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authorMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
committerMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
commit5f8de423f190bbb79a62f804151bc24824fa32d8 (patch)
tree10027f336435511475e392454359edea8e25895d /xpcom/glue/nsClassHashtable.h
parent49ee0794b5d912db1f95dce6eb52d781dc210db5 (diff)
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Add m-esr52 at 52.6.0
Diffstat (limited to 'xpcom/glue/nsClassHashtable.h')
-rw-r--r--xpcom/glue/nsClassHashtable.h140
1 files changed, 140 insertions, 0 deletions
diff --git a/xpcom/glue/nsClassHashtable.h b/xpcom/glue/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 "mozilla/Move.h"
+#include "nsBaseHashtable.h"
+#include "nsHashKeys.h"
+#include "nsAutoPtr.h"
+
+/**
+ * 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, nsAutoPtr<T>, T*>
+{
+public:
+ typedef typename KeyClass::KeyType KeyType;
+ typedef T* UserDataType;
+ typedef nsBaseHashtable<KeyClass, nsAutoPtr<T>, T*> base_type;
+
+ using base_type::IsEmpty;
+
+ nsClassHashtable() {}
+ explicit nsClassHashtable(uint32_t aInitLength)
+ : nsBaseHashtable<KeyClass, nsAutoPtr<T>, T*>(aInitLength)
+ {
+ }
+
+ /**
+ * Looks up aKey in the hash table. If it doesn't exist a new object of
+ * KeyClass will be created (using the arguments provided) and then returned.
+ */
+ template<typename... Args>
+ UserDataType LookupOrAdd(KeyType aKey, Args&&... aConstructionArgs);
+
+ /**
+ * @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.
+ */
+ UserDataType Get(KeyType aKey) const;
+
+ /**
+ * Remove the entry for the given key from the hashtable and return it in
+ * aOut. If the key is not in the hashtable, aOut's pointer is set to
+ * nullptr.
+ *
+ * Normally, an entry is deleted when it's removed from an nsClassHashtable,
+ * but this function transfers ownership of the entry back to the caller
+ * through aOut -- the entry will be deleted when aOut goes out of scope.
+ *
+ * @param aKey the key to get and remove from the hashtable
+ */
+ void RemoveAndForget(KeyType aKey, nsAutoPtr<T>& aOut);
+};
+
+//
+// nsClassHashtable definitions
+//
+
+template<class KeyClass, class T>
+template<typename... Args>
+T*
+nsClassHashtable<KeyClass, T>::LookupOrAdd(KeyType aKey,
+ Args&&... aConstructionArgs)
+{
+ typename base_type::EntryType* ent = this->PutEntry(aKey);
+ if (!ent->mData) {
+ ent->mData = new T(mozilla::Forward<Args>(aConstructionArgs)...);
+ }
+ return ent->mData;
+}
+
+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->mData;
+ }
+
+ 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->mData;
+}
+
+template<class KeyClass, class T>
+void
+nsClassHashtable<KeyClass, T>::RemoveAndForget(KeyType aKey, nsAutoPtr<T>& aOut)
+{
+ aOut = nullptr;
+
+ typename base_type::EntryType* ent = this->GetEntry(aKey);
+ if (!ent) {
+ return;
+ }
+
+ // Transfer ownership from ent->mData into aOut.
+ aOut = mozilla::Move(ent->mData);
+
+ this->Remove(aKey);
+}
+
+#endif // nsClassHashtable_h__