session_manager.c File Reference

Session allocation helpers built from a resettable arena and RC payloads. More...

#include <cwist/sys/session/session_manager.h>
#include <cwist/core/mem/alloc.h>
#include <stdlib.h>
#include <string.h>

Include dependency graph for session_manager.c:

Go to the source code of this file.

Functions
void	session_arena_init (struct session_arena *arena, uint8_t *buffer, size_t capacity)
	Initialize a linear arena over caller-provided storage.
void *	session_arena_alloc (struct session_arena *arena, size_t size)
	Allocate aligned bytes from the request arena.
void	session_arena_reset (struct session_arena *arena)
	Rewind the arena so subsequent allocations reuse the full buffer.
void	session_rc_init (struct session_rc_header *header, void(*destructor)(void *))
	Initialize the reference-count metadata for a shared payload.
void *	session_shared_alloc (size_t payload_size, void(*destructor)(void *))
	Allocate a shared payload with an in-band reference-count header.
void	session_shared_inc (void *payload)
	Increment the reference count for a shared payload.
void	session_shared_dec (void *payload)
	Drop a reference and destroy the payload when the count reaches zero.
void	session_manager_init (struct session_manager *manager, uint8_t *buffer, size_t capacity)
	Initialize the request-scoped allocator state for a session manager.
void	session_manager_reset (struct session_manager *manager)
	Reset all request-scoped allocations owned by the manager.

Detailed Description

Session allocation helpers built from a resettable arena and RC payloads.

Definition in file session_manager.c.

Function Documentation

session_arena_alloc()

void * session_arena_alloc	(	struct session_arena *	arena,
		size_t	size
	)

Allocate aligned bytes from the request arena.

Allocate aligned storage from the request arena.

Allocate from a session arena.

Parameters

arena	Arena that owns the backing storage.
size	Number of bytes requested before alignment.

Returns

Pointer to a contiguous region, or NULL when the arena is exhausted.

Definition at line 30 of file session_manager.c.

References session_arena::buffer, cap, session_arena::capacity, and session_arena::offset.

session_arena_init()

void session_arena_init	(	struct session_arena *	arena,
		uint8_t *	buffer,
		size_t	capacity
	)

Initialize a linear arena over caller-provided storage.

Bind a caller-owned buffer to a session arena and reset its cursor.

Initialize a session arena.

Parameters

arena	Arena to initialize.
buffer	Backing storage to consume sequentially.
capacity	Total number of bytes available in buffer.

Definition at line 17 of file session_manager.c.

References session_arena::buffer, session_arena::capacity, and session_arena::offset.

Referenced by session_manager_init().

session_arena_reset()

void session_arena_reset

(

struct session_arena *

arena

)

Rewind the arena so subsequent allocations reuse the full buffer.

Reset the request arena so future allocations reuse the full buffer.

Reset a session arena.

Parameters

arena

Arena to reset.

Definition at line 46 of file session_manager.c.

References session_arena::offset.

Referenced by session_manager_reset().

session_manager_init()

void session_manager_init	(	struct session_manager *	manager,
		uint8_t *	buffer,
		size_t	capacity
	)

Initialize the request-scoped allocator state for a session manager.

Initialize a session manager around a caller-supplied arena buffer.

Initialize session manager.

Parameters

manager	Manager to initialize.
buffer	Backing arena storage.
capacity	Size of buffer in bytes.

Definition at line 116 of file session_manager.c.

References cap, and session_arena_init().

session_manager_reset()

void session_manager_reset

(

struct session_manager *

manager

)

Reset all request-scoped allocations owned by the manager.

Reset session manager.

Parameters

manager

Manager whose arena should be rewound.

Definition at line 125 of file session_manager.c.

References cap, and session_arena_reset().

session_rc_init()

void session_rc_init	(	struct session_rc_header *	header,
		void(*)(void *)	destructor
	)

Initialize the reference-count metadata for a shared payload.

Initialize the metadata that tracks a shared session allocation.

Initialize reference-counted header.

Parameters

header	Header that precedes the payload.
destructor	Optional callback run just before the payload is freed.

Definition at line 56 of file session_manager.c.

References session_rc_header::destructor, and session_rc_header::ref_count.

Referenced by session_shared_alloc().

session_shared_alloc()

void * session_shared_alloc	(	size_t	payload_size,
		void(*)(void *)	destructor
	)

Allocate a shared payload with an in-band reference-count header.

Allocate a zeroed payload preceded by a reference-count header.

Allocate shared session memory.

Parameters

payload_size	Number of bytes visible to callers.
destructor	Optional callback invoked before memory is released.

Returns

Zeroed payload pointer, or NULL when allocation fails.

Definition at line 68 of file session_manager.c.

References cap, cwist_alloc(), session_rc_header::destructor, and session_rc_init().

session_shared_dec()

void session_shared_dec

(

void *

payload

)

Drop a reference and destroy the payload when the count reaches zero.

Decrement the reference count and free the payload when it reaches zero.

Decrement reference count and free if zero.

Parameters

payload

Payload returned by session_shared_alloc().

Definition at line 96 of file session_manager.c.

References cap, cwist_free(), session_rc_header::destructor, and session_rc_header::ref_count.

session_shared_inc()

void session_shared_inc

(

void *

payload

)

Increment the reference count for a shared payload.

Increment reference count.

Parameters

payload

Payload returned by session_shared_alloc().

Definition at line 84 of file session_manager.c.

References cap, and session_rc_header::ref_count.