michael@0: /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: #ifndef nsContentIndexCache_h__
michael@0: #define nsContentIndexCache_h__
michael@0: 
michael@0: #include "js/HashTable.h"
michael@0: 
michael@0: class nsIContent;
michael@0: 
michael@0: namespace mozilla {
michael@0: namespace dom {
michael@0: class Element;
michael@0: } // namespace dom
michael@0: } // namespace mozilla
michael@0: 
michael@0: /*
michael@0:  * A class that computes and caches the indices used for :nth-* pseudo-class
michael@0:  * matching.
michael@0:  */
michael@0: 
michael@0: class nsNthIndexCache {
michael@0: private:
michael@0:   typedef mozilla::dom::Element Element;
michael@0: 
michael@0: public:
michael@0:   /**
michael@0:    * Constructor and destructor out of line so that we don't try to
michael@0:    * instantiate the hashtable template all over the place.
michael@0:    */
michael@0:   nsNthIndexCache();
michael@0:   ~nsNthIndexCache();
michael@0: 
michael@0:   // Returns a 1-based index of the child in its parent.  If the child
michael@0:   // is not in its parent's child list (i.e., it is anonymous content),
michael@0:   // returns 0.
michael@0:   // If aCheckEdgeOnly is true, the function will return 1 if the result
michael@0:   // is 1, and something other than 1 (maybe or maybe not a valid
michael@0:   // result) otherwise.
michael@0:   // This must only be called on nodes which have a non-null parent.
michael@0:   int32_t GetNthIndex(Element* aChild, bool aIsOfType, bool aIsFromEnd,
michael@0:                       bool aCheckEdgeOnly);
michael@0: 
michael@0:   void Reset();
michael@0: 
michael@0: private:
michael@0:   /**
michael@0:    * Returns true if aSibling and aElement should be considered in the same
michael@0:    * list for nth-index purposes, taking aIsOfType into account.
michael@0:    */
michael@0:   inline bool SiblingMatchesElement(nsIContent* aSibling, Element* aElement,
michael@0:                                     bool aIsOfType);
michael@0: 
michael@0:   // This node's index for this cache.
michael@0:   // If -2, needs to be computed.
michael@0:   // If -1, needs to be computed but known not to be 1.
michael@0:   // If 0, the node is not at any index in its parent.
michael@0:   typedef int32_t CacheEntry;
michael@0: 
michael@0:   class SystemAllocPolicy {
michael@0:   public:
michael@0:     void *malloc_(size_t bytes) { return ::malloc(bytes); }
michael@0:     void *calloc_(size_t bytes) { return ::calloc(bytes, 1); }
michael@0:     void *realloc_(void *p, size_t bytes) { return ::realloc(p, bytes); }
michael@0:     void free_(void *p) { ::free(p); }
michael@0:     void reportAllocOverflow() const {}
michael@0:   };
michael@0: 
michael@0:   typedef js::HashMap<nsIContent*, CacheEntry, js::DefaultHasher<nsIContent*>,
michael@0:                       SystemAllocPolicy> Cache;
michael@0: 
michael@0:   /**
michael@0:    * Returns true if aResult has been set to the correct value for aChild and
michael@0:    * no more work needs to be done.  Returns false otherwise.
michael@0:    *
michael@0:    * aResult is an inout parameter.  The in value is the number of elements
michael@0:    * that are in the half-open range (aSibling, aChild] (so including aChild
michael@0:    * but not including aSibling) that match aChild.  The out value is the
michael@0:    * correct index for aChild if this function returns true and the number of
michael@0:    * elements in the closed range [aSibling, aChild] that match aChild
michael@0:    * otherwise.
michael@0:    */
michael@0:   inline bool IndexDeterminedFromPreviousSibling(nsIContent* aSibling,
michael@0:                                                  Element* aChild,
michael@0:                                                  bool aIsOfType,
michael@0:                                                  bool aIsFromEnd,
michael@0:                                                  const Cache& aCache,
michael@0:                                                  int32_t& aResult);
michael@0: 
michael@0:   // Caches of indices for :nth-child(), :nth-last-child(),
michael@0:   // :nth-of-type(), :nth-last-of-type(), keyed by Element*.
michael@0:   //
michael@0:   // The first subscript is 0 for -child and 1 for -of-type, the second
michael@0:   // subscript is 0 for nth- and 1 for nth-last-.
michael@0:   Cache mCaches[2][2];
michael@0: };
michael@0: 
michael@0: #endif /* nsContentIndexCache_h__ */