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