The 1st step to implement new type of scan,TidScan.

Now WHERE restriction on ctid is allowed though it is
sequentially scanned.

1 files changed, 126 insertions, 4 deletions

diff --git a/src/backend/utils/adt/tid.c b/src/backend/utils/adt/tid.c
index 9e4b81ec095..93fb33f8a95 100644
--- a/src/backend/utils/adt/tid.c
+++ b/src/backend/utils/adt/tid.c
@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/tid.c,v 1.11 1999/07/17 20:18:00 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/tid.c,v 1.12 1999/10/11 06:28:26 inoue Exp $
  *
  * NOTES
  *	  input routine largely stolen from boxin().
@@ -28,9 +28,9 @@
  * ----------------------------------------------------------------
  */
 ItemPointer
-tidin(char *str)
+tidin(const char *str)
 {
-	char	   *p,
+	const	char	   *p,
 			   *coord[NTIDARGS];
 	int			i;
 	ItemPointer result;
@@ -45,8 +45,12 @@ tidin(char *str)
 		if (*p == DELIM || (*p == LDELIM && !i))
 			coord[i++] = p + 1;
 
-	if (i < NTIDARGS - 1)
+	/* if (i < NTIDARGS - 1) */
+	if (i < NTIDARGS)
+	{
+		elog(ERROR, "%s invalid tid format", str);
 		return NULL;
+	}
 
 	blockNumber = (BlockNumber) atoi(coord[0]);
 	offsetNumber = (OffsetNumber) atoi(coord[1]);
@@ -70,6 +74,14 @@ tidout(ItemPointer itemPtr)
 	BlockId		blockId;
 	char		buf[32];
 	char	   *str;
+	static char *invalidTid = "()";
+
+	if (!itemPtr || !ItemPointerIsValid(itemPtr))
+	{
+		str = palloc(strlen(invalidTid));
+		strcpy(str, invalidTid);
+		return str;
+	}
 
 	blockId = &(itemPtr->ip_blkid);
 
@@ -83,3 +95,113 @@ tidout(ItemPointer itemPtr)
 
 	return str;
 }
+
+/*****************************************************************************
+ *	 PUBLIC ROUTINES														 *
+ *****************************************************************************/
+
+bool
+tideq(ItemPointer arg1, ItemPointer arg2)
+{
+	if ((!arg1) || (!arg2))
+	{
+		return false;
+	}
+	
+	return ( BlockIdGetBlockNumber(&(arg1->ip_blkid)) ==
+		 BlockIdGetBlockNumber(&(arg2->ip_blkid)) &&
+		 arg1->ip_posid == arg2->ip_posid );
+}
+
+bool
+tidne(ItemPointer arg1, ItemPointer arg2)
+{
+	if ((!arg1) || (!arg2))
+	{
+		return false;
+	}
+	return ( BlockIdGetBlockNumber(&(arg1->ip_blkid)) !=
+		 BlockIdGetBlockNumber(&(arg2->ip_blkid)) ||
+		 arg1->ip_posid != arg2->ip_posid );
+}
+
+text *
+tid_text(ItemPointer tid)
+{
+	char	   *str;
+
+	if (!tid)	return (text *)NULL;
+	str = tidout(tid);
+
+	return textin(str);
+}	/* tid_text() */
+
+ItemPointer
+text_tid(const text *string)
+{
+	ItemPointer	result;
+	char		*str;
+
+	if (!string)	return (ItemPointer)0;
+
+	str = textout(string);
+	result = tidin(str);
+	pfree(str);
+
+	return result;
+}	/* text_tid() */
+
+
+/*
+ *	Functions to get latest tid of a specified tuple.
+ *	Maybe these implementations is moved
+ *	to another place
+*/
+#include <utils/relcache.h>
+ItemPointer
+currtid_byreloid(Oid reloid, ItemPointer tid)
+{
+	ItemPointer	result = NULL, ret;
+	Relation	rel;
+
+	result = (ItemPointer) palloc(sizeof(ItemPointerData));
+	ItemPointerSetInvalid(result);
+	if (rel = heap_open(reloid, AccessShareLock), rel)
+	{
+		ret = heap_get_latest_tid(rel, SnapshotNow, tid);
+		if (ret)
+			ItemPointerCopy(ret, result);
+		heap_close(rel, AccessShareLock);
+	}
+	else
+		elog(ERROR, "Relation %u not found", reloid);
+
+	return result;
+}	/* currtid_byreloid() */
+
+ItemPointer
+currtid_byrelname(const text *relname, ItemPointer tid)
+{
+	ItemPointer	result = NULL, ret;
+	char		*str;
+	Relation	rel;
+
+	if (!relname)	return result;
+
+	str = textout(relname);
+
+	result = (ItemPointer) palloc(sizeof(ItemPointerData));
+	ItemPointerSetInvalid(result);
+	if (rel = heap_openr(str, AccessShareLock), rel)
+	{
+		ret = heap_get_latest_tid(rel, SnapshotNow, tid);
+		if (ret)
+			ItemPointerCopy(ret, result);
+		heap_close(rel, AccessShareLock);
+	}
+	else
+		elog(ERROR, "Relation %s not found", relname);
+	pfree(str);
+
+	return result;
+}	/* currtid_byrelname() */