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xpcom/glue/nsInterfaceHashtable.h@97036ab72558 (annotated)

xpcom/glue/nsInterfaceHashtable.h

Tue, 06 Jan 2015 21:39:09 +0100

author

Michael Schloh von Bennewitz <michael@schloh.com>

date

Tue, 06 Jan 2015 21:39:09 +0100

branch

TOR_BUG_9701

changeset 8

97036ab72558

permissions

-rw-r--r--

Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

michael@0	1	/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
michael@0	2	/* This Source Code Form is subject to the terms of the Mozilla Public
michael@0	3	* License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0	4	* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0	5
michael@0	6	#ifndef nsInterfaceHashtable_h__
michael@0	7	#define nsInterfaceHashtable_h__
michael@0	8
michael@0	9	#include "nsBaseHashtable.h"
michael@0	10	#include "nsHashKeys.h"
michael@0	11	#include "nsCOMPtr.h"
michael@0	12
michael@0	13	/**
michael@0	14	* templated hashtable class maps keys to interface pointers.
michael@0	15	* See nsBaseHashtable for complete declaration.
michael@0	16	* @param KeyClass a wrapper-class for the hashtable key, see nsHashKeys.h
michael@0	17	* for a complete specification.
michael@0	18	* @param Interface the interface-type being wrapped
michael@0	19	* @see nsDataHashtable, nsClassHashtable
michael@0	20	*/
michael@0	21	template<class KeyClass,class Interface>
michael@0	22	class nsInterfaceHashtable :
michael@0	23	public nsBaseHashtable< KeyClass, nsCOMPtr<Interface> , Interface* >
michael@0	24	{
michael@0	25	public:
michael@0	26	typedef typename KeyClass::KeyType KeyType;
michael@0	27	typedef Interface* UserDataType;
michael@0	28	typedef nsBaseHashtable< KeyClass, nsCOMPtr<Interface> , Interface* >
michael@0	29	base_type;
michael@0	30
michael@0	31	nsInterfaceHashtable()
michael@0	32	{
michael@0	33	}
michael@0	34	explicit nsInterfaceHashtable(uint32_t aInitSize)
michael@0	35	: nsBaseHashtable<KeyClass,nsCOMPtr<Interface>,Interface*>(aInitSize)
michael@0	36	{
michael@0	37	}
michael@0	38
michael@0	39	/**
michael@0	40	* @copydoc nsBaseHashtable::Get
michael@0	41	* @param pData This is an XPCOM getter, so pData is already_addrefed.
michael@0	42	* If the key doesn't exist, pData will be set to nullptr.
michael@0	43	*/
michael@0	44	bool Get(KeyType aKey, UserDataType* pData) const;
michael@0	45
michael@0	46	/**
michael@0	47	* @copydoc nsBaseHashtable::Get
michael@0	48	*/
michael@0	49	already_AddRefed<Interface> Get(KeyType aKey) const;
michael@0	50
michael@0	51	/**
michael@0	52	* Gets a weak reference to the hashtable entry.
michael@0	53	* @param aFound If not nullptr, will be set to true if the entry is found,
michael@0	54	* to false otherwise.
michael@0	55	* @return The entry, or nullptr if not found. Do not release this pointer!
michael@0	56	*/
michael@0	57	Interface* GetWeak(KeyType aKey, bool* aFound = nullptr) const;
michael@0	58	};
michael@0	59
michael@0	60	template <typename K, typename T>
michael@0	61	inline void
michael@0	62	ImplCycleCollectionUnlink(nsInterfaceHashtable<K, T>& aField)
michael@0	63	{
michael@0	64	aField.Clear();
michael@0	65	}
michael@0	66
michael@0	67	template <typename K, typename T>
michael@0	68	inline void
michael@0	69	ImplCycleCollectionTraverse(nsCycleCollectionTraversalCallback& aCallback,
michael@0	70	const nsInterfaceHashtable<K, T>& aField,
michael@0	71	const char* aName,
michael@0	72	uint32_t aFlags = 0)
michael@0	73	{
michael@0	74	nsBaseHashtableCCTraversalData userData(aCallback, aName, aFlags);
michael@0	75
michael@0	76	aField.EnumerateRead(ImplCycleCollectionTraverse_EnumFunc<typename K::KeyType,T*>,
michael@0	77	&userData);
michael@0	78	}
michael@0	79
michael@0	80	//
michael@0	81	// nsInterfaceHashtable definitions
michael@0	82	//
michael@0	83
michael@0	84	template<class KeyClass,class Interface>
michael@0	85	bool
michael@0	86	nsInterfaceHashtable<KeyClass,Interface>::Get
michael@0	87	(KeyType aKey, UserDataType* pInterface) const
michael@0	88	{
michael@0	89	typename base_type::EntryType* ent = this->GetEntry(aKey);
michael@0	90
michael@0	91	if (ent)
michael@0	92	{
michael@0	93	if (pInterface)
michael@0	94	{
michael@0	95	*pInterface = ent->mData;
michael@0	96
michael@0	97	NS_IF_ADDREF(*pInterface);
michael@0	98	}
michael@0	99
michael@0	100	return true;
michael@0	101	}
michael@0	102
michael@0	103	// if the key doesn't exist, set *pInterface to null
michael@0	104	// so that it is a valid XPCOM getter
michael@0	105	if (pInterface)
michael@0	106	*pInterface = nullptr;
michael@0	107
michael@0	108	return false;
michael@0	109	}
michael@0	110
michael@0	111	template<class KeyClass, class Interface>
michael@0	112	already_AddRefed<Interface>
michael@0	113	nsInterfaceHashtable<KeyClass,Interface>::Get(KeyType aKey) const
michael@0	114	{
michael@0	115	typename base_type::EntryType* ent = this->GetEntry(aKey);
michael@0	116	if (!ent)
michael@0	117	return nullptr;
michael@0	118
michael@0	119	nsCOMPtr<Interface> copy = ent->mData;
michael@0	120	return copy.forget();
michael@0	121	}
michael@0	122
michael@0	123	template<class KeyClass,class Interface>
michael@0	124	Interface*
michael@0	125	nsInterfaceHashtable<KeyClass,Interface>::GetWeak
michael@0	126	(KeyType aKey, bool* aFound) const
michael@0	127	{
michael@0	128	typename base_type::EntryType* ent = this->GetEntry(aKey);
michael@0	129
michael@0	130	if (ent)
michael@0	131	{
michael@0	132	if (aFound)
michael@0	133	*aFound = true;
michael@0	134
michael@0	135	return ent->mData;
michael@0	136	}
michael@0	137
michael@0	138	// Key does not exist, return nullptr and set aFound to false
michael@0	139	if (aFound)
michael@0	140	*aFound = false;
michael@0	141	return nullptr;
michael@0	142	}
michael@0	143
michael@0	144	#endif // nsInterfaceHashtable_h__