Refactor ParamListInfo initialization

There were six copies of identical nontrivial code.  Put it into a
function.

src/backend/commands/prepare.c

@@ -393,17 +393,7 @@ EvaluateParams(PreparedStatement *pstmt, List *params,
 	/* Prepare the expressions for execution */
 	exprstates = ExecPrepareExprList(params, estate);
 
-	paramLI = (ParamListInfo)
-		palloc(offsetof(ParamListInfoData, params) +
-			   num_params * sizeof(ParamExternData));
-	/* we have static list of params, so no hooks needed */
-	paramLI->paramFetch = NULL;
-	paramLI->paramFetchArg = NULL;
-	paramLI->paramCompile = NULL;
-	paramLI->paramCompileArg = NULL;
-	paramLI->parserSetup = NULL;
-	paramLI->parserSetupArg = NULL;
-	paramLI->numParams = num_params;
+	paramLI = makeParamList(num_params);
 
 	i = 0;
 	foreach(l, exprstates)

src/backend/executor/functions.c

@@ -906,21 +906,10 @@ postquel_sub_params(SQLFunctionCachePtr fcache,
 	if (nargs > 0)
 	{
 		ParamListInfo paramLI;
-		int			i;
 
 		if (fcache->paramLI == NULL)
 		{
-			paramLI = (ParamListInfo)
-				palloc(offsetof(ParamListInfoData, params) +
-					   nargs * sizeof(ParamExternData));
-			/* we have static list of params, so no hooks needed */
-			paramLI->paramFetch = NULL;
-			paramLI->paramFetchArg = NULL;
-			paramLI->paramCompile = NULL;
-			paramLI->paramCompileArg = NULL;
-			paramLI->parserSetup = NULL;
-			paramLI->parserSetupArg = NULL;
-			paramLI->numParams = nargs;
+			paramLI = makeParamList(nargs);
 			fcache->paramLI = paramLI;
 		}
 		else
@@ -929,7 +918,7 @@ postquel_sub_params(SQLFunctionCachePtr fcache,
 			Assert(paramLI->numParams == nargs);
 		}
 
-		for (i = 0; i < nargs; i++)
+		for (int i = 0; i < nargs; i++)
 		{
 			ParamExternData *prm = &paramLI->params[i];
 

src/backend/executor/spi.c

@@ -2387,20 +2387,9 @@ _SPI_convert_params(int nargs, Oid *argtypes,
 
 	if (nargs > 0)
 	{
-		int			i;
-
-		paramLI = (ParamListInfo) palloc(offsetof(ParamListInfoData, params) +
-										 nargs * sizeof(ParamExternData));
-		/* we have static list of params, so no hooks needed */
-		paramLI->paramFetch = NULL;
-		paramLI->paramFetchArg = NULL;
-		paramLI->paramCompile = NULL;
-		paramLI->paramCompileArg = NULL;
-		paramLI->parserSetup = NULL;
-		paramLI->parserSetupArg = NULL;
-		paramLI->numParams = nargs;
-
-		for (i = 0; i < nargs; i++)
+		paramLI = makeParamList(nargs);
+
+		for (int i = 0; i < nargs; i++)
 		{
 			ParamExternData *prm = &paramLI->params[i];
 

src/backend/nodes/params.c

@@ -22,6 +22,33 @@
 #include "utils/lsyscache.h"
 
 
+/*
+ * 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.
+ */
+ParamListInfo
+makeParamList(int numParams)
+{
+	ParamListInfo retval;
+	Size		size;
+
+	size = offsetof(ParamListInfoData, params) +
+		numParams * sizeof(ParamExternData);
+
+	retval = (ParamListInfo) palloc(size);
+	retval->paramFetch = NULL;
+	retval->paramFetchArg = NULL;
+	retval->paramCompile = NULL;
+	retval->paramCompileArg = NULL;
+	retval->parserSetup = NULL;
+	retval->parserSetupArg = NULL;
+	retval->numParams = numParams;
+
+	return retval;
+}
+
 /*
  * Copy a ParamListInfo structure.
  *
@@ -36,25 +63,13 @@ ParamListInfo
 copyParamList(ParamListInfo from)
 {
 	ParamListInfo retval;
-	Size		size;
-	int			i;
 
 	if (from == NULL || from->numParams <= 0)
 		return NULL;
 
-	size = offsetof(ParamListInfoData, params) +
-		from->numParams * sizeof(ParamExternData);
-
-	retval = (ParamListInfo) palloc(size);
-	retval->paramFetch = NULL;
-	retval->paramFetchArg = NULL;
-	retval->paramCompile = NULL;
-	retval->paramCompileArg = NULL;
-	retval->parserSetup = NULL;
-	retval->parserSetupArg = NULL;
-	retval->numParams = from->numParams;
+	retval = makeParamList(from->numParams);
 
-	for (i = 0; i < from->numParams; i++)
+	for (int i = 0; i < from->numParams; i++)
 	{
 		ParamExternData *oprm;
 		ParamExternData *nprm = &retval->params[i];
@@ -211,26 +226,14 @@ ParamListInfo
 RestoreParamList(char **start_address)
 {
 	ParamListInfo paramLI;
-	Size		size;
-	int			i;
 	int			nparams;
 
 	memcpy(&nparams, *start_address, sizeof(int));
 	*start_address += sizeof(int);
 
-	size = offsetof(ParamListInfoData, params) +
-		nparams * sizeof(ParamExternData);
-
-	paramLI = (ParamListInfo) palloc(size);
-	paramLI->paramFetch = NULL;
-	paramLI->paramFetchArg = NULL;
-	paramLI->paramCompile = NULL;
-	paramLI->paramCompileArg = NULL;
-	paramLI->parserSetup = NULL;
-	paramLI->parserSetupArg = NULL;
-	paramLI->numParams = nparams;
+	paramLI = makeParamList(nparams);
 
-	for (i = 0; i < nparams; i++)
+	for (int i = 0; i < nparams; i++)
 	{
 		ParamExternData *prm = &paramLI->params[i];
 

src/backend/tcop/postgres.c

@@ -1731,16 +1731,7 @@ exec_bind_message(StringInfo input_message)
 	 */
 	if (numParams > 0)
 	{
-		params = (ParamListInfo) palloc(offsetof(ParamListInfoData, params) +
-										numParams * sizeof(ParamExternData));
-		/* we have static list of params, so no hooks needed */
-		params->paramFetch = NULL;
-		params->paramFetchArg = NULL;
-		params->paramCompile = NULL;
-		params->paramCompileArg = NULL;
-		params->parserSetup = NULL;
-		params->parserSetupArg = NULL;
-		params->numParams = numParams;
+		params = makeParamList(numParams);
 
 		for (int paramno = 0; paramno < numParams; paramno++)
 		{

src/include/nodes/params.h

@@ -151,6 +151,7 @@ typedef struct ParamExecData
 
 
 /* Functions found in src/backend/nodes/params.c */
+extern ParamListInfo makeParamList(int numParams);
 extern ParamListInfo copyParamList(ParamListInfo from);
 extern Size EstimateParamListSpace(ParamListInfo paramLI);
 extern void SerializeParamList(ParamListInfo paramLI, char **start_address);

src/pl/plpgsql/src/pl_exec.c

@@ -3874,8 +3874,7 @@ plpgsql_estate_setup(PLpgSQL_execstate *estate,
 	estate->datum_context = CurrentMemoryContext;
 
 	/* initialize our ParamListInfo with appropriate hook functions */
-	estate->paramLI = (ParamListInfo)
-		palloc(offsetof(ParamListInfoData, params));
+	estate->paramLI = makeParamList(0);
 	estate->paramLI->paramFetch = plpgsql_param_fetch;
 	estate->paramLI->paramFetchArg = (void *) estate;
 	estate->paramLI->paramCompile = plpgsql_param_compile;