plsample.c File Reference

#include "postgres.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_type.h"
#include "commands/event_trigger.h"
#include "commands/trigger.h"
#include "funcapi.h"
#include "utils/builtins.h"
#include "utils/lsyscache.h"
#include "utils/syscache.h"

Include dependency graph for plsample.c:

Go to the source code of this file.

Functions
	PG_FUNCTION_INFO_V1 (plsample_call_handler)
static Datum	plsample_func_handler (PG_FUNCTION_ARGS)
Datum	plsample_call_handler (PG_FUNCTION_ARGS)

Variables
	PG_MODULE_MAGIC

Function Documentation

PG_FUNCTION_INFO_V1()

PG_FUNCTION_INFO_V1

(

plsample_call_handler

)

plsample_call_handler()

Datum plsample_call_handler

(

PG_FUNCTION_ARGS

)

Definition at line 37 of file plsample.c.

References CALLED_AS_EVENT_TRIGGER, CALLED_AS_TRIGGER, PG_END_TRY, PG_FINALLY, PG_TRY, and plsample_func_handler().

{
    Datum       retval = (Datum) 0;

    PG_TRY();
    {
        /*
         * Determine if called as function or trigger and call appropriate
         * subhandler.
         */
        if (CALLED_AS_TRIGGER(fcinfo))
        {
            /*
             * This function has been called as a trigger function, where
             * (TriggerData *) fcinfo->context includes the information of the
             * context.
             */
        }
        else if (CALLED_AS_EVENT_TRIGGER(fcinfo))
        {
            /*
             * This function is called as an event trigger function, where
             * (EventTriggerData *) fcinfo->context includes the information
             * of the context.
             */
        }
        else
        {
            /* Regular function handler */
            retval = plsample_func_handler(fcinfo);
        }
    }
    PG_FINALLY();
    {
    }
    PG_END_TRY();

    return retval;
}

plsample_func_handler()

static Datum plsample_func_handler ( PG_FUNCTION_ARGS  )

static

Definition at line 83 of file plsample.c.

References ALLOCSET_SMALL_SIZES, AllocSetContextCreate, DatumGetCString, DirectFunctionCall1, elog, ereport, errmsg(), ERROR, fmgr_info_cxt(), get_func_arg_info(), GETSTRUCT, getTypeIOParam(), HeapTupleIsValid, i, InputFunctionCall(), NameStr, NOTICE, ObjectIdGetDatum, OutputFunctionCall(), palloc0(), PG_RETURN_DATUM, PG_RETURN_NULL, PROCOID, proname, pstrdup(), ReleaseSysCache(), SearchSysCache(), SearchSysCache1(), source, SysCacheGetAttr(), textout(), TopMemoryContext, TYPEOID, and value.

Referenced by plsample_call_handler().

{
    HeapTuple   pl_tuple;
    Datum       ret;
    char       *source;
    bool        isnull;
    FmgrInfo   *arg_out_func;
    Form_pg_type type_struct;
    HeapTuple   type_tuple;
    Form_pg_proc pl_struct;
    volatile MemoryContext proc_cxt = NULL;
    Oid        *argtypes;
    char      **argnames;
    char       *argmodes;
    char       *proname;
    Form_pg_type pg_type_entry;
    Oid         result_typioparam;
    Oid         prorettype;
    FmgrInfo    result_in_func;
    int         numargs;

    /* Fetch the source text of the function. */
    pl_tuple = SearchSysCache(PROCOID,
                              ObjectIdGetDatum(fcinfo->flinfo->fn_oid), 0, 0, 0);
    if (!HeapTupleIsValid(pl_tuple))
        elog(ERROR, "cache lookup failed for function %u",
             fcinfo->flinfo->fn_oid);

    /*
     * Extract and print the source text of the function.  This can be used as
     * a base for the function validation and execution.
     */
    pl_struct = (Form_pg_proc) GETSTRUCT(pl_tuple);
    proname = pstrdup(NameStr(pl_struct->proname));
    ret = SysCacheGetAttr(PROCOID, pl_tuple, Anum_pg_proc_prosrc, &isnull);
    if (isnull)
        elog(ERROR, "could not find source text of function \"%s\"",
             proname);
    source = DatumGetCString(DirectFunctionCall1(textout, ret));
    ereport(NOTICE,
            (errmsg("source text of function \"%s\": %s",
                    proname, source)));

    /*
     * Allocate a context that will hold all the Postgres data for the
     * procedure.
     */
    proc_cxt = AllocSetContextCreate(TopMemoryContext,
                                     "PL/Sample function",
                                     ALLOCSET_SMALL_SIZES);

    arg_out_func = (FmgrInfo *) palloc0(fcinfo->nargs * sizeof(FmgrInfo));
    numargs = get_func_arg_info(pl_tuple, &argtypes, &argnames, &argmodes);

    /*
     * Iterate through all of the function arguments, printing each input
     * value.
     */
    for (int i = 0; i < numargs; i++)
    {
        Oid         argtype = pl_struct->proargtypes.values[i];
        char       *value;

        type_tuple = SearchSysCache1(TYPEOID, ObjectIdGetDatum(argtype));
        if (!HeapTupleIsValid(type_tuple))
            elog(ERROR, "cache lookup failed for type %u", argtype);

        type_struct = (Form_pg_type) GETSTRUCT(type_tuple);
        fmgr_info_cxt(type_struct->typoutput, &(arg_out_func[i]), proc_cxt);
        ReleaseSysCache(type_tuple);

        value = OutputFunctionCall(&arg_out_func[i], fcinfo->args[i].value);
        ereport(NOTICE,
                (errmsg("argument: %d; name: %s; value: %s",
                        i, argnames[i], value)));
    }

    /* Type of the result */
    prorettype = pl_struct->prorettype;
    ReleaseSysCache(pl_tuple);

    /*
     * Get the required information for input conversion of the return value.
     *
     * If the function uses VOID as result, it is better to return NULL.
     * Anyway, let's be honest.  This is just a template, so there is not much
     * we can do here.  This returns NULL except if the result type is text,
     * where the result is the source text of the function.
     */
    if (prorettype != TEXTOID)
        PG_RETURN_NULL();

    type_tuple = SearchSysCache1(TYPEOID,
                                 ObjectIdGetDatum(prorettype));
    if (!HeapTupleIsValid(type_tuple))
        elog(ERROR, "cache lookup failed for type %u", prorettype);
    pg_type_entry = (Form_pg_type) GETSTRUCT(type_tuple);
    result_typioparam = getTypeIOParam(type_tuple);

    fmgr_info_cxt(pg_type_entry->typinput, &result_in_func, proc_cxt);
    ReleaseSysCache(type_tuple);

    ret = InputFunctionCall(&result_in_func, source, result_typioparam, -1);
    PG_RETURN_DATUM(ret);
}

Variable Documentation

PG_MODULE_MAGIC

PG_MODULE_MAGIC

Definition at line 27 of file plsample.c.