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dc13d5d307
postgresql/src/backend/commands/trigger.c
Vadim B. Mikheev dc13d5d307 Before row insertion triggers call.
1997-09-04 13:19:01 +00:00

613 lines
18 KiB
C
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/*-------------------------------------------------------------------------
*
* trigger.c--
* PostgreSQL TRIGGERs support code.
*
*-------------------------------------------------------------------------
*/
#include <string.h>
#include "postgres.h"
#include "nodes/parsenodes.h"
#include "nodes/memnodes.h"
#include "commands/trigger.h"
#include "catalog/catalog.h"
#include "catalog/catname.h"
#include "catalog/indexing.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_language.h"
#include "catalog/pg_trigger.h"
#include "access/genam.h"
#include "access/heapam.h"
#include "access/xact.h"
#include "storage/lmgr.h"
#include "storage/bufmgr.h"
#include "utils/mcxt.h"
#include "utils/inval.h"
#include "utils/builtins.h"
#ifndef NO_SECURITY
#include "miscadmin.h"
#include "utils/acl.h"
#include "utils/syscache.h"
#endif
TriggerData *CurrentTriggerData = NULL;
void RelationBuildTriggers (Relation relation);
void FreeTriggerDesc (Relation relation);
static void DescribeTrigger (TriggerDesc *trigdesc, Trigger *trigger);
extern void fmgr_info(Oid procedureId, func_ptr *function, int *nargs);
extern GlobalMemory CacheCxt;
void
CreateTrigger (CreateTrigStmt *stmt)
{
int16 tgtype;
int16 tgattr[8] = {0};
Datum values[Natts_pg_trigger];
char nulls[Natts_pg_trigger];
Relation rel;
Relation tgrel;
HeapScanDesc tgscan;
ScanKeyData key;
Relation relrdesc;
HeapTuple tuple;
ItemPointerData oldTID;
Relation idescs[Num_pg_trigger_indices];
Relation ridescs[Num_pg_class_indices];
MemoryContext oldcxt;
Oid fargtypes[8];
int found = 0;
int i;
if ( IsSystemRelationName (stmt->relname) )
elog(WARN, "CreateTrigger: can't create trigger for system relation %s", stmt->relname);
#ifndef NO_SECURITY
if ( !pg_ownercheck (GetPgUserName (), stmt->relname, RELNAME))
elog(WARN, "%s: %s", stmt->relname, aclcheck_error_strings[ACLCHECK_NOT_OWNER]);
#endif
rel = heap_openr (stmt->relname);
if ( !RelationIsValid (rel) )
elog (WARN, "CreateTrigger: there is no relation %s", stmt->relname);
RelationSetLockForWrite (rel);
TRIGGER_CLEAR_TYPE (tgtype);
if ( stmt->before )
TRIGGER_SETT_BEFORE (tgtype);
if ( stmt->row )
TRIGGER_SETT_ROW (tgtype);
for (i = 0; i < 3 && stmt->actions[i]; i++)
{
switch ( stmt->actions[i] )
{
case 'i':
if ( TRIGGER_FOR_INSERT (tgtype) )
elog (WARN, "CreateTrigger: double INSERT event specified");
TRIGGER_SETT_INSERT (tgtype);
break;
case 'd':
if ( TRIGGER_FOR_DELETE (tgtype) )
elog (WARN, "CreateTrigger: double DELETE event specified");
TRIGGER_SETT_DELETE (tgtype);
break;
case 'u':
if ( TRIGGER_FOR_UPDATE (tgtype) )
elog (WARN, "CreateTrigger: double UPDATE event specified");
TRIGGER_SETT_UPDATE (tgtype);
break;
default:
elog (WARN, "CreateTrigger: unknown event specified");
break;
}
}
/* Scan pg_trigger */
tgrel = heap_openr (TriggerRelationName);
RelationSetLockForWrite (tgrel);
ScanKeyEntryInitialize(&key, 0, Anum_pg_trigger_tgrelid,
ObjectIdEqualRegProcedure, rel->rd_id);
tgscan = heap_beginscan (tgrel, 0, NowTimeQual, 1, &key);
while (tuple = heap_getnext (tgscan, 0, (Buffer *)NULL), PointerIsValid(tuple))
{
Form_pg_trigger pg_trigger = (Form_pg_trigger) GETSTRUCT (tuple);
if ( namestrcmp (&(pg_trigger->tgname), stmt->trigname) == 0 )
elog (WARN, "CreateTrigger: trigger %s already defined on relation %s",
stmt->trigname, stmt->relname);
else
found++;
}
heap_endscan (tgscan);
memset (fargtypes, 0, 8 * sizeof(Oid));
tuple = SearchSysCacheTuple (PRONAME,
PointerGetDatum (stmt->funcname),
0, PointerGetDatum (fargtypes), 0);
if ( !HeapTupleIsValid (tuple) ||
((Form_pg_proc)GETSTRUCT(tuple))->prorettype != 0 ||
((Form_pg_proc)GETSTRUCT(tuple))->pronargs != 0 )
elog (WARN, "CreateTrigger: function %s () does not exist", stmt->funcname);
if ( ((Form_pg_proc)GETSTRUCT(tuple))->prolang != ClanguageId )
elog (WARN, "CreateTrigger: only C functions are supported");
memset (nulls, ' ', Natts_pg_trigger * sizeof (char));
values[Anum_pg_trigger_tgrelid - 1] = ObjectIdGetDatum (rel->rd_id);
values[Anum_pg_trigger_tgname - 1] = NameGetDatum (namein (stmt->trigname));
values[Anum_pg_trigger_tgfoid - 1] = ObjectIdGetDatum (tuple->t_oid);
values[Anum_pg_trigger_tgtype - 1] = Int16GetDatum (tgtype);
if ( stmt->args )
{
List *le;
char *args;
int16 nargs = length (stmt->args);
int len = 0;
foreach (le, stmt->args)
{
char *ar = (char *) lfirst (le);
len += strlen (ar) + 4;
}
args = (char *) palloc (len + 1);
args[0] = 0;
foreach (le, stmt->args)
sprintf (args + strlen (args), "%s\\000", (char *)lfirst (le));
values[Anum_pg_trigger_tgnargs - 1] = Int16GetDatum (nargs);
values[Anum_pg_trigger_tgargs - 1] = PointerGetDatum (byteain (args));
}
else
{
values[Anum_pg_trigger_tgnargs - 1] = Int16GetDatum (0);
values[Anum_pg_trigger_tgargs - 1] = PointerGetDatum (byteain (""));
}
values[Anum_pg_trigger_tgattr - 1] = PointerGetDatum (tgattr);
tuple = heap_formtuple (tgrel->rd_att, values, nulls);
heap_insert (tgrel, tuple);
CatalogOpenIndices (Num_pg_trigger_indices, Name_pg_trigger_indices, idescs);
CatalogIndexInsert (idescs, Num_pg_trigger_indices, tgrel, tuple);
CatalogCloseIndices (Num_pg_trigger_indices, idescs);
pfree (tuple);
RelationUnsetLockForWrite (tgrel);
heap_close (tgrel);
pfree (DatumGetPointer(values[Anum_pg_trigger_tgname - 1]));
pfree (DatumGetPointer(values[Anum_pg_trigger_tgargs - 1]));
/* update pg_class */
relrdesc = heap_openr (RelationRelationName);
tuple = ClassNameIndexScan (relrdesc, stmt->relname);
if ( !PointerIsValid (tuple) )
{
heap_close(relrdesc);
elog(WARN, "CreateTrigger: relation %s not found in pg_class", stmt->relname);
}
((Form_pg_class) GETSTRUCT(tuple))->reltriggers = found + 1;
RelationInvalidateHeapTuple (relrdesc, tuple);
oldTID = tuple->t_ctid;
heap_replace (relrdesc, &oldTID, tuple);
CatalogOpenIndices (Num_pg_class_indices, Name_pg_class_indices, ridescs);
CatalogIndexInsert (ridescs, Num_pg_class_indices, relrdesc, tuple);
CatalogCloseIndices (Num_pg_class_indices, ridescs);
pfree(tuple);
heap_close(relrdesc);
CommandCounterIncrement ();
oldcxt = MemoryContextSwitchTo ((MemoryContext)CacheCxt);
FreeTriggerDesc (rel);
rel->rd_rel->reltriggers = found + 1;
RelationBuildTriggers (rel);
MemoryContextSwitchTo (oldcxt);
heap_close (rel);
return;
}
void
DropTrigger (DropTrigStmt *stmt)
{
Relation rel;
Relation tgrel;
HeapScanDesc tgscan;
ScanKeyData key;
Relation relrdesc;
HeapTuple tuple;
ItemPointerData oldTID;
Relation ridescs[Num_pg_class_indices];
MemoryContext oldcxt;
int found = 0;
int tgfound = 0;
#ifndef NO_SECURITY
if ( !pg_ownercheck (GetPgUserName (), stmt->relname, RELNAME))
elog(WARN, "%s: %s", stmt->relname, aclcheck_error_strings[ACLCHECK_NOT_OWNER]);
#endif
rel = heap_openr (stmt->relname);
if ( !RelationIsValid (rel) )
elog (WARN, "DropTrigger: there is no relation %s", stmt->relname);
RelationSetLockForWrite (rel);
tgrel = heap_openr (TriggerRelationName);
RelationSetLockForWrite (tgrel);
ScanKeyEntryInitialize(&key, 0, Anum_pg_trigger_tgrelid,
ObjectIdEqualRegProcedure, rel->rd_id);
tgscan = heap_beginscan (tgrel, 0, NowTimeQual, 1, &key);
while (tuple = heap_getnext (tgscan, 0, (Buffer *)NULL), PointerIsValid(tuple))
{
Form_pg_trigger pg_trigger = (Form_pg_trigger) GETSTRUCT (tuple);
if ( namestrcmp (&(pg_trigger->tgname), stmt->trigname) == 0 )
{
heap_delete (tgrel, &tuple->t_ctid);
tgfound++;
}
else
found++;
}
if ( tgfound == 0 )
elog (WARN, "DropTrigger: there is no trigger %s on relation %s",
stmt->trigname, stmt->relname);
if ( tgfound > 1 )
elog (NOTICE, "DropTrigger: found (and deleted) %d trigger %s on relation %s",
tgfound, stmt->trigname, stmt->relname);
heap_endscan (tgscan);
RelationUnsetLockForWrite (tgrel);
heap_close (tgrel);
/* update pg_class */
relrdesc = heap_openr (RelationRelationName);
tuple = ClassNameIndexScan (relrdesc, stmt->relname);
if ( !PointerIsValid (tuple) )
{
heap_close(relrdesc);
elog(WARN, "DropTrigger: relation %s not found in pg_class", stmt->relname);
}
((Form_pg_class) GETSTRUCT(tuple))->reltriggers = found;
RelationInvalidateHeapTuple (relrdesc, tuple);
oldTID = tuple->t_ctid;
heap_replace (relrdesc, &oldTID, tuple);
CatalogOpenIndices (Num_pg_class_indices, Name_pg_class_indices, ridescs);
CatalogIndexInsert (ridescs, Num_pg_class_indices, relrdesc, tuple);
CatalogCloseIndices (Num_pg_class_indices, ridescs);
pfree(tuple);
heap_close(relrdesc);
CommandCounterIncrement ();
oldcxt = MemoryContextSwitchTo ((MemoryContext)CacheCxt);
FreeTriggerDesc (rel);
rel->rd_rel->reltriggers = found;
if ( found > 0 )
RelationBuildTriggers (rel);
MemoryContextSwitchTo (oldcxt);
heap_close (rel);
return;
}
void
RelationRemoveTriggers (Relation rel)
{
Relation tgrel;
HeapScanDesc tgscan;
ScanKeyData key;
HeapTuple tup;
tgrel = heap_openr (TriggerRelationName);
RelationSetLockForWrite (tgrel);
ScanKeyEntryInitialize(&key, 0, Anum_pg_trigger_tgrelid,
ObjectIdEqualRegProcedure, rel->rd_id);
tgscan = heap_beginscan (tgrel, 0, NowTimeQual, 1, &key);
while (tup = heap_getnext (tgscan, 0, (Buffer *)NULL), PointerIsValid(tup))
heap_delete (tgrel, &tup->t_ctid);
heap_endscan (tgscan);
RelationUnsetLockForWrite (tgrel);
heap_close (tgrel);
}
void
RelationBuildTriggers (Relation relation)
{
TriggerDesc *trigdesc = (TriggerDesc *) palloc (sizeof (TriggerDesc));
int ntrigs = relation->rd_rel->reltriggers;
Trigger *triggers = NULL;
Trigger *build;
Relation tgrel;
Form_pg_trigger pg_trigger;
Relation irel;
ScanKeyData skey;
HeapTuple tuple;
IndexScanDesc sd;
RetrieveIndexResult indexRes;
Buffer buffer;
ItemPointer iptr;
struct varlena *val;
bool isnull;
int found;
memset (trigdesc, 0, sizeof (TriggerDesc));
ScanKeyEntryInitialize(&skey,
(bits16)0x0,
(AttrNumber)1,
(RegProcedure)ObjectIdEqualRegProcedure,
ObjectIdGetDatum(relation->rd_id));
tgrel = heap_openr(TriggerRelationName);
RelationSetLockForRead (tgrel);
irel = index_openr(TriggerRelidIndex);
sd = index_beginscan(irel, false, 1, &skey);
for (found = 0; ; )
{
indexRes = index_getnext(sd, ForwardScanDirection);
if (!indexRes)
break;
iptr = &indexRes->heap_iptr;
tuple = heap_fetch(tgrel, NowTimeQual, iptr, &buffer);
pfree(indexRes);
if (!HeapTupleIsValid(tuple))
continue;
if ( found == ntrigs )
elog (WARN, "RelationBuildTriggers: unexpected record found for rel %.*s",
NAMEDATALEN, relation->rd_rel->relname.data);
pg_trigger = (Form_pg_trigger) GETSTRUCT (tuple);
if ( triggers == NULL )
triggers = (Trigger *) palloc (sizeof (Trigger));
else
triggers = (Trigger *) repalloc (triggers, (found + 1) * sizeof (Trigger));
build = &(triggers[found]);
build->tgname = nameout (&(pg_trigger->tgname));
build->tgfoid = pg_trigger->tgfoid;
build->tgfunc = NULL;
build->tgtype = pg_trigger->tgtype;
build->tgnargs = pg_trigger->tgnargs;
memcpy (build->tgattr, &(pg_trigger->tgattr), 8 * sizeof (int16));
val = (struct varlena*) fastgetattr (tuple,
Anum_pg_trigger_tgargs,
tgrel->rd_att, &isnull);
if ( isnull )
elog (WARN, "RelationBuildTriggers: tgargs IS NULL for rel %.*s",
NAMEDATALEN, relation->rd_rel->relname.data);
if ( build->tgnargs > 0 )
{
char *p;
int i;
val = (struct varlena*) fastgetattr (tuple,
Anum_pg_trigger_tgargs,
tgrel->rd_att, &isnull);
if ( isnull )
elog (WARN, "RelationBuildTriggers: tgargs IS NULL for rel %.*s",
NAMEDATALEN, relation->rd_rel->relname.data);
p = (char *) VARDATA (val);
build->tgargs = (char**) palloc (build->tgnargs * sizeof (char*));
for (i = 0; i < build->tgnargs; i++)
{
build->tgargs[i] = (char*) palloc (strlen (p) + 1);
strcpy (build->tgargs[i], p);
p += strlen (p) + 1;
}
}
else
build->tgargs = NULL;
found++;
ReleaseBuffer(buffer);
}
if ( found < ntrigs )
elog (WARN, "RelationBuildTriggers: %d record not found for rel %.*s",
ntrigs - found,
NAMEDATALEN, relation->rd_rel->relname.data);
index_endscan (sd);
pfree (sd);
index_close (irel);
RelationUnsetLockForRead (tgrel);
heap_close (tgrel);
/* Build trigdesc */
trigdesc->triggers = triggers;
for (found = 0; found < ntrigs; found++)
{
build = &(triggers[found]);
DescribeTrigger (trigdesc, build);
}
relation->trigdesc = trigdesc;
}
void
FreeTriggerDesc (Relation relation)
{
TriggerDesc *trigdesc = relation->trigdesc;
Trigger ***t;
Trigger *trigger;
int i;
if ( trigdesc == NULL )
return;
t = trigdesc->tg_before_statement;
for (i = 0; i < 3; i++)
if ( t[i] != NULL )
pfree (t[i]);
t = trigdesc->tg_before_row;
for (i = 0; i < 3; i++)
if ( t[i] != NULL )
pfree (t[i]);
t = trigdesc->tg_after_row;
for (i = 0; i < 3; i++)
if ( t[i] != NULL )
pfree (t[i]);
t = trigdesc->tg_after_statement;
for (i = 0; i < 3; i++)
if ( t[i] != NULL )
pfree (t[i]);
trigger = trigdesc->triggers;
for (i = 0; i < relation->rd_rel->reltriggers; i++)
{
pfree (trigger->tgname);
if ( trigger->tgnargs > 0 )
{
while ( --(trigger->tgnargs) >= 0 )
pfree (trigger->tgargs[trigger->tgnargs]);
pfree (trigger->tgargs);
}
trigger++;
}
pfree (trigdesc->triggers);
pfree (trigdesc);
relation->trigdesc = NULL;
return;
}
static void
DescribeTrigger (TriggerDesc *trigdesc, Trigger *trigger)
{
uint16 *n;
Trigger ***t, ***tp;
if ( TRIGGER_FOR_ROW (trigger->tgtype) ) /* Is ROW/STATEMENT trigger */
{
if ( TRIGGER_FOR_BEFORE (trigger->tgtype) )
{
n = trigdesc->n_before_row;
t = trigdesc->tg_before_row;
}
else
{
n = trigdesc->n_after_row;
t = trigdesc->tg_after_row;
}
}
else /* STATEMENT (NI) */
{
if ( TRIGGER_FOR_BEFORE (trigger->tgtype) )
{
n = trigdesc->n_before_statement;
t = trigdesc->tg_before_statement;
}
else
{
n = trigdesc->n_after_statement;
t = trigdesc->tg_after_statement;
}
}
if ( TRIGGER_FOR_INSERT (trigger->tgtype) )
{
tp = &(t[TRIGGER_EVENT_INSERT]);
if ( *tp == NULL )
*tp = (Trigger **) palloc (sizeof (Trigger *));
else
*tp = (Trigger **) repalloc (*tp, (n[TRIGGER_EVENT_INSERT] + 1) *
sizeof (Trigger *));
(*tp)[n[TRIGGER_EVENT_INSERT]] = trigger;
(n[TRIGGER_EVENT_INSERT])++;
}
if ( TRIGGER_FOR_DELETE (trigger->tgtype) )
{
tp = &(t[TRIGGER_EVENT_DELETE]);
if ( *tp == NULL )
*tp = (Trigger **) palloc (sizeof (Trigger *));
else
*tp = (Trigger **) repalloc (*tp, (n[TRIGGER_EVENT_DELETE] + 1) *
sizeof (Trigger *));
(*tp)[n[TRIGGER_EVENT_DELETE]] = trigger;
(n[TRIGGER_EVENT_DELETE])++;
}
if ( TRIGGER_FOR_UPDATE (trigger->tgtype) )
{
tp = &(t[TRIGGER_EVENT_UPDATE]);
if ( *tp == NULL )
*tp = (Trigger **) palloc (sizeof (Trigger *));
else
*tp = (Trigger **) repalloc (*tp, (n[TRIGGER_EVENT_UPDATE] + 1) *
sizeof (Trigger *));
(*tp)[n[TRIGGER_EVENT_UPDATE]] = trigger;
(n[TRIGGER_EVENT_UPDATE])++;
}
}
HeapTuple
ExecBRInsertTriggers (Relation rel, HeapTuple tuple)
{
int ntrigs = rel->trigdesc->n_before_row[TRIGGER_EVENT_INSERT];
Trigger **trigger = rel->trigdesc->tg_before_row[TRIGGER_EVENT_INSERT];
HeapTuple newtuple = tuple;
int nargs;
int i;
CurrentTriggerData = (TriggerData *) palloc (sizeof (TriggerData));
CurrentTriggerData->tg_event = TRIGGER_EVENT_INSERT|TRIGGER_EVENT_ROW;
CurrentTriggerData->tg_relation = rel;
CurrentTriggerData->tg_newtuple = NULL;
for (i = 0; i < ntrigs; i++)
{
CurrentTriggerData->tg_trigtuple = newtuple;
CurrentTriggerData->tg_trigger = trigger[i];
if ( trigger[i]->tgfunc == NULL )
fmgr_info (trigger[i]->tgfoid, &(trigger[i]->tgfunc), &nargs);
newtuple = (HeapTuple) ( (*(trigger[i]->tgfunc)) () );
if ( newtuple == NULL )
break;
}
pfree (CurrentTriggerData);
CurrentTriggerData = NULL;
return (newtuple);
}
void
ExecARInsertTriggers (Relation rel, HeapTuple tuple)
{
return;
}
bool
ExecBRDeleteTriggers (Relation rel, ItemPointer tupleid)
{
return (true);
}
void
ExecARDeleteTriggers (Relation rel, ItemPointer tupleid)
{
return;
}
HeapTuple
ExecBRUpdateTriggers (Relation rel, ItemPointer tupleid, HeapTuple tuple)
{
return (tuple);
}
void
ExecARUpdateTriggers (Relation rel, ItemPointer tupleid, HeapTuple tuple)
{
return;
}
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