Functions for dealing with Veil variables. More...

#include "postgres.h"
#include "veil_datatypes.h"
#include "utils/hsearch.h"
#include "storage/shmem.h"
#include "veil_funcs.h"

Macros
#define	SESSION_HASH_ELEMS 32
	Baselines the number of session variables that can be created in each context.

Functions
static HTAB *	create_session_hash ()
	Create, or attach to, a hash for session variables.

VarEntry *	vl_lookup_shared_variable (char *name)
	Define a new, or attach to an existing, shared variable. More...

VarEntry *	vl_lookup_variable (char *name)
	Lookup a variable by name, creating it as as a session variable if it does not already exist. More...

veil_variable_t *	vl_next_variable (veil_variable_t *prev)
	Return the next variable from a scan of the hash of variables. More...

void	vl_ClearInt4Array (Int4Array *array)
	Reset all Int4 entries in an Int4Array (to zero). More...

Int4Array *	vl_NewInt4Array (Int4Array *current, bool shared, int32 min, int32 max)
	Return a newly initialised (zeroed) Int4Array. More...

void	vl_Int4ArraySet (Int4Array *array, int32 idx, int32 value)
	Set an entry within an Int4Array. More...

int32	vl_Int4ArrayGet (Int4Array *array, int32 idx)
	Get an entry from an Int4Array. More...

Variables
static HTAB *	session_hash = NULL
	This identifies the hash table for all session variables. More...

Detailed Description

Functions for dealing with Veil variables.

Author:       Marc Munro
Copyright (c) 2005 - 2011 Marc Munro
License:      BSD

Variables may be either session or shared, and are used to retain state between function calls. Shared variables are available to all suitably privileged sessions within a database. Session variables hold values that are private to a single session.

Definition in file veil_variables.c.

Function Documentation

◆ vl_lookup_shared_variable()

VarEntry* vl_lookup_shared_variable ( char * name )

Define a new, or attach to an existing, shared variable.

Raise an ERROR if the variable already exists as a session variable or if we cannot create the variable due to resource limitations (out of memory, or out of space in the shared hash).

Parameters

name	The name of the variable.

Returns: Pointer to the shared variable. If the variable is newly created by this call then it will be unitialised (ie it will have a NULL obj reference).

Definition at line 70 of file veil_variables.c.

References create_session_hash(), VarEntry::obj, session_hash, VarEntry::shared, and vl_get_shared_hash().

Referenced by veil_share().

◆ vl_lookup_variable()

VarEntry* vl_lookup_variable ( char * name )

Lookup a variable by name, creating it as as a session variable if it does not already exist.

Parameters

name	The name of the variable

Returns: Pointer to the shared or session variable. If the variable is newly created by this call then it will be unitialised (ie it will have a NULL obj reference).

Definition at line 122 of file veil_variables.c.

References create_session_hash(), VarEntry::obj, session_hash, VarEntry::shared, and vl_get_shared_hash().

Referenced by deserialise_bitmap(), deserialise_bitmap_array(), deserialise_bitmap_hash(), deserialise_int4array(), deserialise_int4var(), deserialise_range(), GetBitmap(), GetBitmapArray(), GetBitmapHash(), GetBitmapRef(), GetInt4Array(), GetInt4Var(), GetRange(), veil_clear_bitmap(), veil_clear_bitmap_array(), veil_clear_bitmap_hash(), veil_init_bitmap(), veil_init_bitmap_array(), veil_init_bitmap_hash(), veil_init_int4array(), and vl_serialise_var().

◆ vl_next_variable()

veil_variable_t* vl_next_variable ( veil_variable_t * prev )

Return the next variable from a scan of the hash of variables.

Note that this function is not re-entrant.

Parameters

prev	The last variable retrieved by a scan, or NULL if starting a new scan.

Returns: The next variable encountered in the scan. NULL if we have finished.

Definition at line 167 of file veil_variables.c.

References create_session_hash(), VarEntry::key, veil_variable_t::name, VarEntry::obj, session_hash, VarEntry::shared, veil_variable_t::shared, Object::type, veil_variable_t::type, vl_get_shared_hash(), and vl_ObjTypeName().

Referenced by veil_variables().

◆ vl_ClearInt4Array()

void vl_ClearInt4Array ( Int4Array * array )

Reset all Int4 entries in an Int4Array (to zero).

Parameters

array The array to be reset.

Definition at line 224 of file veil_variables.c.

References Int4Array::array, Int4Array::arraymax, and Int4Array::arrayzero.

Referenced by veil_clear_int4array(), and vl_NewInt4Array().

◆ vl_NewInt4Array()

Int4Array* vl_NewInt4Array	(	Int4Array *	current,
		bool	shared,
		int32	min,
		int32	max
	)

Return a newly initialised (zeroed) Int4Array.

It may already exist in which case it will be re-used if possible. It may be created in either session or shared memory depending on the value of shared.

Parameters

current	Pointer to an existing Int4Array if one exists.
shared	Whether to create the variable in shared or session memory.
min	Index of the first entry in the array.
max	Index of the last entry in the array.

Definition at line 246 of file veil_variables.c.

References Int4Array::arraymax, Int4Array::arrayzero, Int4Array::type, vl_ClearInt4Array(), vl_malloc(), and vl_shmalloc().

Referenced by veil_init_int4array().