diff options
Diffstat (limited to 'src/backend/storage/ipc/shmqueue.c')
| -rw-r--r-- | src/backend/storage/ipc/shmqueue.c | 274 |
1 files changed, 138 insertions, 136 deletions
diff --git a/src/backend/storage/ipc/shmqueue.c b/src/backend/storage/ipc/shmqueue.c index f727b5719f5..8080fc70208 100644 --- a/src/backend/storage/ipc/shmqueue.c +++ b/src/backend/storage/ipc/shmqueue.c @@ -1,19 +1,19 @@ /*------------------------------------------------------------------------- * * shmqueue.c-- - * shared memory linked lists + * shared memory linked lists * * Copyright (c) 1994, Regents of the University of California * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/storage/ipc/shmqueue.c,v 1.3 1997/08/19 21:33:06 momjian Exp $ + * $Header: /cvsroot/pgsql/src/backend/storage/ipc/shmqueue.c,v 1.4 1997/09/07 04:48:42 momjian Exp $ * * NOTES * * Package for managing doubly-linked lists in shared memory. - * The only tricky thing is that SHM_QUEUE will usually be a field - * in a larger record. SHMQueueGetFirst has to return a pointer + * The only tricky thing is that SHM_QUEUE will usually be a field + * in a larger record. SHMQueueGetFirst has to return a pointer * to the record itself instead of a pointer to the SHMQueue field * of the record. It takes an extra pointer and does some extra * pointer arithmetic to do this correctly. @@ -22,178 +22,181 @@ * *------------------------------------------------------------------------- */ -#include <stdio.h> /* for sprintf() */ +#include <stdio.h> /* for sprintf() */ #include "postgres.h" -#include "storage/shmem.h" /* where the declarations go */ +#include "storage/shmem.h" /* where the declarations go */ /*#define SHMQUEUE_DEBUG*/ #ifdef SHMQUEUE_DEBUG -#define SHMQUEUE_DEBUG_DEL /* deletions */ -#define SHMQUEUE_DEBUG_HD /* head inserts */ -#define SHMQUEUE_DEBUG_TL /* tail inserts */ +#define SHMQUEUE_DEBUG_DEL /* deletions */ +#define SHMQUEUE_DEBUG_HD /* head inserts */ +#define SHMQUEUE_DEBUG_TL /* tail inserts */ #define SHMQUEUE_DEBUG_ELOG NOTICE -#endif /* SHMQUEUE_DEBUG */ +#endif /* SHMQUEUE_DEBUG */ /* * ShmemQueueInit -- make the head of a new queue point - * to itself + * to itself */ void -SHMQueueInit(SHM_QUEUE *queue) +SHMQueueInit(SHM_QUEUE * queue) { - Assert(SHM_PTR_VALID(queue)); - (queue)->prev = (queue)->next = MAKE_OFFSET(queue); + Assert(SHM_PTR_VALID(queue)); + (queue)->prev = (queue)->next = MAKE_OFFSET(queue); } /* * SHMQueueIsDetached -- TRUE if element is not currently - * in a queue. + * in a queue. */ #ifdef NOT_USED bool -SHMQueueIsDetached(SHM_QUEUE *queue) +SHMQueueIsDetached(SHM_QUEUE * queue) { - Assert(SHM_PTR_VALID(queue)); - return ((queue)->prev == INVALID_OFFSET); + Assert(SHM_PTR_VALID(queue)); + return ((queue)->prev == INVALID_OFFSET); } + #endif /* * SHMQueueElemInit -- clear an element's links */ void -SHMQueueElemInit(SHM_QUEUE *queue) +SHMQueueElemInit(SHM_QUEUE * queue) { - Assert(SHM_PTR_VALID(queue)); - (queue)->prev = (queue)->next = INVALID_OFFSET; + Assert(SHM_PTR_VALID(queue)); + (queue)->prev = (queue)->next = INVALID_OFFSET; } /* * SHMQueueDelete -- remove an element from the queue and - * close the links + * close the links */ void -SHMQueueDelete(SHM_QUEUE *queue) +SHMQueueDelete(SHM_QUEUE * queue) { - SHM_QUEUE *nextElem = (SHM_QUEUE *) MAKE_PTR((queue)->next); - SHM_QUEUE *prevElem = (SHM_QUEUE *) MAKE_PTR((queue)->prev); - - Assert(SHM_PTR_VALID(queue)); - Assert(SHM_PTR_VALID(nextElem)); - Assert(SHM_PTR_VALID(prevElem)); - + SHM_QUEUE *nextElem = (SHM_QUEUE *) MAKE_PTR((queue)->next); + SHM_QUEUE *prevElem = (SHM_QUEUE *) MAKE_PTR((queue)->prev); + + Assert(SHM_PTR_VALID(queue)); + Assert(SHM_PTR_VALID(nextElem)); + Assert(SHM_PTR_VALID(prevElem)); + #ifdef SHMQUEUE_DEBUG_DEL - dumpQ(queue, "in SHMQueueDelete: begin"); -#endif /* SHMQUEUE_DEBUG_DEL */ - - prevElem->next = (queue)->next; - nextElem->prev = (queue)->prev; - + dumpQ(queue, "in SHMQueueDelete: begin"); +#endif /* SHMQUEUE_DEBUG_DEL */ + + prevElem->next = (queue)->next; + nextElem->prev = (queue)->prev; + #ifdef SHMQUEUE_DEBUG_DEL - dumpQ((SHM_QUEUE *)MAKE_PTR(queue->prev), "in SHMQueueDelete: end"); -#endif /* SHMQUEUE_DEBUG_DEL */ + dumpQ((SHM_QUEUE *) MAKE_PTR(queue->prev), "in SHMQueueDelete: end"); +#endif /* SHMQUEUE_DEBUG_DEL */ } #ifdef SHMQUEUE_DEBUG void -dumpQ(SHM_QUEUE *q, char *s) +dumpQ(SHM_QUEUE * q, char *s) { - char elem[16]; - char buf[1024]; - SHM_QUEUE *start = q; - int count = 0; - - sprintf(buf, "q prevs: %x", MAKE_OFFSET(q)); - q = (SHM_QUEUE *)MAKE_PTR(q->prev); - while (q != start) + char elem[16]; + char buf[1024]; + SHM_QUEUE *start = q; + int count = 0; + + sprintf(buf, "q prevs: %x", MAKE_OFFSET(q)); + q = (SHM_QUEUE *) MAKE_PTR(q->prev); + while (q != start) { - sprintf(elem, "--->%x", MAKE_OFFSET(q)); - strcat(buf, elem); - q = (SHM_QUEUE *)MAKE_PTR(q->prev); - if (q->prev == MAKE_OFFSET(q)) - break; - if (count++ > 40) + sprintf(elem, "--->%x", MAKE_OFFSET(q)); + strcat(buf, elem); + q = (SHM_QUEUE *) MAKE_PTR(q->prev); + if (q->prev == MAKE_OFFSET(q)) + break; + if (count++ > 40) { - strcat(buf, "BAD PREV QUEUE!!"); - break; + strcat(buf, "BAD PREV QUEUE!!"); + break; } } - sprintf(elem, "--->%x", MAKE_OFFSET(q)); - strcat(buf, elem); - elog(SHMQUEUE_DEBUG_ELOG, "%s: %s", s, buf); - - sprintf(buf, "q nexts: %x", MAKE_OFFSET(q)); - count = 0; - q = (SHM_QUEUE *)MAKE_PTR(q->next); - while (q != start) + sprintf(elem, "--->%x", MAKE_OFFSET(q)); + strcat(buf, elem); + elog(SHMQUEUE_DEBUG_ELOG, "%s: %s", s, buf); + + sprintf(buf, "q nexts: %x", MAKE_OFFSET(q)); + count = 0; + q = (SHM_QUEUE *) MAKE_PTR(q->next); + while (q != start) { - sprintf(elem, "--->%x", MAKE_OFFSET(q)); - strcat(buf, elem); - q = (SHM_QUEUE *)MAKE_PTR(q->next); - if (q->next == MAKE_OFFSET(q)) - break; - if (count++ > 10) + sprintf(elem, "--->%x", MAKE_OFFSET(q)); + strcat(buf, elem); + q = (SHM_QUEUE *) MAKE_PTR(q->next); + if (q->next == MAKE_OFFSET(q)) + break; + if (count++ > 10) { - strcat(buf, "BAD NEXT QUEUE!!"); - break; + strcat(buf, "BAD NEXT QUEUE!!"); + break; } } - sprintf(elem, "--->%x", MAKE_OFFSET(q)); - strcat(buf, elem); - elog(SHMQUEUE_DEBUG_ELOG, "%s: %s", s, buf); + sprintf(elem, "--->%x", MAKE_OFFSET(q)); + strcat(buf, elem); + elog(SHMQUEUE_DEBUG_ELOG, "%s: %s", s, buf); } -#endif /* SHMQUEUE_DEBUG */ + +#endif /* SHMQUEUE_DEBUG */ /* * SHMQueueInsertHD -- put elem in queue between the queue head - * and its "prev" element. + * and its "prev" element. */ #ifdef NOT_USED void -SHMQueueInsertHD(SHM_QUEUE *queue, SHM_QUEUE *elem) +SHMQueueInsertHD(SHM_QUEUE * queue, SHM_QUEUE * elem) { - SHM_QUEUE *prevPtr = (SHM_QUEUE *) MAKE_PTR((queue)->prev); - SHMEM_OFFSET elemOffset = MAKE_OFFSET(elem); - - Assert(SHM_PTR_VALID(queue)); - Assert(SHM_PTR_VALID(elem)); - + SHM_QUEUE *prevPtr = (SHM_QUEUE *) MAKE_PTR((queue)->prev); + SHMEM_OFFSET elemOffset = MAKE_OFFSET(elem); + + Assert(SHM_PTR_VALID(queue)); + Assert(SHM_PTR_VALID(elem)); + #ifdef SHMQUEUE_DEBUG_HD - dumpQ(queue, "in SHMQueueInsertHD: begin"); -#endif /* SHMQUEUE_DEBUG_HD */ - - (elem)->next = prevPtr->next; - (elem)->prev = queue->prev; - (queue)->prev = elemOffset; - prevPtr->next = elemOffset; - + dumpQ(queue, "in SHMQueueInsertHD: begin"); +#endif /* SHMQUEUE_DEBUG_HD */ + + (elem)->next = prevPtr->next; + (elem)->prev = queue->prev; + (queue)->prev = elemOffset; + prevPtr->next = elemOffset; + #ifdef SHMQUEUE_DEBUG_HD - dumpQ(queue, "in SHMQueueInsertHD: end"); -#endif /* SHMQUEUE_DEBUG_HD */ + dumpQ(queue, "in SHMQueueInsertHD: end"); +#endif /* SHMQUEUE_DEBUG_HD */ } + #endif void -SHMQueueInsertTL(SHM_QUEUE *queue, SHM_QUEUE *elem) +SHMQueueInsertTL(SHM_QUEUE * queue, SHM_QUEUE * elem) { - SHM_QUEUE *nextPtr = (SHM_QUEUE *) MAKE_PTR((queue)->next); - SHMEM_OFFSET elemOffset = MAKE_OFFSET(elem); - - Assert(SHM_PTR_VALID(queue)); - Assert(SHM_PTR_VALID(elem)); - + SHM_QUEUE *nextPtr = (SHM_QUEUE *) MAKE_PTR((queue)->next); + SHMEM_OFFSET elemOffset = MAKE_OFFSET(elem); + + Assert(SHM_PTR_VALID(queue)); + Assert(SHM_PTR_VALID(elem)); + #ifdef SHMQUEUE_DEBUG_TL - dumpQ(queue, "in SHMQueueInsertTL: begin"); -#endif /* SHMQUEUE_DEBUG_TL */ - - (elem)->prev = nextPtr->prev; - (elem)->next = queue->next; - (queue)->next = elemOffset; - nextPtr->prev = elemOffset; - + dumpQ(queue, "in SHMQueueInsertTL: begin"); +#endif /* SHMQUEUE_DEBUG_TL */ + + (elem)->prev = nextPtr->prev; + (elem)->next = queue->next; + (queue)->next = elemOffset; + nextPtr->prev = elemOffset; + #ifdef SHMQUEUE_DEBUG_TL - dumpQ(queue, "in SHMQueueInsertTL: end"); -#endif /* SHMQUEUE_DEBUG_TL */ + dumpQ(queue, "in SHMQueueInsertTL: end"); +#endif /* SHMQUEUE_DEBUG_TL */ } /* @@ -203,52 +206,51 @@ SHMQueueInsertTL(SHM_QUEUE *queue, SHM_QUEUE *elem) * a larger structure, we want to return a pointer to the * whole structure rather than a pointer to its SHMQueue field. * I.E. struct { - * int stuff; - * SHMQueue elem; - * } ELEMType; + * int stuff; + * SHMQueue elem; + * } ELEMType; * when this element is in a queue (queue->next) is struct.elem. * nextQueue allows us to calculate the offset of the SHMQueue * field in the structure. * * call to SHMQueueFirst should take these parameters: * - * &(queueHead),&firstElem,&(firstElem->next) + * &(queueHead),&firstElem,&(firstElem->next) * * Note that firstElem may well be uninitialized. if firstElem * is initially K, &(firstElem->next) will be K+ the offset to * next. */ void -SHMQueueFirst(SHM_QUEUE *queue, Pointer *nextPtrPtr, SHM_QUEUE *nextQueue) +SHMQueueFirst(SHM_QUEUE * queue, Pointer * nextPtrPtr, SHM_QUEUE * nextQueue) { - SHM_QUEUE *elemPtr = (SHM_QUEUE *) MAKE_PTR((queue)->next); - - Assert(SHM_PTR_VALID(queue)); - *nextPtrPtr = (Pointer) (((unsigned long) *nextPtrPtr) + - ((unsigned long) elemPtr) - ((unsigned long) nextQueue)); - - /* - nextPtrPtr a ptr to a structure linked in the queue - nextQueue is the SHMQueue field of the structure - *nextPtrPtr - nextQueue is 0 minus the offset of the queue - field n the record - elemPtr + (*nextPtrPtr - nexQueue) is the start of the - structure containing elemPtr. - */ + SHM_QUEUE *elemPtr = (SHM_QUEUE *) MAKE_PTR((queue)->next); + + Assert(SHM_PTR_VALID(queue)); + *nextPtrPtr = (Pointer) (((unsigned long) *nextPtrPtr) + + ((unsigned long) elemPtr) - ((unsigned long) nextQueue)); + + /* + * nextPtrPtr a ptr to a structure linked in the queue nextQueue is + * the SHMQueue field of the structure nextPtrPtr - nextQueue is 0 + * minus the offset of the queue field n the record elemPtr + + * (*nextPtrPtr - nexQueue) is the start of the structure containing + * elemPtr. + */ } /* * SHMQueueEmpty -- TRUE if queue head is only element, FALSE otherwise */ bool -SHMQueueEmpty(SHM_QUEUE *queue) +SHMQueueEmpty(SHM_QUEUE * queue) { - Assert(SHM_PTR_VALID(queue)); - - if (queue->prev == MAKE_OFFSET(queue)) + Assert(SHM_PTR_VALID(queue)); + + if (queue->prev == MAKE_OFFSET(queue)) { - Assert(queue->next = MAKE_OFFSET(queue)); - return(TRUE); + Assert(queue->next = MAKE_OFFSET(queue)); + return (TRUE); } - return(FALSE); + return (FALSE); } |