1 files changed, 66 insertions, 0 deletions
diff --git a/xpcom/ds/nsDataHashtable.h b/xpcom/ds/nsDataHashtable.h
new file mode 100644
index 0000000000..c2409cb896
--- /dev/null
+++ b/xpcom/ds/nsDataHashtable.h
@@ -0,0 +1,66 @@
+/* -*- 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 nsDataHashtable_h__
+#define nsDataHashtable_h__
+
+#include "nsHashKeys.h"
+#include "nsBaseHashtable.h"
+#include "mozilla/Maybe.h"
+
+/**
+ * templated hashtable class maps keys to simple datatypes.
+ * See nsBaseHashtable for complete declaration
+ * @param KeyClass a wrapper-class for the hashtable key, see nsHashKeys.h
+ *   for a complete specification.
+ * @param DataType the simple datatype being wrapped
+ * @see nsInterfaceHashtable, nsClassHashtable
+ */
+template <class KeyClass, class DataType>
+class nsDataHashtable : public nsBaseHashtable<KeyClass, DataType, DataType> {
+ private:
+  typedef nsBaseHashtable<KeyClass, DataType, DataType> BaseClass;
+
+ public:
+  using typename BaseClass::EntryType;
+  using typename BaseClass::KeyType;
+
+  nsDataHashtable() = default;
+  explicit nsDataHashtable(uint32_t aInitLength) : BaseClass(aInitLength) {}
+
+  /**
+   * Retrieve a reference to the value for a key.
+   *
+   * @param aKey the key to retrieve.
+   * @return a reference to the found value, or nullptr if no entry was found
+   * with the given key.
+   */
+  DataType* GetValue(KeyType aKey) {
+    if (EntryType* ent = this->GetEntry(aKey)) {
+      return ent->GetModifiableData();
+    }
+    return nullptr;
+  }
+
+  /**
+   * Retrieve the value for a key and remove the corresponding entry at
+   * the same time.
+   *
+   * @param aKey the key to retrieve and remove
+   * @return the found value, or Nothing if no entry was found with the
+   *   given key.
+   */
+  mozilla::Maybe<DataType> GetAndRemove(KeyType aKey) {
+    mozilla::Maybe<DataType> value;
+    if (EntryType* ent = this->GetEntry(aKey)) {
+      value.emplace(std::move(*ent->GetModifiableData()));
+      this->RemoveEntry(ent);
+    }
+    return value;
+  }
+};
+
+#endif  // nsDataHashtable_h__