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author | Matt A. Tobin <mattatobin@localhost.localdomain> | 2018-02-02 04:16:08 -0500 |
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committer | Matt A. Tobin <mattatobin@localhost.localdomain> | 2018-02-02 04:16:08 -0500 |
commit | 5f8de423f190bbb79a62f804151bc24824fa32d8 (patch) | |
tree | 10027f336435511475e392454359edea8e25895d /xpcom/glue/nsBaseHashtable.h | |
parent | 49ee0794b5d912db1f95dce6eb52d781dc210db5 (diff) | |
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Add m-esr52 at 52.6.0
Diffstat (limited to 'xpcom/glue/nsBaseHashtable.h')
-rw-r--r-- | xpcom/glue/nsBaseHashtable.h | 270 |
1 files changed, 270 insertions, 0 deletions
diff --git a/xpcom/glue/nsBaseHashtable.h b/xpcom/glue/nsBaseHashtable.h new file mode 100644 index 000000000..f52df3dd1 --- /dev/null +++ b/xpcom/glue/nsBaseHashtable.h @@ -0,0 +1,270 @@ +/* -*- 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 nsBaseHashtable_h__ +#define nsBaseHashtable_h__ + +#include "mozilla/MemoryReporting.h" +#include "mozilla/Move.h" +#include "nsTHashtable.h" +#include "nsDebug.h" + +template<class KeyClass, class DataType, class UserDataType> +class nsBaseHashtable; // forward declaration + +/** + * the private nsTHashtable::EntryType class used by nsBaseHashtable + * @see nsTHashtable for the specification of this class + * @see nsBaseHashtable for template parameters + */ +template<class KeyClass, class DataType> +class nsBaseHashtableET : public KeyClass +{ +public: + DataType mData; + friend class nsTHashtable<nsBaseHashtableET<KeyClass, DataType>>; + +private: + typedef typename KeyClass::KeyType KeyType; + typedef typename KeyClass::KeyTypePointer KeyTypePointer; + + explicit nsBaseHashtableET(KeyTypePointer aKey); + nsBaseHashtableET(nsBaseHashtableET<KeyClass, DataType>&& aToMove); + ~nsBaseHashtableET(); +}; + +/** + * templated hashtable for simple data types + * This class manages simple data types that do not need construction or + * destruction. + * + * @param KeyClass a wrapper-class for the hashtable key, see nsHashKeys.h + * for a complete specification. + * @param DataType the datatype stored in the hashtable, + * for example, uint32_t or nsCOMPtr. If UserDataType is not the same, + * DataType must implicitly cast to UserDataType + * @param UserDataType the user sees, for example uint32_t or nsISupports* + */ +template<class KeyClass, class DataType, class UserDataType> +class nsBaseHashtable + : protected nsTHashtable<nsBaseHashtableET<KeyClass, DataType>> +{ + typedef mozilla::fallible_t fallible_t; + +public: + typedef typename KeyClass::KeyType KeyType; + typedef nsBaseHashtableET<KeyClass, DataType> EntryType; + + using nsTHashtable<EntryType>::Contains; + + nsBaseHashtable() {} + explicit nsBaseHashtable(uint32_t aInitLength) + : nsTHashtable<EntryType>(aInitLength) + { + } + + /** + * Return the number of entries in the table. + * @return number of entries + */ + uint32_t Count() const { return nsTHashtable<EntryType>::Count(); } + + /** + * retrieve the value for a key. + * @param aKey the key to retreive + * @param aData data associated with this key will be placed at this + * pointer. If you only need to check if the key exists, aData + * may be null. + * @return true if the key exists. If key does not exist, aData is not + * modified. + */ + bool Get(KeyType aKey, UserDataType* aData) const + { + EntryType* ent = this->GetEntry(aKey); + if (!ent) { + return false; + } + + if (aData) { + *aData = ent->mData; + } + + return true; + } + + /** + * Get the value, returning a zero-initialized POD or a default-initialized + * object if the entry is not present in the table. + * + * @param aKey the key to retrieve + * @return The found value, or UserDataType{} if no entry was found with the + * given key. + * @note If zero/default-initialized values are stored in the table, it is + * not possible to distinguish between such a value and a missing entry. + */ + UserDataType Get(KeyType aKey) const + { + EntryType* ent = this->GetEntry(aKey); + if (!ent) { + return UserDataType{}; + } + + return ent->mData; + } + + /** + * Add key to the table if not already present, and return a reference to its + * value. If key is not already in the table then the value is default + * constructed. + */ + DataType& GetOrInsert(const KeyType& aKey) + { + EntryType* ent = this->GetEntry(aKey); + if (ent) { + return ent->mData; + } + + ent = this->PutEntry(aKey); + return ent->mData; + } + + /** + * put a new value for the associated key + * @param aKey the key to put + * @param aData the new data + * @return always true, unless memory allocation failed + */ + void Put(KeyType aKey, const UserDataType& aData) + { + if (!Put(aKey, aData, mozilla::fallible)) { + NS_ABORT_OOM(this->mTable.EntrySize() * this->mTable.EntryCount()); + } + } + + MOZ_MUST_USE bool Put(KeyType aKey, const UserDataType& aData, + const fallible_t&) + { + EntryType* ent = this->PutEntry(aKey, mozilla::fallible); + if (!ent) { + return false; + } + + ent->mData = aData; + + return true; + } + + /** + * remove the data for the associated key + * @param aKey the key to remove from the hashtable + */ + void Remove(KeyType aKey) { this->RemoveEntry(aKey); } + + // This is an iterator that also allows entry removal. Example usage: + // + // for (auto iter = table.Iter(); !iter.Done(); iter.Next()) { + // const KeyType key = iter.Key(); + // const UserDataType data = iter.UserData(); + // // or + // const DataType& data = iter.Data(); + // // ... do stuff with |key| and/or |data| ... + // // ... possibly call iter.Remove() once ... + // } + // + class Iterator : public PLDHashTable::Iterator + { + public: + typedef PLDHashTable::Iterator Base; + + explicit Iterator(nsBaseHashtable* aTable) : Base(&aTable->mTable) {} + Iterator(Iterator&& aOther) : Base(aOther.mTable) {} + ~Iterator() {} + + KeyType Key() const { return static_cast<EntryType*>(Get())->GetKey(); } + UserDataType UserData() const + { + return static_cast<EntryType*>(Get())->mData; + } + DataType& Data() const { return static_cast<EntryType*>(Get())->mData; } + + private: + Iterator() = delete; + Iterator(const Iterator&) = delete; + Iterator& operator=(const Iterator&) = delete; + Iterator& operator=(const Iterator&&) = delete; + }; + + Iterator Iter() { return Iterator(this); } + + Iterator ConstIter() const + { + return Iterator(const_cast<nsBaseHashtable*>(this)); + } + + /** + * reset the hashtable, removing all entries + */ + void Clear() { nsTHashtable<EntryType>::Clear(); } + + /** + * Measure the size of the table's entry storage. The size of things pointed + * to by entries must be measured separately; hence the "Shallow" prefix. + * + * @param aMallocSizeOf the function used to measure heap-allocated blocks + * @return the summed size of the table's storage + */ + size_t ShallowSizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const + { + return this->mTable.ShallowSizeOfExcludingThis(aMallocSizeOf); + } + + /** + * Like ShallowSizeOfExcludingThis, but includes sizeof(*this). + */ + size_t ShallowSizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const + { + return aMallocSizeOf(this) + ShallowSizeOfExcludingThis(aMallocSizeOf); + } + + /** + * Swap the elements in this hashtable with the elements in aOther. + */ + void SwapElements(nsBaseHashtable& aOther) + { + nsTHashtable<EntryType>::SwapElements(aOther); + } + + +#ifdef DEBUG + using nsTHashtable<EntryType>::MarkImmutable; +#endif +}; + +// +// nsBaseHashtableET definitions +// + +template<class KeyClass, class DataType> +nsBaseHashtableET<KeyClass, DataType>::nsBaseHashtableET(KeyTypePointer aKey) + : KeyClass(aKey) + , mData() +{ +} + +template<class KeyClass, class DataType> +nsBaseHashtableET<KeyClass, DataType>::nsBaseHashtableET( + nsBaseHashtableET<KeyClass, DataType>&& aToMove) + : KeyClass(mozilla::Move(aToMove)) + , mData(mozilla::Move(aToMove.mData)) +{ +} + +template<class KeyClass, class DataType> +nsBaseHashtableET<KeyClass, DataType>::~nsBaseHashtableET() +{ +} + +#endif // nsBaseHashtable_h__ |