1 files changed, 222 insertions, 0 deletions
diff --git a/dom/base/nsAttrAndChildArray.h b/dom/base/nsAttrAndChildArray.h
new file mode 100644
index 000000000..f34370c43
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+++ b/dom/base/nsAttrAndChildArray.h
@@ -0,0 +1,222 @@
+/* -*- 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.
+ */
+
+#ifndef nsAttrAndChildArray_h___
+#define nsAttrAndChildArray_h___
+
+#include "mozilla/Attributes.h"
+#include "mozilla/MemoryReporting.h"
+#include "mozilla/dom/BorrowedAttrInfo.h"
+
+#include "nscore.h"
+#include "nsAttrName.h"
+#include "nsAttrValue.h"
+#include "nsCaseTreatment.h"
+
+class nsINode;
+class nsIContent;
+class nsMappedAttributes;
+class nsHTMLStyleSheet;
+class nsRuleWalker;
+class nsMappedAttributeElement;
+
+#define ATTRCHILD_ARRAY_GROWSIZE 8
+#define ATTRCHILD_ARRAY_LINEAR_THRESHOLD 32
+
+#define ATTRCHILD_ARRAY_ATTR_SLOTS_BITS 10
+
+#define ATTRCHILD_ARRAY_MAX_ATTR_COUNT \
+    ((1 << ATTRCHILD_ARRAY_ATTR_SLOTS_BITS) - 1)
+
+#define ATTRCHILD_ARRAY_MAX_CHILD_COUNT \
+    (~uint32_t(0) >> ATTRCHILD_ARRAY_ATTR_SLOTS_BITS)
+
+#define ATTRCHILD_ARRAY_ATTR_SLOTS_COUNT_MASK \
+    ((1 << ATTRCHILD_ARRAY_ATTR_SLOTS_BITS) - 1)
+
+
+#define ATTRSIZE (sizeof(InternalAttr) / sizeof(void*))
+
+class nsAttrAndChildArray
+{
+  typedef mozilla::dom::BorrowedAttrInfo BorrowedAttrInfo;
+public:
+  nsAttrAndChildArray();
+  ~nsAttrAndChildArray();
+
+  uint32_t ChildCount() const
+  {
+    return mImpl ? (mImpl->mAttrAndChildCount >> ATTRCHILD_ARRAY_ATTR_SLOTS_BITS) : 0;
+  }
+  nsIContent* ChildAt(uint32_t aPos) const
+  {
+    NS_ASSERTION(aPos < ChildCount(), "out-of-bounds access in nsAttrAndChildArray");
+    return reinterpret_cast<nsIContent*>(mImpl->mBuffer[AttrSlotsSize() + aPos]);
+  }
+  nsIContent* GetSafeChildAt(uint32_t aPos) const;
+  nsIContent * const * GetChildArray(uint32_t* aChildCount) const;
+  nsresult AppendChild(nsIContent* aChild)
+  {
+    return InsertChildAt(aChild, ChildCount());
+  }
+  nsresult InsertChildAt(nsIContent* aChild, uint32_t aPos);
+  void RemoveChildAt(uint32_t aPos);
+  // Like RemoveChildAt but hands the reference to the child being
+  // removed back to the caller instead of just releasing it.
+  already_AddRefed<nsIContent> TakeChildAt(uint32_t aPos);
+  int32_t IndexOfChild(const nsINode* aPossibleChild) const;
+
+  bool HasAttrs() const
+  {
+    return MappedAttrCount() || (AttrSlotCount() && AttrSlotIsTaken(0));
+  }
+
+  uint32_t AttrCount() const;
+  const nsAttrValue* GetAttr(nsIAtom* aLocalName,
+                             int32_t aNamespaceID = kNameSpaceID_None) const;
+  // As above but using a string attr name and always using
+  // kNameSpaceID_None.  This is always case-sensitive.
+  const nsAttrValue* GetAttr(const nsAString& aName) const;
+  // Get an nsAttrValue by qualified name.  Can optionally do
+  // ASCII-case-insensitive name matching.
+  const nsAttrValue* GetAttr(const nsAString& aName,
+                             nsCaseTreatment aCaseSensitive) const;
+  const nsAttrValue* AttrAt(uint32_t aPos) const;
+  // SetAndSwapAttr swaps the current attribute value with aValue.
+  nsresult SetAndSwapAttr(nsIAtom* aLocalName, nsAttrValue& aValue);
+  nsresult SetAndSwapAttr(mozilla::dom::NodeInfo* aName, nsAttrValue& aValue);
+
+  // Remove the attr at position aPos.  The value of the attr is placed in
+  // aValue; any value that was already in aValue is destroyed.
+  nsresult RemoveAttrAt(uint32_t aPos, nsAttrValue& aValue);
+
+  // Returns attribute name at given position, *not* out-of-bounds safe
+  const nsAttrName* AttrNameAt(uint32_t aPos) const;
+
+  // Returns the attribute info at a given position, *not* out-of-bounds safe
+  BorrowedAttrInfo AttrInfoAt(uint32_t aPos) const;
+
+  // Returns attribute name at given position or null if aPos is out-of-bounds
+  const nsAttrName* GetSafeAttrNameAt(uint32_t aPos) const;
+
+  const nsAttrName* GetExistingAttrNameFromQName(const nsAString& aName) const;
+  int32_t IndexOfAttr(nsIAtom* aLocalName, int32_t aNamespaceID = kNameSpaceID_None) const;
+
+  nsresult SetAndTakeMappedAttr(nsIAtom* aLocalName, nsAttrValue& aValue,
+                                nsMappedAttributeElement* aContent,
+                                nsHTMLStyleSheet* aSheet);
+  nsresult SetMappedAttrStyleSheet(nsHTMLStyleSheet* aSheet) {
+    if (!mImpl || !mImpl->mMappedAttrs) {
+      return NS_OK;
+    }
+    return DoSetMappedAttrStyleSheet(aSheet);
+  }
+  void WalkMappedAttributeStyleRules(nsRuleWalker* aRuleWalker);
+
+  void Compact();
+
+  bool CanFitMoreAttrs() const
+  {
+    return AttrSlotCount() < ATTRCHILD_ARRAY_MAX_ATTR_COUNT ||
+           !AttrSlotIsTaken(ATTRCHILD_ARRAY_MAX_ATTR_COUNT - 1);
+  }
+
+  size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
+  bool HasMappedAttrs() const
+  {
+    return MappedAttrCount();
+  }
+
+private:
+  nsAttrAndChildArray(const nsAttrAndChildArray& aOther) = delete;
+  nsAttrAndChildArray& operator=(const nsAttrAndChildArray& aOther) = delete;
+
+  void Clear();
+
+  uint32_t NonMappedAttrCount() const;
+  uint32_t MappedAttrCount() const;
+
+  // Returns a non-null zero-refcount object.
+  nsMappedAttributes*
+  GetModifiableMapped(nsMappedAttributeElement* aContent,
+                      nsHTMLStyleSheet* aSheet,
+                      bool aWillAddAttr);
+  nsresult MakeMappedUnique(nsMappedAttributes* aAttributes);
+
+  uint32_t AttrSlotsSize() const
+  {
+    return AttrSlotCount() * ATTRSIZE;
+  }
+
+  uint32_t AttrSlotCount() const
+  {
+    return mImpl ? mImpl->mAttrAndChildCount & ATTRCHILD_ARRAY_ATTR_SLOTS_COUNT_MASK : 0;
+  }
+
+  bool AttrSlotIsTaken(uint32_t aSlot) const
+  {
+    NS_PRECONDITION(aSlot < AttrSlotCount(), "out-of-bounds");
+    return mImpl->mBuffer[aSlot * ATTRSIZE];
+  }
+
+  void SetChildCount(uint32_t aCount)
+  {
+    mImpl->mAttrAndChildCount =
+        (mImpl->mAttrAndChildCount & ATTRCHILD_ARRAY_ATTR_SLOTS_COUNT_MASK) |
+        (aCount << ATTRCHILD_ARRAY_ATTR_SLOTS_BITS);
+  }
+
+  void SetAttrSlotCount(uint32_t aCount)
+  {
+    mImpl->mAttrAndChildCount =
+        (mImpl->mAttrAndChildCount & ~ATTRCHILD_ARRAY_ATTR_SLOTS_COUNT_MASK) |
+        aCount;
+  }
+
+  void SetAttrSlotAndChildCount(uint32_t aSlotCount, uint32_t aChildCount)
+  {
+    mImpl->mAttrAndChildCount = aSlotCount |
+      (aChildCount << ATTRCHILD_ARRAY_ATTR_SLOTS_BITS);
+  }
+
+  bool GrowBy(uint32_t aGrowSize);
+  bool AddAttrSlot();
+
+  /**
+   * Set *aPos to aChild and update sibling pointers as needed.  aIndex is the
+   * index at which aChild is actually being inserted.  aChildCount is the
+   * number of kids we had before the insertion.
+   */
+  inline void SetChildAtPos(void** aPos, nsIContent* aChild, uint32_t aIndex,
+                            uint32_t aChildCount);
+
+  /**
+   * Guts of SetMappedAttrStyleSheet for the rare case when we have mapped attrs
+   */
+  nsresult DoSetMappedAttrStyleSheet(nsHTMLStyleSheet* aSheet);
+
+  struct InternalAttr
+  {
+    nsAttrName mName;
+    nsAttrValue mValue;
+  };
+
+  struct Impl {
+    uint32_t mAttrAndChildCount;
+    uint32_t mBufferSize;
+    nsMappedAttributes* mMappedAttrs;
+    void* mBuffer[1];
+  };
+
+  Impl* mImpl;
+};
+
+#endif