Base class for cache layer--will try a next cache and respond with the data to any previous cache layers so they can store that data as well. More...

#include <CacheLayer.hpp>

Inheritance diagram for Sirikata::Transfer::CacheLayer:

Collaboration diagram for Sirikata::Transfer::CacheLayer:

List of all members.

Classes
struct	CacheEntry
Public Member Functions
virtual	~CacheLayer ()
	CacheLayer (CacheLayer *tryNext)
	Constructor needs to know what cache layer to try next, and what to return to.
void	setRespondTo (CacheLayer *newRespond)
void	setNext (CacheLayer *newNext)
	If you want to change the ordering of the cache layers.
CacheLayer *	getNext () const
CacheLayer *	getResponder () const
void	addToCache (const Fingerprint &fileId, const DenseDataPtr &data)
virtual void	purgeFromCache (const Fingerprint &fileId)
	Purges this hash from all subsequent caches.
virtual void	getData (const Fingerprint &fileId, const Range &requestedRange, const TransferCallback &callback)
	Query this cache layer.
Protected Member Functions
void	populateParentCaches (const Fingerprint &fileId, const DenseDataPtr &data)
	Goes up the heirararchy of cache layers filling in data.
virtual void	destroyCacheEntry (const Fingerprint &fileId, CacheEntry *cacheLayerData, cache_usize_type releaseSize)
	Called after a cache entry has been destroyed-- Does not remove the item from other caches in the chain.
virtual void	populateCache (const Fingerprint &fileId, const DenseDataPtr &data)
	Goes up the heirararchy of cache layers filling in data.
Private Member Functions
void	setResponder (CacheLayer *other)
Private Attributes
CacheLayer *	mRespondTo
CacheLayer *	mNext
Friends
class	CacheMap

Detailed Description

Base class for cache layer--will try a next cache and respond with the data to any previous cache layers so they can store that data as well.

Constructor & Destructor Documentation

virtual Sirikata::Transfer::CacheLayer::~CacheLayer ( ) [inline, virtual]

References mNext, and setResponder().

Sirikata::Transfer::CacheLayer::CacheLayer ( CacheLayer * tryNext ) [inline]

Constructor needs to know what cache layer to try next, and what to return to.

References setResponder().

Member Function Documentation

void Sirikata::Transfer::CacheLayer::addToCache	(	const Fingerprint &	fileId,
		const DenseDataPtr &	data
	)		`[inline]`

References addToCache(), mNext, and populateCache().

Referenced by addToCache().

virtual void Sirikata::Transfer::CacheLayer::destroyCacheEntry	(	const Fingerprint &	fileId,
		CacheEntry *	cacheLayerData,
		cache_usize_type	releaseSize
	)		`[inline, protected, virtual]`

Called after a cache entry has been destroyed-- Does not remove the item from other caches in the chain.

Should be called only from CacheMap.

Reimplemented in Sirikata::Transfer::DiskCacheLayer, and Sirikata::Transfer::MemoryCacheLayer.

Referenced by Sirikata::Transfer::CacheMap::destroyCacheLayerEntry().

virtual void Sirikata::Transfer::CacheLayer::getData	(	const Fingerprint &	fileId,
		const Range &	requestedRange,
		const TransferCallback &	callback
	)		`[inline, virtual]`

Query this cache layer.

If successful, call callback with the data and also call populateCache in order to populate the previous cache levels.

Parameters:

fid	A unique identifier corresponding to the file (contains a hash).
requestedRange	A Range object specifying a single range that you need.
callback	To be called with the data if successful, or NULL if failed.

Returns:: false, if the callback happened synchronously (i.e. in memory cache)

Reimplemented in Sirikata::Transfer::DiskCacheLayer, and Sirikata::Transfer::MemoryCacheLayer.

References getData(), and mNext.

Referenced by Sirikata::Transfer::DiskCacheLayer::getData(), and getData().

CacheLayer* Sirikata::Transfer::CacheLayer::getNext ( ) const [inline]

References mNext.

CacheLayer* Sirikata::Transfer::CacheLayer::getResponder ( ) const [inline]

References mRespondTo.

virtual void Sirikata::Transfer::CacheLayer::populateCache	(	const Fingerprint &	fileId,
		const DenseDataPtr &	data
	)		`[inline, protected, virtual]`

Goes up the heirararchy of cache layers filling in data.

Parameters:

fileId	the Fingerprint to store this data in CacheMap.
data	Data to be stored in this CacheLayer.

Reimplemented in Sirikata::Transfer::DiskCacheLayer, and Sirikata::Transfer::MemoryCacheLayer.

References populateParentCaches().

Referenced by addToCache(), and populateParentCaches().

void Sirikata::Transfer::CacheLayer::populateParentCaches	(	const Fingerprint &	fileId,
		const DenseDataPtr &	data
	)		`[inline, protected]`

Goes up the heirararchy of cache layers filling in data.

Note that you must *NOT* call the callback until you have populated the cache.

Todo:: : Handle two requests for the same chunk at the same time.

References mRespondTo, and populateCache().

Referenced by Sirikata::Transfer::MemoryCacheLayer::getData(), Sirikata::Transfer::MemoryCacheLayer::populateCache(), Sirikata::Transfer::DiskCacheLayer::populateCache(), populateCache(), and Sirikata::Transfer::DiskCacheLayer::workerThread().

virtual void Sirikata::Transfer::CacheLayer::purgeFromCache ( const Fingerprint & fileId ) [inline, virtual]

Purges this hash from all subsequent caches.

In general, it is not useful to do this manually, since the CachePolicy handles freeing extra data, and it is usually assumed that the cache is correct.

Validity checking should probably be added elsewhere--though it is not really feasable for incomplete downloads if we used a range.

Reimplemented in Sirikata::Transfer::DiskCacheLayer, and Sirikata::Transfer::MemoryCacheLayer.

References mNext, and purgeFromCache().

Referenced by Sirikata::Transfer::DiskCacheLayer::purgeFromCache(), and purgeFromCache().

void Sirikata::Transfer::CacheLayer::setNext ( CacheLayer * newNext ) [inline]

If you want to change the ordering of the cache layers.

This may be safe, but it's probably not smart to use except when constructing or destroying a CacheLayer.

References mNext, and setResponder().

void Sirikata::Transfer::CacheLayer::setResponder ( CacheLayer * other ) [inline, private]

References mRespondTo.

Referenced by CacheLayer(), setNext(), and ~CacheLayer().

void Sirikata::Transfer::CacheLayer::setRespondTo ( CacheLayer * newRespond ) [inline]