1 files changed, 310 insertions, 0 deletions
diff --git a/src/backend/replication/repl_scanner.l b/src/backend/replication/repl_scanner.l
new file mode 100644
index 0000000..8a075e2
--- /dev/null
+++ b/src/backend/replication/repl_scanner.l
@@ -0,0 +1,310 @@
+%{
+/*-------------------------------------------------------------------------
+ *
+ * repl_scanner.l
+ *	  a lexical scanner for the replication commands
+ *
+ * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ *
+ * IDENTIFICATION
+ *	  src/backend/replication/repl_scanner.l
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "utils/builtins.h"
+#include "parser/scansup.h"
+
+/* Avoid exit() on fatal scanner errors (a bit ugly -- see yy_fatal_error) */
+#undef fprintf
+#define fprintf(file, fmt, msg)  fprintf_to_ereport(fmt, msg)
+
+static void
+fprintf_to_ereport(const char *fmt, const char *msg)
+{
+	ereport(ERROR, (errmsg_internal("%s", msg)));
+}
+
+/* Handle to the buffer that the lexer uses internally */
+static YY_BUFFER_STATE scanbufhandle;
+
+/* Pushed-back token (we only handle one) */
+static int	repl_pushed_back_token;
+
+/* Work area for collecting literals */
+static StringInfoData litbuf;
+
+static void startlit(void);
+static char *litbufdup(void);
+static void addlit(char *ytext, int yleng);
+static void addlitchar(unsigned char ychar);
+
+/* LCOV_EXCL_START */
+
+%}
+
+%option 8bit
+%option never-interactive
+%option nodefault
+%option noinput
+%option nounput
+%option noyywrap
+%option warn
+%option prefix="replication_yy"
+
+/*
+ * Exclusive states:
+ *  <xd> delimited identifiers (double-quoted identifiers)
+ *  <xq> standard single-quoted strings
+ */
+%x xd
+%x xq
+
+space			[ \t\n\r\f]
+
+quote			'
+quotestop		{quote}
+
+/* Extended quote
+ * xqdouble implements embedded quote, ''''
+ */
+xqstart			{quote}
+xqdouble		{quote}{quote}
+xqinside		[^']+
+
+/* Double quote
+ * Allows embedded spaces and other special characters into identifiers.
+ */
+dquote			\"
+xdstart			{dquote}
+xdstop			{dquote}
+xddouble		{dquote}{dquote}
+xdinside		[^"]+
+
+digit			[0-9]
+hexdigit		[0-9A-Fa-f]
+
+ident_start		[A-Za-z\200-\377_]
+ident_cont		[A-Za-z\200-\377_0-9\$]
+
+identifier		{ident_start}{ident_cont}*
+
+%%
+
+%{
+	/* This code is inserted at the start of replication_yylex() */
+
+	/* If we have a pushed-back token, return that. */
+	if (repl_pushed_back_token)
+	{
+		int			result = repl_pushed_back_token;
+
+		repl_pushed_back_token = 0;
+		return result;
+	}
+%}
+
+BASE_BACKUP			{ return K_BASE_BACKUP; }
+FAST			{ return K_FAST; }
+IDENTIFY_SYSTEM		{ return K_IDENTIFY_SYSTEM; }
+SHOW		{ return K_SHOW; }
+LABEL			{ return K_LABEL; }
+NOWAIT			{ return K_NOWAIT; }
+PROGRESS			{ return K_PROGRESS; }
+MAX_RATE		{ return K_MAX_RATE; }
+WAL			{ return K_WAL; }
+TABLESPACE_MAP			{ return K_TABLESPACE_MAP; }
+NOVERIFY_CHECKSUMS	{ return K_NOVERIFY_CHECKSUMS; }
+TIMELINE			{ return K_TIMELINE; }
+START_REPLICATION	{ return K_START_REPLICATION; }
+CREATE_REPLICATION_SLOT		{ return K_CREATE_REPLICATION_SLOT; }
+DROP_REPLICATION_SLOT		{ return K_DROP_REPLICATION_SLOT; }
+TIMELINE_HISTORY	{ return K_TIMELINE_HISTORY; }
+PHYSICAL			{ return K_PHYSICAL; }
+RESERVE_WAL			{ return K_RESERVE_WAL; }
+LOGICAL				{ return K_LOGICAL; }
+SLOT				{ return K_SLOT; }
+TEMPORARY			{ return K_TEMPORARY; }
+EXPORT_SNAPSHOT		{ return K_EXPORT_SNAPSHOT; }
+NOEXPORT_SNAPSHOT	{ return K_NOEXPORT_SNAPSHOT; }
+USE_SNAPSHOT		{ return K_USE_SNAPSHOT; }
+WAIT				{ return K_WAIT; }
+MANIFEST			{ return K_MANIFEST; }
+MANIFEST_CHECKSUMS	{ return K_MANIFEST_CHECKSUMS; }
+
+{space}+		{ /* do nothing */ }
+
+{digit}+		{
+					yylval.uintval = strtoul(yytext, NULL, 10);
+					return UCONST;
+				}
+
+{hexdigit}+\/{hexdigit}+		{
+					uint32	hi,
+							lo;
+					if (sscanf(yytext, "%X/%X", &hi, &lo) != 2)
+						yyerror("invalid streaming start location");
+					yylval.recptr = ((uint64) hi) << 32 | lo;
+					return RECPTR;
+				}
+
+{xqstart}		{
+					BEGIN(xq);
+					startlit();
+				}
+
+<xq>{quotestop}	{
+					yyless(1);
+					BEGIN(INITIAL);
+					yylval.str = litbufdup();
+					return SCONST;
+				}
+
+<xq>{xqdouble}	{
+					addlitchar('\'');
+				}
+
+<xq>{xqinside}  {
+					addlit(yytext, yyleng);
+				}
+
+{xdstart}		{
+					BEGIN(xd);
+					startlit();
+				}
+
+<xd>{xdstop}	{
+					int len;
+					yyless(1);
+					BEGIN(INITIAL);
+					yylval.str = litbufdup();
+					len = strlen(yylval.str);
+					truncate_identifier(yylval.str, len, true);
+					return IDENT;
+				}
+
+<xd>{xdinside}  {
+					addlit(yytext, yyleng);
+				}
+
+{identifier}	{
+					int len = strlen(yytext);
+
+					yylval.str = downcase_truncate_identifier(yytext, len, true);
+					return IDENT;
+				}
+
+.				{
+					/* Any char not recognized above is returned as itself */
+					return yytext[0];
+				}
+
+<xq,xd><<EOF>>	{ yyerror("unterminated quoted string"); }
+
+
+<<EOF>>			{
+					yyterminate();
+				}
+
+%%
+
+/* LCOV_EXCL_STOP */
+
+static void
+startlit(void)
+{
+	initStringInfo(&litbuf);
+}
+
+static char *
+litbufdup(void)
+{
+	return litbuf.data;
+}
+
+static void
+addlit(char *ytext, int yleng)
+{
+	appendBinaryStringInfo(&litbuf, ytext, yleng);
+}
+
+static void
+addlitchar(unsigned char ychar)
+{
+	appendStringInfoChar(&litbuf, ychar);
+}
+
+void
+yyerror(const char *message)
+{
+	ereport(ERROR,
+			(errcode(ERRCODE_SYNTAX_ERROR),
+			 errmsg_internal("%s", message)));
+}
+
+
+void
+replication_scanner_init(const char *str)
+{
+	Size		slen = strlen(str);
+	char	   *scanbuf;
+
+	/*
+	 * Might be left over after ereport()
+	 */
+	if (YY_CURRENT_BUFFER)
+		yy_delete_buffer(YY_CURRENT_BUFFER);
+
+	/*
+	 * Make a scan buffer with special termination needed by flex.
+	 */
+	scanbuf = (char *) palloc(slen + 2);
+	memcpy(scanbuf, str, slen);
+	scanbuf[slen] = scanbuf[slen + 1] = YY_END_OF_BUFFER_CHAR;
+	scanbufhandle = yy_scan_buffer(scanbuf, slen + 2);
+
+	/* Make sure we start in proper state */
+	BEGIN(INITIAL);
+	repl_pushed_back_token = 0;
+}
+
+void
+replication_scanner_finish(void)
+{
+	yy_delete_buffer(scanbufhandle);
+	scanbufhandle = NULL;
+}
+
+/*
+ * Check to see if the first token of a command is a WalSender keyword.
+ *
+ * To keep repl_scanner.l minimal, we don't ask it to know every construct
+ * that the core lexer knows.  Therefore, we daren't lex more than the
+ * first token of a general SQL command.  That will usually look like an
+ * IDENT token here, although some other cases are possible.
+ */
+bool
+replication_scanner_is_replication_command(void)
+{
+	int			first_token = replication_yylex();
+
+	switch (first_token)
+	{
+		case K_IDENTIFY_SYSTEM:
+		case K_BASE_BACKUP:
+		case K_START_REPLICATION:
+		case K_CREATE_REPLICATION_SLOT:
+		case K_DROP_REPLICATION_SLOT:
+		case K_TIMELINE_HISTORY:
+		case K_SHOW:
+			/* Yes; push back the first token so we can parse later. */
+			repl_pushed_back_token = first_token;
+			return true;
+		default:
+			/* Nope; we don't bother to push back the token. */
+			return false;
+	}
+}