database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-08-21 10:42:50 +03:00
Code Activity

Add support for invoking parser callback hooks via SPI and in cached plans.

Browse Source 
As proof of concept, modify plpgsql to use the hooks.  plpgsql is still
inserting $n symbols textually, but the "back end" of the parsing process now
goes through the ParamRef hook instead of using a fixed parameter-type array,
and then execution only fetches actually-referenced parameters, using a hook
added to ParamListInfo.

Although there's a lot left to be done in plpgsql, this already cures the
"if (TG_OP = 'INSERT' and NEW.foo ...)"  problem, as illustrated by the
changed regression test.
This commit is contained in:
Tom Lane
2009-11-04 22:26:08 +00:00
parent 48912acc08
commit 9bedd128d6
23 changed files with 1110 additions and 533 deletions
Download Patch File Download Diff File Expand all files Collapse all files

82
src/backend/nodes/params.c
View File

@@ -8,7 +8,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/nodes/params.c,v 1.11 2009/01/01 17:23:43 momjian Exp $
* $PostgreSQL: pgsql/src/backend/nodes/params.c,v 1.12 2009/11/04 22:26:06 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -16,6 +16,7 @@
#include "postgres.h"
#include "nodes/params.h"
#include "parser/parse_param.h"
#include "utils/datum.h"
#include "utils/lsyscache.h"
@@ -24,6 +25,11 @@
* Copy a ParamListInfo structure.
*
* The result is allocated in CurrentMemoryContext.
*
* Note: the intent of this function is to make a static, self-contained
* set of parameter values. If dynamic parameter hooks are present, we
* intentionally do not copy them into the result. Rather, we forcibly
* instantiate all available parameter values and copy the datum values.
*/
ParamListInfo
copyParamList(ParamListInfo from)
@@ -40,54 +46,76 @@ copyParamList(ParamListInfo from)
(from->numParams - 1) *sizeof(ParamExternData);
retval = (ParamListInfo) palloc(size);
memcpy(retval, from, size);
retval->paramFetch = NULL;
retval->paramFetchArg = NULL;
retval->parserSetup = NULL;
retval->parserSetupArg = NULL;
retval->numParams = from->numParams;
/*
* Flat-copy is not good enough for pass-by-ref data values, so make a
* pass over the array to copy those.
*/
for (i = 0; i < retval->numParams; i++)
for (i = 0; i < from->numParams; i++)
{
ParamExternData *prm = &retval->params[i];
ParamExternData *oprm = &from->params[i];
ParamExternData *nprm = &retval->params[i];
int16 typLen;
bool typByVal;
if (prm->isnull || !OidIsValid(prm->ptype))
/* give hook a chance in case parameter is dynamic */
if (!OidIsValid(oprm->ptype) && from->paramFetch != NULL)
(*from->paramFetch) (from, i+1);
/* flat-copy the parameter info */
*nprm = *oprm;
/* need datumCopy in case it's a pass-by-reference datatype */
if (nprm->isnull || !OidIsValid(nprm->ptype))
continue;
get_typlenbyval(prm->ptype, &typLen, &typByVal);
prm->value = datumCopy(prm->value, typByVal, typLen);
get_typlenbyval(nprm->ptype, &typLen, &typByVal);
nprm->value = datumCopy(nprm->value, typByVal, typLen);
}
return retval;
}
/*
* Extract an array of parameter type OIDs from a ParamListInfo.
* Set up the parser to treat the given list of run-time parameters
* as available external parameters during parsing of a new query.
*
* The result is allocated in CurrentMemoryContext.
* Note that the parser doesn't actually care about the *values* of the given
* parameters, only about their *types*. Also, the code that originally
* provided the ParamListInfo may have provided a setupHook, which should
* override applying parse_fixed_parameters().
*/
void
getParamListTypes(ParamListInfo params,
Oid **param_types, int *num_params)
setupParserWithParamList(struct ParseState *pstate,
ParamListInfo params)
{
Oid *ptypes;
int i;
if (params == NULL) /* no params, nothing to do */
return;
if (params == NULL || params->numParams <= 0)
/* If there is a parserSetup hook, it gets to do this */
if (params->parserSetup != NULL)
{
*param_types = NULL;
*num_params = 0;
(*params->parserSetup) (pstate, params->parserSetupArg);
return;
}
ptypes = (Oid *) palloc(params->numParams * sizeof(Oid));
*param_types = ptypes;
*num_params = params->numParams;
for (i = 0; i < params->numParams; i++)
/* Else, treat any available parameters as being of fixed type */
if (params->numParams > 0)
{
ParamExternData *prm = &params->params[i];
Oid *ptypes;
int i;
ptypes[i] = prm->ptype;
ptypes = (Oid *) palloc(params->numParams * sizeof(Oid));
for (i = 0; i < params->numParams; i++)
{
ParamExternData *prm = &params->params[i];
/* give hook a chance in case parameter is dynamic */
if (!OidIsValid(prm->ptype) && params->paramFetch != NULL)
(*params->paramFetch) (params, i+1);
ptypes[i] = prm->ptype;
}
parse_fixed_parameters(pstate, ptypes, params->numParams);
}
}