tor-browser

The Tor Browser
git clone https://git.dasho.dev/tor-browser.git
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WeakMapPtr.cpp (2987B)

      1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
      2 * vim: set ts=8 sts=2 et sw=2 tw=80:
      3 * This Source Code Form is subject to the terms of the Mozilla Public
      4 * License, v. 2.0. If a copy of the MPL was not distributed with this
      5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
      6 
      7 #include "js/WeakMapPtr.h"
      8 
      9 #include "gc/WeakMap-inl.h"
     10 
     11 //
     12 // Machinery for the externally-linkable JS::WeakMapPtr, which wraps js::WeakMap
     13 // for a few public data types.
     14 //
     15 
     16 using namespace js;
     17 
     18 namespace WeakMapDetails {
     19 
     20 template <typename T>
     21 struct DataType {};
     22 
     23 template <>
     24 struct DataType<JSObject*> {
     25  static JSObject* NullValue() { return nullptr; }
     26 };
     27 
     28 template <>
     29 struct DataType<JS::Value> {
     30  static JS::Value NullValue() { return JS::UndefinedValue(); }
     31 };
     32 
     33 template <typename K, typename V>
     34 struct Utils {
     35  using KeyType = K;
     36  using ValueType = V;
     37  using Type = WeakMap<KeyType, ValueType, ZoneAllocPolicy>;
     38  using PtrType = Type*;
     39  static PtrType cast(void* ptr) { return static_cast<PtrType>(ptr); }
     40 };
     41 
     42 }  // namespace WeakMapDetails
     43 
     44 template <typename K, typename V>
     45 void JS::WeakMapPtr<K, V>::destroy() {
     46  MOZ_ASSERT(initialized());
     47  js_delete(WeakMapDetails::Utils<K, V>::cast(ptr));
     48  ptr = nullptr;
     49 }
     50 
     51 template <typename K, typename V>
     52 bool JS::WeakMapPtr<K, V>::init(JSContext* cx) {
     53  MOZ_ASSERT(!initialized());
     54  typename WeakMapDetails::Utils<K, V>::PtrType map =
     55      cx->new_<typename WeakMapDetails::Utils<K, V>::Type>(cx);
     56  if (!map) {
     57    return false;
     58  }
     59  ptr = map;
     60  return true;
     61 }
     62 
     63 template <typename K, typename V>
     64 void JS::WeakMapPtr<K, V>::trace(JSTracer* trc) {
     65  MOZ_ASSERT(initialized());
     66  return WeakMapDetails::Utils<K, V>::cast(ptr)->trace(trc);
     67 }
     68 
     69 template <typename K, typename V>
     70 V JS::WeakMapPtr<K, V>::lookup(const K& key) {
     71  MOZ_ASSERT(initialized());
     72  typename WeakMapDetails::Utils<K, V>::Type::Ptr result =
     73      WeakMapDetails::Utils<K, V>::cast(ptr)->lookup(key);
     74  if (!result) {
     75    return WeakMapDetails::DataType<V>::NullValue();
     76  }
     77  return result->value();
     78 }
     79 
     80 template <typename K, typename V>
     81 bool JS::WeakMapPtr<K, V>::put(JSContext* cx, const K& key, const V& value) {
     82  MOZ_ASSERT(initialized());
     83  return WeakMapDetails::Utils<K, V>::cast(ptr)->put(key, value);
     84 }
     85 
     86 template <typename K, typename V>
     87 V JS::WeakMapPtr<K, V>::removeValue(const K& key) {
     88  using Map = typename WeakMapDetails::Utils<K, V>::Type;
     89  using Ptr = typename Map::Ptr;
     90 
     91  MOZ_ASSERT(initialized());
     92 
     93  Map* map = WeakMapDetails::Utils<K, V>::cast(ptr);
     94  if (Ptr result = map->lookup(key)) {
     95    V value = result->value();
     96    map->remove(result);
     97    return value;
     98  }
     99  return WeakMapDetails::DataType<V>::NullValue();
    100 }
    101 
    102 //
    103 // Supported specializations of JS::WeakMap:
    104 //
    105 
    106 template class JS_PUBLIC_API JS::WeakMapPtr<JSObject*, JSObject*>;
    107 
    108 #ifdef DEBUG
    109 // Nobody's using this at the moment, but we want to make sure it compiles.
    110 template class JS_PUBLIC_API JS::WeakMapPtr<JSObject*, JS::Value>;
    111 #endif