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The contents of command.c, creatinh.c, define.c, remove.c and rename.c
have been divided according to the type of object manipulated - so ALTER TABLE code is in tablecmds.c, aggregate commands in aggregatecmds.c and so on. A few common support routines remain in define.c (prototypes in src/include/commands/defrem.h). No code has been changed except for includes to reflect the new files. The prototypes for aggregatecmds.c, functioncmds.c, operatorcmds.c, and typecmds.c remain in src/include/commands/defrem.h. From John Gray <jgray@azuli.co.uk>
This commit is contained in:
Tom Lane
234
src/backend/commands/portalcmds.c
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234
src/backend/commands/portalcmds.c
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/*-------------------------------------------------------------------------
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*
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* portalcmds.c
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* portal support code
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*
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* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/commands/portalcmds.c,v 1.1 2002/04/15 05:22:03 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#include "postgres.h"
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#include "commands/portalcmds.h"
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#include "executor/executor.h"
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/*
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* PortalCleanup
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*/
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void
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PortalCleanup(Portal portal)
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{
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MemoryContext oldcontext;
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/*
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* sanity checks
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*/
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AssertArg(PortalIsValid(portal));
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AssertArg(portal->cleanup == PortalCleanup);
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/*
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* set proper portal-executor context before calling ExecMain.
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*/
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oldcontext = MemoryContextSwitchTo(PortalGetHeapMemory(portal));
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/*
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* tell the executor to shutdown the query
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*/
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ExecutorEnd(PortalGetQueryDesc(portal), PortalGetState(portal));
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/*
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* switch back to previous context
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*/
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MemoryContextSwitchTo(oldcontext);
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}
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/*
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* PerformPortalFetch
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*
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* name: name of portal
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* forward: forward or backward fetch?
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* count: # of tuples to fetch (0 implies all)
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* dest: where to send results
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* completionTag: points to a buffer of size COMPLETION_TAG_BUFSIZE
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* in which to store a command completion status string.
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*
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* completionTag may be NULL if caller doesn't want a status string.
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*/
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void
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PerformPortalFetch(char *name,
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bool forward,
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int count,
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CommandDest dest,
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char *completionTag)
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{
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Portal portal;
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QueryDesc *queryDesc;
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EState *estate;
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MemoryContext oldcontext;
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ScanDirection direction;
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CommandId savedId;
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bool temp_desc = false;
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/* initialize completion status in case of early exit */
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if (completionTag)
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strcpy(completionTag, (dest == None) ? "MOVE 0" : "FETCH 0");
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/*
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* sanity checks
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*/
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if (name == NULL)
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{
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elog(WARNING, "PerformPortalFetch: missing portal name");
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return;
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}
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/*
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* get the portal from the portal name
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*/
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portal = GetPortalByName(name);
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if (!PortalIsValid(portal))
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{
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elog(WARNING, "PerformPortalFetch: portal \"%s\" not found",
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name);
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return;
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}
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/*
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* switch into the portal context
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*/
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oldcontext = MemoryContextSwitchTo(PortalGetHeapMemory(portal));
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queryDesc = PortalGetQueryDesc(portal);
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estate = PortalGetState(portal);
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/*
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* If the requested destination is not the same as the query's
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* original destination, make a temporary QueryDesc with the proper
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* destination. This supports MOVE, for example, which will pass in
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* dest = None.
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*
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* EXCEPTION: if the query's original dest is RemoteInternal (ie, it's a
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* binary cursor) and the request is Remote, we do NOT override the
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* original dest. This is necessary since a FETCH command will pass
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* dest = Remote, not knowing whether the cursor is binary or not.
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*/
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if (dest != queryDesc->dest &&
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!(queryDesc->dest == RemoteInternal && dest == Remote))
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{
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QueryDesc *qdesc = (QueryDesc *) palloc(sizeof(QueryDesc));
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memcpy(qdesc, queryDesc, sizeof(QueryDesc));
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qdesc->dest = dest;
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queryDesc = qdesc;
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temp_desc = true;
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}
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/*
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* Restore the scanCommandId that was current when the cursor was
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* opened. This ensures that we see the same tuples throughout the
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* execution of the cursor.
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*/
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savedId = GetScanCommandId();
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SetScanCommandId(PortalGetCommandId(portal));
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/*
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* Determine which direction to go in, and check to see if we're
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* already at the end of the available tuples in that direction. If
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* so, set the direction to NoMovement to avoid trying to fetch any
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* tuples. (This check exists because not all plan node types
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* are robust about being called again if they've already returned
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* NULL once.) Then call the executor (we must not skip this, because
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* the destination needs to see a setup and shutdown even if no tuples
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* are available). Finally, update the atStart/atEnd state depending
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* on the number of tuples that were retrieved.
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*/
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if (forward)
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{
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if (portal->atEnd)
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direction = NoMovementScanDirection;
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else
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direction = ForwardScanDirection;
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ExecutorRun(queryDesc, estate, direction, (long) count);
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if (estate->es_processed > 0)
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portal->atStart = false; /* OK to back up now */
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if (count <= 0 || (int) estate->es_processed < count)
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portal->atEnd = true; /* we retrieved 'em all */
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}
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else
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{
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if (portal->atStart)
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direction = NoMovementScanDirection;
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else
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direction = BackwardScanDirection;
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ExecutorRun(queryDesc, estate, direction, (long) count);
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if (estate->es_processed > 0)
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portal->atEnd = false; /* OK to go forward now */
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if (count <= 0 || (int) estate->es_processed < count)
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portal->atStart = true; /* we retrieved 'em all */
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}
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/* Return command status if wanted */
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if (completionTag)
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snprintf(completionTag, COMPLETION_TAG_BUFSIZE, "%s %u",
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(dest == None) ? "MOVE" : "FETCH",
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estate->es_processed);
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/*
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* Restore outer command ID.
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*/
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SetScanCommandId(savedId);
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/*
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* Clean up and switch back to old context.
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*/
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if (temp_desc)
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pfree(queryDesc);
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MemoryContextSwitchTo(oldcontext);
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}
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/*
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* PerformPortalClose
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*/
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void
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PerformPortalClose(char *name, CommandDest dest)
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{
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Portal portal;
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/*
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* sanity checks
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*/
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if (name == NULL)
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{
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elog(WARNING, "PerformPortalClose: missing portal name");
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return;
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}
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/*
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* get the portal from the portal name
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*/
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portal = GetPortalByName(name);
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if (!PortalIsValid(portal))
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{
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elog(WARNING, "PerformPortalClose: portal \"%s\" not found",
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name);
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return;
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}
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/*
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* Note: PortalCleanup is called as a side-effect
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*/
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PortalDrop(portal);
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}
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