From: "René Scharfe" <l.s.r@web.de>
To: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
Cc: git@vger.kernel.org, "Junio C Hamano" <gitster@pobox.com>,
"Jeff King" <peff@peff.net>, "Taylor Blau" <me@ttaylorr.com>,
"Đoàn Trần Công Danh" <congdanhqx@gmail.com>,
"SZEDER Gábor" <szeder.dev@gmail.com>,
"Lukáš Doktor" <ldoktor@redhat.com>,
"Johannes Schindelin" <Johannes.Schindelin@gmx.de>
Subject: Re: [PATCH 09/13] parse-options API: don't restrict OPT_SUBCOMMAND() to one *_fn type
Date: Sat, 5 Nov 2022 18:26:55 +0100 [thread overview]
Message-ID: <25776063-a672-fc65-bed3-1bc8536ab8b3@web.de> (raw)
In-Reply-To: <221105.861qqhxz0o.gmgdl@evledraar.gmail.com>
Am 05.11.22 um 14:52 schrieb Ævar Arnfjörð Bjarmason:
>
> I think that's an "unportable" extension covered in "J.5 Common
> extensions", specifically "J.5.7 Function pointer casts":
>
> A pointer to an object or to void may be cast to a pointer to a
> function, allowing data to be invoked as a function
>
> Thus, since the standard already establishes that valid "void *" and
> "intptr_t" pointers can be cast'd back & forth, the J.5.7 bridges the
> gap between the two saying a function pointer can be converted to
> either.
>
> Now, I may be missing something here, but I was under the impression
> that "intptr_t" wasn't special in any way here, and that any casting of
> a function pointer to either it or a "void *" was what was made portable
> by "J.5.7".
Do you mean "possible" or "workable" instead of "portable" here? As you
write above, J.5.7 is an extension, not (fully) portable.
> Anyway, like ssize_t and a few other things this is extended upon and
> made standard by POSIX. I.e. we're basically talking about whether this
> passes:
>
> assert(sizeof(void (*)(void)) == sizeof(void*))
>
> And per POSIX
> (https://pubs.opengroup.org/onlinepubs/9699919799/functions/dlsym.html):
>
> Note that conversion from a void * pointer to a function pointer
> as in:
>
> fptr = (int (*)(int))dlsym(handle, "my_function");
>
> is not defined by the ISO C standard. This standard requires
> this conversion to work correctly on conforming implementations.
Conversion from object pointer to function pointer can still work if
function pointers are wider.
> So I think aside from other concerns this should be safe to use, as
> real-world data backing that up we've had a intptr_t converted to a
> function pointer since v2.35.0: 5cb28270a1f (pack-objects: lazily set up
> "struct rev_info", don't leak, 2022-03-28).
That may not have reached unusual architectures, yet. Let's replace
that cast with something boring before someone gets hurt. Something
like this?
diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index 573d0b20b7..9e6f1530c6 100644
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -4154,14 +4154,15 @@ struct po_filter_data {
struct rev_info revs;
};
-static struct list_objects_filter_options *po_filter_revs_init(void *value)
+static int list_objects_filter_cb(const struct option *opt,
+ const char *arg, int unset)
{
- struct po_filter_data *data = value;
+ struct po_filter_data *data = opt->value;
repo_init_revisions(the_repository, &data->revs, NULL);
data->have_revs = 1;
- return &data->revs.filter;
+ return opt_parse_list_objects_filter(&data->revs.filter, arg, unset);
}
int cmd_pack_objects(int argc, const char **argv, const char *prefix)
@@ -4265,7 +4266,7 @@ int cmd_pack_objects(int argc, const char **argv, const char *prefix)
&write_bitmap_index,
N_("write a bitmap index if possible"),
WRITE_BITMAP_QUIET, PARSE_OPT_HIDDEN),
- OPT_PARSE_LIST_OBJECTS_FILTER_INIT(&pfd, po_filter_revs_init),
+ OPT_PARSE_LIST_OBJECTS_FILTER_F(&pfd, list_objects_filter_cb),
OPT_CALLBACK_F(0, "missing", NULL, N_("action"),
N_("handling for missing objects"), PARSE_OPT_NONEG,
option_parse_missing_action),
diff --git a/list-objects-filter-options.c b/list-objects-filter-options.c
index 5339660238..2e560c2fdb 100644
--- a/list-objects-filter-options.c
+++ b/list-objects-filter-options.c
@@ -286,15 +286,9 @@ void parse_list_objects_filter(
die("%s", errbuf.buf);
}
-int opt_parse_list_objects_filter(const struct option *opt,
+int opt_parse_list_objects_filter(struct list_objects_filter_options *filter_options,
const char *arg, int unset)
{
- struct list_objects_filter_options *filter_options = opt->value;
- opt_lof_init init = (opt_lof_init)opt->defval;
-
- if (init)
- filter_options = init(opt->value);
-
if (unset || !arg)
list_objects_filter_set_no_filter(filter_options);
else
@@ -302,6 +296,12 @@ int opt_parse_list_objects_filter(const struct option *opt,
return 0;
}
+int opt_parse_list_objects_filter_cb(const struct option *opt,
+ const char *arg, int unset)
+{
+ return opt_parse_list_objects_filter(opt->value, arg, unset);
+}
+
const char *list_objects_filter_spec(struct list_objects_filter_options *filter)
{
if (!filter->filter_spec.len)
diff --git a/list-objects-filter-options.h b/list-objects-filter-options.h
index 7eeadab2dd..fc6b4da06d 100644
--- a/list-objects-filter-options.h
+++ b/list-objects-filter-options.h
@@ -107,31 +107,26 @@ void parse_list_objects_filter(
struct list_objects_filter_options *filter_options,
const char *arg);
+int opt_parse_list_objects_filter(struct list_objects_filter_options *filter_options,
+ const char *arg, int unset);
+
/**
* The opt->value to opt_parse_list_objects_filter() is either a
* "struct list_objects_filter_option *" when using
* OPT_PARSE_LIST_OBJECTS_FILTER().
*
- * Or, if using no "struct option" field is used by the callback,
- * except the "defval" which is expected to be an "opt_lof_init"
- * function, which is called with the "opt->value" and must return a
- * pointer to the ""struct list_objects_filter_option *" to be used.
- *
- * The OPT_PARSE_LIST_OBJECTS_FILTER_INIT() can be used e.g. the
- * "struct list_objects_filter_option" is embedded in a "struct
- * rev_info", which the "defval" could be tasked with lazily
- * initializing. See cmd_pack_objects() for an example.
+ * Or, OPT_PARSE_LIST_OBJECTS_FILTER_F() can be used to specify a
+ * custom callback function that may expect a different type.
*/
-int opt_parse_list_objects_filter(const struct option *opt,
- const char *arg, int unset);
+int opt_parse_list_objects_filter_cb(const struct option *opt,
+ const char *arg, int unset);
typedef struct list_objects_filter_options *(*opt_lof_init)(void *);
-#define OPT_PARSE_LIST_OBJECTS_FILTER_INIT(fo, init) \
+#define OPT_PARSE_LIST_OBJECTS_FILTER_F(fo, fn) \
{ OPTION_CALLBACK, 0, "filter", (fo), N_("args"), \
- N_("object filtering"), 0, opt_parse_list_objects_filter, \
- (intptr_t)(init) }
+ N_("object filtering"), 0, (fn) }
#define OPT_PARSE_LIST_OBJECTS_FILTER(fo) \
- OPT_PARSE_LIST_OBJECTS_FILTER_INIT((fo), NULL)
+ OPT_PARSE_LIST_OBJECTS_FILTER_F((fo), opt_parse_list_objects_filter_cb)
/*
* Translates abbreviated numbers in the filter's filter_spec into their
next prev parent reply other threads:[~2022-11-05 17:27 UTC|newest]
Thread overview: 106+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-04 6:31 "git bisect run" strips "--log" from the list of arguments Lukáš Doktor
2022-11-04 9:45 ` Jeff King
2022-11-04 11:10 ` Đoàn Trần Công Danh
2022-11-04 12:51 ` Jeff King
2022-11-04 11:36 ` Ævar Arnfjörð Bjarmason
2022-11-04 12:45 ` Jeff King
2022-11-04 13:07 ` Ævar Arnfjörð Bjarmason
2022-11-04 12:37 ` SZEDER Gábor
2022-11-04 12:44 ` Jeff King
2022-11-04 11:40 ` [PATCH 0/3] Convert git-bisect--helper to OPT_SUBCOMMAND Đoàn Trần Công Danh
2022-11-04 11:40 ` [PATCH 1/3] bisect--helper: remove unused options Đoàn Trần Công Danh
2022-11-04 12:53 ` Jeff King
2022-11-04 11:40 ` [PATCH 2/3] bisect--helper: move all subcommands into their own functions Đoàn Trần Công Danh
2022-11-04 12:55 ` Jeff King
2022-11-04 13:32 ` Ævar Arnfjörð Bjarmason
2022-11-04 14:03 ` Đoàn Trần Công Danh
2022-11-04 11:40 ` [PATCH 3/3] bisect--helper: parse subcommand with OPT_SUBCOMMAND Đoàn Trần Công Danh
2022-11-04 13:00 ` Jeff King
2022-11-04 13:46 ` Ævar Arnfjörð Bjarmason
2022-11-04 14:07 ` Đoàn Trần Công Danh
2022-11-04 13:55 ` [PATCH 0/3] Convert git-bisect--helper to OPT_SUBCOMMAND Ævar Arnfjörð Bjarmason
2022-11-05 17:03 ` [PATCH v2 " Đoàn Trần Công Danh
2022-11-05 17:03 ` [PATCH v2 1/3] bisect--helper: remove unused options Đoàn Trần Công Danh
2022-11-05 17:03 ` [PATCH v2 2/3] bisect--helper: move all subcommands into their own functions Đoàn Trần Công Danh
2022-11-05 17:13 ` Đoàn Trần Công Danh
2022-11-05 17:03 ` [PATCH v2 3/3] bisect--helper: parse subcommand with OPT_SUBCOMMAND Đoàn Trần Công Danh
2022-11-05 17:07 ` [PATCH 00/13] Turn git-bisect to be builtin Đoàn Trần Công Danh
2022-11-05 17:07 ` [PATCH 01/13] bisect tests: test for v2.30.0 "bisect run" regressions Đoàn Trần Công Danh
2022-11-07 21:31 ` Ævar Arnfjörð Bjarmason
2022-11-08 1:17 ` Đoàn Trần Công Danh
2022-11-05 17:07 ` [PATCH 02/13] bisect: refactor bisect_run() to match CodingGuidelines Đoàn Trần Công Danh
2022-11-05 17:07 ` [PATCH 03/13] bisect--helper: pass arg[cv] down to do_bisect_run Đoàn Trần Công Danh
2022-11-05 17:07 ` [PATCH 04/13] bisect: fix output regressions in v2.30.0 Đoàn Trần Công Danh
2022-11-05 17:07 ` [PATCH 05/13] bisect run: keep some of the post-v2.30.0 output Đoàn Trần Công Danh
2022-11-07 21:40 ` Ævar Arnfjörð Bjarmason
2022-11-08 1:26 ` Đoàn Trần Công Danh
2022-11-08 3:11 ` Ævar Arnfjörð Bjarmason
2022-11-05 17:07 ` [PATCH 06/13] bisect--helper: remove unused arguments from do_bisect_run Đoàn Trần Công Danh
2022-11-05 17:07 ` [PATCH 07/13] bisect--helper: pretend we're real bisect when report error Đoàn Trần Công Danh
2022-11-07 21:29 ` Ævar Arnfjörð Bjarmason
2022-11-05 17:07 ` [PATCH 08/13] bisect test: test exit codes on bad usage Đoàn Trần Công Danh
2022-11-05 17:07 ` [PATCH 09/13] bisect--helper: emit usage for "git bisect" Đoàn Trần Công Danh
2022-11-05 17:07 ` [PATCH 10/13] bisect--helper: make `state` optional Đoàn Trần Công Danh
2022-11-05 17:07 ` [PATCH 11/13] bisect--helper: remove subcommand state Đoàn Trần Công Danh
2022-11-07 21:45 ` Ævar Arnfjörð Bjarmason
2022-11-08 1:27 ` Đoàn Trần Công Danh
2022-11-05 17:07 ` [PATCH 12/13] bisect--helper: log: allow arbitrary number of arguments Đoàn Trần Công Danh
2022-11-05 17:07 ` [PATCH 13/13] Turn `git bisect` into a full built-in Đoàn Trần Công Danh
2022-11-05 23:18 ` [PATCH v2 0/3] Convert git-bisect--helper to OPT_SUBCOMMAND Taylor Blau
2022-11-10 16:36 ` [PATCH v3 " Đoàn Trần Công Danh
2022-11-10 16:36 ` [PATCH v3 1/3] bisect--helper: remove unused options Đoàn Trần Công Danh
2022-11-11 12:42 ` Ævar Arnfjörð Bjarmason
2022-11-10 16:36 ` [PATCH v3 2/3] bisect--helper: move all subcommands into their own functions Đoàn Trần Công Danh
2022-11-11 13:51 ` Ævar Arnfjörð Bjarmason
2022-11-10 16:36 ` [PATCH v3 3/3] bisect--helper: parse subcommand with OPT_SUBCOMMAND Đoàn Trần Công Danh
2022-11-10 16:36 ` [PATCH v2 00/11] Turn git-bisect to be builtin Đoàn Trần Công Danh
2022-11-10 16:36 ` [PATCH v2 01/11] bisect tests: test for v2.30.0 "bisect run" regressions Đoàn Trần Công Danh
2022-11-10 16:36 ` [PATCH v2 02/11] bisect: refactor bisect_run() to match CodingGuidelines Đoàn Trần Công Danh
2022-11-10 16:36 ` [PATCH v2 03/11] bisect: fix output regressions in v2.30.0 Đoàn Trần Công Danh
2022-11-10 16:36 ` [PATCH v2 04/11] bisect run: keep some of the post-v2.30.0 output Đoàn Trần Công Danh
2022-11-10 16:36 ` [PATCH v2 05/11] bisect-run: verify_good: account for non-negative exit status Đoàn Trần Công Danh
2022-11-10 16:36 ` [PATCH v2 06/11] bisect--helper: identify as bisect when report error Đoàn Trần Công Danh
2022-11-10 16:36 ` [PATCH v2 07/11] bisect test: test exit codes on bad usage Đoàn Trần Công Danh
2022-11-10 16:36 ` [PATCH v2 08/11] bisect--helper: emit usage for "git bisect" Đoàn Trần Công Danh
2022-11-10 16:36 ` [PATCH v2 09/11] bisect--helper: handle states directly Đoàn Trần Công Danh
2022-11-10 16:36 ` [PATCH v2 10/11] bisect--helper: log: allow arbitrary number of arguments Đoàn Trần Công Danh
2022-11-11 14:01 ` Ævar Arnfjörð Bjarmason
2022-11-10 16:36 ` [PATCH v2 11/11] Turn `git bisect` into a full built-in Đoàn Trần Công Danh
2022-11-11 13:53 ` Ævar Arnfjörð Bjarmason
2022-11-11 15:37 ` Jeff King
2022-11-11 21:09 ` Ævar Arnfjörð Bjarmason
2022-11-11 22:07 ` [PATCH v2 00/11] Turn git-bisect to be builtin Taylor Blau
2022-11-15 19:18 ` Taylor Blau
2022-11-15 19:36 ` Jeff King
2022-11-15 19:40 ` Taylor Blau
2022-11-11 12:32 ` [PATCH v3 0/3] Convert git-bisect--helper to OPT_SUBCOMMAND Ævar Arnfjörð Bjarmason
2022-11-04 13:22 ` [PATCH 00/13] bisect: v2.30.0 "run" regressions + make it built-in Ævar Arnfjörð Bjarmason
2022-11-04 13:22 ` [PATCH 01/13] bisect tests: test for v2.30.0 "bisect run" regressions Ævar Arnfjörð Bjarmason
2022-11-04 13:22 ` [PATCH 02/13] bisect: refactor bisect_run() to match CodingGuidelines Ævar Arnfjörð Bjarmason
2022-11-04 13:22 ` [PATCH 03/13] bisect: fix output regressions in v2.30.0 Ævar Arnfjörð Bjarmason
2022-11-04 13:22 ` [PATCH 04/13] bisect run: fix "--log" eating regression " Ævar Arnfjörð Bjarmason
2022-11-04 13:22 ` [PATCH 05/13] bisect run: keep some of the post-v2.30.0 output Ævar Arnfjörð Bjarmason
2022-11-04 13:22 ` [PATCH 06/13] bisect test: test exit codes on bad usage Ævar Arnfjörð Bjarmason
2022-11-04 13:22 ` [PATCH 07/13] bisect--helper: emit usage for "git bisect" Ævar Arnfjörð Bjarmason
2022-11-04 13:22 ` [PATCH 08/13] bisect--helper: have all functions take state, argc, argv, prefix Ævar Arnfjörð Bjarmason
2022-11-04 13:22 ` [PATCH 09/13] parse-options API: don't restrict OPT_SUBCOMMAND() to one *_fn type Ævar Arnfjörð Bjarmason
2022-11-05 8:32 ` René Scharfe
2022-11-05 11:34 ` Đoàn Trần Công Danh
2022-11-05 21:32 ` Phillip Wood
2022-11-05 13:52 ` Ævar Arnfjörð Bjarmason
2022-11-05 16:36 ` Phillip Wood
2022-11-05 21:59 ` Ævar Arnfjörð Bjarmason
2022-11-05 17:26 ` René Scharfe [this message]
2022-11-05 22:33 ` Ævar Arnfjörð Bjarmason
2022-11-06 8:25 ` René Scharfe
2022-11-06 13:28 ` Ævar Arnfjörð Bjarmason
2022-11-12 10:42 ` René Scharfe
2022-11-12 16:34 ` Jeff King
2022-11-12 16:55 ` Ævar Arnfjörð Bjarmason
2022-11-13 17:31 ` René Scharfe
2022-11-04 13:22 ` [PATCH 10/13] bisect--helper: remove dead --bisect-{next-check,autostart} code Ævar Arnfjörð Bjarmason
2022-11-04 13:22 ` [PATCH 11/13] bisect--helper: convert to OPT_SUBCOMMAND_CB() Ævar Arnfjörð Bjarmason
2022-11-04 13:22 ` [PATCH 12/13] bisect--helper: make `state` optional Ævar Arnfjörð Bjarmason
2022-11-04 13:22 ` [PATCH 13/13] Turn `git bisect` into a full built-in Ævar Arnfjörð Bjarmason
2022-11-05 0:13 ` [PATCH 00/13] bisect: v2.30.0 "run" regressions + make it built-in Taylor Blau
2022-11-10 12:50 ` Johannes Schindelin
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