The Tor Browser / file comparison
comparison: xpcom/glue/nsJSThingHashtable.h
xpcom/glue/nsJSThingHashtable.h
- branch
- TOR_BUG_9701
- changeset 8
- 97036ab72558
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| -1:000000000000 | 0:2f650c981739 |
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| 1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ | |
| 2 /* This Source Code Form is subject to the terms of the Mozilla Public | |
| 3 * License, v. 2.0. If a copy of the MPL was not distributed with this | |
| 4 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ | |
| 5 | |
| 6 #ifndef nsJSThingHashtable_h__ | |
| 7 #define nsJSThingHashtable_h__ | |
| 8 | |
| 9 #include "nsHashKeys.h" | |
| 10 #include "nsBaseHashtable.h" | |
| 11 | |
| 12 namespace JS { | |
| 13 template <class T> | |
| 14 class Heap; | |
| 15 } /* namespace JS */ | |
| 16 | |
| 17 /** | |
| 18 * A wrapper for hash keys that sets ALLOW_MEMMOVE to false. | |
| 19 * | |
| 20 * This is used in the implementation of nsJSThingHashtable and is not intended | |
| 21 * to be used directly. | |
| 22 * | |
| 23 * It is necessary for hash tables containing JS::Heap<T> values as these must | |
| 24 * be copied rather than memmoved. | |
| 25 */ | |
| 26 template<class T> | |
| 27 class nsHashKeyDisallowMemmove : public T | |
| 28 { | |
| 29 public: | |
| 30 nsHashKeyDisallowMemmove(const T& key) : T(key) {} | |
| 31 enum { ALLOW_MEMMOVE = false }; | |
| 32 }; | |
| 33 | |
| 34 | |
| 35 /** | |
| 36 * Templated hashtable class for use on the heap where the values are JS GC things. | |
| 37 * | |
| 38 * Storing JS GC thing pointers on the heap requires wrapping them in a | |
| 39 * JS::Heap<T>, and this class takes care of that while presenting an interface | |
| 40 * in terms of the wrapped type T. | |
| 41 * | |
| 42 * For example, to store a hashtable mapping strings to JSObject pointers, you | |
| 43 * can declare a data member like this: | |
| 44 * | |
| 45 * nsJSThingHashtable<nsStringHashKey, JSObject*> mStringToObjectMap; | |
| 46 * | |
| 47 * See nsBaseHashtable for complete declaration | |
| 48 * @param KeyClass a wrapper-class for the hashtable key, see nsHashKeys.h | |
| 49 * for a complete specification. | |
| 50 * @param DataType the datatype being wrapped, must be a JS GC thing. | |
| 51 * @see nsInterfaceHashtable, nsClassHashtable | |
| 52 */ | |
| 53 template<class KeyClass,class DataType> | |
| 54 class nsJSThingHashtable : | |
| 55 public nsBaseHashtable<nsHashKeyDisallowMemmove<KeyClass>, JS::Heap<DataType>, DataType> | |
| 56 { }; | |
| 57 | |
| 58 #endif // nsJSThingHashtable_h__ |
