1 files changed, 70 insertions, 0 deletions
diff --git a/xpcom/ds/nsTHashMap.h b/xpcom/ds/nsTHashMap.h
new file mode 100644
index 0000000000..8357d2ae7b
--- /dev/null
+++ b/xpcom/ds/nsTHashMap.h
@@ -0,0 +1,70 @@
+/* -*- 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 XPCOM_DS_NSTHASHMAP_H_
+#define XPCOM_DS_NSTHASHMAP_H_
+
+#include "mozilla/Attributes.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/UniquePtr.h"
+#include "nsBaseHashtable.h"
+#include "nsCOMPtr.h"
+#include "nsHashKeys.h"
+#include "nsHashtablesFwd.h"
+#include <type_traits>
+
+namespace mozilla::detail {
+template <class KeyType>
+struct nsKeyClass<
+    KeyType, std::enable_if_t<sizeof(KeyType) &&
+                              std::is_base_of_v<PLDHashEntryHdr, KeyType>>> {
+  using type = KeyType;
+};
+
+template <typename KeyType>
+struct nsKeyClass<KeyType*> {
+  using type = nsPtrHashKey<KeyType>;
+};
+
+template <>
+struct nsKeyClass<nsCString> {
+  using type = nsCStringHashKey;
+};
+
+// This uses the case-sensitive hash key class, if you want the
+// case-insensitive hash key, use nsStringCaseInsensitiveHashKey explicitly.
+template <>
+struct nsKeyClass<nsString> {
+  using type = nsStringHashKey;
+};
+
+template <typename KeyType>
+struct nsKeyClass<KeyType, std::enable_if_t<std::is_integral_v<KeyType> ||
+                                            std::is_enum_v<KeyType>>> {
+  using type = nsIntegralHashKey<KeyType>;
+};
+
+template <>
+struct nsKeyClass<nsCOMPtr<nsISupports>> {
+  using type = nsISupportsHashKey;
+};
+
+template <typename T>
+struct nsKeyClass<RefPtr<T>> {
+  using type = nsRefPtrHashKey<T>;
+};
+
+template <>
+struct nsKeyClass<nsID> {
+  using type = nsIDHashKey;
+};
+
+}  // namespace mozilla::detail
+
+// The actual definition of nsTHashMap is in nsHashtablesFwd.h, since it is a
+// type alias.
+
+#endif  // XPCOM_DS_NSTHASHMAP_H_