entropic::SessionScoped< T > Class Template Reference

One T per session key, under one leaf mutex (gh#158). More...

#include <entropic/mcp/session_scoped.h>

Public Member Functions
template<typename Fn >
auto	with (const std::string &key, Fn &&fn)
	Run fn on key's state, creating it empty on first use.
template<typename Fn >
auto	peek (const std::string &key, Fn &&fn) const
	Run fn on key's state WITHOUT creating it.
bool	release (const std::string &key)
	Forget key's state.
std::size_t	session_count () const
	Sessions currently holding state (bounded-growth probe).

Detailed Description

template<typename T>
class entropic::SessionScoped< T >

One T per session key, under one leaf mutex (gh#158).

Every accessor takes the lock for its whole body and calls nothing but the supplied functor under it, so it is a LEAF lock: nothing that holds it waits on another. A functor must not re-enter the same instance.

Template Parameters

T	Per-session state (default-constructible).

Version

2.13.0

Definition at line 61 of file session_scoped.h.

Member Function Documentation

peek()

template<typename T >

template<typename Fn >

auto entropic::SessionScoped< T >::peek ( const std::string &  key, Fn &&  fn  ) const

inline

Run fn on key's state WITHOUT creating it.

A lookup must not allocate an entry, or merely asking "did this session read X?" would grow the map for sessions that never read.

Parameters

key	Session key.
fn	Callable taking const T* (nullptr when absent).

Returns

Whatever fn returns. @req REQ-LOOP-009

Version

2.13.0

Definition at line 90 of file session_scoped.h.

release()

template<typename T >

bool entropic::SessionScoped< T >::release ( const std::string &  key )

inline

Forget key's state.

Parameters

key	Session key.

Returns

true when an entry existed and was erased. @req REQ-LOOP-009

Version

2.13.0

Definition at line 103 of file session_scoped.h.

session_count()

template<typename T >

std::size_t entropic::SessionScoped< T >::session_count ( ) const

inline

Sessions currently holding state (bounded-growth probe).

Returns

Entry count. @req REQ-LOOP-009

Version

2.13.0

Definition at line 114 of file session_scoped.h.

with()

template<typename T >

template<typename Fn >

auto entropic::SessionScoped< T >::with ( const std::string &  key, Fn &&  fn  )

inline

Run fn on key's state, creating it empty on first use.

Parameters

key	Session key.
fn	Callable taking T&.

Returns

Whatever fn returns. @req REQ-LOOP-009

Version

2.13.0

Definition at line 72 of file session_scoped.h.

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

• entropic/mcp/session_scoped.h