Adds SQL/JSON constructors to ruleutils_15.c

Relevant PG commits:
f4fb45d15c59d7add2e1b81a9d477d0119a9691a
cc7401d5ca498a84d9b47fd2e01cebd8e830e558

src/backend/distributed/deparser/ruleutils_15.c

@@ -425,6 +425,12 @@ static void get_coercion_expr(Node *arg, deparse_context *context,
 				  Node *parentNode);
 static void get_const_expr(Const *constval, deparse_context *context,
 			   int showtype);
+static void get_json_constructor(JsonConstructorExpr *ctor,
+								 deparse_context *context, bool showimplicit);
+static void get_json_agg_constructor(JsonConstructorExpr *ctor,
+									 deparse_context *context,
+									 const char *funcname,
+									 bool is_json_objectagg);
 static void get_const_collation(Const *constval, deparse_context *context);
 static void simple_quote_literal(StringInfo buf, const char *val);
 static void get_sublink_expr(SubLink *sublink, deparse_context *context);
@@ -2885,7 +2891,8 @@ get_rule_sortgroupclause(Index ref, List *tlist, bool force_colno,
 		bool		need_paren = (PRETTY_PAREN(context)
 								  || IsA(expr, FuncExpr)
 								  || IsA(expr, Aggref)
-								  || IsA(expr, WindowFunc));
+								  || IsA(expr, WindowFunc)
+								  || IsA(expr, JsonConstructorExpr));
 
 		if (need_paren)
 			appendStringInfoChar(context->buf, '(');
@@ -4846,6 +4853,7 @@ isSimpleNode(Node *node, Node *parentNode, int prettyFlags)
         case T_GroupingFunc:
 		case T_WindowFunc:
 		case T_FuncExpr:
+        case T_JsonConstructorExpr:
 			/* function-like: name(..) or name[..] */
 			return true;
 
@@ -5133,12 +5141,12 @@ get_rule_expr_paren(Node *node, deparse_context *context,
  * get_json_format			- Parse back a JsonFormat node
  */
 static void
-get_json_format(JsonFormat *format, deparse_context *context)
+get_json_format(JsonFormat *format, StringInfo buf)
 {
 	if (format->format_type == JS_FORMAT_DEFAULT)
 		return;
 
-	appendStringInfoString(context->buf,
+	appendStringInfoString(buf,
 						   format->format_type == JS_FORMAT_JSONB ?
 						   " FORMAT JSONB" : " FORMAT JSON");
 
@@ -5148,7 +5156,7 @@ get_json_format(JsonFormat *format, deparse_context *context)
 			format->encoding == JS_ENC_UTF16 ? "UTF16" :
 			format->encoding == JS_ENC_UTF32 ? "UTF32" : "UTF8";
 
-		appendStringInfo(context->buf, " ENCODING %s", encoding);
+		appendStringInfo(buf, " ENCODING %s", encoding);
 	}
 }
 
@@ -5156,20 +5164,20 @@ get_json_format(JsonFormat *format, deparse_context *context)
  * get_json_returning		- Parse back a JsonReturning structure
  */
 static void
-get_json_returning(JsonReturning *returning, deparse_context *context,
+get_json_returning(JsonReturning *returning, StringInfo buf,
 				   bool json_format_by_default)
 {
 	if (!OidIsValid(returning->typid))
 		return;
 
-	appendStringInfo(context->buf, " RETURNING %s",
+	appendStringInfo(buf, " RETURNING %s",
 					 format_type_with_typemod(returning->typid,
 											  returning->typmod));
 
 	if (!json_format_by_default ||
 		returning->format->format_type !=
-			(returning->typid == JSONBOID ? JS_FORMAT_JSONB : JS_FORMAT_JSON))
+		(returning->typid == JSONBOID ? JS_FORMAT_JSONB : JS_FORMAT_JSON))
-		get_json_format(returning->format, context);
+		get_json_format(returning->format, buf);
 }
 
 /* ----------
@@ -6358,10 +6366,14 @@ get_rule_expr(Node *node, deparse_context *context,
 				JsonValueExpr *jve = (JsonValueExpr *) node;
 
 				get_rule_expr((Node *) jve->raw_expr, context, false);
-				get_json_format(jve->format, context);
+				get_json_format(jve->format, context->buf);
 			}
 			break;
 
+        case T_JsonConstructorExpr:
+			get_json_constructor((JsonConstructorExpr *) node, context, false);
+			break;
+
 		case T_List:
 			{
 				char	   *sep;
@@ -6636,6 +6648,77 @@ get_func_expr(FuncExpr *expr, deparse_context *context,
 	appendStringInfoChar(buf, ')');
 }
 
+static void
+get_json_constructor_options(JsonConstructorExpr *ctor, StringInfo buf)
+{
+	if (ctor->absent_on_null)
+	{
+		if (ctor->type == JSCTOR_JSON_OBJECT ||
+			ctor->type == JSCTOR_JSON_OBJECTAGG)
+			appendStringInfoString(buf, " ABSENT ON NULL");
+	}
+	else
+	{
+		if (ctor->type == JSCTOR_JSON_ARRAY ||
+			ctor->type == JSCTOR_JSON_ARRAYAGG)
+			appendStringInfoString(buf, " NULL ON NULL");
+	}
+
+	if (ctor->unique)
+		appendStringInfoString(buf, " WITH UNIQUE KEYS");
+
+	get_json_returning(ctor->returning, buf, true);
+}
+
+static void
+get_json_constructor(JsonConstructorExpr *ctor, deparse_context *context,
+					 bool showimplicit)
+{
+	StringInfo	buf = context->buf;
+	const char *funcname;
+	int			nargs;
+	ListCell   *lc;
+
+	switch (ctor->type)
+	{
+		case JSCTOR_JSON_OBJECT:
+			funcname = "JSON_OBJECT";
+			break;
+		case JSCTOR_JSON_ARRAY:
+			funcname = "JSON_ARRAY";
+			break;
+		case JSCTOR_JSON_OBJECTAGG:
+			get_json_agg_constructor(ctor, context, "JSON_OBJECTAGG", true);
+			return;
+		case JSCTOR_JSON_ARRAYAGG:
+			get_json_agg_constructor(ctor, context, "JSON_ARRAYAGG", false);
+			return;
+		default:
+			elog(ERROR, "invalid JsonConstructorExprType %d", ctor->type);
+	}
+
+	appendStringInfo(buf, "%s(", funcname);
+
+	nargs = 0;
+	foreach(lc, ctor->args)
+	{
+		if (nargs > 0)
+		{
+			const char *sep = ctor->type == JSCTOR_JSON_OBJECT &&
+				(nargs % 2) != 0 ? " : " : ", ";
+
+			appendStringInfoString(buf, sep);
+		}
+
+		get_rule_expr((Node *) lfirst(lc), context, true);
+
+		nargs++;
+	}
+
+	get_json_constructor_options(ctor, buf);
+
+	appendStringInfo(buf, ")");
+}
 
 /*
  * get_proc_expr			- Parse back a CallStmt node
@@ -6682,16 +6765,17 @@ get_proc_expr(CallStmt *stmt, deparse_context *context,
 }
 
 /*
- * get_agg_expr			- Parse back an Aggref node
+ * get_agg_expr_helper			- Parse back an Aggref node
  */
 static void
-get_agg_expr(Aggref *aggref, deparse_context *context,
+get_agg_expr_helper(Aggref *aggref, deparse_context *context,
-			 Aggref *original_aggref)
+					Aggref *original_aggref, const char *funcname,
+					const char *options, bool is_json_objectagg)
 {
 	StringInfo	buf = context->buf;
 	Oid			argtypes[FUNC_MAX_ARGS];
 	int			nargs;
-	bool		use_variadic;
+	bool		use_variadic = false;
 
 	/*
 	 * For a combining aggregate, we look up and deparse the corresponding
@@ -6722,13 +6806,14 @@ get_agg_expr(Aggref *aggref, deparse_context *context,
 	/* Extract the argument types as seen by the parser */
 	nargs = get_aggregate_argtypes(aggref, argtypes);
 
+    if (!funcname)
+		funcname = generate_function_name(aggref->aggfnoid, nargs, NIL,
+										  argtypes, aggref->aggvariadic,
+										  &use_variadic,
+										  context->special_exprkind);
+
 	/* Print the aggregate name, schema-qualified if needed */
-	appendStringInfo(buf, "%s(%s",
+	appendStringInfo(buf, "%s(%s", funcname,
-					 generate_function_name(aggref->aggfnoid, nargs,
-											NIL, argtypes,
-											aggref->aggvariadic,
-											&use_variadic,
-											context->special_exprkind),
 					 (aggref->aggdistinct != NIL) ? "DISTINCT " : "");
 
 	if (AGGKIND_IS_ORDERED_SET(aggref->aggkind))
@@ -6764,7 +6849,17 @@ get_agg_expr(Aggref *aggref, deparse_context *context,
 				if (tle->resjunk)
 					continue;
 				if (i++ > 0)
-					appendStringInfoString(buf, ", ");
+				{
+					if (is_json_objectagg)
+					{
+						if (i > 2)
+							break; /* skip ABSENT ON NULL and WITH UNIQUE args */
+
+						appendStringInfoString(buf, " : ");
+					}
+					else
+						appendStringInfoString(buf, ", ");
+				}
 				if (use_variadic && i == nargs)
 					appendStringInfoString(buf, "VARIADIC ");
 				get_rule_expr(arg, context, true);
@@ -6778,6 +6873,9 @@ get_agg_expr(Aggref *aggref, deparse_context *context,
 		}
 	}
 
+    if (options)
+		appendStringInfoString(buf, options);
+
 	if (aggref->aggfilter != NULL)
 	{
 		appendStringInfoString(buf, ") FILTER (WHERE ");
@@ -6787,6 +6885,16 @@ get_agg_expr(Aggref *aggref, deparse_context *context,
 	appendStringInfoChar(buf, ')');
 }
 
+/*
+ * get_agg_expr			- Parse back an Aggref node
+ */
+static void
+get_agg_expr(Aggref *aggref, deparse_context *context, Aggref *original_aggref)
+{
+	get_agg_expr_helper(aggref, context, original_aggref, NULL, NULL,
+						false);
+}
+
 /*
  * This is a helper function for get_agg_expr().  It's used when we deparse
  * a combining Aggref; resolve_special_varno locates the corresponding partial
@@ -6806,10 +6914,12 @@ get_agg_combine_expr(Node *node, deparse_context *context, void *callback_arg)
 }
 
 /*
- * get_windowfunc_expr	- Parse back a WindowFunc node
+ * get_windowfunc_expr_helper	- Parse back a WindowFunc node
  */
 static void
-get_windowfunc_expr(WindowFunc *wfunc, deparse_context *context)
+get_windowfunc_expr_helper(WindowFunc *wfunc, deparse_context *context,
+						   const char *funcname, const char *options,
+						   bool is_json_objectagg)
 {
 	StringInfo	buf = context->buf;
 	Oid			argtypes[FUNC_MAX_ARGS];
@@ -6833,16 +6943,30 @@ get_windowfunc_expr(WindowFunc *wfunc, deparse_context *context)
 		nargs++;
 	}
 
-	appendStringInfo(buf, "%s(",
+	if (!funcname)
-					 generate_function_name(wfunc->winfnoid, nargs,
+		funcname = generate_function_name(wfunc->winfnoid, nargs, argnames,
-											argnames, argtypes,
+										  argtypes, false, NULL,
-											false, NULL,
+										  context->special_exprkind);
-											context->special_exprkind));
+
+	appendStringInfo(buf, "%s(", funcname);
+
 	/* winstar can be set only in zero-argument aggregates */
 	if (wfunc->winstar)
 		appendStringInfoChar(buf, '*');
 	else
-		get_rule_expr((Node *) wfunc->args, context, true);
+	{
+		if (is_json_objectagg)
+		{
+			get_rule_expr((Node *) linitial(wfunc->args), context, false);
+			appendStringInfoString(buf, " : ");
+			get_rule_expr((Node *) lsecond(wfunc->args), context, false);
+		}
+		else
+			get_rule_expr((Node *) wfunc->args, context, true);
+	}
+
+	if (options)
+		appendStringInfoString(buf, options);
 
 	if (wfunc->aggfilter != NULL)
 	{
@@ -6879,6 +7003,14 @@ get_windowfunc_expr(WindowFunc *wfunc, deparse_context *context)
 	}
 }
 
+/*
+ * get_windowfunc_expr	- Parse back a WindowFunc node
+ */
+static void
+get_windowfunc_expr(WindowFunc *wfunc, deparse_context *context)
+{
+	get_windowfunc_expr_helper(wfunc, context, NULL, NULL, false);
+}
 
 /*
  * get_func_sql_syntax		- Parse back a SQL-syntax function call
@@ -7120,6 +7252,30 @@ get_func_sql_syntax(FuncExpr *expr, deparse_context *context)
 	return false;
 }
 
+/*
+ * get_json_agg_constructor - Parse back an aggregate JsonConstructorExpr node
+ */
+static void
+get_json_agg_constructor(JsonConstructorExpr *ctor, deparse_context *context,
+						 const char *funcname, bool is_json_objectagg)
+{
+	StringInfoData options;
+
+	initStringInfo(&options);
+	get_json_constructor_options(ctor, &options);
+
+	if (IsA(ctor->func, Aggref))
+		get_agg_expr_helper((Aggref *) ctor->func, context,
+							(Aggref *) ctor->func,
+							funcname, options.data, is_json_objectagg);
+	else if (IsA(ctor->func, WindowFunc))
+		get_windowfunc_expr_helper((WindowFunc *) ctor->func, context,
+								   funcname, options.data,
+								   is_json_objectagg);
+	else
+		elog(ERROR, "invalid JsonConstructorExpr underlying node type: %d",
+			 nodeTag(ctor->func));
+}
 
 /* ----------
  * get_coercion_expr