1 files changed, 522 insertions, 0 deletions
diff --git a/dom/base/AttrArray.cpp b/dom/base/AttrArray.cpp
new file mode 100644
index 0000000000..1c7b5fc35b
--- /dev/null
+++ b/dom/base/AttrArray.cpp
@@ -0,0 +1,522 @@
+/* -*- 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/. */
+
+/*
+ * Storage of the children and attributes of a DOM node; storage for
+ * the two is unified to minimize footprint.
+ */
+
+#include "AttrArray.h"
+
+#include "mozilla/CheckedInt.h"
+#include "mozilla/MathAlgorithms.h"
+#include "mozilla/MemoryReporting.h"
+#include "mozilla/dom/Document.h"
+
+#include "nsMappedAttributeElement.h"
+#include "nsString.h"
+#include "nsHTMLStyleSheet.h"
+#include "nsMappedAttributes.h"
+#include "nsUnicharUtils.h"
+#include "nsContentUtils.h"  // nsAutoScriptBlocker
+
+using mozilla::CheckedUint32;
+using mozilla::dom::Document;
+
+AttrArray::Impl::~Impl() {
+  for (InternalAttr& attr : NonMappedAttrs()) {
+    attr.~InternalAttr();
+  }
+
+  NS_IF_RELEASE(mMappedAttrs);
+}
+
+const nsAttrValue* AttrArray::GetAttr(const nsAtom* aLocalName,
+                                      int32_t aNamespaceID) const {
+  if (aNamespaceID == kNameSpaceID_None) {
+    // This should be the common case so lets make an optimized loop
+    for (const InternalAttr& attr : NonMappedAttrs()) {
+      if (attr.mName.Equals(aLocalName)) {
+        return &attr.mValue;
+      }
+    }
+
+    if (mImpl && mImpl->mMappedAttrs) {
+      return mImpl->mMappedAttrs->GetAttr(aLocalName);
+    }
+  } else {
+    for (const InternalAttr& attr : NonMappedAttrs()) {
+      if (attr.mName.Equals(aLocalName, aNamespaceID)) {
+        return &attr.mValue;
+      }
+    }
+  }
+
+  return nullptr;
+}
+
+const nsAttrValue* AttrArray::GetAttr(const nsAString& aLocalName) const {
+  for (const InternalAttr& attr : NonMappedAttrs()) {
+    if (attr.mName.Equals(aLocalName)) {
+      return &attr.mValue;
+    }
+  }
+
+  if (mImpl && mImpl->mMappedAttrs) {
+    return mImpl->mMappedAttrs->GetAttr(aLocalName);
+  }
+
+  return nullptr;
+}
+
+const nsAttrValue* AttrArray::GetAttr(const nsAString& aName,
+                                      nsCaseTreatment aCaseSensitive) const {
+  // Check whether someone is being silly and passing non-lowercase
+  // attr names.
+  if (aCaseSensitive == eIgnoreCase &&
+      nsContentUtils::StringContainsASCIIUpper(aName)) {
+    // Try again with a lowercased name, but make sure we can't reenter this
+    // block by passing eCaseSensitive for aCaseSensitive.
+    nsAutoString lowercase;
+    nsContentUtils::ASCIIToLower(aName, lowercase);
+    return GetAttr(lowercase, eCaseMatters);
+  }
+
+  for (const InternalAttr& attr : NonMappedAttrs()) {
+    if (attr.mName.QualifiedNameEquals(aName)) {
+      return &attr.mValue;
+    }
+  }
+
+  if (mImpl && mImpl->mMappedAttrs) {
+    return mImpl->mMappedAttrs->GetAttr(aName);
+  }
+
+  return nullptr;
+}
+
+const nsAttrValue* AttrArray::AttrAt(uint32_t aPos) const {
+  NS_ASSERTION(aPos < AttrCount(), "out-of-bounds access in AttrArray");
+
+  uint32_t nonmapped = NonMappedAttrCount();
+  if (aPos < nonmapped) {
+    return &mImpl->NonMappedAttrs()[aPos].mValue;
+  }
+
+  return mImpl->mMappedAttrs->AttrAt(aPos - nonmapped);
+}
+
+template <typename Name>
+inline nsresult AttrArray::AddNewAttribute(Name* aName, nsAttrValue& aValue) {
+  MOZ_ASSERT(!mImpl || mImpl->mCapacity >= mImpl->mAttrCount);
+  if (!mImpl || mImpl->mCapacity == mImpl->mAttrCount) {
+    if (!GrowBy(1)) {
+      return NS_ERROR_OUT_OF_MEMORY;
+    }
+  }
+
+  InternalAttr& attr = mImpl->mBuffer[mImpl->mAttrCount++];
+  new (&attr.mName) nsAttrName(aName);
+  new (&attr.mValue) nsAttrValue();
+  attr.mValue.SwapValueWith(aValue);
+  return NS_OK;
+}
+
+nsresult AttrArray::SetAndSwapAttr(nsAtom* aLocalName, nsAttrValue& aValue,
+                                   bool* aHadValue) {
+  *aHadValue = false;
+
+  for (InternalAttr& attr : NonMappedAttrs()) {
+    if (attr.mName.Equals(aLocalName)) {
+      attr.mValue.SwapValueWith(aValue);
+      *aHadValue = true;
+      return NS_OK;
+    }
+  }
+
+  return AddNewAttribute(aLocalName, aValue);
+}
+
+nsresult AttrArray::SetAndSwapAttr(mozilla::dom::NodeInfo* aName,
+                                   nsAttrValue& aValue, bool* aHadValue) {
+  int32_t namespaceID = aName->NamespaceID();
+  nsAtom* localName = aName->NameAtom();
+  if (namespaceID == kNameSpaceID_None) {
+    return SetAndSwapAttr(localName, aValue, aHadValue);
+  }
+
+  *aHadValue = false;
+  for (InternalAttr& attr : NonMappedAttrs()) {
+    if (attr.mName.Equals(localName, namespaceID)) {
+      attr.mName.SetTo(aName);
+      attr.mValue.SwapValueWith(aValue);
+      *aHadValue = true;
+      return NS_OK;
+    }
+  }
+
+  return AddNewAttribute(aName, aValue);
+}
+
+nsresult AttrArray::RemoveAttrAt(uint32_t aPos, nsAttrValue& aValue) {
+  NS_ASSERTION(aPos < AttrCount(), "out-of-bounds");
+
+  uint32_t nonmapped = NonMappedAttrCount();
+  if (aPos < nonmapped) {
+    mImpl->mBuffer[aPos].mValue.SwapValueWith(aValue);
+    mImpl->mBuffer[aPos].~InternalAttr();
+
+    memmove(mImpl->mBuffer + aPos, mImpl->mBuffer + aPos + 1,
+            (mImpl->mAttrCount - aPos - 1) * sizeof(InternalAttr));
+
+    --mImpl->mAttrCount;
+
+    return NS_OK;
+  }
+
+  if (MappedAttrCount() == 1) {
+    // We're removing the last mapped attribute.  Can't swap in this
+    // case; have to copy.
+    aValue.SetTo(*mImpl->mMappedAttrs->AttrAt(0));
+    NS_RELEASE(mImpl->mMappedAttrs);
+
+    return NS_OK;
+  }
+
+  RefPtr<nsMappedAttributes> mapped =
+      GetModifiableMapped(nullptr, nullptr, false);
+
+  mapped->RemoveAttrAt(aPos - nonmapped, aValue);
+
+  return MakeMappedUnique(mapped);
+}
+
+mozilla::dom::BorrowedAttrInfo AttrArray::AttrInfoAt(uint32_t aPos) const {
+  NS_ASSERTION(aPos < AttrCount(), "out-of-bounds access in AttrArray");
+
+  uint32_t nonmapped = NonMappedAttrCount();
+  if (aPos < nonmapped) {
+    InternalAttr& attr = mImpl->mBuffer[aPos];
+    return BorrowedAttrInfo(&attr.mName, &attr.mValue);
+  }
+
+  return BorrowedAttrInfo(mImpl->mMappedAttrs->NameAt(aPos - nonmapped),
+                          mImpl->mMappedAttrs->AttrAt(aPos - nonmapped));
+}
+
+const nsAttrName* AttrArray::AttrNameAt(uint32_t aPos) const {
+  NS_ASSERTION(aPos < AttrCount(), "out-of-bounds access in AttrArray");
+
+  uint32_t nonmapped = NonMappedAttrCount();
+  if (aPos < nonmapped) {
+    return &mImpl->mBuffer[aPos].mName;
+  }
+
+  return mImpl->mMappedAttrs->NameAt(aPos - nonmapped);
+}
+
+const nsAttrName* AttrArray::GetSafeAttrNameAt(uint32_t aPos) const {
+  uint32_t nonmapped = NonMappedAttrCount();
+  if (aPos < nonmapped) {
+    return &mImpl->mBuffer[aPos].mName;
+  }
+
+  if (aPos >= AttrCount()) {
+    return nullptr;
+  }
+
+  return mImpl->mMappedAttrs->NameAt(aPos - nonmapped);
+}
+
+const nsAttrName* AttrArray::GetExistingAttrNameFromQName(
+    const nsAString& aName) const {
+  for (const InternalAttr& attr : NonMappedAttrs()) {
+    if (attr.mName.QualifiedNameEquals(aName)) {
+      return &attr.mName;
+    }
+  }
+
+  if (mImpl && mImpl->mMappedAttrs) {
+    return mImpl->mMappedAttrs->GetExistingAttrNameFromQName(aName);
+  }
+
+  return nullptr;
+}
+
+int32_t AttrArray::IndexOfAttr(const nsAtom* aLocalName,
+                               int32_t aNamespaceID) const {
+  if (!mImpl) {
+    return -1;
+  }
+
+  int32_t idx;
+  if (mImpl->mMappedAttrs && aNamespaceID == kNameSpaceID_None) {
+    idx = mImpl->mMappedAttrs->IndexOfAttr(aLocalName);
+    if (idx >= 0) {
+      return NonMappedAttrCount() + idx;
+    }
+  }
+
+  uint32_t i = 0;
+  if (aNamespaceID == kNameSpaceID_None) {
+    // This should be the common case so lets make an optimized loop
+    // Note that here we don't check for AttrSlotIsTaken() in the loop
+    // condition for the sake of performance because comparing aLocalName
+    // against null would fail in the loop body (since Equals() just compares
+    // the raw pointer value of aLocalName to what AttrSlotIsTaken() would be
+    // checking.
+    for (const InternalAttr& attr : NonMappedAttrs()) {
+      if (attr.mName.Equals(aLocalName)) {
+        return i;
+      }
+      ++i;
+    }
+  } else {
+    for (const InternalAttr& attr : NonMappedAttrs()) {
+      if (attr.mName.Equals(aLocalName, aNamespaceID)) {
+        return i;
+      }
+      ++i;
+    }
+  }
+
+  return -1;
+}
+
+nsresult AttrArray::SetAndSwapMappedAttr(nsAtom* aLocalName,
+                                         nsAttrValue& aValue,
+                                         nsMappedAttributeElement* aContent,
+                                         nsHTMLStyleSheet* aSheet,
+                                         bool* aHadValue) {
+  bool willAdd = true;
+  if (mImpl && mImpl->mMappedAttrs) {
+    willAdd = !mImpl->mMappedAttrs->GetAttr(aLocalName);
+  }
+
+  RefPtr<nsMappedAttributes> mapped =
+      GetModifiableMapped(aContent, aSheet, willAdd);
+
+  mapped->SetAndSwapAttr(aLocalName, aValue, aHadValue);
+
+  return MakeMappedUnique(mapped);
+}
+
+nsresult AttrArray::DoSetMappedAttrStyleSheet(nsHTMLStyleSheet* aSheet) {
+  MOZ_ASSERT(mImpl && mImpl->mMappedAttrs, "Should have mapped attrs here!");
+  if (aSheet == mImpl->mMappedAttrs->GetStyleSheet()) {
+    return NS_OK;
+  }
+
+  RefPtr<nsMappedAttributes> mapped =
+      GetModifiableMapped(nullptr, nullptr, false);
+
+  mapped->DropStyleSheetReference();
+  mapped->SetStyleSheet(aSheet);
+
+  return MakeMappedUnique(mapped);
+}
+
+nsresult AttrArray::DoUpdateMappedAttrRuleMapper(
+    nsMappedAttributeElement& aElement) {
+  MOZ_ASSERT(mImpl && mImpl->mMappedAttrs, "Should have mapped attrs here!");
+
+  // First two args don't matter if the assert holds.
+  RefPtr<nsMappedAttributes> mapped =
+      GetModifiableMapped(nullptr, nullptr, false);
+
+  mapped->SetRuleMapper(aElement.GetAttributeMappingFunction());
+
+  return MakeMappedUnique(mapped);
+}
+
+void AttrArray::Compact() {
+  if (!mImpl) {
+    return;
+  }
+
+  if (!mImpl->mAttrCount && !mImpl->mMappedAttrs) {
+    mImpl.reset();
+    return;
+  }
+
+  // Nothing to do.
+  if (mImpl->mAttrCount == mImpl->mCapacity) {
+    return;
+  }
+
+  Impl* impl = mImpl.release();
+  impl = static_cast<Impl*>(
+      realloc(impl, Impl::AllocationSizeForAttributes(impl->mAttrCount)));
+  MOZ_ASSERT(impl, "failed to reallocate to a smaller buffer!");
+  impl->mCapacity = impl->mAttrCount;
+  mImpl.reset(impl);
+}
+
+uint32_t AttrArray::DoGetMappedAttrCount() const {
+  MOZ_ASSERT(mImpl && mImpl->mMappedAttrs);
+  return static_cast<uint32_t>(mImpl->mMappedAttrs->Count());
+}
+
+nsresult AttrArray::ForceMapped(nsMappedAttributeElement* aContent,
+                                Document* aDocument) {
+  nsHTMLStyleSheet* sheet = aDocument->GetAttributeStyleSheet();
+  RefPtr<nsMappedAttributes> mapped =
+      GetModifiableMapped(aContent, sheet, false, 0);
+  return MakeMappedUnique(mapped);
+}
+
+void AttrArray::ClearMappedServoStyle() {
+  if (mImpl && mImpl->mMappedAttrs) {
+    mImpl->mMappedAttrs->ClearServoStyle();
+  }
+}
+
+nsMappedAttributes* AttrArray::GetModifiableMapped(
+    nsMappedAttributeElement* aContent, nsHTMLStyleSheet* aSheet,
+    bool aWillAddAttr, int32_t aAttrCount) {
+  if (mImpl && mImpl->mMappedAttrs) {
+    return mImpl->mMappedAttrs->Clone(aWillAddAttr);
+  }
+
+  MOZ_ASSERT(aContent, "Trying to create modifiable without content");
+
+  nsMapRuleToAttributesFunc mapRuleFunc =
+      aContent->GetAttributeMappingFunction();
+  return new (aAttrCount) nsMappedAttributes(aSheet, mapRuleFunc);
+}
+
+nsresult AttrArray::MakeMappedUnique(nsMappedAttributes* aAttributes) {
+  NS_ASSERTION(aAttributes, "missing attributes");
+
+  if (!mImpl && !GrowBy(1)) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+
+  if (!aAttributes->GetStyleSheet()) {
+    // This doesn't currently happen, but it could if we do loading right
+
+    RefPtr<nsMappedAttributes> mapped(aAttributes);
+    mapped.swap(mImpl->mMappedAttrs);
+
+    return NS_OK;
+  }
+
+  RefPtr<nsMappedAttributes> mapped =
+      aAttributes->GetStyleSheet()->UniqueMappedAttributes(aAttributes);
+  NS_ENSURE_TRUE(mapped, NS_ERROR_OUT_OF_MEMORY);
+
+  if (mapped != aAttributes) {
+    // Reset the stylesheet of aAttributes so that it doesn't spend time
+    // trying to remove itself from the hash. There is no risk that aAttributes
+    // is in the hash since it will always have come from GetModifiableMapped,
+    // which never returns maps that are in the hash (such hashes are by
+    // nature not modifiable).
+    aAttributes->DropStyleSheetReference();
+  }
+  mapped.swap(mImpl->mMappedAttrs);
+
+  return NS_OK;
+}
+
+const nsMappedAttributes* AttrArray::GetMapped() const {
+  return mImpl ? mImpl->mMappedAttrs : nullptr;
+}
+
+nsresult AttrArray::EnsureCapacityToClone(const AttrArray& aOther) {
+  MOZ_ASSERT(!mImpl,
+             "AttrArray::EnsureCapacityToClone requires the array be empty "
+             "when called");
+
+  uint32_t attrCount = aOther.NonMappedAttrCount();
+  if (!attrCount) {
+    return NS_OK;
+  }
+
+  // No need to use a CheckedUint32 because we are cloning. We know that we
+  // have already allocated an AttrArray of this size.
+  mImpl.reset(
+      static_cast<Impl*>(malloc(Impl::AllocationSizeForAttributes(attrCount))));
+  NS_ENSURE_TRUE(mImpl, NS_ERROR_OUT_OF_MEMORY);
+
+  mImpl->mMappedAttrs = nullptr;
+  mImpl->mCapacity = attrCount;
+  mImpl->mAttrCount = 0;
+
+  return NS_OK;
+}
+
+bool AttrArray::GrowBy(uint32_t aGrowSize) {
+  const uint32_t kLinearThreshold = 16;
+  const uint32_t kLinearGrowSize = 4;
+
+  CheckedUint32 capacity = mImpl ? mImpl->mCapacity : 0;
+  CheckedUint32 minCapacity = capacity;
+  minCapacity += aGrowSize;
+  if (!minCapacity.isValid()) {
+    return false;
+  }
+
+  if (capacity.value() <= kLinearThreshold) {
+    do {
+      capacity += kLinearGrowSize;
+      if (!capacity.isValid()) {
+        return false;
+      }
+    } while (capacity.value() < minCapacity.value());
+  } else {
+    uint32_t shift = mozilla::CeilingLog2(minCapacity.value());
+    if (shift >= 32) {
+      return false;
+    }
+    capacity = 1u << shift;
+  }
+
+  CheckedUint32 sizeInBytes = capacity.value();
+  sizeInBytes *= sizeof(InternalAttr);
+  if (!sizeInBytes.isValid()) {
+    return false;
+  }
+
+  sizeInBytes += sizeof(Impl);
+  if (!sizeInBytes.isValid()) {
+    return false;
+  }
+
+  MOZ_ASSERT(sizeInBytes.value() ==
+             Impl::AllocationSizeForAttributes(capacity.value()));
+
+  const bool needToInitialize = !mImpl;
+  Impl* newImpl =
+      static_cast<Impl*>(realloc(mImpl.release(), sizeInBytes.value()));
+  NS_ENSURE_TRUE(newImpl, false);
+
+  mImpl.reset(newImpl);
+
+  // Set initial counts if we didn't have a buffer before
+  if (needToInitialize) {
+    mImpl->mMappedAttrs = nullptr;
+    mImpl->mAttrCount = 0;
+  }
+
+  mImpl->mCapacity = capacity.value();
+  return true;
+}
+
+size_t AttrArray::SizeOfExcludingThis(
+    mozilla::MallocSizeOf aMallocSizeOf) const {
+  size_t n = 0;
+  if (mImpl) {
+    // Don't add the size taken by *mMappedAttrs because it's shared.
+
+    n += aMallocSizeOf(mImpl.get());
+
+    for (const InternalAttr& attr : NonMappedAttrs()) {
+      n += attr.mValue.SizeOfExcludingThis(aMallocSizeOf);
+    }
+  }
+
+  return n;
+}