1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/js/src/vm/WeakMapPtr.cpp Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,129 @@
1.4 +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
1.5 + * vim: set ts=8 sts=4 et sw=4 tw=99:
1.6 + * This Source Code Form is subject to the terms of the Mozilla Public
1.7 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.8 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.9 +
1.10 +#include "js/WeakMapPtr.h"
1.11 +
1.12 +#include "jsweakmap.h"
1.13 +
1.14 +//
1.15 +// Machinery for the externally-linkable JS::WeakMapPtr, which wraps js::WeakMap
1.16 +// for a few public data types.
1.17 +//
1.18 +
1.19 +using namespace js;
1.20 +
1.21 +namespace {
1.22 +
1.23 +template<typename T>
1.24 +struct DataType
1.25 +{
1.26 +};
1.27 +
1.28 +template<>
1.29 +struct DataType<JSObject*>
1.30 +{
1.31 + typedef EncapsulatedPtrObject Encapsulated;
1.32 + static JSObject *NullValue() { return nullptr; }
1.33 +};
1.34 +
1.35 +template<>
1.36 +struct DataType<JS::Value>
1.37 +{
1.38 + typedef EncapsulatedValue Encapsulated;
1.39 + static JS::Value NullValue() { return JS::UndefinedValue(); }
1.40 +};
1.41 +
1.42 +template <typename K, typename V>
1.43 +struct Utils
1.44 +{
1.45 + typedef typename DataType<K>::Encapsulated KeyType;
1.46 + typedef typename DataType<V>::Encapsulated ValueType;
1.47 + typedef WeakMap<KeyType, ValueType> Type;
1.48 + typedef Type* PtrType;
1.49 + static PtrType cast(void *ptr) { return static_cast<PtrType>(ptr); }
1.50 +};
1.51 +
1.52 +} /* namespace */
1.53 +
1.54 +template <typename K, typename V>
1.55 +void
1.56 +JS::WeakMapPtr<K, V>::destroy()
1.57 +{
1.58 + MOZ_ASSERT(initialized());
1.59 + auto map = Utils<K, V>::cast(ptr);
1.60 + // If this destruction happens mid-GC, we might be in the compartment's list
1.61 + // of known live weakmaps. If we are, remove ourselves before deleting.
1.62 + if (map->isInList())
1.63 + WeakMapBase::removeWeakMapFromList(map);
1.64 + map->check();
1.65 + js_delete(map);
1.66 + ptr = nullptr;
1.67 +}
1.68 +
1.69 +template <typename K, typename V>
1.70 +bool
1.71 +JS::WeakMapPtr<K, V>::init(JSContext *cx)
1.72 +{
1.73 + MOZ_ASSERT(!initialized());
1.74 + typename Utils<K, V>::PtrType map = cx->runtime()->new_<typename Utils<K,V>::Type>(cx);
1.75 + if (!map || !map->init())
1.76 + return false;
1.77 + ptr = map;
1.78 + return true;
1.79 +}
1.80 +
1.81 +template <typename K, typename V>
1.82 +void
1.83 +JS::WeakMapPtr<K, V>::trace(JSTracer *trc)
1.84 +{
1.85 + MOZ_ASSERT(initialized());
1.86 + return Utils<K, V>::cast(ptr)->trace(trc);
1.87 +}
1.88 +
1.89 +template <typename K, typename V>
1.90 +V
1.91 +JS::WeakMapPtr<K, V>::lookup(const K &key)
1.92 +{
1.93 + MOZ_ASSERT(initialized());
1.94 + typename Utils<K, V>::Type::Ptr result = Utils<K, V>::cast(ptr)->lookup(key);
1.95 + if (!result)
1.96 + return DataType<V>::NullValue();
1.97 + return result->value();
1.98 +}
1.99 +
1.100 +template <typename K, typename V>
1.101 +/* static */ void
1.102 +JS::WeakMapPtr<K, V>::keyMarkCallback(JSTracer *trc, K key, void *data)
1.103 +{
1.104 + auto map = static_cast< JS::WeakMapPtr<K, V>* >(data);
1.105 + K prior = key;
1.106 + JS_CallObjectTracer(trc, &key, "WeakMapPtr key");
1.107 + return Utils<K, V>::cast(map->ptr)->rekeyIfMoved(prior, key);
1.108 +}
1.109 +
1.110 +template <typename K, typename V>
1.111 +bool
1.112 +JS::WeakMapPtr<K, V>::put(JSContext *cx, const K &key, const V &value)
1.113 +{
1.114 + MOZ_ASSERT(initialized());
1.115 + if (!Utils<K, V>::cast(ptr)->put(key, value))
1.116 + return false;
1.117 + JS_StoreObjectPostBarrierCallback(cx, keyMarkCallback, key, this);
1.118 + // Values do not need to be barriered because only put() is supported,
1.119 + // which is always an initializing write.
1.120 + return true;
1.121 +}
1.122 +
1.123 +//
1.124 +// Supported specializations of JS::WeakMap:
1.125 +//
1.126 +
1.127 +template class JS::WeakMapPtr<JSObject*, JSObject*>;
1.128 +
1.129 +#ifdef DEBUG
1.130 +// Nobody's using this at the moment, but we want to make sure it compiles.
1.131 +template class JS::WeakMapPtr<JSObject*, JS::Value>;
1.132 +#endif
