git/parse-options-cb.c
Jeff King 517fe807d6 assert NOARG/NONEG behavior of parse-options callbacks
When we define a parse-options callback, the flags we put in the option
struct must match what the callback expects. For example, a callback
which does not handle the "unset" parameter should only be used with
PARSE_OPT_NONEG. But since the callback and the option struct are not
defined next to each other, it's easy to get this wrong (as earlier
patches in this series show).

Fortunately, the compiler can help us here: compiling with
-Wunused-parameters can show us which callbacks ignore their "unset"
parameters (and likewise, ones that ignore "arg" expect to be triggered
with PARSE_OPT_NOARG).

But after we've inspected a callback and determined that all of its
callers use the right flags, what do we do next? We'd like to silence
the compiler warning, but do so in a way that will catch any wrong calls
in the future.

We can do that by actually checking those variables and asserting that
they match our expectations. Because this is such a common pattern,
we'll introduce some helper macros. The resulting messages aren't
as descriptive as we could make them, but the file/line information from
BUG() is enough to identify the problem (and anyway, the point is that
these should never be seen).

Each of the annotated callbacks in this patch triggers
-Wunused-parameters, and was manually inspected to make sure all callers
use the correct options (so none of these BUGs should be triggerable).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-06 12:56:29 +09:00

243 lines
5.2 KiB
C

#include "git-compat-util.h"
#include "parse-options.h"
#include "cache.h"
#include "commit.h"
#include "color.h"
#include "string-list.h"
#include "argv-array.h"
#include "sha1-array.h"
/*----- some often used options -----*/
int parse_opt_abbrev_cb(const struct option *opt, const char *arg, int unset)
{
int v;
if (!arg) {
v = unset ? 0 : DEFAULT_ABBREV;
} else {
v = strtol(arg, (char **)&arg, 10);
if (*arg)
return opterror(opt, "expects a numerical value", 0);
if (v && v < MINIMUM_ABBREV)
v = MINIMUM_ABBREV;
else if (v > 40)
v = 40;
}
*(int *)(opt->value) = v;
return 0;
}
int parse_opt_expiry_date_cb(const struct option *opt, const char *arg,
int unset)
{
if (unset)
arg = "never";
if (parse_expiry_date(arg, (timestamp_t *)opt->value))
die(_("malformed expiration date '%s'"), arg);
return 0;
}
int parse_opt_color_flag_cb(const struct option *opt, const char *arg,
int unset)
{
int value;
if (!arg)
arg = unset ? "never" : (const char *)opt->defval;
value = git_config_colorbool(NULL, arg);
if (value < 0)
return opterror(opt,
"expects \"always\", \"auto\", or \"never\"", 0);
*(int *)opt->value = value;
return 0;
}
int parse_opt_verbosity_cb(const struct option *opt, const char *arg,
int unset)
{
int *target = opt->value;
BUG_ON_OPT_ARG(arg);
if (unset)
/* --no-quiet, --no-verbose */
*target = 0;
else if (opt->short_name == 'v') {
if (*target >= 0)
(*target)++;
else
*target = 1;
} else {
if (*target <= 0)
(*target)--;
else
*target = -1;
}
return 0;
}
int parse_opt_commits(const struct option *opt, const char *arg, int unset)
{
struct object_id oid;
struct commit *commit;
BUG_ON_OPT_NEG(unset);
if (!arg)
return -1;
if (get_oid(arg, &oid))
return error("malformed object name %s", arg);
commit = lookup_commit_reference(the_repository, &oid);
if (!commit)
return error("no such commit %s", arg);
commit_list_insert(commit, opt->value);
return 0;
}
int parse_opt_object_name(const struct option *opt, const char *arg, int unset)
{
struct object_id oid;
if (unset) {
oid_array_clear(opt->value);
return 0;
}
if (!arg)
return -1;
if (get_oid(arg, &oid))
return error(_("malformed object name '%s'"), arg);
oid_array_append(opt->value, &oid);
return 0;
}
int parse_opt_tertiary(const struct option *opt, const char *arg, int unset)
{
int *target = opt->value;
BUG_ON_OPT_ARG(arg);
*target = unset ? 2 : 1;
return 0;
}
struct option *parse_options_concat(struct option *a, struct option *b)
{
struct option *ret;
size_t i, a_len = 0, b_len = 0;
for (i = 0; a[i].type != OPTION_END; i++)
a_len++;
for (i = 0; b[i].type != OPTION_END; i++)
b_len++;
ALLOC_ARRAY(ret, st_add3(a_len, b_len, 1));
for (i = 0; i < a_len; i++)
ret[i] = a[i];
for (i = 0; i < b_len; i++)
ret[a_len + i] = b[i];
ret[a_len + b_len] = b[b_len]; /* final OPTION_END */
return ret;
}
int parse_opt_string_list(const struct option *opt, const char *arg, int unset)
{
struct string_list *v = opt->value;
if (unset) {
string_list_clear(v, 0);
return 0;
}
if (!arg)
return -1;
string_list_append(v, arg);
return 0;
}
int parse_opt_noop_cb(const struct option *opt, const char *arg, int unset)
{
return 0;
}
/**
* Report that the option is unknown, so that other code can handle
* it. This can be used as a callback together with
* OPTION_LOWLEVEL_CALLBACK to allow an option to be documented in the
* "-h" output even if it's not being handled directly by
* parse_options().
*/
int parse_opt_unknown_cb(const struct option *opt, const char *arg, int unset)
{
return -2;
}
/**
* Recreates the command-line option in the strbuf.
*/
static int recreate_opt(struct strbuf *sb, const struct option *opt,
const char *arg, int unset)
{
strbuf_reset(sb);
if (opt->long_name) {
strbuf_addstr(sb, unset ? "--no-" : "--");
strbuf_addstr(sb, opt->long_name);
if (arg) {
strbuf_addch(sb, '=');
strbuf_addstr(sb, arg);
}
} else if (opt->short_name && !unset) {
strbuf_addch(sb, '-');
strbuf_addch(sb, opt->short_name);
if (arg)
strbuf_addstr(sb, arg);
} else
return -1;
return 0;
}
/**
* For an option opt, recreates the command-line option in opt->value which
* must be an char* initialized to NULL. This is useful when we need to pass
* the command-line option to another command. Since any previous value will be
* overwritten, this callback should only be used for options where the last
* one wins.
*/
int parse_opt_passthru(const struct option *opt, const char *arg, int unset)
{
static struct strbuf sb = STRBUF_INIT;
char **opt_value = opt->value;
if (recreate_opt(&sb, opt, arg, unset) < 0)
return -1;
free(*opt_value);
*opt_value = strbuf_detach(&sb, NULL);
return 0;
}
/**
* For an option opt, recreate the command-line option, appending it to
* opt->value which must be a argv_array. This is useful when we need to pass
* the command-line option, which can be specified multiple times, to another
* command.
*/
int parse_opt_passthru_argv(const struct option *opt, const char *arg, int unset)
{
static struct strbuf sb = STRBUF_INIT;
struct argv_array *opt_value = opt->value;
if (recreate_opt(&sb, opt, arg, unset) < 0)
return -1;
argv_array_push(opt_value, sb.buf);
return 0;
}