1 files changed, 60 insertions, 0 deletions
diff --git a/js/src/vm/PropertyKey.h b/js/src/vm/PropertyKey.h
new file mode 100644
index 0000000000..56e2cfea0c
--- /dev/null
+++ b/js/src/vm/PropertyKey.h
@@ -0,0 +1,60 @@
+/* -*- 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/. */
+
+#ifndef vm_PropertyKey_h
+#define vm_PropertyKey_h
+
+#include "mozilla/HashFunctions.h"  // mozilla::HashGeneric
+
+#include "NamespaceImports.h"  // js::PropertyKey
+
+#include "js/HashTable.h"   // js::DefaultHasher
+#include "js/Id.h"          // JS::PropertyKey
+#include "vm/StringType.h"  // JSAtom::hash
+#include "vm/SymbolType.h"  // JS::Symbol::hash
+
+namespace js {
+
+static MOZ_ALWAYS_INLINE HashNumber HashPropertyKey(PropertyKey key) {
+  // HashGeneric alone would work, but bits of atom and symbol addresses
+  // could then be recovered from the hash code. See bug 1330769.
+  if (MOZ_LIKELY(key.isAtom())) {
+    return key.toAtom()->hash();
+  }
+  if (key.isSymbol()) {
+    return key.toSymbol()->hash();
+  }
+  return mozilla::HashGeneric(key.asRawBits());
+}
+
+// Like HashPropertyKey but optimized for callers that only use atom or symbol
+// keys.
+static MOZ_ALWAYS_INLINE HashNumber
+HashAtomOrSymbolPropertyKey(PropertyKey key) {
+  if (MOZ_LIKELY(key.isAtom())) {
+    return key.toAtom()->hash();
+  }
+  return key.toSymbol()->hash();
+}
+
+}  // namespace js
+
+namespace mozilla {
+
+template <>
+struct DefaultHasher<JS::PropertyKey> {
+  using Lookup = JS::PropertyKey;
+  static HashNumber hash(JS::PropertyKey key) {
+    return js::HashPropertyKey(key);
+  }
+  static bool match(JS::PropertyKey key1, JS::PropertyKey key2) {
+    return key1 == key2;
+  }
+};
+
+}  // namespace mozilla
+
+#endif /* vm_PropertyKey_h */