1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/layout/style/nsNthIndexCache.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,99 @@
1.4 +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
1.5 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.6 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.7 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.8 +#ifndef nsContentIndexCache_h__
1.9 +#define nsContentIndexCache_h__
1.10 +
1.11 +#include "js/HashTable.h"
1.12 +
1.13 +class nsIContent;
1.14 +
1.15 +namespace mozilla {
1.16 +namespace dom {
1.17 +class Element;
1.18 +} // namespace dom
1.19 +} // namespace mozilla
1.20 +
1.21 +/*
1.22 + * A class that computes and caches the indices used for :nth-* pseudo-class
1.23 + * matching.
1.24 + */
1.25 +
1.26 +class nsNthIndexCache {
1.27 +private:
1.28 + typedef mozilla::dom::Element Element;
1.29 +
1.30 +public:
1.31 + /**
1.32 + * Constructor and destructor out of line so that we don't try to
1.33 + * instantiate the hashtable template all over the place.
1.34 + */
1.35 + nsNthIndexCache();
1.36 + ~nsNthIndexCache();
1.37 +
1.38 + // Returns a 1-based index of the child in its parent. If the child
1.39 + // is not in its parent's child list (i.e., it is anonymous content),
1.40 + // returns 0.
1.41 + // If aCheckEdgeOnly is true, the function will return 1 if the result
1.42 + // is 1, and something other than 1 (maybe or maybe not a valid
1.43 + // result) otherwise.
1.44 + // This must only be called on nodes which have a non-null parent.
1.45 + int32_t GetNthIndex(Element* aChild, bool aIsOfType, bool aIsFromEnd,
1.46 + bool aCheckEdgeOnly);
1.47 +
1.48 + void Reset();
1.49 +
1.50 +private:
1.51 + /**
1.52 + * Returns true if aSibling and aElement should be considered in the same
1.53 + * list for nth-index purposes, taking aIsOfType into account.
1.54 + */
1.55 + inline bool SiblingMatchesElement(nsIContent* aSibling, Element* aElement,
1.56 + bool aIsOfType);
1.57 +
1.58 + // This node's index for this cache.
1.59 + // If -2, needs to be computed.
1.60 + // If -1, needs to be computed but known not to be 1.
1.61 + // If 0, the node is not at any index in its parent.
1.62 + typedef int32_t CacheEntry;
1.63 +
1.64 + class SystemAllocPolicy {
1.65 + public:
1.66 + void *malloc_(size_t bytes) { return ::malloc(bytes); }
1.67 + void *calloc_(size_t bytes) { return ::calloc(bytes, 1); }
1.68 + void *realloc_(void *p, size_t bytes) { return ::realloc(p, bytes); }
1.69 + void free_(void *p) { ::free(p); }
1.70 + void reportAllocOverflow() const {}
1.71 + };
1.72 +
1.73 + typedef js::HashMap<nsIContent*, CacheEntry, js::DefaultHasher<nsIContent*>,
1.74 + SystemAllocPolicy> Cache;
1.75 +
1.76 + /**
1.77 + * Returns true if aResult has been set to the correct value for aChild and
1.78 + * no more work needs to be done. Returns false otherwise.
1.79 + *
1.80 + * aResult is an inout parameter. The in value is the number of elements
1.81 + * that are in the half-open range (aSibling, aChild] (so including aChild
1.82 + * but not including aSibling) that match aChild. The out value is the
1.83 + * correct index for aChild if this function returns true and the number of
1.84 + * elements in the closed range [aSibling, aChild] that match aChild
1.85 + * otherwise.
1.86 + */
1.87 + inline bool IndexDeterminedFromPreviousSibling(nsIContent* aSibling,
1.88 + Element* aChild,
1.89 + bool aIsOfType,
1.90 + bool aIsFromEnd,
1.91 + const Cache& aCache,
1.92 + int32_t& aResult);
1.93 +
1.94 + // Caches of indices for :nth-child(), :nth-last-child(),
1.95 + // :nth-of-type(), :nth-last-of-type(), keyed by Element*.
1.96 + //
1.97 + // The first subscript is 0 for -child and 1 for -of-type, the second
1.98 + // subscript is 0 for nth- and 1 for nth-last-.
1.99 + Cache mCaches[2][2];
1.100 +};
1.101 +
1.102 +#endif /* nsContentIndexCache_h__ */
