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7e735035f2
The basic rule we follow here is to always first include 'postgres.h' or 'postgres_fe.h' whichever is applicable, then system header includes and then Postgres header includes. In this, we also follow that all the Postgres header includes are in order based on their ASCII value. We generally follow these rules, but the code has deviated in many places. This commit makes it consistent just for contrib modules. The later commits will enforce similar rules in other parts of code. Author: Vignesh C Reviewed-by: Amit Kapila Discussion: https://postgr.es/m/CALDaNm2Sznv8RR6Ex-iJO6xAdsxgWhCoETkaYX=+9DW3q0QCfA@mail.gmail.com
131 lines
3.7 KiB
C
131 lines
3.7 KiB
C
/*
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moddatetime.c
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contrib/spi/moddatetime.c
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What is this?
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It is a function to be called from a trigger for the purpose of updating
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a modification datetime stamp in a record when that record is UPDATEd.
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Credits
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This is 95%+ based on autoinc.c, which I used as a starting point as I do
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not really know what I am doing. I also had help from
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Jan Wieck <jwieck@debis.com> who told me about the timestamp_in("now") function.
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OH, me, I'm Terry Mackintosh <terry@terrym.com>
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*/
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#include "postgres.h"
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#include "access/htup_details.h"
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#include "catalog/pg_type.h"
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#include "commands/trigger.h"
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#include "executor/spi.h"
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#include "utils/builtins.h"
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#include "utils/rel.h"
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PG_MODULE_MAGIC;
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PG_FUNCTION_INFO_V1(moddatetime);
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Datum
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moddatetime(PG_FUNCTION_ARGS)
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{
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TriggerData *trigdata = (TriggerData *) fcinfo->context;
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Trigger *trigger; /* to get trigger name */
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int nargs; /* # of arguments */
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int attnum; /* positional number of field to change */
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Oid atttypid; /* type OID of field to change */
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Datum newdt; /* The current datetime. */
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bool newdtnull; /* null flag for it */
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char **args; /* arguments */
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char *relname; /* triggered relation name */
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Relation rel; /* triggered relation */
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HeapTuple rettuple = NULL;
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TupleDesc tupdesc; /* tuple description */
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if (!CALLED_AS_TRIGGER(fcinfo))
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/* internal error */
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elog(ERROR, "moddatetime: not fired by trigger manager");
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if (!TRIGGER_FIRED_FOR_ROW(trigdata->tg_event))
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/* internal error */
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elog(ERROR, "moddatetime: must be fired for row");
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if (!TRIGGER_FIRED_BEFORE(trigdata->tg_event))
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/* internal error */
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elog(ERROR, "moddatetime: must be fired before event");
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if (TRIGGER_FIRED_BY_INSERT(trigdata->tg_event))
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/* internal error */
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elog(ERROR, "moddatetime: cannot process INSERT events");
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else if (TRIGGER_FIRED_BY_UPDATE(trigdata->tg_event))
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rettuple = trigdata->tg_newtuple;
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else
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/* internal error */
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elog(ERROR, "moddatetime: cannot process DELETE events");
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rel = trigdata->tg_relation;
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relname = SPI_getrelname(rel);
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trigger = trigdata->tg_trigger;
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nargs = trigger->tgnargs;
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if (nargs != 1)
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/* internal error */
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elog(ERROR, "moddatetime (%s): A single argument was expected", relname);
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args = trigger->tgargs;
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/* must be the field layout? */
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tupdesc = rel->rd_att;
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/*
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* This gets the position in the tuple of the field we want. args[0] being
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* the name of the field to update, as passed in from the trigger.
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*/
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attnum = SPI_fnumber(tupdesc, args[0]);
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/*
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* This is where we check to see if the field we are supposed to update
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* even exists.
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*/
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if (attnum <= 0)
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ereport(ERROR,
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(errcode(ERRCODE_TRIGGERED_ACTION_EXCEPTION),
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errmsg("\"%s\" has no attribute \"%s\"",
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relname, args[0])));
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/*
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* Check the target field has an allowed type, and get the current
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* datetime as a value of that type.
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*/
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atttypid = SPI_gettypeid(tupdesc, attnum);
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if (atttypid == TIMESTAMPOID)
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newdt = DirectFunctionCall3(timestamp_in,
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CStringGetDatum("now"),
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ObjectIdGetDatum(InvalidOid),
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Int32GetDatum(-1));
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else if (atttypid == TIMESTAMPTZOID)
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newdt = DirectFunctionCall3(timestamptz_in,
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CStringGetDatum("now"),
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ObjectIdGetDatum(InvalidOid),
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Int32GetDatum(-1));
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else
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{
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ereport(ERROR,
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(errcode(ERRCODE_TRIGGERED_ACTION_EXCEPTION),
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errmsg("attribute \"%s\" of \"%s\" must be type TIMESTAMP or TIMESTAMPTZ",
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args[0], relname)));
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newdt = (Datum) 0; /* keep compiler quiet */
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}
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newdtnull = false;
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/* Replace the attnum'th column with newdt */
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rettuple = heap_modify_tuple_by_cols(rettuple, tupdesc,
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1, &attnum, &newdt, &newdtnull);
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/* Clean up */
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pfree(relname);
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return PointerGetDatum(rettuple);
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}
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