A MemoryContentCache holds a set of Data packets and answers an Interest to return the correct Data packet. More...

#include <memory-content-cache.hpp>

Classes
class	Content
	Content is a private class to hold the name and encoding for each entry in the cache. More...

class	PendingInterest
	A PendingInterest holds an interest which onInterest received but could not satisfy. More...

Public Types
typedef std::vector < ptr_lib::shared_ptr< const Content > >	ContentList

typedef func_lib::function < void(const ptr_lib::shared_ptr < ContentList > &contentList)>	OnContentRemoved
	An OnContentRemoved function object is called when content is removed from the cache. More...

Public Member Functions
	MemoryContentCache (Face *face, Milliseconds cleanupIntervalMilliseconds=1000.0)
	Create a new MemoryContentCache to use the given Face. More...

void	registerPrefix (const Name &prefix, const OnRegisterFailed &onRegisterFailed, const OnInterestCallback &onDataNotFound=OnInterestCallback(), const ForwardingFlags &flags=ForwardingFlags(), WireFormat &wireFormat=*WireFormat::getDefaultWireFormat())
	Call registerPrefix on the Face given to the constructor so that this MemoryContentCache will answer interests whose name has the prefix. More...

void	registerPrefix (const Name &prefix, const OnRegisterFailed &onRegisterFailed, const OnRegisterSuccess &onRegisterSuccess, const OnInterestCallback &onDataNotFound=OnInterestCallback(), const ForwardingFlags &flags=ForwardingFlags(), WireFormat &wireFormat=*WireFormat::getDefaultWireFormat())
	Call registerPrefix on the Face given to the constructor so that this MemoryContentCache will answer interests whose name has the prefix. More...

void	setInterestFilter (const InterestFilter &filter, const OnInterestCallback &onDataNotFound=OnInterestCallback())
	Call setInterestFilter on the Face given to the constructor so that this MemoryContentCache will answer interests whose name matches the filter. More...

void	setInterestFilter (const Name &prefix, const OnInterestCallback &onDataNotFound=OnInterestCallback())
	Call setInterestFilter on the Face given to the constructor so that this MemoryContentCache will answer interests whose name has the prefix. More...

void	unregisterAll ()
	Call Face.unsetInterestFilter and Face.removeRegisteredPrefix for all the prefixes given to the setInterestFilter and registerPrefix method on this MemoryContentCache object so that it will not receive interests any more. More...

void	add (const Data &data)
	Add the Data packet to the cache so that it is available to use to answer interests. More...

void	storePendingInterest (const ptr_lib::shared_ptr< const Interest > &interest, Face &face)
	Store an interest from an OnInterest callback in the internal pending interest table (normally because there is no Data packet available yet to satisfy the interest). More...

const OnInterestCallback &	getStorePendingInterest ()
	Return a callback to use for onDataNotFound in registerPrefix which simply calls storePendingInterest() to store the interest that doesn't match a Data packet. More...

void	getPendingInterestsForName (const Name &name, std::vector< ptr_lib::shared_ptr< const PendingInterest > > &pendingInterests)
	Remove timed-out pending interests, then for each pending interest which matches according to Interest.matchesName(name), append the PendingInterest entry to the given pendingInterests list. More...

void	getPendingInterestsWithPrefix (const Name &prefix, std::vector< ptr_lib::shared_ptr< const PendingInterest > > &pendingInterests)
	Remove timed-out pending interests, then for each pending interest which matches according to prefix.isPrefixOf(interest.getName()), append the PendingInterest entry to the given pendingInterests list. More...

void	setOnContentRemoved (const OnContentRemoved &onContentRemoved)
	Set the OnContentRemoved callback to call when stale content is removed from the cache during cleanup. More...

Milliseconds	getMinimumCacheLifetime ()
	Get the minimum lifetime before removing stale content from the cache. More...

void	setMinimumCacheLifetime (Milliseconds minimumCacheLifetime)
	Set the minimum lifetime before removing stale content from the cache which can keep content in the cache longer than the lifetime defined in the meta info. More...

Detailed Description

A MemoryContentCache holds a set of Data packets and answers an Interest to return the correct Data packet.

The cache is periodically cleaned up to remove each stale Data packet based on its FreshnessPeriod (if it has one).

Note: This class is an experimental feature. See the API docs for more detail at http://named-data.net/doc/ndn-ccl-api/memory-content-cache.html .

Member Typedef Documentation

typedef func_lib::function<void (const ptr_lib::shared_ptr<ContentList>& contentList)> ndn::MemoryContentCache::OnContentRemoved

An OnContentRemoved function object is called when content is removed from the cache.

See setOnContentRemoved().

Constructor & Destructor Documentation

ndn::MemoryContentCache::MemoryContentCache	(	Face *	face,
		Milliseconds	cleanupIntervalMilliseconds = `1000.0`
	)

inline

Create a new MemoryContentCache to use the given Face.

Parameters

face	The Face to use to call registerPrefix and setInterestFilter, and which will call this object's OnInterest callback.
cleanupIntervalMilliseconds	(optional) The interval in milliseconds between each check to clean up stale content in the cache. If omitted, use a default of 1000 milliseconds. If this is a large number, then effectively the stale content will not be removed from the cache.

Member Function Documentation

void ndn::MemoryContentCache::add ( const Data & data )

inline

Add the Data packet to the cache so that it is available to use to answer interests.

If data.getMetaInfo().getFreshnessPeriod() is not negative, set the staleness time to now plus the maximum of data.getMetaInfo().getFreshnessPeriod() and minimumCacheLifetime, which is checked during cleanup to remove stale content. This also checks if cleanupIntervalMilliseconds milliseconds have passed and removes stale content from the cache. After removing stale content, remove timed-out pending interests from storePendingInterest(), then if the added Data packet satisfies any interest, send it through the transport and remove the interest from the pending interest table. Because this modifies the internal tables, you should call this on the same thread as processEvents, which can also modify the tables.

Parameters

data	The Data packet object to put in the cache. This copies the fields from the object.

Milliseconds ndn::MemoryContentCache::getMinimumCacheLifetime ( )

inline

Get the minimum lifetime before removing stale content from the cache.

Returns: The minimum cache lifetime in milliseconds.

void ndn::MemoryContentCache::getPendingInterestsForName	(	const Name &	name,
		std::vector< ptr_lib::shared_ptr< const PendingInterest > > &	pendingInterests
	)

inline

Remove timed-out pending interests, then for each pending interest which matches according to Interest.matchesName(name), append the PendingInterest entry to the given pendingInterests list.

(To get interests with a given prefix, see getPendingInterestsWithPrefix().) Because this modifies the internal tables, you should call this on the same thread as processEvents, which can also modify the tables.

Parameters

name	The name to check.
pendingInterests	The vector to receive the matching PendingInterest objects. This first clears the list before adding objects. You should not modify the PendingInterest objects.

void ndn::MemoryContentCache::getPendingInterestsWithPrefix	(	const Name &	prefix,
		std::vector< ptr_lib::shared_ptr< const PendingInterest > > &	pendingInterests
	)

inline

Remove timed-out pending interests, then for each pending interest which matches according to prefix.isPrefixOf(interest.getName()), append the PendingInterest entry to the given pendingInterests list.

Note that interest selectors are ignored. (To get interests which would match a given data packet name, see getPendingInterestsForName().) Because this modifies the internal tables, you should call this on the same thread as processEvents, which can also modify the tables.

Parameters

prefix	The prefix of the interest names to match.
pendingInterests	The vector to receive the matching PendingInterest objects. This first clears the list before adding objects. You should not modify the PendingInterest objects.

const OnInterestCallback& ndn::MemoryContentCache::getStorePendingInterest ( )

inline

Return a callback to use for onDataNotFound in registerPrefix which simply calls storePendingInterest() to store the interest that doesn't match a Data packet.

add(data) will check if the added Data packet satisfies any pending interest and send it.

Returns: A callback to use for onDataNotFound in registerPrefix().

void ndn::MemoryContentCache::registerPrefix	(	const Name &	prefix,
		const OnRegisterFailed &	onRegisterFailed,
		const OnInterestCallback &	onDataNotFound = `OnInterestCallback()`,
		const ForwardingFlags &	flags = `ForwardingFlags()`,
		WireFormat &	wireFormat = `*WireFormat::getDefaultWireFormat()`
	)

inline

Call registerPrefix on the Face given to the constructor so that this MemoryContentCache will answer interests whose name has the prefix.

Alternatively, if the Face's registerPrefix has already been called, then you can call this object's setInterestFilter.

Parameters

prefix	The Name for the prefix to register. This copies the Name.
onRegisterFailed	A function object to call if failed to retrieve the connected hub’s ID or failed to register the prefix. This calls onRegisterFailed(prefix) where prefix is the prefix given to registerPrefix. NOTE: The library will log any exceptions thrown by this callback, but for better error handling the callback should catch and properly handle any exceptions.
onDataNotFound	(optional) If a data packet for an interest is not found in the cache, this forwards the interest by calling onDataNotFound(prefix, interest, face, interestFilterId, filter). Your callback can find the Data packet for the interest and call face.putData(data). If your callback cannot find the Data packet, it can optionally call storePendingInterest(interest, face) to store the pending interest in this object to be satisfied by a later call to add(data). If you want to automatically store all pending interests, you can simply use getStorePendingInterest() for onDataNotFound. If onDataNotFound is an empty OnInterestCallback(), this does not use it. This copies the function object, so you may need to use func_lib::ref() as appropriate. NOTE: The library will log any exceptions thrown by this callback, but for better error handling the callback should catch and properly handle any exceptions.
flags	(optional) See Face::registerPrefix.
wireFormat	(optional) See Face::registerPrefix.

void ndn::MemoryContentCache::registerPrefix	(	const Name &	prefix,
		const OnRegisterFailed &	onRegisterFailed,
		const OnRegisterSuccess &	onRegisterSuccess,
		const OnInterestCallback &	onDataNotFound = `OnInterestCallback()`,
		const ForwardingFlags &	flags = `ForwardingFlags()`,
		WireFormat &	wireFormat = `*WireFormat::getDefaultWireFormat()`
	)

inline

Call registerPrefix on the Face given to the constructor so that this MemoryContentCache will answer interests whose name has the prefix.

Alternatively, if the Face's registerPrefix has already been called, then you can call this object's setInterestFilter.

Parameters

prefix	The Name for the prefix to register. This copies the Name.
onRegisterFailed	A function object to call if failed to retrieve the connected hub’s ID or failed to register the prefix. This calls onRegisterFailed(prefix) where prefix is the prefix given to registerPrefix.
onRegisterSuccess	(optional) A function object to call registerPrefix receives a success message from the forwarder. This calls onRegisterSuccess(prefix, registeredPrefixId) where prefix and registeredPrefixId are the values given to registerPrefix. If onRegisterSuccess is an empty OnRegisterSuccess(), this does not use it.
onDataNotFound	(optional) If a data packet for an interest is not found in the cache, this forwards the interest by calling onDataNotFound(prefix, interest, face, interestFilterId, filter). Your callback can find the Data packet for the interest and call face.putData(data). If your callback cannot find the Data packet, it can optionally call storePendingInterest(interest, face) to store the pending interest in this object to be satisfied by a later call to add(data). If you want to automatically store all pending interests, you can simply use getStorePendingInterest() for onDataNotFound. If onDataNotFound is an empty OnInterestCallback(), this does not use it. This copies the function object, so you may need to use func_lib::ref() as appropriate.
flags	(optional) See Face::registerPrefix.
wireFormat	(optional) See Face::registerPrefix.

void ndn::MemoryContentCache::setInterestFilter	(	const InterestFilter &	filter,
		const OnInterestCallback &	onDataNotFound = `OnInterestCallback()`
	)

inline

Call setInterestFilter on the Face given to the constructor so that this MemoryContentCache will answer interests whose name matches the filter.

Parameters

filter The InterestFilter with a prefix and optional regex filter used to match the name of an incoming Interest. This makes a copy of filter.

onDataNotFound (optional) If a data packet for an interest is not found in the cache, this forwards the interest by calling onDataNotFound(prefix, interest, face, interestFilterId, filter). Your callback can find the Data packet for the interest and call face.putData(data). Note: If you call setInterestFilter multiple times where filter.getPrefix() is the same, it is undetermined which onDataNotFound will be called. If your callback cannot find the Data packet, it can optionally call storePendingInterest(interest, face) to store the pending interest in this object to be satisfied by a later call to add(data). If you want to automatically store all pending interests, you can simply use getStorePendingInterest() for onDataNotFound. If onDataNotFound is an empty OnInterestCallback(), this does not use it. This copies the function object, so you may need to use func_lib::ref() as appropriate. NOTE: The library will log any exceptions thrown by this callback, but for better error handling the callback should catch and properly handle any exceptions.

void ndn::MemoryContentCache::setInterestFilter	(	const Name &	prefix,
		const OnInterestCallback &	onDataNotFound = `OnInterestCallback()`
	)

inline

Call setInterestFilter on the Face given to the constructor so that this MemoryContentCache will answer interests whose name has the prefix.

Parameters

prefix The Name prefix used to match the name of an incoming Interest. This copies the Name.

onDataNotFound (optional) If a data packet for an interest is not found in the cache, this forwards the interest by calling onDataNotFound(prefix, interest, face, interestFilterId, filter). Your callback can find the Data packet for the interest and call face.putData(data). If your callback cannot find the Data packet, it can optionally call storePendingInterest(interest, face) to store the pending interest in this object to be satisfied by a later call to add(data). If you want to automatically store all pending interests, you can simply use getStorePendingInterest() for onDataNotFound. If onDataNotFound is an empty OnInterestCallback(), this does not use it. This copies the function object, so you may need to use func_lib::ref() as appropriate. NOTE: The library will log any exceptions thrown by this callback, but for better error handling the callback should catch and properly handle any exceptions.

void ndn::MemoryContentCache::setMinimumCacheLifetime ( Milliseconds minimumCacheLifetime )

inline

Set the minimum lifetime before removing stale content from the cache which can keep content in the cache longer than the lifetime defined in the meta info.

This can be useful for matching interests where MustBeFresh is false. The default minimum cache lifetime is zero, meaning that content is removed when its lifetime expires.

Parameters

minimumCacheLifetime The minimum cache lifetime in milliseconds.

void ndn::MemoryContentCache::setOnContentRemoved ( const OnContentRemoved & onContentRemoved )

inline

Set the OnContentRemoved callback to call when stale content is removed from the cache during cleanup.

Note: Because onContentRemoved is called while processing incoming Interests, it should return quickly to allow the Interest to be processed quickly.

Parameters

onContentRemoved This calls onContentRemoved(contentList) where contentList is the list of MemoryContentCache::Content objects that were removed, where each Content has the Name and encoding of the removed content.

void ndn::MemoryContentCache::storePendingInterest	(	const ptr_lib::shared_ptr< const Interest > &	interest,
		Face &	face
	)

inline

Store an interest from an OnInterest callback in the internal pending interest table (normally because there is no Data packet available yet to satisfy the interest).

add(data) will check if the added Data packet satisfies any pending interest and send it through the face. Because this modifies the internal tables, you should call this on the same thread as processEvents, which can also modify the tables.

Parameters

interest	The Interest for which we don't have a Data packet yet. You should not modify the interest after calling this.
face	The Face with the connection which received the interest. This comes from the onInterest callback.

void ndn::MemoryContentCache::unregisterAll ( )

inline

Call Face.unsetInterestFilter and Face.removeRegisteredPrefix for all the prefixes given to the setInterestFilter and registerPrefix method on this MemoryContentCache object so that it will not receive interests any more.

You can call this if you want to "shut down" this MemoryContentCache while your application is still running.

The documentation for this class was generated from the following file:

include/ndn-cpp/util/memory-content-cache.hpp

Classes

Public Types

Public Member Functions

Detailed Description

Member Typedef Documentation

Constructor & Destructor Documentation

Member Function Documentation