Index: src/backend/commands/rename.c
===================================================================
RCS file: /projects/cvsroot/pgsql/src/backend/commands/rename.c,v
retrieving revision 1.61
diff -r1.61 rename.c
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> #include "catalog/pg_trigger.h"
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> #include "commands/trigger.h" /* pg_trigger->tgargs bytea def */
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> #include "utils/builtins.h"
> #include "utils/fmgroids.h"
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> /* 
>  * update_trigger_tgargs - synchronize tgargs with renamed column.
>  *    This should only be called after we /know/ the column name
>  *    was renamed.
>  *
>  * related: CreateTrigger - format of tgargs
>  *
>  * What happens here is best said in SQL:
>  *
>  *   UPDATE pg_trigger SET tgargs = update_tgargs()
>  *   WHERE tgrelid = ${attoid}
>  *      OR tgconstrrelid = ${attoid};
>  *
>  *
>  *     the pseudo-function updated_tgargs()'s description and behavior 
>  *     is as follows.
>  *
>  *     tgargs split on '\0' into an array:
>  *       tgargs[0] = trigger_name
>  *       tgargs[1] = table_1
>  *       tgargs[2] = table_2
>  *       tgargs[3] = (brent's a lazy monkey)
>  *       tgargs[4] = column_1
>  *       tgargs[5] = column_2
>  *     
>  *     An updated tgargs array will be created, setting 
>  *     column_N = ${newattname} where table_N = ${relname}
>  *
>  *     if( tgargs[1] == relname )
>  *       tgargs[4] = newattname
>  *     else if( tgargs[2] == relname )
>  *       tgargs[5] = newattname
>  *
>  *     This updated tgargs array is then rejoined with '\0' and would 
>  *     be returned from the pseudo-function to update the tuple to
>  *     contain the working tgargs.
>  *
>  *
>  *     TODO: there are two blocks of identical code. consolidate.
>  *           It's a hassle to make changes twice ;-)  Learn to
>  *           program in C -- dbv 20011110
>  */
> 
> static void 
> update_trigger_tgargs(const char* relname, const char* newattname)
> {
>   Relation          rel;
>   Relation          tgrel;
>   ScanKeyData       skey;
>   HeapScanDesc      tgscan;
>   HeapTuple         tuple;
> 	bool		          isnull;
>   Datum             values[Natts_pg_trigger];
>   char              nulls[Natts_pg_trigger];
>   char              replaces[Natts_pg_trigger];
>  
>   rel = heap_openr(relname, AccessExclusiveLock);
> 
>   /* update trigger tgargs for this relname */
>   tgrel = heap_openr(TriggerRelationName, AccessShareLock);
>   ScanKeyEntryInitialize(&skey, 0, Anum_pg_trigger_tgrelid,
>                      F_OIDEQ, RelationGetRelid(rel));
>   tgscan = heap_beginscan(tgrel, 0, SnapshotNow, 1, &skey);
>   while (HeapTupleIsValid(tuple = heap_getnext(tgscan, 0)))
>   {
>     Form_pg_trigger pg_trigger = (Form_pg_trigger) GETSTRUCT(tuple);
> 		struct varlena* val = (struct varlena *) fastgetattr(tuple,
> 											 Anum_pg_trigger_tgargs,
> 											 tgrel->rd_att, &isnull);
>     if(!isnull){
>       int i = 0;
>       char* ap;
>       int newlen = val->vl_len;
>       char* argp = (char*)VARDATA(val);
>       struct varlena* newtgargs;
> 
>       int               ia;
>   
>       char** arga = (char **)
> 				MemoryContextAlloc(CurrentMemoryContext,
> 								   pg_trigger->tgnargs * sizeof(char *));
> 
>       /* create an array of the tgargs parts */
>       for (i = 0; i < pg_trigger->tgnargs; i++)
> 			{
> 				arga[i] = MemoryContextStrdup(CurrentMemoryContext,argp);
> 				argp += strlen(argp)+1;
> 			}
> 
>       /* fix the column names */
>       if( strcmp(arga[RI_FK_RELNAME_ARGNO],relname) == 0 )
>       {
>         newlen += ( strlen(newattname) 
>                   - strlen(arga[RI_FK_ATTNAME_ARGNO]) );
>         pfree(arga[RI_FK_ATTNAME_ARGNO]);
>         arga[RI_FK_ATTNAME_ARGNO] 
>               = MemoryContextStrdup(CurrentMemoryContext,newattname);
>       }
>       else if( strcmp(arga[RI_PK_RELNAME_ARGNO],relname) == 0 )
>       {
>         newlen += (strlen(newattname) 
>                   - strlen(arga[RI_PK_ATTNAME_ARGNO]) );
>         pfree(arga[RI_PK_ATTNAME_ARGNO]);
>         arga[RI_PK_ATTNAME_ARGNO] 
>               = MemoryContextStrdup(CurrentMemoryContext,newattname);
>       }
>       
>       /* 
>        * now, reconstruct the byte area 
>        * 
>        * FRAGILE:? I'd feel better /not/ manually creating this varlena.
>        */
>       newtgargs = (struct varlena*)MemoryContextAlloc(CurrentMemoryContext,sizeof(struct varlena*) + newlen);
>       newtgargs->vl_len = newlen;
>       memset(newtgargs->vl_dat,0x00,newlen);
>       ap = newtgargs->vl_dat;
>       for (i = 0; i < pg_trigger->tgnargs; i++)
> 			{
>         char* sp = arga[i];
>         while( (*ap++ = *sp++) );
> 			}
>       
>       for (ia = 0; ia < Natts_pg_trigger; ++ia)
>       {
>         values[ia] = (Datum) 0;
>         replaces[ia] = ' ';
>         nulls[ia] = ' ';
>       }
>       values[Anum_pg_trigger_tgargs - 1] = PointerGetDatum(newtgargs);
>       replaces[Anum_pg_trigger_tgargs - 1] = 'r';
> 
>       tuple = heap_modifytuple(tuple,tgrel,values,nulls,replaces);
>       simple_heap_update(tgrel,&tuple->t_self,tuple);
> 
>       /* synchronize trigger indexes for updated tuple */
>       {
>   			Relation	irelations[Num_pg_attr_indices];
>   			CatalogOpenIndices(Num_pg_trigger_indices, Name_pg_trigger_indices, irelations);
>   			CatalogIndexInsert(irelations, Num_pg_trigger_indices, tgrel, tuple);
>   			CatalogCloseIndices(Num_pg_trigger_indices, irelations);
>   		}
> 
>       /* free up our scratch memory... */
>       for (i = 0; i < pg_trigger->tgnargs; i++)
> 				pfree(arga[i]);
>       pfree(arga);
>       pfree(newtgargs);
>     }
> 	  heap_freetuple(tuple);
>   }
>   heap_endscan(tgscan);
>   heap_close(tgrel, AccessShareLock);
> 
>   /* update referenced relation trigger tgargs */
>   tgrel = heap_openr(TriggerRelationName, AccessShareLock);
>   ScanKeyEntryInitialize(&skey, 0, Anum_pg_trigger_tgconstrrelid,
>                      F_OIDEQ, RelationGetRelid(rel));
>   tgscan = heap_beginscan(tgrel, 0, SnapshotNow, 1, &skey);
>   while (HeapTupleIsValid(tuple = heap_getnext(tgscan, 0)))
>   {
>     Form_pg_trigger pg_trigger = (Form_pg_trigger) GETSTRUCT(tuple);
> 		struct varlena* val = (struct varlena *) fastgetattr(tuple,
> 											 Anum_pg_trigger_tgargs,
> 											 tgrel->rd_att, &isnull);
>     if(!isnull){
>       int i = 0;
>       char* ap;
>       int newlen = val->vl_len;
>       char* argp = (char*)VARDATA(val);
>       struct varlena* newtgargs;
> 
>       int               ia;
>   
>       char** arga = (char **)
> 				MemoryContextAlloc(CurrentMemoryContext,
> 								   pg_trigger->tgnargs * sizeof(char *));
> 
>       /* create an array of the tgargs parts */
>       for (i = 0; i < pg_trigger->tgnargs; i++)
> 			{
> 				arga[i] = MemoryContextStrdup(CurrentMemoryContext,argp);
> 				argp += strlen(argp)+1;
> 			}
>       
>       /* fix the column names */
>       if( strcmp(arga[RI_FK_RELNAME_ARGNO],relname) == 0 )
>       {
>         newlen += ( strlen(newattname) 
>                   - strlen(arga[RI_FK_ATTNAME_ARGNO]) );
>         pfree(arga[RI_FK_ATTNAME_ARGNO]);
>         arga[RI_FK_ATTNAME_ARGNO] 
>               = MemoryContextStrdup(CurrentMemoryContext,newattname);
>       }
>       else if( strcmp(arga[RI_PK_RELNAME_ARGNO],relname) == 0 )
>       {
>         newlen += (strlen(newattname) 
>                   - strlen(arga[RI_PK_ATTNAME_ARGNO]) );
>         pfree(arga[RI_PK_ATTNAME_ARGNO]);
>         arga[RI_PK_ATTNAME_ARGNO] 
>               = MemoryContextStrdup(CurrentMemoryContext,newattname);
>       }
>       
>       /* 
>        * now, reconstruct the byte area 
>        * 
>        * FRAGILE:? I'd feel better /not/ manually creating this varlena.
>        */
>       newtgargs = (struct varlena*)MemoryContextAlloc(CurrentMemoryContext,sizeof(struct varlena*) + newlen);
>       newtgargs->vl_len = newlen;
>       memset(newtgargs->vl_dat,0x00,newlen);
>       ap = newtgargs->vl_dat;
>       for (i = 0; i < pg_trigger->tgnargs; i++)
> 			{
>         char* sp = arga[i];
>         while( (*ap++ = *sp++) );
> 			}
> 
>       for (ia = 0; ia < Natts_pg_trigger; ++ia)
>       {
>         values[ia] = (Datum) 0;
>         replaces[ia] = ' ';
>         nulls[ia] = ' ';
>       }
>       values[Anum_pg_trigger_tgargs - 1] = PointerGetDatum(newtgargs);
>       replaces[Anum_pg_trigger_tgargs - 1] = 'r';
> 
>       tuple = heap_modifytuple(tuple,tgrel,values,nulls,replaces);
>       simple_heap_update(tgrel,&tuple->t_self,tuple);
> 
>       /* synchronize trigger indexes for updated tuple */
>       {
>   			Relation	irelations[Num_pg_attr_indices];
>   			CatalogOpenIndices(Num_pg_trigger_indices, Name_pg_trigger_indices, irelations);
>   			CatalogIndexInsert(irelations, Num_pg_trigger_indices, tgrel, tuple);
>   			CatalogCloseIndices(Num_pg_trigger_indices, irelations);
>   		}
>       
>       /* free up our scratch memory... */
>       for (i = 0; i < pg_trigger->tgnargs; i++)
> 				pfree(arga[i]);
>       pfree(arga);
>       pfree(newtgargs);
>     }
> 	  heap_freetuple(tuple);
>   }
>   heap_endscan(tgscan);
>   heap_close(tgrel, AccessShareLock);
> 
>   heap_close(rel, NoLock);
> }
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< 	Oid			relid;
---
> 	Oid			relid; 
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< 
---
>   
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>   
>   /* update the tgargs for for any tuple in pg_trigger that 
>    * refers to this column.
>    */
>   update_trigger_tgargs(relname, newattname);
>