Certain git commands, such as git-pull, are simply wrappers around other
git commands like git-fetch, git-merge and git-rebase. As such, these
wrapper commands will typically need to "pass through" command-line
options of the commands they wrap.
Implement the parse_opt_passthru() parse-options callback, which will
reconstruct the command-line option into an char* string, such that it
can be passed to another git command.
Helped-by: Johannes Schindelin <johannes.schindelin@xxxxxx>
Helped-by: Junio C Hamano <gitster@xxxxxxxxx>
Helped-by: Stefan Beller <sbeller@xxxxxxxxxx>
Signed-off-by: Paul Tan <pyokagan@xxxxxxxxx>
---
Notes:
v3
* Reverted back to returning newly-allocated strings. Junio raised the
concern that it may not be such a good idea to burden the users of the
API to always use X.buf to access the string. Personally I believe
that memory management safety is usually more important, but I don't
have strong feelings about this.
* Extracted out the "option reconstruction" logic into a private
function so that it can be shared with parse_opt_passthru_argv() in
the next patch.
* Introduced the OPT_PASSTHRU() macro and documented it in
Documentation/technical/api-parse-options.txt. This macro relieves the
user of having to specify OPTION_CALLBACK and parse_opt_passthru() for
every option.
* The function used to be named parse_opt_pass_strbuf() to save
horizontal space, but then again parse_opt_passthru() is probably a
better name.
* Added comment to the docstring that the callback should only be used
for options where the last one wins.
Documentation/technical/api-parse-options.txt | 7 ++++
parse-options-cb.c | 49 +++++++++++++++++++++++++++
parse-options.h | 3 ++
3 files changed, 59 insertions(+)
diff --git a/Documentation/technical/api-parse-options.txt b/Documentation/technical/api-parse-options.txt
index 1f2db31..85d10ab 100644
--- a/Documentation/technical/api-parse-options.txt
+++ b/Documentation/technical/api-parse-options.txt
@@ -212,6 +212,13 @@ There are some macros to easily define options:
Use it to hide deprecated options that are still to be recognized
and ignored silently.
+`OPT_PASSTHRU(short, long, &char_var, arg_str, description, flags)`::
+ Introduce an option that will be reconstructed into a char* string,
+ which must be initialized to NULL. This is useful when you need to
+ pass the command-line option to another command. Any previous value
+ will be overwritten, so this should only be used for options where
+ the last one specified on the command line wins.
+
The last element of the array must be `OPT_END()`.
diff --git a/parse-options-cb.c b/parse-options-cb.c
index be8c413..68bc593 100644
--- a/parse-options-cb.c
+++ b/parse-options-cb.c
@@ -134,3 +134,52 @@ int parse_opt_noop_cb(const struct option *opt, const char *arg, int unset)
{
return 0;
}
+
+/**
+ * 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;
+
+ if (*opt_value)
+ free(*opt_value);
+
+ *opt_value = strbuf_detach(&sb, NULL);
+
+ return 0;
+}
diff --git a/parse-options.h b/parse-options.h
index c71e9da..5b0f886 100644
--- a/parse-options.h
+++ b/parse-options.h
@@ -224,6 +224,7 @@ extern int parse_opt_with_commit(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_passthru(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))
@@ -242,5 +243,7 @@ extern int parse_opt_noop_cb(const struct option *, const char *, int);
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 }
#endif
--
2.1.4
--
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