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postgres/src/backend/bootstrap/bootscanner.l
Peter Eisentraut 3e4bacb171 bootstrap: pure parser and reentrant scanner
Use the flex %option reentrant and the bison option %pure-parser to
make the generated scanner and parser pure, reentrant, and
thread-safe.

Make the generated scanner use palloc() etc. instead of malloc() etc.

For the bootstrap scanner and parser, reentrancy and memory management
aren't that important, but we make this change here anyway so that all
the scanners and parsers in the backend use a similar set of options
and APIs.

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
2024-12-19 15:37:44 +01:00

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%top{
/*-------------------------------------------------------------------------
*
* bootscanner.l
* a lexical scanner for the bootstrap parser
*
* Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* src/backend/bootstrap/bootscanner.l
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
/*
* NB: include bootparse.h only AFTER including bootstrap.h, because bootstrap.h
* includes node definitions needed for YYSTYPE.
*/
#include "bootstrap/bootstrap.h"
#include "bootparse.h"
#include "utils/guc.h"
}
%{
/* LCOV_EXCL_START */
/* 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)));
}
%}
%option reentrant
%option bison-bridge
%option 8bit
%option never-interactive
%option nodefault
%option noinput
%option nounput
%option noyywrap
%option noyyalloc
%option noyyrealloc
%option noyyfree
%option warn
%option prefix="boot_yy"
id [-A-Za-z0-9_]+
sid \'([^']|\'\')*\'
/*
* Keyword tokens return the keyword text (as a constant string) in yylval->kw,
* just in case that's needed because we want to treat the keyword as an
* unreserved identifier. Note that _null_ is not treated as a keyword
* for this purpose; it's the one "reserved word" in the bootstrap syntax.
*
* Notice that all the keywords are case-sensitive, and for historical
* reasons some must be upper case.
*
* String tokens return a palloc'd string in yylval->str.
*/
%%
open { yylval->kw = "open"; return OPEN; }
close { yylval->kw = "close"; return XCLOSE; }
create { yylval->kw = "create"; return XCREATE; }
OID { yylval->kw = "OID"; return OBJ_ID; }
bootstrap { yylval->kw = "bootstrap"; return XBOOTSTRAP; }
shared_relation { yylval->kw = "shared_relation"; return XSHARED_RELATION; }
rowtype_oid { yylval->kw = "rowtype_oid"; return XROWTYPE_OID; }
insert { yylval->kw = "insert"; return INSERT_TUPLE; }
_null_ { return NULLVAL; }
"," { return COMMA; }
"=" { return EQUALS; }
"(" { return LPAREN; }
")" { return RPAREN; }
[\n] { yylineno++; }
[\r\t ] ;
^\#[^\n]* ; /* drop everything after "#" for comments */
declare { yylval->kw = "declare"; return XDECLARE; }
build { yylval->kw = "build"; return XBUILD; }
indices { yylval->kw = "indices"; return INDICES; }
unique { yylval->kw = "unique"; return UNIQUE; }
index { yylval->kw = "index"; return INDEX; }
on { yylval->kw = "on"; return ON; }
using { yylval->kw = "using"; return USING; }
toast { yylval->kw = "toast"; return XTOAST; }
FORCE { yylval->kw = "FORCE"; return XFORCE; }
NOT { yylval->kw = "NOT"; return XNOT; }
NULL { yylval->kw = "NULL"; return XNULL; }
{id} {
yylval->str = pstrdup(yytext);
return ID;
}
{sid} {
/* strip quotes and escapes */
yylval->str = DeescapeQuotedString(yytext);
return ID;
}
. {
elog(ERROR, "syntax error at line %d: unexpected character \"%s\"", yylineno, yytext);
}
%%
/* LCOV_EXCL_STOP */
void
boot_yyerror(yyscan_t yyscanner, const char *message)
{
struct yyguts_t * yyg = (struct yyguts_t *) yyscanner; /* needed for yylineno macro */
elog(ERROR, "%s at line %d", message, yylineno);
}
/*
* Interface functions to make flex use palloc() instead of malloc().
* It'd be better to make these static, but flex insists otherwise.
*/
void *
yyalloc(yy_size_t size, yyscan_t yyscanner)
{
return palloc(size);
}
void *
yyrealloc(void *ptr, yy_size_t size, yyscan_t yyscanner)
{
if (ptr)
return repalloc(ptr, size);
else
return palloc(size);
}
void
yyfree(void *ptr, yyscan_t yyscanner)
{
if (ptr)
pfree(ptr);
}