52 lines
1.6 KiB
C
52 lines
1.6 KiB
C
/*-------------------------------------------------------------------------
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*
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* proclist_types.h
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* doubly-linked lists of pgprocnos
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*
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* See proclist.h for functions that operate on these types.
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*
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* Portions Copyright (c) 2016-2023, PostgreSQL Global Development Group
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*
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* IDENTIFICATION
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* src/include/storage/proclist_types.h
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*-------------------------------------------------------------------------
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*/
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#ifndef PROCLIST_TYPES_H
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#define PROCLIST_TYPES_H
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/*
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* A node in a doubly-linked list of processes. The link fields contain
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* the 0-based PGPROC indexes of the next and previous process, or
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* INVALID_PGPROCNO in the next-link of the last node and the prev-link
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* of the first node. A node that is currently not in any list
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* should have next == prev == 0; this is not a possible state for a node
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* that is in a list, because we disallow circularity.
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*/
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typedef struct proclist_node
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{
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int next; /* pgprocno of the next PGPROC */
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int prev; /* pgprocno of the prev PGPROC */
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} proclist_node;
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/*
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* Header of a doubly-linked list of PGPROCs, identified by pgprocno.
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* An empty list is represented by head == tail == INVALID_PGPROCNO.
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*/
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typedef struct proclist_head
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{
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int head; /* pgprocno of the head PGPROC */
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int tail; /* pgprocno of the tail PGPROC */
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} proclist_head;
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/*
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* List iterator allowing some modifications while iterating.
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*/
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typedef struct proclist_mutable_iter
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{
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int cur; /* pgprocno of the current PGPROC */
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int next; /* pgprocno of the next PGPROC */
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} proclist_mutable_iter;
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#endif /* PROCLIST_TYPES_H */
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