postgresql/src/include/storage/proclist_types.h

54 lines
1.6 KiB
C

/*-------------------------------------------------------------------------
*
* proclist_types.h
* doubly-linked lists of pgprocnos
*
* See proclist.h for functions that operate on these types.
*
* Portions Copyright (c) 2016-2024, PostgreSQL Global Development Group
*
* IDENTIFICATION
* src/include/storage/proclist_types.h
*-------------------------------------------------------------------------
*/
#ifndef PROCLIST_TYPES_H
#define PROCLIST_TYPES_H
#include "storage/procnumber.h"
/*
* A node in a doubly-linked list of processes. The link fields contain
* the 0-based PGPROC indexes of the next and previous process, or
* INVALID_PROC_NUMBER in the next-link of the last node and the prev-link
* of the first node. A node that is currently not in any list
* should have next == prev == 0; this is not a possible state for a node
* that is in a list, because we disallow circularity.
*/
typedef struct proclist_node
{
ProcNumber next; /* pgprocno of the next PGPROC */
ProcNumber prev; /* pgprocno of the prev PGPROC */
} proclist_node;
/*
* Header of a doubly-linked list of PGPROCs, identified by pgprocno.
* An empty list is represented by head == tail == INVALID_PROC_NUMBER.
*/
typedef struct proclist_head
{
ProcNumber head; /* pgprocno of the head PGPROC */
ProcNumber tail; /* pgprocno of the tail PGPROC */
} proclist_head;
/*
* List iterator allowing some modifications while iterating.
*/
typedef struct proclist_mutable_iter
{
ProcNumber cur; /* pgprocno of the current PGPROC */
ProcNumber next; /* pgprocno of the next PGPROC */
} proclist_mutable_iter;
#endif /* PROCLIST_TYPES_H */