1 files changed, 60 insertions, 3 deletions

diff --git a/src/backend/nodes/params.c b/src/backend/nodes/params.c
index ed2ee6a975a..1719119fc28 100644
--- a/src/backend/nodes/params.c
+++ b/src/backend/nodes/params.c
@@ -17,19 +17,27 @@
 
 #include "access/xact.h"
 #include "mb/stringinfo_mb.h"
-#include "nodes/bitmapset.h"
 #include "nodes/params.h"
+#include "parser/parse_node.h"
 #include "storage/shmem.h"
 #include "utils/datum.h"
 #include "utils/lsyscache.h"
 #include "utils/memutils.h"
 
 
+static void paramlist_parser_setup(ParseState *pstate, void *arg);
+static Node *paramlist_param_ref(ParseState *pstate, ParamRef *pref);
+
+
 /*
  * Allocate and initialize a new ParamListInfo structure.
  *
  * To make a new structure for the "dynamic" way (with hooks), pass 0 for
  * numParams and set numParams manually.
+ *
+ * A default parserSetup function is supplied automatically.  Callers may
+ * override it if they choose.  (Note that most use-cases for ParamListInfos
+ * will never use the parserSetup function anyway.)
  */
 ParamListInfo
 makeParamList(int numParams)
@@ -45,8 +53,8 @@ makeParamList(int numParams)
 	retval->paramFetchArg = NULL;
 	retval->paramCompile = NULL;
 	retval->paramCompileArg = NULL;
-	retval->parserSetup = NULL;
-	retval->parserSetupArg = NULL;
+	retval->parserSetup = paramlist_parser_setup;
+	retval->parserSetupArg = (void *) retval;
 	retval->paramValuesStr = NULL;
 	retval->numParams = numParams;
 
@@ -102,6 +110,55 @@ copyParamList(ParamListInfo from)
 	return retval;
 }
 
+
+/*
+ * Set up to parse a query containing references to parameters
+ * sourced from a ParamListInfo.
+ */
+static void
+paramlist_parser_setup(ParseState *pstate, void *arg)
+{
+	pstate->p_paramref_hook = paramlist_param_ref;
+	/* no need to use p_coerce_param_hook */
+	pstate->p_ref_hook_state = arg;
+}
+
+/*
+ * Transform a ParamRef using parameter type data from a ParamListInfo.
+ */
+static Node *
+paramlist_param_ref(ParseState *pstate, ParamRef *pref)
+{
+	ParamListInfo paramLI = (ParamListInfo) pstate->p_ref_hook_state;
+	int			paramno = pref->number;
+	ParamExternData *prm;
+	ParamExternData prmdata;
+	Param	   *param;
+
+	/* check parameter number is valid */
+	if (paramno <= 0 || paramno > paramLI->numParams)
+		return NULL;
+
+	/* give hook a chance in case parameter is dynamic */
+	if (paramLI->paramFetch != NULL)
+		prm = paramLI->paramFetch(paramLI, paramno, false, &prmdata);
+	else
+		prm = &paramLI->params[paramno - 1];
+
+	if (!OidIsValid(prm->ptype))
+		return NULL;
+
+	param = makeNode(Param);
+	param->paramkind = PARAM_EXTERN;
+	param->paramid = paramno;
+	param->paramtype = prm->ptype;
+	param->paramtypmod = -1;
+	param->paramcollid = get_typcollation(param->paramtype);
+	param->location = pref->location;
+
+	return (Node *) param;
+}
+
 /*
  * Estimate the amount of space required to serialize a ParamListInfo.
  */