From 9aebb56bde723f7dce7d932b8005bc41bd094a21 Mon Sep 17 00:00:00 2001
From: Petr Jelinek <pjmodos@pjmodos.net>
Date: Fri, 8 Aug 2014 14:55:47 +0200
Subject: [PATCH 27/44] deparse: Support ALTER FUNCTION

---
 src/backend/tcop/deparse_utility.c | 114 ++++++++++++++++++++++++++++++++++++-
 1 file changed, 113 insertions(+), 1 deletion(-)

diff --git a/src/backend/tcop/deparse_utility.c b/src/backend/tcop/deparse_utility.c
index 2177eac..b208f56 100644
--- a/src/backend/tcop/deparse_utility.c
+++ b/src/backend/tcop/deparse_utility.c
@@ -2989,6 +2989,118 @@ deparse_CreateFunction(Oid objectId, Node *parsetree)
 }
 
 /*
+ * deparse_AlterFunctionStmt
+ *		Deparse a AlterFunctionStmt (ALTER FUNCTION)
+ *
+ * Given a function OID and the parsetree that created it, return the JSON
+ * blob representing the alter command.
+ *
+ * XXX this is missing the per-function custom-GUC thing.
+ */
+static ObjTree *
+deparse_AlterFunction(Oid objectId, Node *parsetree)
+{
+	AlterFunctionStmt *node = (AlterFunctionStmt *) parsetree;
+	ObjTree	   *alterFunc;
+	ObjTree	   *sign;
+	HeapTuple	procTup;
+	Form_pg_proc procForm;
+	List	   *params;
+	List	   *elems = NIL;
+	ListCell   *cell;
+	int			i;
+
+	/* get the pg_proc tuple */
+	procTup = SearchSysCache1(PROCOID, objectId);
+	if (!HeapTupleIsValid(procTup))
+		elog(ERROR, "cache lookup failure for function with OID %u",
+			 objectId);
+	procForm = (Form_pg_proc) GETSTRUCT(procTup);
+
+	alterFunc = new_objtree_VA("ALTER FUNCTION %{signature}s %{definition: }s", 0);
+
+	sign = new_objtree_VA("%{identity}D(%{arguments:, }s)", 0);
+
+	params = NIL;
+
+	/*
+	 * ALTER FUNCTION does not change signature so we can use catalog
+	 * to get input type Oids.
+	 */
+	for (i = 0; i < procForm->pronargs; i++)
+	{
+		ObjTree	   *tmp = new_objtree_VA("%{type}T", 0);
+
+		append_object_object(tmp, "type",
+							 new_objtree_for_type(procForm->proargtypes.values[i], -1));
+		params = lappend(params, new_object_object(tmp));
+	}
+
+	append_array_object(sign, "arguments", params);
+	append_object_object(sign, "identity",
+						 new_objtree_for_qualname_id(ProcedureRelationId,
+													 objectId));
+	append_object_object(alterFunc, "signature", sign);
+
+	foreach(cell, node->actions)
+	{
+		DefElem	*defel = (DefElem *) lfirst(cell);
+		ObjTree	   *tmp = NULL;
+
+		if (strcmp(defel->defname, "volatility") == 0)
+		{
+			tmp = new_objtree_VA(strVal(defel->arg), 0);
+		}
+		else if (strcmp(defel->defname, "strict") == 0)
+		{
+			tmp = new_objtree_VA(intVal(defel->arg) ?
+								 "RETURNS NULL ON NULL INPUT" :
+								 "CALLED ON NULL INPUT", 0);
+		}
+		else if (strcmp(defel->defname, "security") == 0)
+		{
+			tmp = new_objtree_VA(intVal(defel->arg) ?
+								 "SECURITY DEFINER" : "SECURITY INVOKER", 0);
+		}
+		else if (strcmp(defel->defname, "leakproof") == 0)
+		{
+			tmp = new_objtree_VA(intVal(defel->arg) ?
+								 "LEAKPROOF" : "", 0);
+		}
+		else if (strcmp(defel->defname, "cost") == 0)
+		{
+			tmp = new_objtree_VA("COST %{cost}n", 1,
+								 "cost", ObjTypeFloat,
+								 defGetNumeric(defel));
+		}
+		else if (strcmp(defel->defname, "rows") == 0)
+		{
+			tmp = new_objtree_VA("ROWS %{rows}n", 0);
+			if (defGetNumeric(defel) == 0)
+				append_bool_object(tmp, "present", false);
+			else
+				append_float_object(tmp, "rows",
+									defGetNumeric(defel));
+		}
+		else if (strcmp(defel->defname, "set") == 0)
+		{
+			VariableSetStmt *sstmt = (VariableSetStmt *) defel->arg;
+			char *value = ExtractSetVariableArgs(sstmt);
+
+			tmp = deparse_FunctionSet(sstmt->kind, sstmt->name, value);
+		}
+
+		elems = lappend(elems, new_object_object(tmp));
+	}
+
+	append_array_object(alterFunc, "definition", elems);
+
+	ReleaseSysCache(procTup);
+
+	return alterFunc;
+}
+
+/*
  * Return the given object type as a string.
  */
 static const char *
@@ -4828,7 +4940,7 @@ deparse_simple_command(StashedCommand *cmd)
 			break;
 
 		case T_AlterFunctionStmt:
-			elog(ERROR, "unimplemented deparse of %s", CreateCommandTag(parsetree));
+			command = deparse_AlterFunction(objectId, parsetree);
 			break;
 
 		case T_RuleStmt:
-- 
2.1.4