mirror of
https://git.postgresql.org/git/postgresql.git
synced 2024-07-20 13:49:37 +02:00
64d15e4240
This function formerly crashed if called as a statement-level trigger, or if a column-name argument wasn't given. In passing, add the trigger name to all error messages from the function. (None of them are expected cases, so this shouldn't pose any compatibility risk.) Marc Cousin, reviewed by Sawada Masahiko
119 lines
2.8 KiB
C
119 lines
2.8 KiB
C
/*
|
|
* PostgreSQL definitions for managed Large Objects.
|
|
*
|
|
* contrib/lo/lo.c
|
|
*
|
|
*/
|
|
|
|
#include "postgres.h"
|
|
|
|
#include "commands/trigger.h"
|
|
#include "executor/spi.h"
|
|
#include "libpq/be-fsstubs.h"
|
|
#include "utils/rel.h"
|
|
|
|
|
|
PG_MODULE_MAGIC;
|
|
|
|
#define atooid(x) ((Oid) strtoul((x), NULL, 10))
|
|
|
|
|
|
/* forward declarations */
|
|
Datum lo_manage(PG_FUNCTION_ARGS);
|
|
|
|
|
|
/*
|
|
* This is the trigger that protects us from orphaned large objects
|
|
*/
|
|
PG_FUNCTION_INFO_V1(lo_manage);
|
|
|
|
Datum
|
|
lo_manage(PG_FUNCTION_ARGS)
|
|
{
|
|
TriggerData *trigdata = (TriggerData *) fcinfo->context;
|
|
int attnum; /* attribute number to monitor */
|
|
char **args; /* Args containing attr name */
|
|
TupleDesc tupdesc; /* Tuple Descriptor */
|
|
HeapTuple rettuple; /* Tuple to be returned */
|
|
bool isdelete; /* are we deleting? */
|
|
HeapTuple newtuple; /* The new value for tuple */
|
|
HeapTuple trigtuple; /* The original value of tuple */
|
|
|
|
if (!CALLED_AS_TRIGGER(fcinfo)) /* internal error */
|
|
elog(ERROR, "%s: not fired by trigger manager",
|
|
trigdata->tg_trigger->tgname);
|
|
|
|
if (!TRIGGER_FIRED_FOR_ROW(trigdata->tg_event)) /* internal error */
|
|
elog(ERROR, "%s: must be fired for row",
|
|
trigdata->tg_trigger->tgname);
|
|
|
|
/*
|
|
* Fetch some values from trigdata
|
|
*/
|
|
newtuple = trigdata->tg_newtuple;
|
|
trigtuple = trigdata->tg_trigtuple;
|
|
tupdesc = trigdata->tg_relation->rd_att;
|
|
args = trigdata->tg_trigger->tgargs;
|
|
|
|
if (args == NULL) /* internal error */
|
|
elog(ERROR, "%s: no column name provided in the trigger definition",
|
|
trigdata->tg_trigger->tgname);
|
|
|
|
/* tuple to return to Executor */
|
|
if (TRIGGER_FIRED_BY_UPDATE(trigdata->tg_event))
|
|
rettuple = newtuple;
|
|
else
|
|
rettuple = trigtuple;
|
|
|
|
/* Are we deleting the row? */
|
|
isdelete = TRIGGER_FIRED_BY_DELETE(trigdata->tg_event);
|
|
|
|
/* Get the column we're interested in */
|
|
attnum = SPI_fnumber(tupdesc, args[0]);
|
|
|
|
if (attnum <= 0)
|
|
elog(ERROR, "%s: column \"%s\" does not exist",
|
|
trigdata->tg_trigger->tgname, args[0]);
|
|
|
|
/*
|
|
* Handle updates
|
|
*
|
|
* Here, if the value of the monitored attribute changes, then the large
|
|
* object associated with the original value is unlinked.
|
|
*/
|
|
if (newtuple != NULL)
|
|
{
|
|
char *orig = SPI_getvalue(trigtuple, tupdesc, attnum);
|
|
char *newv = SPI_getvalue(newtuple, tupdesc, attnum);
|
|
|
|
if (orig != NULL && (newv == NULL || strcmp(orig, newv) != 0))
|
|
DirectFunctionCall1(lo_unlink,
|
|
ObjectIdGetDatum(atooid(orig)));
|
|
|
|
if (newv)
|
|
pfree(newv);
|
|
if (orig)
|
|
pfree(orig);
|
|
}
|
|
|
|
/*
|
|
* Handle deleting of rows
|
|
*
|
|
* Here, we unlink the large object associated with the managed attribute
|
|
*/
|
|
if (isdelete)
|
|
{
|
|
char *orig = SPI_getvalue(trigtuple, tupdesc, attnum);
|
|
|
|
if (orig != NULL)
|
|
{
|
|
DirectFunctionCall1(lo_unlink,
|
|
ObjectIdGetDatum(atooid(orig)));
|
|
|
|
pfree(orig);
|
|
}
|
|
}
|
|
|
|
return PointerGetDatum(rettuple);
|
|
}
|