From 5df539dda3589ff8764ed1d0efd391964666337b Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Mon, 2 Dec 2024 10:35:37 +0100
Subject: [PATCH v2 08/11] syncrep parser: Use flex yyextra

Use flex yyextra to handle context information, instead of global
variables.  This complements the earlier patch to make the scanner
reentrant.
---
 src/backend/replication/syncrep_scanner.l | 24 +++++++++++++++++------
 1 file changed, 18 insertions(+), 6 deletions(-)

diff --git a/src/backend/replication/syncrep_scanner.l b/src/backend/replication/syncrep_scanner.l
index 9eac11229c6..42e6852ea15 100644
--- a/src/backend/replication/syncrep_scanner.l
+++ b/src/backend/replication/syncrep_scanner.l
@@ -37,7 +37,11 @@ fprintf_to_ereport(const char *fmt, const char *msg)
 	ereport(ERROR, (errmsg_internal("%s", msg)));
 }
 
-static StringInfoData xdbuf;	/* FIXME */
+struct syncrep_yy_extra_type
+{
+	StringInfoData xdbuf;
+};
+#define YY_EXTRA_TYPE struct syncrep_yy_extra_type *
 
 /* LCOV_EXCL_START */
 
@@ -84,18 +88,18 @@ xdinside		[^"]+
 [Ff][Ii][Rr][Ss][Tt]	{ return FIRST; }
 
 {xdstart}	{
-				initStringInfo(&xdbuf);
+				initStringInfo(&yyextra->xdbuf);
 				BEGIN(xd);
 		}
 <xd>{xddouble} {
-				appendStringInfoChar(&xdbuf, '"');
+				appendStringInfoChar(&yyextra->xdbuf, '"');
 		}
 <xd>{xdinside} {
-				appendStringInfoString(&xdbuf, yytext);
+				appendStringInfoString(&yyextra->xdbuf, yytext);
 		}
 <xd>{xdstop} {
-				yylval->str = xdbuf.data;
-				xdbuf.data = NULL;
+				yylval->str = yyextra->xdbuf.data;
+				yyextra->xdbuf.data = NULL;
 				BEGIN(INITIAL);
 				return NAME;
 		}
@@ -128,6 +132,10 @@ xdinside		[^"]+
 
 /* LCOV_EXCL_STOP */
 
+/* see scan.l */
+#undef yyextra
+#define yyextra (((struct yyguts_t *) yyscanner)->yyextra_r)
+
 /* Needs to be here for access to yytext */
 void
 syncrep_yyerror(yyscan_t yyscanner, const char *message)
@@ -149,18 +157,22 @@ void
 syncrep_scanner_init(const char *str, yyscan_t *yyscannerp)
 {
 	yyscan_t	yyscanner;
+	struct syncrep_yy_extra_type *yyext = palloc0_object(struct syncrep_yy_extra_type);
 
 	if (yylex_init(yyscannerp) != 0)
 		elog(ERROR, "yylex_init() failed: %m");
 
 	yyscanner = *yyscannerp;
 
+	yyset_extra(yyext, yyscanner);
+
 	yy_scan_string(str, yyscanner);
 }
 
 void
 syncrep_scanner_finish(yyscan_t yyscanner)
 {
+	pfree(yyextra);
 	yylex_destroy(yyscanner);
 }
 
-- 
2.47.1