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git-commit-vandalism/parse-options.h
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

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#ifndef PARSE_OPTIONS_H
#define PARSE_OPTIONS_H
enum parse_opt_type {
/* special types */
OPTION_END,
OPTION_ARGUMENT,
OPTION_GROUP,
OPTION_NUMBER,
/* options with no arguments */
OPTION_BIT,
OPTION_NEGBIT,
OPTION_COUNTUP,
OPTION_SET_INT,
OPTION_CMDMODE,
/* options with arguments (usually) */
OPTION_STRING,
OPTION_INTEGER,
OPTION_MAGNITUDE,
OPTION_CALLBACK,
OPTION_LOWLEVEL_CALLBACK,
OPTION_FILENAME
};
enum parse_opt_flags {
PARSE_OPT_KEEP_DASHDASH = 1,
PARSE_OPT_STOP_AT_NON_OPTION = 2,
PARSE_OPT_KEEP_ARGV0 = 4,
PARSE_OPT_KEEP_UNKNOWN = 8,
PARSE_OPT_NO_INTERNAL_HELP = 16
};
enum parse_opt_option_flags {
PARSE_OPT_OPTARG = 1,
PARSE_OPT_NOARG = 2,
PARSE_OPT_NONEG = 4,
PARSE_OPT_HIDDEN = 8,
PARSE_OPT_LASTARG_DEFAULT = 16,
PARSE_OPT_NODASH = 32,
PARSE_OPT_LITERAL_ARGHELP = 64,
PARSE_OPT_SHELL_EVAL = 256,
PARSE_OPT_NOCOMPLETE = 512,
PARSE_OPT_COMP_ARG = 1024
};
struct option;
typedef int parse_opt_cb(const struct option *, const char *arg, int unset);
struct parse_opt_ctx_t;
typedef int parse_opt_ll_cb(struct parse_opt_ctx_t *ctx,
const struct option *opt, int unset);
/*
* `type`::
* holds the type of the option, you must have an OPTION_END last in your
* array.
*
* `short_name`::
* the character to use as a short option name, '\0' if none.
*
* `long_name`::
* the long option name, without the leading dashes, NULL if none.
*
* `value`::
* stores pointers to the values to be filled.
*
* `argh`::
* token to explain the kind of argument this option wants. Keep it
* homogeneous across the repository. Should be wrapped by N_() for
* translation.
*
* `help`::
* the short help associated to what the option does.
* Must never be NULL (except for OPTION_END).
* OPTION_GROUP uses this pointer to store the group header.
* Should be wrapped by N_() for translation.
*
* `flags`::
* mask of parse_opt_option_flags.
* PARSE_OPT_OPTARG: says that the argument is optional (not for BOOLEANs)
* PARSE_OPT_NOARG: says that this option does not take an argument
* PARSE_OPT_NONEG: says that this option cannot be negated
* PARSE_OPT_HIDDEN: this option is skipped in the default usage, and
* shown only in the full usage.
* PARSE_OPT_LASTARG_DEFAULT: says that this option will take the default
* value if no argument is given when the option
* is last on the command line. If the option is
* not last it will require an argument.
* Should not be used with PARSE_OPT_OPTARG.
* PARSE_OPT_NODASH: this option doesn't start with a dash.
* PARSE_OPT_LITERAL_ARGHELP: says that argh shouldn't be enclosed in brackets
* (i.e. '<argh>') in the help message.
* Useful for options with multiple parameters.
* PARSE_OPT_NOCOMPLETE: by default all visible options are completable
* by git-completion.bash. This option suppresses that.
* PARSE_OPT_COMP_ARG: this option forces to git-completion.bash to
* complete an option as --name= not --name even if
* the option takes optional argument.
*
* `callback`::
* pointer to the callback to use for OPTION_CALLBACK or
* OPTION_LOWLEVEL_CALLBACK.
*
* `defval`::
* default value to fill (*->value) with for PARSE_OPT_OPTARG.
* OPTION_{BIT,SET_INT} store the {mask,integer} to put in the value when met.
* CALLBACKS can use it like they want.
*/
struct option {
enum parse_opt_type type;
int short_name;
const char *long_name;
void *value;
const char *argh;
const char *help;
int flags;
parse_opt_cb *callback;
intptr_t defval;
};
#define OPT_BIT_F(s, l, v, h, b, f) { OPTION_BIT, (s), (l), (v), NULL, (h), \
PARSE_OPT_NOARG|(f), NULL, (b) }
#define OPT_COUNTUP_F(s, l, v, h, f) { OPTION_COUNTUP, (s), (l), (v), NULL, \
(h), PARSE_OPT_NOARG|(f) }
#define OPT_SET_INT_F(s, l, v, h, i, f) { OPTION_SET_INT, (s), (l), (v), NULL, \
(h), PARSE_OPT_NOARG | (f), NULL, (i) }
#define OPT_BOOL_F(s, l, v, h, f) OPT_SET_INT_F(s, l, v, h, 1, f)
#define OPT_END() { OPTION_END }
#define OPT_ARGUMENT(l, h) { OPTION_ARGUMENT, 0, (l), NULL, NULL, \
(h), PARSE_OPT_NOARG}
#define OPT_GROUP(h) { OPTION_GROUP, 0, NULL, NULL, NULL, (h) }
#define OPT_BIT(s, l, v, h, b) OPT_BIT_F(s, l, v, h, b, 0)
#define OPT_NEGBIT(s, l, v, h, b) { OPTION_NEGBIT, (s), (l), (v), NULL, \
(h), PARSE_OPT_NOARG, NULL, (b) }
#define OPT_COUNTUP(s, l, v, h) OPT_COUNTUP_F(s, l, v, h, 0)
#define OPT_SET_INT(s, l, v, h, i) OPT_SET_INT_F(s, l, v, h, i, 0)
#define OPT_BOOL(s, l, v, h) OPT_BOOL_F(s, l, v, h, 0)
#define OPT_HIDDEN_BOOL(s, l, v, h) { OPTION_SET_INT, (s), (l), (v), NULL, \
(h), PARSE_OPT_NOARG | PARSE_OPT_HIDDEN, NULL, 1}
#define OPT_CMDMODE(s, l, v, h, i) { OPTION_CMDMODE, (s), (l), (v), NULL, \
(h), PARSE_OPT_NOARG|PARSE_OPT_NONEG, NULL, (i) }
#define OPT_INTEGER(s, l, v, h) { OPTION_INTEGER, (s), (l), (v), N_("n"), (h) }
#define OPT_MAGNITUDE(s, l, v, h) { OPTION_MAGNITUDE, (s), (l), (v), \
N_("n"), (h), PARSE_OPT_NONEG }
#define OPT_STRING(s, l, v, a, h) { OPTION_STRING, (s), (l), (v), (a), (h) }
#define OPT_STRING_LIST(s, l, v, a, h) \
{ OPTION_CALLBACK, (s), (l), (v), (a), \
(h), 0, &parse_opt_string_list }
#define OPT_UYN(s, l, v, h) { OPTION_CALLBACK, (s), (l), (v), NULL, \
(h), PARSE_OPT_NOARG, &parse_opt_tertiary }
#define OPT_EXPIRY_DATE(s, l, v, h) \
{ OPTION_CALLBACK, (s), (l), (v), N_("expiry-date"),(h), 0, \
parse_opt_expiry_date_cb }
#define OPT_CALLBACK(s, l, v, a, h, f) \
{ OPTION_CALLBACK, (s), (l), (v), (a), (h), 0, (f) }
#define OPT_NUMBER_CALLBACK(v, h, f) \
{ OPTION_NUMBER, 0, NULL, (v), NULL, (h), \
PARSE_OPT_NOARG | PARSE_OPT_NONEG, (f) }
#define OPT_FILENAME(s, l, v, h) { OPTION_FILENAME, (s), (l), (v), \
N_("file"), (h) }
#define OPT_COLOR_FLAG(s, l, v, h) \
{ OPTION_CALLBACK, (s), (l), (v), N_("when"), (h), PARSE_OPT_OPTARG, \
parse_opt_color_flag_cb, (intptr_t)"always" }
#define OPT_NOOP_NOARG(s, l) \
{ OPTION_CALLBACK, (s), (l), NULL, NULL, \
N_("no-op (backward compatibility)"), \
PARSE_OPT_HIDDEN | PARSE_OPT_NOARG, parse_opt_noop_cb }
/* parse_options() will filter out the processed options and leave the
* non-option arguments in argv[]. usagestr strings should be marked
* for translation with N_().
* Returns the number of arguments left in argv[].
*/
extern int parse_options(int argc, const char **argv, const char *prefix,
const struct option *options,
const char * const usagestr[], int flags);
extern NORETURN void usage_with_options(const char * const *usagestr,
const struct option *options);
extern NORETURN void usage_msg_opt(const char *msg,
const char * const *usagestr,
const struct option *options);
extern int optbug(const struct option *opt, const char *reason);
extern int opterror(const struct option *opt, const char *reason, int flags);
#if defined(__GNUC__)
#define opterror(o,r,f) (opterror((o),(r),(f)), const_error())
#endif
/*
* Use these assertions for callbacks that expect to be called with NONEG and
* NOARG respectively, and do not otherwise handle the "unset" and "arg"
* parameters.
*/
#define BUG_ON_OPT_NEG(unset) do { \
if ((unset)) \
BUG("option callback does not expect negation"); \
} while (0)
#define BUG_ON_OPT_ARG(arg) do { \
if ((arg)) \
BUG("option callback does not expect an argument"); \
} while (0)
/*----- incremental advanced APIs -----*/
enum {
PARSE_OPT_HELP = -1,
PARSE_OPT_DONE,
PARSE_OPT_NON_OPTION,
PARSE_OPT_ERROR,
PARSE_OPT_UNKNOWN
};
/*
* It's okay for the caller to consume argv/argc in the usual way.
* Other fields of that structure are private to parse-options and should not
* be modified in any way.
*/
struct parse_opt_ctx_t {
const char **argv;
const char **out;
int argc, cpidx, total;
const char *opt;
int flags;
const char *prefix;
};
extern void parse_options_start(struct parse_opt_ctx_t *ctx,
int argc, const char **argv, const char *prefix,
const struct option *options, int flags);
extern int parse_options_step(struct parse_opt_ctx_t *ctx,
const struct option *options,
const char * const usagestr[]);
extern int parse_options_end(struct parse_opt_ctx_t *ctx);
extern struct option *parse_options_concat(struct option *a, struct option *b);
/*----- some often used options -----*/
extern int parse_opt_abbrev_cb(const struct option *, const char *, int);
extern int parse_opt_expiry_date_cb(const struct option *, const char *, int);
extern int parse_opt_color_flag_cb(const struct option *, const char *, int);
extern int parse_opt_verbosity_cb(const struct option *, const char *, int);
extern int parse_opt_object_name(const struct option *, const char *, int);
extern int parse_opt_commits(const struct option *, const char *, int);
extern int parse_opt_tertiary(const struct option *, const char *, int);
extern int parse_opt_string_list(const struct option *, const char *, int);
extern int parse_opt_noop_cb(const struct option *, const char *, int);
extern int parse_opt_unknown_cb(const struct option *, const char *, int);
extern int parse_opt_passthru(const struct option *, const char *, int);
extern int parse_opt_passthru_argv(const struct option *, const char *, int);
#define OPT__VERBOSE(var, h) OPT_COUNTUP('v', "verbose", (var), (h))
#define OPT__QUIET(var, h) OPT_COUNTUP('q', "quiet", (var), (h))
#define OPT__VERBOSITY(var) \
{ OPTION_CALLBACK, 'v', "verbose", (var), NULL, N_("be more verbose"), \
PARSE_OPT_NOARG, &parse_opt_verbosity_cb, 0 }, \
{ OPTION_CALLBACK, 'q', "quiet", (var), NULL, N_("be more quiet"), \
PARSE_OPT_NOARG, &parse_opt_verbosity_cb, 0 }
#define OPT__DRY_RUN(var, h) OPT_BOOL('n', "dry-run", (var), (h))
#define OPT__FORCE(var, h, f) OPT_COUNTUP_F('f', "force", (var), (h), (f))
#define OPT__ABBREV(var) \
{ OPTION_CALLBACK, 0, "abbrev", (var), N_("n"), \
N_("use <n> digits to display SHA-1s"), \
PARSE_OPT_OPTARG, &parse_opt_abbrev_cb, 0 }
#define OPT__COLOR(var, h) \
OPT_COLOR_FLAG(0, "color", (var), (h))
#define OPT_COLUMN(s, l, v, h) \
{ OPTION_CALLBACK, (s), (l), (v), N_("style"), (h), PARSE_OPT_OPTARG, parseopt_column_callback }
#define OPT_PASSTHRU(s, l, v, a, h, f) \
{ OPTION_CALLBACK, (s), (l), (v), (a), (h), (f), parse_opt_passthru }
#define OPT_PASSTHRU_ARGV(s, l, v, a, h, f) \
{ OPTION_CALLBACK, (s), (l), (v), (a), (h), (f), parse_opt_passthru_argv }
#define _OPT_CONTAINS_OR_WITH(name, variable, help, flag) \
{ OPTION_CALLBACK, 0, name, (variable), N_("commit"), (help), \
PARSE_OPT_LASTARG_DEFAULT | flag, \
parse_opt_commits, (intptr_t) "HEAD" \
}
#define OPT_CONTAINS(v, h) _OPT_CONTAINS_OR_WITH("contains", v, h, PARSE_OPT_NONEG)
#define OPT_NO_CONTAINS(v, h) _OPT_CONTAINS_OR_WITH("no-contains", v, h, PARSE_OPT_NONEG)
#define OPT_WITH(v, h) _OPT_CONTAINS_OR_WITH("with", v, h, PARSE_OPT_HIDDEN | PARSE_OPT_NONEG)
#define OPT_WITHOUT(v, h) _OPT_CONTAINS_OR_WITH("without", v, h, PARSE_OPT_HIDDEN | PARSE_OPT_NONEG)
#endif
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