michael@0: /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #ifndef nsRefPtrHashtable_h__
michael@0: #define nsRefPtrHashtable_h__
michael@0: 
michael@0: #include "nsBaseHashtable.h"
michael@0: #include "nsHashKeys.h"
michael@0: #include "nsAutoPtr.h"
michael@0: 
michael@0: /**
michael@0:  * templated hashtable class maps keys to reference pointers.
michael@0:  * See nsBaseHashtable for complete declaration.
michael@0:  * @param KeyClass a wrapper-class for the hashtable key, see nsHashKeys.h
michael@0:  *   for a complete specification.
michael@0:  * @param RefPtr the reference-type being wrapped
michael@0:  * @see nsDataHashtable, nsClassHashtable
michael@0:  */
michael@0: template<class KeyClass, class RefPtr>
michael@0: class nsRefPtrHashtable :
michael@0:   public nsBaseHashtable< KeyClass, nsRefPtr<RefPtr> , RefPtr* >
michael@0: {
michael@0: public:
michael@0:   typedef typename KeyClass::KeyType KeyType;
michael@0:   typedef RefPtr* UserDataType;
michael@0:   typedef nsBaseHashtable< KeyClass, nsRefPtr<RefPtr> , RefPtr* > base_type;
michael@0: 
michael@0:   nsRefPtrHashtable()
michael@0:   {
michael@0:   }
michael@0:   explicit nsRefPtrHashtable(uint32_t aInitSize)
michael@0:     : nsBaseHashtable<KeyClass,nsRefPtr<RefPtr>,RefPtr*>(aInitSize)
michael@0:   {
michael@0:   }
michael@0: 
michael@0:   /**
michael@0:    * @copydoc nsBaseHashtable::Get
michael@0:    * @param pData This is an XPCOM getter, so pData is already_addrefed.
michael@0:    *   If the key doesn't exist, pData will be set to nullptr.
michael@0:    */
michael@0:   bool Get(KeyType aKey, UserDataType* pData) const;
michael@0: 
michael@0:   /**
michael@0:    * Gets a weak reference to the hashtable entry.
michael@0:    * @param aFound If not nullptr, will be set to true if the entry is found,
michael@0:    *               to false otherwise.
michael@0:    * @return The entry, or nullptr if not found. Do not release this pointer!
michael@0:    */
michael@0:   RefPtr* GetWeak(KeyType aKey, bool* aFound = nullptr) const;
michael@0: 
michael@0:   // Overload Remove, rather than overriding it.
michael@0:   using base_type::Remove;
michael@0: 
michael@0:   /**
michael@0:    * Remove the data for the associated key, swapping the current value into
michael@0:    * pData, thereby avoiding calls to AddRef and Release.
michael@0:    * @param aKey the key to remove from the hashtable
michael@0:    * @param pData This is an XPCOM getter, so pData is already_addrefed.
michael@0:    *   If the key doesn't exist, pData will be set to nullptr. Must be non-null.
michael@0:    */
michael@0:   bool Remove(KeyType aKey, UserDataType* pData);
michael@0: };
michael@0: 
michael@0: template <typename K, typename T>
michael@0: inline void
michael@0: ImplCycleCollectionUnlink(nsRefPtrHashtable<K, T>& aField)
michael@0: {
michael@0:   aField.Clear();
michael@0: }
michael@0: 
michael@0: template <typename K, typename T>
michael@0: inline void
michael@0: ImplCycleCollectionTraverse(nsCycleCollectionTraversalCallback& aCallback,
michael@0:                             nsRefPtrHashtable<K, T>& aField,
michael@0:                             const char* aName,
michael@0:                             uint32_t aFlags = 0)
michael@0: {
michael@0:   nsBaseHashtableCCTraversalData userData(aCallback, aName, aFlags);
michael@0: 
michael@0:   aField.EnumerateRead(ImplCycleCollectionTraverse_EnumFunc<typename K::KeyType,T*>,
michael@0:                        &userData);
michael@0: }
michael@0: 
michael@0: //
michael@0: // nsRefPtrHashtable definitions
michael@0: //
michael@0: 
michael@0: template<class KeyClass, class RefPtr>
michael@0: bool
michael@0: nsRefPtrHashtable<KeyClass,RefPtr>::Get
michael@0:   (KeyType aKey, UserDataType* pRefPtr) const
michael@0: {
michael@0:   typename base_type::EntryType* ent = this->GetEntry(aKey);
michael@0: 
michael@0:   if (ent) {
michael@0:     if (pRefPtr) {
michael@0:       *pRefPtr = ent->mData;
michael@0: 
michael@0:       NS_IF_ADDREF(*pRefPtr);
michael@0:     }
michael@0: 
michael@0:     return true;
michael@0:   }
michael@0: 
michael@0:   // if the key doesn't exist, set *pRefPtr to null
michael@0:   // so that it is a valid XPCOM getter
michael@0:   if (pRefPtr) {
michael@0:     *pRefPtr = nullptr;
michael@0:   }
michael@0: 
michael@0:   return false;
michael@0: }
michael@0: 
michael@0: template<class KeyClass, class RefPtr>
michael@0: RefPtr*
michael@0: nsRefPtrHashtable<KeyClass,RefPtr>::GetWeak
michael@0:   (KeyType aKey, bool* aFound) const
michael@0: {
michael@0:   typename base_type::EntryType* ent = this->GetEntry(aKey);
michael@0: 
michael@0:   if (ent) {
michael@0:     if (aFound) {
michael@0:       *aFound = true;
michael@0:     }
michael@0: 
michael@0:     return ent->mData;
michael@0:   }
michael@0: 
michael@0:   // Key does not exist, return nullptr and set aFound to false
michael@0:   if (aFound) {
michael@0:     *aFound = false;
michael@0:   }
michael@0: 
michael@0:   return nullptr;
michael@0: }
michael@0: 
michael@0: template<class KeyClass, class RefPtr>
michael@0: bool
michael@0: nsRefPtrHashtable<KeyClass,RefPtr>::Remove(KeyType aKey,
michael@0:                                            UserDataType* pRefPtr)
michael@0: {
michael@0:   MOZ_ASSERT(pRefPtr);
michael@0:   typename base_type::EntryType* ent = this->GetEntry(aKey);
michael@0: 
michael@0:   if (ent) {
michael@0:     ent->mData.forget(pRefPtr);
michael@0:     this->Remove(aKey);
michael@0:     return true;
michael@0:   }
michael@0: 
michael@0:   // If the key doesn't exist, set *pRefPtr to null
michael@0:   // so that it is a valid XPCOM getter.
michael@0:   *pRefPtr = nullptr;
michael@0:   return false;
michael@0: }
michael@0: 
michael@0: #endif // nsRefPtrHashtable_h__