call
 322   // would end up reading bad data from InternalList()!
 323   domItem->InsertingIntoList(this, aIndex, IsAnimValList());
 324
 325   return domItem.forget();
 326 }
 327
 328 already_AddRefed<DOMSVGPoint> DOMSVGPointList::RemoveItem(uint32_t aIndex,
 329                                                           ErrorResult& aError) {
 330   if (IsAnimValList()) {
 331     aError.Throw(NS_ERROR_DOM_NO_MODIFICATION_ALLOWED_ERR);
 332     return nullptr;
 333   }
 334
 335   if (aIndex >= LengthNoFlush()) {
 336     aError.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
 337     return nullptr;
 338   }
 339
 340   AutoChangePointListNotifier notifier(this);
 341   // Now that we know we're removing, keep animVal list in sync as necessary.
 342   // Do this *before* touching InternalList() so the removed item can get its
 343   // internal value.
 344   MaybeRemoveItemFromAnimValListAt(aIndex);
 345
 346   // We have to return the removed item, so get it, creating it if necessary:
 347   RefPtr<DOMSVGPoint> result = GetItemAt(aIndex);
 348
 349   // Notify the DOM item of removal *before* modifying the lists so that the
 350   // DOM item can copy its *old* value:
 351   mItems[aIndex]->RemovingFromList();
 352
 353   InternalList().RemoveItem(aIndex);
 354   mItems.RemoveElementAt(aIndex);
 355
 356   UpdateListIndicesFromIndex(mItems, aIndex);
 357
 358   return result.forget();
 359 }
 360
 361 already_AddRefed<DOMSVGPoint> DOMSVGPointList::GetItemAt(uint32_t aIndex) {
 362   MOZ_ASSERT(aIndex < mItems.Length());
 363
 364   if (!mItems[aIndex]) {
 365     mItems[aIndex] = new DOMSVGPoint(this, aIndex, IsAnimValList());
 366   }
 367   RefPtr<DOMSVGPoint> result = mItems[aIndex];
 368   return result.forget();
 369 }
 370
 371 void DOMSVGPointList::MaybeInsertNullInAnimValListAt(uint32_t aIndex) {
 372   MOZ_ASSERT(!IsAnimValList(), "call from baseVal to animVal");
 373
 374   if (!AnimListMirrorsBaseList()) {
 375     return;
 376   }
 377
 378   // The anim val list is in sync with the base val list
 379   DOMSVGPointList* animVal =
 380       GetDOMWrapperIfExists(InternalAList().GetAnimValKey());
 381
 382   MOZ_ASSERT(animVal, "AnimListMirrorsBaseList() promised a non-null animVal");
 383   MOZ_ASSERT(animVal->mItems.Length() == mItems.Length(),
 384              "animVal list not in sync!");
 385   MOZ_ALWAYS_TRUE(animVal->mItems.InsertElementAt(aIndex, nullptr, fallible));
 386
 387   UpdateListIndicesFromIndex(animVal->mItems, aIndex + 1);
 388 }
 389
 390 void DOMSVGPointList::MaybeRemoveItemFromAnimValListAt(uint32_t aIndex) {
 391   MOZ_ASSERT(!IsAnimValList(), "call from baseVal to animVal");
 392
 393   if (!AnimListMirrorsBaseList()) {
 394     return;
 395   }
 396
 397   // This needs to be a strong reference; otherwise, the RemovingFromList call
 398   // below might drop the last reference to animVal before we're done with it.
 399   RefPtr<DOMSVGPointList> animVal =
 400       GetDOMWrapperIfExists(InternalAList().GetAnimValKey());
 401
 402   MOZ_ASSERT(animVal, "AnimListMirrorsBaseList() promised a non-null animVal");
 403   MOZ_ASSERT(animVal->mItems.Length() == mItems.Length(),
 404              "animVal list not in sync!");
 405
 406   if (animVal->mItems[aIndex]) {
 407     animVal->mItems[aIndex]->RemovingFromList();
 408   }
 409   animVal->mItems.RemoveElementAt(aIndex);
 410
 411   UpdateListIndicesFromIndex(animVal->mItems, aIndex);
 412 }
 413
 414 }  // namespace mozilla::dom