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guc: reentrant scanner

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Use the flex %option reentrant to make the generated scanner
reentrant, and perhaps eventually thread-safe, but that will require
additional work.

Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi>
Reviewed-by: Andreas Karlsson <andreas@proxel.se>
Discussion: https://www.postgresql.org/message-id/flat/eb6faeac-2a8a-4b69-9189-c33c520e5b7b@eisentraut.org
This commit is contained in:
Peter Eisentraut 2024-12-25 14:18:07 +01:00
parent 2a7425d7ee
commit d663f150b5
1 changed files with 19 additions and 11 deletions
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30
src/backend/utils/misc/guc-file.l
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@ -57,6 +57,7 @@ static int GUC_flex_fatal(const char *msg);
%}
%option reentrant
%option 8bit
%option never-interactive
%option nodefault
@ -353,6 +354,8 @@ ParseConfigFp(FILE *fp, const char *config_file, int depth, int elevel,
unsigned int save_ConfigFileLineno = ConfigFileLineno;
sigjmp_buf *save_GUC_flex_fatal_jmp = GUC_flex_fatal_jmp;
sigjmp_buf flex_fatal_jmp;
yyscan_t scanner;
struct yyguts_t *yyg; /* needed for yytext macro */
volatile YY_BUFFER_STATE lex_buffer = NULL;
int errorcount;
int token;
@ -381,11 +384,15 @@ ParseConfigFp(FILE *fp, const char *config_file, int depth, int elevel,
ConfigFileLineno = 1;
errorcount = 0;
lex_buffer = yy_create_buffer(fp, YY_BUF_SIZE);
yy_switch_to_buffer(lex_buffer);
if (yylex_init(&scanner) != 0)
elog(elevel, "yylex_init() failed: %m");
yyg = (struct yyguts_t *) scanner;
lex_buffer = yy_create_buffer(fp, YY_BUF_SIZE, scanner);
yy_switch_to_buffer(lex_buffer, scanner);
/* This loop iterates once per logical line */
while ((token = yylex()))
while ((token = yylex(scanner)))
{
char *opt_name = NULL;
char *opt_value = NULL;
@ -400,9 +407,9 @@ ParseConfigFp(FILE *fp, const char *config_file, int depth, int elevel,
opt_name = pstrdup(yytext);
/* next we have an optional equal sign; discard if present */
token = yylex();
token = yylex(scanner);
if (token == GUC_EQUALS)
token = yylex();
token = yylex(scanner);
/* now we must have the option value */
if (token != GUC_ID &&
@ -417,7 +424,7 @@ ParseConfigFp(FILE *fp, const char *config_file, int depth, int elevel,
opt_value = pstrdup(yytext);
/* now we'd like an end of line, or possibly EOF */
token = yylex();
token = yylex(scanner);
if (token != GUC_EOL)
{
if (token != 0)
@ -438,7 +445,7 @@ ParseConfigFp(FILE *fp, const char *config_file, int depth, int elevel,
depth + 1, elevel,
head_p, tail_p))
OK = false;
yy_switch_to_buffer(lex_buffer);
yy_switch_to_buffer(lex_buffer, scanner);
pfree(opt_name);
pfree(opt_value);
}
@ -453,7 +460,7 @@ ParseConfigFp(FILE *fp, const char *config_file, int depth, int elevel,
depth + 1, elevel,
head_p, tail_p))
OK = false;
yy_switch_to_buffer(lex_buffer);
yy_switch_to_buffer(lex_buffer, scanner);
pfree(opt_name);
pfree(opt_value);
}
@ -468,7 +475,7 @@ ParseConfigFp(FILE *fp, const char *config_file, int depth, int elevel,
depth + 1, elevel,
head_p, tail_p))
OK = false;
yy_switch_to_buffer(lex_buffer);
yy_switch_to_buffer(lex_buffer, scanner);
pfree(opt_name);
pfree(opt_value);
}
@ -545,14 +552,15 @@ parse_error:
/* resync to next end-of-line or EOF */
while (token != GUC_EOL && token != 0)
token = yylex();
token = yylex(scanner);
/* break out of loop on EOF */
if (token == 0)
break;
}
cleanup:
yy_delete_buffer(lex_buffer);
yy_delete_buffer(lex_buffer, scanner);
yylex_destroy(scanner);
/* Each recursion level must save and restore these static variables. */
ConfigFileLineno = save_ConfigFileLineno;
GUC_flex_fatal_jmp = save_GUC_flex_fatal_jmp;