Represents a CS replacement policy. More...

#include <daemon/table/cs-policy.hpp>

Inheritance diagram for nfd::cs::Policy:

Collaboration diagram for nfd::cs::Policy:

Public Types
using	EntryRef = Table::const_iterator
	A reference to a CS entry. More...

Public Member Functions
virtual	~Policy ()=default

void	afterInsert (EntryRef i)
	Invoked by CS after a new entry is inserted. More...

void	afterRefresh (EntryRef i)
	Invoked by CS after an existing entry is refreshed by same Data. More...

void	beforeErase (EntryRef i)
	Invoked by CS before an entry is erased due to management command. More...

void	beforeUse (EntryRef i)
	Invoked by CS before an entry is used to match a lookup. More...

Cs *	getCs () const noexcept
	Returns a pointer to the associated CS instance. More...

size_t	getLimit () const noexcept
	Gets hard limit (in number of entries). More...

const std::string &	getName () const noexcept

void	setCs (Cs *cs) noexcept
	Sets the associated CS instance. More...

void	setLimit (size_t nMaxEntries)
	Sets hard limit (in number of entries). More...

Static Public Member Functions
static unique_ptr< Policy >	create (const std::string &policyName)
	Returns a cs::Policy identified by `policyName`, or nullptr if `policyName` is unknown. More...

static std::set< std::string >	getPolicyNames ()
	Returns a list of available policy names. More...

template<typename P >
static void	registerPolicy (const std::string &policyName=P::POLICY_NAME)

Public Attributes
signal::Signal< Policy, EntryRef >	beforeEvict
	Signal emitted when an entry is being evicted. More...

Protected Member Functions
	Policy (std::string_view policyName)

virtual void	doAfterInsert (EntryRef i)=0
	Invoked after a new entry is created in CS. More...

virtual void	doAfterRefresh (EntryRef i)=0
	Invoked after an existing entry is refreshed by same Data. More...

virtual void	doBeforeErase (EntryRef i)=0
	Invoked before an entry is erased due to management command. More...

virtual void	doBeforeUse (EntryRef i)=0
	Invoked before an entry is used to match a lookup. More...

virtual void	evictEntries ()=0
	Evicts zero or more entries. More...

Detailed Description

Represents a CS replacement policy.

Definition at line 38 of file cs-policy.hpp.

Member Typedef Documentation

◆ EntryRef

using nfd::cs::Policy::EntryRef = Table::const_iterator

A reference to a CS entry.

Note: operator< of EntryRef compares the Data name enclosed in the Entry.

Definition at line 113 of file cs-policy.hpp.

Constructor & Destructor Documentation

◆ ~Policy()

virtual nfd::cs::Policy::~Policy ( )

virtualdefault

◆ Policy()

nfd::cs::Policy::Policy ( std::string_view policyName )

explicitprotected

Definition at line 61 of file cs-policy.cpp.

Member Function Documentation

◆ afterInsert()

void nfd::cs::Policy::afterInsert ( EntryRef i )

Invoked by CS after a new entry is inserted.

Postcondition: cs.size() <= getLimit()

The policy may evict entries if necessary. During this process, i might be evicted.

Definition at line 75 of file cs-policy.cpp.

◆ afterRefresh()

void nfd::cs::Policy::afterRefresh ( EntryRef i )

Invoked by CS after an existing entry is refreshed by same Data.

The policy may witness this refresh to make better eviction decisions in the future.

Definition at line 82 of file cs-policy.cpp.

◆ beforeErase()

void nfd::cs::Policy::beforeErase ( EntryRef i )

Invoked by CS before an entry is erased due to management command.

Warning: CS must not invoke this method if an entry is erased due to eviction.

Definition at line 89 of file cs-policy.cpp.

◆ beforeUse()

void nfd::cs::Policy::beforeUse ( EntryRef i )

Invoked by CS before an entry is used to match a lookup.

The policy may witness this usage to make better eviction decisions in the future.

Definition at line 96 of file cs-policy.cpp.

◆ create()

unique_ptr< Policy > nfd::cs::Policy::create ( const std::string & policyName )

static

Returns a cs::Policy identified by policyName, or nullptr if policyName is unknown.

Definition at line 45 of file cs-policy.cpp.

◆ doAfterInsert()

virtual void nfd::cs::Policy::doAfterInsert ( EntryRef i )

protectedpure virtual

Invoked after a new entry is created in CS.

When overridden in a subclass, a policy implementation should decide whether to accept i. If i is accepted, it should be inserted into a cleanup index. Otherwise, beforeEvict signal should be emitted with i to inform CS to erase the entry. A policy implementation may decide to evict other entries by emitting beforeEvict signal, in order to keep CS size under limit.

◆ doAfterRefresh()

virtual void nfd::cs::Policy::doAfterRefresh ( EntryRef i )

protectedpure virtual

Invoked after an existing entry is refreshed by same Data.

When overridden in a subclass, a policy implementation may witness this operation and adjust its cleanup index.

◆ doBeforeErase()

virtual void nfd::cs::Policy::doBeforeErase ( EntryRef i )

protectedpure virtual

Invoked before an entry is erased due to management command.

Note: This will not be invoked for an entry being evicted by policy.

When overridden in a subclass, a policy implementation should erase i from its cleanup index without emitted afterErase signal.

◆ doBeforeUse()

virtual void nfd::cs::Policy::doBeforeUse ( EntryRef i )

protectedpure virtual

Invoked before an entry is used to match a lookup.

When overridden in a subclass, a policy implementation may witness this operation and adjust its cleanup index.

◆ evictEntries()

virtual void nfd::cs::Policy::evictEntries ( )

protectedpure virtual

Evicts zero or more entries.

Postcondition: CS size does not exceed hard limit

◆ getCs()

Cs* nfd::cs::Policy::getCs ( ) const

inlinenoexcept

Returns a pointer to the associated CS instance.

Definition at line 77 of file cs-policy.hpp.

◆ getLimit()

size_t nfd::cs::Policy::getLimit ( ) const

inlinenoexcept

Gets hard limit (in number of entries).

Definition at line 95 of file cs-policy.hpp.

◆ getName()

const std::string& nfd::cs::Policy::getName ( ) const

inlinenoexcept

Definition at line 68 of file cs-policy.hpp.

◆ getPolicyNames()

std::set< std::string > nfd::cs::Policy::getPolicyNames ( )

static

Returns a list of available policy names.

Definition at line 53 of file cs-policy.cpp.

◆ registerPolicy()

template<typename P >

static void nfd::cs::Policy::registerPolicy ( const std::string & policyName = P::POLICY_NAME )

inlinestatic

Definition at line 43 of file cs-policy.hpp.

◆ setCs()

void nfd::cs::Policy::setCs ( Cs * cs )

inlinenoexcept

Sets the associated CS instance.

Definition at line 86 of file cs-policy.hpp.

◆ setLimit()

void nfd::cs::Policy::setLimit ( size_t nMaxEntries )

Sets hard limit (in number of entries).

Postcondition: getLimit() == nMaxEntries; cs.size() <= getLimit()

The policy may evict entries if necessary.

Definition at line 67 of file cs-policy.cpp.

Member Data Documentation

◆ beforeEvict

signal::Signal<Policy, EntryRef> nfd::cs::Policy::beforeEvict

Signal emitted when an entry is being evicted.

A policy implementation should emit this signal to cause CS to erase an entry from its index. CS should connect to this signal and erase the entry upon signal emission.

Definition at line 120 of file cs-policy.hpp.

NFD: Named Data Networking Forwarding Daemon 22.12 documentation

Public Types

Public Member Functions

Static Public Member Functions

Public Attributes

Protected Member Functions

Detailed Description

Member Typedef Documentation

◆ EntryRef

Constructor & Destructor Documentation

◆ ~Policy()

◆ Policy()

Member Function Documentation

◆ afterInsert()

◆ afterRefresh()

◆ beforeErase()

◆ beforeUse()

◆ create()

◆ doAfterInsert()

◆ doAfterRefresh()

◆ doBeforeErase()

◆ doBeforeUse()

◆ evictEntries()

◆ getCs()

◆ getLimit()

◆ getName()

◆ getPolicyNames()

◆ registerPolicy()

◆ setCs()

◆ setLimit()

Member Data Documentation

◆ beforeEvict