v21-0003-Export-jsonPathFromParseResult.patch

From d8212221b7d86baa0b5a46c3859353c8f7e9d3ec Mon Sep 17 00:00:00 2001
From: Nikita Glukhov <n.gluhov@postgrespro.ru>
Date: Tue, 8 Jul 2025 22:18:07 -0700
Subject: [PATCH v21 3/5] Export jsonPathFromParseResult()

This is a preparation step for a future commit that will reuse the
aforementioned function.

Authored-by: Nikita Glukhov <glukhov.n.a@gmail.com>
Reviewed-by: Alexandra Wang <alexandra.wang.oss@gmail.com>
Reviewed-by: Andrew Dunstan <andrew@dunslane.net>
Reviewed-by: Matheus Alcantara <matheusssilv97@gmail.com>
Reviewed-by: Jian He <jian.universality@gmail.com>
Reviewed-by: Chao Li <li.evan.chao@gmail.com>
---
 src/backend/utils/adt/jsonpath.c | 19 +++++++++++++++----
 src/include/utils/jsonpath.h     |  4 ++++
 2 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/src/backend/utils/adt/jsonpath.c b/src/backend/utils/adt/jsonpath.c
index 762f7e8a09d..c83774b2a16 100644
--- a/src/backend/utils/adt/jsonpath.c
+++ b/src/backend/utils/adt/jsonpath.c
@@ -166,15 +166,13 @@ jsonpath_send(PG_FUNCTION_ARGS)
  * Converts C-string to a jsonpath value.
  *
  * Uses jsonpath parser to turn string into an AST, then
- * flattenJsonPathParseItem() does second pass turning AST into binary
+ * jsonPathFromParseResult() does second pass turning AST into binary
  * representation of jsonpath.
  */
 static Datum
 jsonPathFromCstring(char *in, int len, struct Node *escontext)
 {
 	JsonPathParseResult *jsonpath = parsejsonpath(in, len, escontext);
-	JsonPath   *res;
-	StringInfoData buf;
 
 	if (SOFT_ERROR_OCCURRED(escontext))
 		return (Datum) 0;
@@ -185,8 +183,21 @@ jsonPathFromCstring(char *in, int len, struct Node *escontext)
 				 errmsg("invalid input syntax for type %s: \"%s\"", "jsonpath",
 						in)));
 
+	return jsonPathFromParseResult(jsonpath, 4 * len, escontext);
+}
+
+/*
+ * Converts jsonpath Abstract Syntax Tree (AST) into jsonpath value in binary.
+ */
+Datum
+jsonPathFromParseResult(const JsonPathParseResult *jsonpath, int estimated_len,
+						struct Node *escontext)
+{
+	JsonPath   *res;
+	StringInfoData buf;
+
 	initStringInfo(&buf);
-	enlargeStringInfo(&buf, 4 * len /* estimation */ );
+	enlargeStringInfo(&buf, estimated_len);
 
 	appendStringInfoSpaces(&buf, JSONPATH_HDRSZ);
 
diff --git a/src/include/utils/jsonpath.h b/src/include/utils/jsonpath.h
index 23a76d233e9..0958bc22bb6 100644
--- a/src/include/utils/jsonpath.h
+++ b/src/include/utils/jsonpath.h
@@ -281,6 +281,10 @@ extern JsonPathParseResult *parsejsonpath(const char *str, int len,
 extern bool jspConvertRegexFlags(uint32 xflags, int *result,
 								 struct Node *escontext);
 
+extern Datum jsonPathFromParseResult(const JsonPathParseResult *jsonpath,
+									 int estimated_len,
+									 struct Node *escontext);
+
 /*
  * Struct for details about external variables passed into jsonpath executor
  */
-- 
2.39.5 (Apple Git-154)