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-rw-r--r--xpcom/ds/nsClassHashtable.h115
1 files changed, 115 insertions, 0 deletions
diff --git a/xpcom/ds/nsClassHashtable.h b/xpcom/ds/nsClassHashtable.h
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+++ b/xpcom/ds/nsClassHashtable.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 nsClassHashtable_h__
+#define nsClassHashtable_h__
+
+#include <utility>
+
+#include "mozilla/UniquePtr.h"
+#include "nsBaseHashtable.h"
+#include "nsHashKeys.h"
+
+/**
+ * Helper class that provides methods to wrap and unwrap the UserDataType.
+ */
+template <class T>
+class nsUniquePtrConverter {
+ public:
+ using UserDataType = T*;
+ using DataType = mozilla::UniquePtr<T>;
+
+ static UserDataType Unwrap(DataType& src) { return src.get(); }
+ static DataType Wrap(UserDataType&& src) { return DataType(std::move(src)); }
+ static DataType Wrap(const UserDataType& src) { return DataType(src); }
+};
+
+/**
+ * templated hashtable class maps keys to C++ object pointers.
+ * See nsBaseHashtable for complete declaration.
+ * @param KeyClass a wrapper-class for the hashtable key, see nsHashKeys.h
+ * for a complete specification.
+ * @param Class the class-type being wrapped
+ * @see nsInterfaceHashtable, nsClassHashtable
+ */
+template <class KeyClass, class T>
+class nsClassHashtable : public nsBaseHashtable<KeyClass, mozilla::UniquePtr<T>,
+ T*, nsUniquePtrConverter<T>> {
+ public:
+ typedef typename KeyClass::KeyType KeyType;
+ typedef T* UserDataType;
+ typedef nsBaseHashtable<KeyClass, mozilla::UniquePtr<T>, T*,
+ nsUniquePtrConverter<T>>
+ base_type;
+
+ using base_type::IsEmpty;
+ using base_type::Remove;
+
+ nsClassHashtable() = default;
+ explicit nsClassHashtable(uint32_t aInitLength) : base_type(aInitLength) {}
+
+ /**
+ * @copydoc nsBaseHashtable::Get
+ * @param aData if the key doesn't exist, pData will be set to nullptr.
+ */
+ bool Get(KeyType aKey, UserDataType* aData) const;
+
+ /**
+ * @copydoc nsBaseHashtable::Get
+ * @returns nullptr if the key is not present.
+ */
+ [[nodiscard]] UserDataType Get(KeyType aKey) const;
+};
+
+template <typename K, typename T>
+inline void ImplCycleCollectionUnlink(nsClassHashtable<K, T>& aField) {
+ aField.Clear();
+}
+
+template <typename K, typename T>
+inline void ImplCycleCollectionTraverse(
+ nsCycleCollectionTraversalCallback& aCallback,
+ const nsClassHashtable<K, T>& aField, const char* aName,
+ uint32_t aFlags = 0) {
+ for (auto iter = aField.ConstIter(); !iter.Done(); iter.Next()) {
+ ImplCycleCollectionTraverse(aCallback, *iter.UserData(), aName, aFlags);
+ }
+}
+
+//
+// nsClassHashtable definitions
+//
+
+template <class KeyClass, class T>
+bool nsClassHashtable<KeyClass, T>::Get(KeyType aKey, T** aRetVal) const {
+ typename base_type::EntryType* ent = this->GetEntry(aKey);
+
+ if (ent) {
+ if (aRetVal) {
+ *aRetVal = ent->GetData().get();
+ }
+
+ return true;
+ }
+
+ if (aRetVal) {
+ *aRetVal = nullptr;
+ }
+
+ return false;
+}
+
+template <class KeyClass, class T>
+T* nsClassHashtable<KeyClass, T>::Get(KeyType aKey) const {
+ typename base_type::EntryType* ent = this->GetEntry(aKey);
+ if (!ent) {
+ return nullptr;
+ }
+
+ return ent->GetData().get();
+}
+
+#endif // nsClassHashtable_h__