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e7128e8dbb
Because of gcc -Wmissing-prototypes, all functions in dynamically loadable modules must have a separate prototype declaration. This is meant to detect global functions that are not declared in header files, but in cases where the function is called via dfmgr, this is redundant. Besides filling up space with boilerplate, this is a frequent source of compiler warnings in extension modules. We can fix that by creating the function prototype as part of the PG_FUNCTION_INFO_V1 macro, which such modules have to use anyway. That makes the code of modules cleaner, because there is one less place where the entry points have to be listed, and creates an additional check that functions have the right prototype. Remove now redundant prototypes from contrib and other modules.
138 lines
4.0 KiB
C
138 lines
4.0 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 "catalog/pg_type.h"
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#include "executor/spi.h"
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#include "commands/trigger.h"
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#include "utils/rel.h"
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#include "utils/timestamp.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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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. The above function must return -1 if name not found?
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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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/* 1 is the number of items in the arrays attnum and newdt.
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attnum is the positional number of the field to be updated.
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newdt is the new datetime stamp.
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NOTE that attnum and newdt are not arrays, but then a 1 element array
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is not an array any more then they are. Thus, they can be considered a
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one element array.
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*/
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rettuple = SPI_modifytuple(rel, rettuple, 1, &attnum, &newdt, NULL);
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if (rettuple == NULL)
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/* internal error */
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elog(ERROR, "moddatetime (%s): %d returned by SPI_modifytuple",
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relname, SPI_result);
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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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