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Diffstat (limited to 'src/include/storage/proclist_types.h')
-rw-r--r-- | src/include/storage/proclist_types.h | 51 |
1 files changed, 51 insertions, 0 deletions
diff --git a/src/include/storage/proclist_types.h b/src/include/storage/proclist_types.h new file mode 100644 index 0000000..aba5578 --- /dev/null +++ b/src/include/storage/proclist_types.h @@ -0,0 +1,51 @@ +/*------------------------------------------------------------------------- + * + * proclist_types.h + * doubly-linked lists of pgprocnos + * + * See proclist.h for functions that operate on these types. + * + * Portions Copyright (c) 2016-2020, PostgreSQL Global Development Group + * + * IDENTIFICATION + * src/include/storage/proclist_types.h + *------------------------------------------------------------------------- + */ + +#ifndef PROCLIST_TYPES_H +#define PROCLIST_TYPES_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_PGPROCNO 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 +{ + int next; /* pgprocno of the next PGPROC */ + int 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_PGPROCNO. + */ +typedef struct proclist_head +{ + int head; /* pgprocno of the head PGPROC */ + int tail; /* pgprocno of the tail PGPROC */ +} proclist_head; + +/* + * List iterator allowing some modifications while iterating. + */ +typedef struct proclist_mutable_iter +{ + int cur; /* pgprocno of the current PGPROC */ + int next; /* pgprocno of the next PGPROC */ +} proclist_mutable_iter; + +#endif /* PROCLIST_TYPES_H */ |