linux/scripts/kconfig/lexer.l
Masahiro Yamada 6a1215888e kconfig: remove 'optional' property support
The 'choice' statement is primarily used to exclusively select one
option, but the 'optional' property allows all entries to be disabled.

In the following example, both A and B can be disabled simultaneously:

    choice
            prompt "choose A, B, or nothing"
            optional

    config A
            bool "A"

    config B
            bool "B"

    endchoice

You can achieve the equivalent outcome by other means.

A common solution is to add another option to guard the choice block.
In the following example, you can set ENABLE_A_B_CHOICE=n to disable
the entire choice block:

    choice
            prompt "choose A or B"
            depends on ENABLE_A_B_CHOICE

    config A
            bool "A"

    config B
            bool "B"

    endchoice

Another approach is to insert one more entry:

    choice
            prompt "choose A, B, or disable both"

    config A
            bool "A"

    config B
            bool "B"

    config DISABLE_A_AND_B
            bool "choose this to disable both A and B"

    endchoice

Some real examples are DEBUG_INFO_NONE, INITRAMFS_COMPRESSION_NONE,
LTO_NONE, etc.

The 'optional' property is even more unnecessary for a tristate choice.

Without the 'optional' property, you can disable A and B; you can set
'm' in the choice prompt, and disable A and B individually:

    choice
            prompt "choose one built-in or make them modular"

    config A
            tristate "A"

    config B
            tristate "B"

    endchoice

In conclusion, the 'optional' property was unneeded.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <n.schier@avm.de>
2024-05-02 19:48:26 +09:00

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/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (C) 2002 Roman Zippel <zippel@linux-m68k.org>
*/
%option nostdinit noyywrap never-interactive full ecs
%option 8bit nodefault yylineno
%x ASSIGN_VAL HELP STRING
%{
#include <assert.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "lkc.h"
#include "preprocess.h"
#include "parser.tab.h"
#define YY_DECL static int yylex1(void)
#define START_STRSIZE 16
/* The Kconfig file currently being parsed. */
const char *cur_filename;
/*
* The line number of the current statement. This does not match yylineno.
* yylineno is used by the lexer, while cur_lineno is used by the parser.
*/
int cur_lineno;
static int prev_prev_token = T_EOL;
static int prev_token = T_EOL;
static char *text;
static int text_size, text_asize;
struct buffer {
struct buffer *parent;
YY_BUFFER_STATE state;
int yylineno;
const char *filename;
int source_lineno;
};
static struct buffer *current_buf;
static int last_ts, first_ts;
static char *expand_token(const char *in, size_t n);
static void append_expanded_string(const char *in);
static void zconf_endhelp(void);
static void zconf_endfile(void);
static void new_string(void)
{
text = xmalloc(START_STRSIZE);
text_asize = START_STRSIZE;
text_size = 0;
*text = 0;
}
static void append_string(const char *str, int size)
{
int new_size = text_size + size + 1;
if (new_size > text_asize) {
new_size += START_STRSIZE - 1;
new_size &= -START_STRSIZE;
text = xrealloc(text, new_size);
text_asize = new_size;
}
memcpy(text + text_size, str, size);
text_size += size;
text[text_size] = 0;
}
static void alloc_string(const char *str, int size)
{
text = xmalloc(size + 1);
memcpy(text, str, size);
text[size] = 0;
}
static void warn_ignored_character(char chr)
{
fprintf(stderr,
"%s:%d:warning: ignoring unsupported character '%c'\n",
cur_filename, yylineno, chr);
}
%}
n [A-Za-z0-9_-]
%%
char open_quote = 0;
#.* /* ignore comment */
[ \t]* /* whitespaces */
\\\n /* escaped new line */
\n return T_EOL;
"bool" return T_BOOL;
"choice" return T_CHOICE;
"comment" return T_COMMENT;
"config" return T_CONFIG;
"def_bool" return T_DEF_BOOL;
"def_tristate" return T_DEF_TRISTATE;
"default" return T_DEFAULT;
"depends" return T_DEPENDS;
"endchoice" return T_ENDCHOICE;
"endif" return T_ENDIF;
"endmenu" return T_ENDMENU;
"help" return T_HELP;
"hex" return T_HEX;
"if" return T_IF;
"imply" return T_IMPLY;
"int" return T_INT;
"mainmenu" return T_MAINMENU;
"menu" return T_MENU;
"menuconfig" return T_MENUCONFIG;
"modules" return T_MODULES;
"on" return T_ON;
"prompt" return T_PROMPT;
"range" return T_RANGE;
"select" return T_SELECT;
"source" return T_SOURCE;
"string" return T_STRING;
"tristate" return T_TRISTATE;
"visible" return T_VISIBLE;
"||" return T_OR;
"&&" return T_AND;
"=" return T_EQUAL;
"!=" return T_UNEQUAL;
"<" return T_LESS;
"<=" return T_LESS_EQUAL;
">" return T_GREATER;
">=" return T_GREATER_EQUAL;
"!" return T_NOT;
"(" return T_OPEN_PAREN;
")" return T_CLOSE_PAREN;
":=" return T_COLON_EQUAL;
"+=" return T_PLUS_EQUAL;
\"|\' {
open_quote = yytext[0];
new_string();
BEGIN(STRING);
}
{n}+ {
alloc_string(yytext, yyleng);
yylval.string = text;
return T_WORD;
}
({n}|$)+ {
/* this token includes at least one '$' */
yylval.string = expand_token(yytext, yyleng);
if (strlen(yylval.string))
return T_WORD;
free(yylval.string);
}
. warn_ignored_character(*yytext);
<ASSIGN_VAL>{
[^[:blank:]\n]+.* {
alloc_string(yytext, yyleng);
yylval.string = text;
return T_ASSIGN_VAL;
}
\n { BEGIN(INITIAL); return T_EOL; }
.
}
<STRING>{
"$".* append_expanded_string(yytext);
[^$'"\\\n]+ {
append_string(yytext, yyleng);
}
\\.? {
append_string(yytext + 1, yyleng - 1);
}
\'|\" {
if (open_quote == yytext[0]) {
BEGIN(INITIAL);
yylval.string = text;
return T_WORD_QUOTE;
} else
append_string(yytext, 1);
}
\n {
fprintf(stderr,
"%s:%d:warning: multi-line strings not supported\n",
cur_filename, cur_lineno);
unput('\n');
BEGIN(INITIAL);
yylval.string = text;
return T_WORD_QUOTE;
}
<<EOF>> {
BEGIN(INITIAL);
yylval.string = text;
return T_WORD_QUOTE;
}
}
<HELP>{
[ \t]+ {
int ts, i;
ts = 0;
for (i = 0; i < yyleng; i++) {
if (yytext[i] == '\t')
ts = (ts & ~7) + 8;
else
ts++;
}
last_ts = ts;
if (first_ts) {
if (ts < first_ts) {
zconf_endhelp();
return T_HELPTEXT;
}
ts -= first_ts;
while (ts > 8) {
append_string(" ", 8);
ts -= 8;
}
append_string(" ", ts);
}
}
[ \t]*\n/[^ \t\n] {
zconf_endhelp();
return T_HELPTEXT;
}
[ \t]*\n {
append_string("\n", 1);
}
[^ \t\n].* {
while (yyleng) {
if ((yytext[yyleng-1] != ' ') && (yytext[yyleng-1] != '\t'))
break;
yyleng--;
}
append_string(yytext, yyleng);
if (!first_ts)
first_ts = last_ts;
}
<<EOF>> {
zconf_endhelp();
return T_HELPTEXT;
}
}
<<EOF>> {
BEGIN(INITIAL);
if (prev_token != T_EOL && prev_token != T_HELPTEXT)
fprintf(stderr, "%s:%d:warning: no new line at end of file\n",
cur_filename, yylineno);
if (current_buf) {
zconf_endfile();
return T_EOL;
}
fclose(yyin);
yyterminate();
}
%%
/* second stage lexer */
int yylex(void)
{
int token;
repeat:
token = yylex1();
if (prev_token == T_EOL || prev_token == T_HELPTEXT) {
if (token == T_EOL)
/* Do not pass unneeded T_EOL to the parser. */
goto repeat;
else
/*
* For the parser, update lineno at the first token
* of each statement. Generally, \n is a statement
* terminator in Kconfig, but it is not always true
* because \n could be escaped by a backslash.
*/
cur_lineno = yylineno;
}
if (prev_prev_token == T_EOL && prev_token == T_WORD &&
(token == T_EQUAL || token == T_COLON_EQUAL || token == T_PLUS_EQUAL))
BEGIN(ASSIGN_VAL);
prev_prev_token = prev_token;
prev_token = token;
return token;
}
static char *expand_token(const char *in, size_t n)
{
char *out;
int c;
char c2;
const char *rest, *end;
new_string();
append_string(in, n);
/*
* get the whole line because we do not know the end of token.
* input() returns 0 (not EOF!) when it reachs the end of file.
*/
while ((c = input()) != 0) {
if (c == '\n') {
unput(c);
break;
}
c2 = c;
append_string(&c2, 1);
}
rest = text;
out = expand_one_token(&rest);
/* push back unused characters to the input stream */
end = rest + strlen(rest);
while (end > rest)
unput(*--end);
free(text);
return out;
}
static void append_expanded_string(const char *str)
{
const char *end;
char *res;
str++;
res = expand_dollar(&str);
/* push back unused characters to the input stream */
end = str + strlen(str);
while (end > str)
unput(*--end);
append_string(res, strlen(res));
free(res);
}
void zconf_starthelp(void)
{
new_string();
last_ts = first_ts = 0;
BEGIN(HELP);
}
static void zconf_endhelp(void)
{
yylval.string = text;
BEGIN(INITIAL);
}
/*
* Try to open specified file with following names:
* ./name
* $(srctree)/name
* The latter is used when srctree is separate from objtree
* when compiling the kernel.
* Return NULL if file is not found.
*/
FILE *zconf_fopen(const char *name)
{
char *env, fullname[PATH_MAX+1];
FILE *f;
f = fopen(name, "r");
if (!f && name != NULL && name[0] != '/') {
env = getenv(SRCTREE);
if (env) {
snprintf(fullname, sizeof(fullname),
"%s/%s", env, name);
f = fopen(fullname, "r");
}
}
return f;
}
void zconf_initscan(const char *name)
{
yyin = zconf_fopen(name);
if (!yyin) {
fprintf(stderr, "can't find file %s\n", name);
exit(1);
}
cur_filename = file_lookup(name);
yylineno = 1;
}
void zconf_nextfile(const char *name)
{
struct buffer *buf = xmalloc(sizeof(*buf));
bool recur_include = false;
buf->state = YY_CURRENT_BUFFER;
buf->yylineno = yylineno;
buf->filename = cur_filename;
buf->source_lineno = cur_lineno;
buf->parent = current_buf;
current_buf = buf;
yyin = zconf_fopen(name);
if (!yyin) {
fprintf(stderr, "%s:%d: can't open file \"%s\"\n",
cur_filename, cur_lineno, name);
exit(1);
}
yy_switch_to_buffer(yy_create_buffer(yyin, YY_BUF_SIZE));
for (buf = current_buf; buf; buf = buf->parent) {
if (!strcmp(buf->filename, name))
recur_include = true;
}
if (recur_include) {
fprintf(stderr,
"Recursive inclusion detected.\n"
"Inclusion path:\n"
" current file : %s\n", name);
for (buf = current_buf; buf; buf = buf->parent)
fprintf(stderr, " included from: %s:%d\n",
buf->filename, buf->source_lineno);
exit(1);
}
yylineno = 1;
cur_filename = file_lookup(name);
}
static void zconf_endfile(void)
{
struct buffer *tmp;
fclose(yyin);
yy_delete_buffer(YY_CURRENT_BUFFER);
yy_switch_to_buffer(current_buf->state);
yylineno = current_buf->yylineno;
cur_filename = current_buf->filename;
tmp = current_buf;
current_buf = current_buf->parent;
free(tmp);
}