xpcom/glue/nsJSThingHashtable.h@97036ab72558 (annotated)
xpcom/glue/nsJSThingHashtable.h
Tue, 06 Jan 2015 21:39:09 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Tue, 06 Jan 2015 21:39:09 +0100
- branch
- TOR_BUG_9701
- changeset 8
- 97036ab72558
- permissions
- -rw-r--r--
Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.
| michael@0 | 1 | /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ |
| michael@0 | 2 | /* This Source Code Form is subject to the terms of the Mozilla Public |
| michael@0 | 3 | * License, v. 2.0. If a copy of the MPL was not distributed with this |
| michael@0 | 4 | * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ |
| michael@0 | 5 | |
| michael@0 | 6 | #ifndef nsJSThingHashtable_h__ |
| michael@0 | 7 | #define nsJSThingHashtable_h__ |
| michael@0 | 8 | |
| michael@0 | 9 | #include "nsHashKeys.h" |
| michael@0 | 10 | #include "nsBaseHashtable.h" |
| michael@0 | 11 | |
| michael@0 | 12 | namespace JS { |
| michael@0 | 13 | template <class T> |
| michael@0 | 14 | class Heap; |
| michael@0 | 15 | } /* namespace JS */ |
| michael@0 | 16 | |
| michael@0 | 17 | /** |
| michael@0 | 18 | * A wrapper for hash keys that sets ALLOW_MEMMOVE to false. |
| michael@0 | 19 | * |
| michael@0 | 20 | * This is used in the implementation of nsJSThingHashtable and is not intended |
| michael@0 | 21 | * to be used directly. |
| michael@0 | 22 | * |
| michael@0 | 23 | * It is necessary for hash tables containing JS::Heap<T> values as these must |
| michael@0 | 24 | * be copied rather than memmoved. |
| michael@0 | 25 | */ |
| michael@0 | 26 | template<class T> |
| michael@0 | 27 | class nsHashKeyDisallowMemmove : public T |
| michael@0 | 28 | { |
| michael@0 | 29 | public: |
| michael@0 | 30 | nsHashKeyDisallowMemmove(const T& key) : T(key) {} |
| michael@0 | 31 | enum { ALLOW_MEMMOVE = false }; |
| michael@0 | 32 | }; |
| michael@0 | 33 | |
| michael@0 | 34 | |
| michael@0 | 35 | /** |
| michael@0 | 36 | * Templated hashtable class for use on the heap where the values are JS GC things. |
| michael@0 | 37 | * |
| michael@0 | 38 | * Storing JS GC thing pointers on the heap requires wrapping them in a |
| michael@0 | 39 | * JS::Heap<T>, and this class takes care of that while presenting an interface |
| michael@0 | 40 | * in terms of the wrapped type T. |
| michael@0 | 41 | * |
| michael@0 | 42 | * For example, to store a hashtable mapping strings to JSObject pointers, you |
| michael@0 | 43 | * can declare a data member like this: |
| michael@0 | 44 | * |
| michael@0 | 45 | * nsJSThingHashtable<nsStringHashKey, JSObject*> mStringToObjectMap; |
| michael@0 | 46 | * |
| michael@0 | 47 | * See nsBaseHashtable for complete declaration |
| michael@0 | 48 | * @param KeyClass a wrapper-class for the hashtable key, see nsHashKeys.h |
| michael@0 | 49 | * for a complete specification. |
| michael@0 | 50 | * @param DataType the datatype being wrapped, must be a JS GC thing. |
| michael@0 | 51 | * @see nsInterfaceHashtable, nsClassHashtable |
| michael@0 | 52 | */ |
| michael@0 | 53 | template<class KeyClass,class DataType> |
| michael@0 | 54 | class nsJSThingHashtable : |
| michael@0 | 55 | public nsBaseHashtable<nsHashKeyDisallowMemmove<KeyClass>, JS::Heap<DataType>, DataType> |
| michael@0 | 56 | { }; |
| michael@0 | 57 | |
| michael@0 | 58 | #endif // nsJSThingHashtable_h__ |
