1 files changed, 114 insertions, 0 deletions
diff --git a/js/src/gc/WeakMapPtr.cpp b/js/src/gc/WeakMapPtr.cpp
new file mode 100644
index 0000000000..f58fc52372
--- /dev/null
+++ b/js/src/gc/WeakMapPtr.cpp
@@ -0,0 +1,114 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set ts=8 sts=2 et sw=2 tw=80:
+ * 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/. */
+
+#include "js/WeakMapPtr.h"
+
+#include "gc/WeakMap-inl.h"
+
+//
+// Machinery for the externally-linkable JS::WeakMapPtr, which wraps js::WeakMap
+// for a few public data types.
+//
+
+using namespace js;
+
+namespace WeakMapDetails {
+
+template <typename T>
+struct DataType {};
+
+template <>
+struct DataType<JSObject*> {
+  using BarrieredType = HeapPtr<JSObject*>;
+  using HasherType = StableCellHasher<BarrieredType>;
+  static JSObject* NullValue() { return nullptr; }
+};
+
+template <>
+struct DataType<JS::Value> {
+  using BarrieredType = HeapPtr<Value>;
+  static JS::Value NullValue() { return JS::UndefinedValue(); }
+};
+
+template <typename K, typename V>
+struct Utils {
+  using KeyType = typename DataType<K>::BarrieredType;
+  using ValueType = typename DataType<V>::BarrieredType;
+  typedef WeakMap<KeyType, ValueType> Type;
+  using PtrType = Type*;
+  static PtrType cast(void* ptr) { return static_cast<PtrType>(ptr); }
+};
+
+}  // namespace WeakMapDetails
+
+template <typename K, typename V>
+void JS::WeakMapPtr<K, V>::destroy() {
+  MOZ_ASSERT(initialized());
+  js_delete(WeakMapDetails::Utils<K, V>::cast(ptr));
+  ptr = nullptr;
+}
+
+template <typename K, typename V>
+bool JS::WeakMapPtr<K, V>::init(JSContext* cx) {
+  MOZ_ASSERT(!initialized());
+  typename WeakMapDetails::Utils<K, V>::PtrType map =
+      cx->new_<typename WeakMapDetails::Utils<K, V>::Type>(cx);
+  if (!map) {
+    return false;
+  }
+  ptr = map;
+  return true;
+}
+
+template <typename K, typename V>
+void JS::WeakMapPtr<K, V>::trace(JSTracer* trc) {
+  MOZ_ASSERT(initialized());
+  return WeakMapDetails::Utils<K, V>::cast(ptr)->trace(trc);
+}
+
+template <typename K, typename V>
+V JS::WeakMapPtr<K, V>::lookup(const K& key) {
+  MOZ_ASSERT(initialized());
+  typename WeakMapDetails::Utils<K, V>::Type::Ptr result =
+      WeakMapDetails::Utils<K, V>::cast(ptr)->lookup(key);
+  if (!result) {
+    return WeakMapDetails::DataType<V>::NullValue();
+  }
+  return result->value();
+}
+
+template <typename K, typename V>
+bool JS::WeakMapPtr<K, V>::put(JSContext* cx, const K& key, const V& value) {
+  MOZ_ASSERT(initialized());
+  return WeakMapDetails::Utils<K, V>::cast(ptr)->put(key, value);
+}
+
+template <typename K, typename V>
+V JS::WeakMapPtr<K, V>::removeValue(const K& key) {
+  typedef typename WeakMapDetails::Utils<K, V>::Type Map;
+  using Ptr = typename Map::Ptr;
+
+  MOZ_ASSERT(initialized());
+
+  Map* map = WeakMapDetails::Utils<K, V>::cast(ptr);
+  if (Ptr result = map->lookup(key)) {
+    V value = result->value();
+    map->remove(result);
+    return value;
+  }
+  return WeakMapDetails::DataType<V>::NullValue();
+}
+
+//
+// Supported specializations of JS::WeakMap:
+//
+
+template class JS_PUBLIC_API JS::WeakMapPtr<JSObject*, JSObject*>;
+
+#ifdef DEBUG
+// Nobody's using this at the moment, but we want to make sure it compiles.
+template class JS_PUBLIC_API JS::WeakMapPtr<JSObject*, JS::Value>;
+#endif