[PATCH 3/6] parse-options: allow git commands to invent new option types
- From
Jonathan Nieder <jrnieder@gmail.com>
- Date
- Nov 30, 2010, 03:08 UTC
- Message-ID
- <20101130030853.GD5326@burratino>
- In-Reply-To
- <20101130025223.GA5326@burratino>
parse-options provides a variety of option behaviors, including OPTION_CALLBACK, which should take care of just about any sane behavior. All supported behaviors obey the following constraint:
A --foo option can only accept (and base its behavior on) one argument, which would be the following command-line argument in the "unsticked" form.
Alas, some existing git commands have options that do not obey that constraint. For example, update-index --cacheinfo takes three arguments, and update-index --resolve takes all later parameters as arguments.
Introduces an OPTION_LOWLEVEL_CALLBACK backdoor to parse-options so such option types can be supported without tempting inventors of other commands through mention in the public API. Commands can set the callback field to a function accepting three arguments: the option parsing context, the option itself, and a flag indicating whether the the option was negated. When the option is encountered, that function is called to take over from get_value(). The return value should be zero for success, -1 for usage errors.
Thanks to Stephen Boyd for API guidance.
Improved-by: Stephen Boyd <bebarino@gmail.com> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> --- Changes from v1:
. lowlevel callbacks inherit standard get_value argument checking . lowlevel callbacks cannot tailor error messages based on long vs short option . OPT_UNSET and OPT_SHORT therefore do not need to be exposed . brief mention in parse-options.h comments.
We can always tweak the API again later. None of the examples in update-index even pay attention to the "unset" bit.
parse-options.c | 3 +++ parse-options.h | 8 +++++++- 2 files changed, 10 insertions(+), 1 deletions(-)
diff --git a/parse-options.c b/parse-options.c index bc92d69..38c8fd3 100644 --- a/parse-options.c +++ b/parse-options.c @@ -81,6 +81,9 @@ static int get_value(struct parse_opt_ctx_t *p, return opterror(opt, "takes no value", flags); switch (opt->type) { + case OPTION_LOWLEVEL_CALLBACK: + return (*(parse_opt_ll_cb *)opt->callback)(p, opt, unset); + case OPTION_BIT: if (unset) *(int *)opt->value &= ~opt->defval; diff --git a/parse-options.h b/parse-options.h index d982f0f..bd0fe16 100644 --- a/parse-options.h +++ b/parse-options.h @@ -17,6 +17,7 @@ enum parse_opt_type { OPTION_STRING, OPTION_INTEGER, OPTION_CALLBACK, + OPTION_LOWLEVEL_CALLBACK, OPTION_FILENAME }; @@ -43,6 +44,10 @@ enum parse_opt_option_flags { 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 @@ -87,7 +92,8 @@ typedef int parse_opt_cb(const struct option *, const char *arg, int unset); * useful for users of OPTION_NEGBIT. * * `callback`:: - * pointer to the callback to use for OPTION_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.
-- 1.7.2.3