1 files changed, 49 insertions, 0 deletions
diff --git a/xpcom/ds/nsPointerHashKeys.h b/xpcom/ds/nsPointerHashKeys.h
new file mode 100644
index 0000000000..0a4af3b2f8
--- /dev/null
+++ b/xpcom/ds/nsPointerHashKeys.h
@@ -0,0 +1,49 @@
+/* -*- 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/. */
+
+/* Definitions for nsPtrHashKey<T> and nsVoidPtrHashKey.  */
+
+#ifndef nsPointerHashKeys_h
+#define nsPointerHashKeys_h
+
+#include "nscore.h"
+
+#include "mozilla/Attributes.h"
+#include "mozilla/HashFunctions.h"
+
+#include "PLDHashTable.h"
+
+/**
+ * hashkey wrapper using T* KeyType
+ *
+ * @see nsTHashtable::EntryType for specification
+ */
+template <class T>
+class nsPtrHashKey : public PLDHashEntryHdr {
+ public:
+  using KeyType = T*;
+  using KeyTypePointer = const T*;
+
+  explicit nsPtrHashKey(const T* aKey) : mKey(const_cast<T*>(aKey)) {}
+  nsPtrHashKey(nsPtrHashKey&& aToMove) = default;
+  ~nsPtrHashKey() = default;
+
+  KeyType GetKey() const { return mKey; }
+  bool KeyEquals(KeyTypePointer aKey) const { return aKey == mKey; }
+
+  static KeyTypePointer KeyToPointer(KeyType aKey) { return aKey; }
+  static PLDHashNumber HashKey(KeyTypePointer aKey) {
+    return mozilla::HashGeneric(aKey);
+  }
+  enum { ALLOW_MEMMOVE = true };
+
+ protected:
+  T* MOZ_NON_OWNING_REF mKey;
+};
+
+using nsVoidPtrHashKey = nsPtrHashKey<const void>;
+
+#endif  // nsPointerHashKeys_h