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-rw-r--r--xpcom/glue/nsDataHashtable.h58
1 files changed, 58 insertions, 0 deletions
diff --git a/xpcom/glue/nsDataHashtable.h b/xpcom/glue/nsDataHashtable.h
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+++ b/xpcom/glue/nsDataHashtable.h
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+/* -*- 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::KeyType;
+ using typename BaseClass::EntryType;
+
+ nsDataHashtable() {}
+ explicit nsDataHashtable(uint32_t aInitLength)
+ : BaseClass(aInitLength)
+ {
+ }
+
+ /**
+ * 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(mozilla::Move(ent->mData));
+ this->RemoveEntry(ent);
+ }
+ return value;
+ }
+};
+
+#endif // nsDataHashtable_h__