real::detail::dfa_lease Class Reference

This thread's DFA set for one regex, for the lifetime of the lease: a scan through it takes no lock, so threads sharing a regex do not queue on its DFAs. More...

#include <onepass.hpp>

Collaboration diagram for real::detail::dfa_lease:

Classes
struct	cache
	The set a thread keeps between leases, and the slot it returns to. More...

Public Member Functions
	dfa_lease (regex_immutables *immut)
	Leases a DFA set for immut, cleared if it was built for an earlier program.
	dfa_lease (const dfa_lease &)=delete
dfa_lease &	operator= (const dfa_lease &)=delete
	dfa_lease (dfa_lease &&)=delete
dfa_lease &	operator= (dfa_lease &&)=delete
	~dfa_lease ()
	Ends the lease: the cached set stays with this thread, a nested one goes back to its pool.
shared_dfa_set &	operator* () const noexcept
	The leased set.
shared_dfa_set *	operator-> () const noexcept
	The leased set's members.

Static Public Member Functions
static void	drop_thread_set (const shared_dfa_slot &slot) noexcept
	Frees this thread's cached set if it came from slot and no lease holds it: the slot's regex is gone, so no lease will ask for it again.

Static Private Member Functions
static cache &	thread_cache ()
	This thread's cache.
static std::shared_ptr< shared_dfa_slot >	slot_for (regex_immutables *immut)
	The slot for immut, created on first use (a shared reference: it may be retired).
static std::unique_ptr< shared_dfa_set >	take (shared_dfa_slot &slot)
	A free set from slot's pool, or a new one.
static void	give (shared_dfa_slot &slot, std::unique_ptr< shared_dfa_set > set) noexcept
	Returns set to slot's pool, or frees it when the pool cannot take it.

Private Attributes
shared_dfa_slot *	slot_ {nullptr}
	The slot the set belongs to.
shared_dfa_set *	set_ {nullptr}
	The leased set.
bool	cached_ {false}
	The set is this thread's cached one.
std::shared_ptr< shared_dfa_slot >	nested_slot_
	The slot of a nested lease.
std::unique_ptr< shared_dfa_set >	nested_set_
	The set of a nested lease.

Detailed Description

This thread's DFA set for one regex, for the lifetime of the lease: a scan through it takes no lock, so threads sharing a regex do not queue on its DFAs.

Each thread keeps the set it last used, with its slot, and gives it back to that slot's pool when it moves to another regex or exits; a repeat lease is an owner check and a generation check. A nested lease (a scan started inside another scan) takes a separate set from the pool and returns it on destruction, so the outer scan's set is never handed away under it.

Constructor & Destructor Documentation

dfa_lease()

real::detail::dfa_lease::dfa_lease ( regex_immutables *  immut )

inlineexplicit

Leases a DFA set for immut, cleared if it was built for an earlier program.

Parameters

[in]

immut

The regex whose DFAs are wanted.

Member Function Documentation

drop_thread_set()

static void real::detail::dfa_lease::drop_thread_set ( const shared_dfa_slot &  slot )

inlinestaticnoexcept

Frees this thread's cached set if it came from slot and no lease holds it: the slot's regex is gone, so no lease will ask for it again.

Parameters

[in]

slot

The retired slot.

give()

static void real::detail::dfa_lease::give ( shared_dfa_slot &  slot, std::unique_ptr< shared_dfa_set >  set  )

inlinestaticprivatenoexcept

Returns set to slot's pool, or frees it when the pool cannot take it.

Called from destructors, so it cannot throw: a lock that fails or a pool that cannot grow leaves set to be freed here instead of pooled, which costs the next lease a rebuild and nothing else.

Parameters

[in,out]	slot	The slot the set belongs to.
[in]	set	The set given back.

operator*()

shared_dfa_set & real::detail::dfa_lease::operator* ( ) const

inlinenoexcept

The leased set.

Returns

The set.

operator->()

shared_dfa_set * real::detail::dfa_lease::operator-> ( ) const

inlinenoexcept

The leased set's members.

Returns

The set.

slot_for()

static std::shared_ptr< shared_dfa_slot > real::detail::dfa_lease::slot_for ( regex_immutables *  immut )

inlinestaticprivate

The slot for immut, created on first use (a shared reference: it may be retired).

Parameters

[in]

immut

The regex whose slot is wanted.

Returns

The slot.

take()

static std::unique_ptr< shared_dfa_set > real::detail::dfa_lease::take ( shared_dfa_slot &  slot )

inlinestaticprivate

A free set from slot's pool, or a new one.

Parameters

[in,out]

slot

The slot whose pool is drawn from.

Returns

The set.

thread_cache()

static cache & real::detail::dfa_lease::thread_cache ( )

inlinestaticprivate

This thread's cache.

Returns

The cache.

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

• include/real/automata/onepass.hpp