Commit afaef55e authored by Christian Couder's avatar Christian Couder Committed by Junio C Hamano

git-compat-util: introduce skip_to_optional_arg()

We often accept both a "--key" option and a "--key=<val>" option.

These options currently are parsed using something like:

if (!strcmp(arg, "--key")) {
	/* do something */
} else if (skip_prefix(arg, "--key=", &arg)) {
	/* do something with arg */
}

which is a bit cumbersome compared to just:

if (skip_to_optional_arg(arg, "--key", &arg)) {
	/* do something with arg */
}

This also introduces skip_to_optional_arg_default() for the few
cases where something different should be done when the first
argument is exactly "--key" than when it is exactly "--key=".

In general it is better for UI consistency and simplicity if
"--key" and "--key=" do the same thing though, so that using
skip_to_optional_arg() should be encouraged compared to
skip_to_optional_arg_default().

Note that these functions can be used to parse any "key=value"
string where "key" is also considered as valid, not just
command line options.
Signed-off-by: Christian Couder's avatarChristian Couder <chriscool@tuxfamily.org>
Signed-off-by: default avatarJunio C Hamano <gitster@pobox.com>
parent 1a4e40aa
......@@ -484,6 +484,29 @@ static inline int skip_prefix(const char *str, const char *prefix,
return 0;
}
/*
* If the string "str" is the same as the string in "prefix", then the "arg"
* parameter is set to the "def" parameter and 1 is returned.
* If the string "str" begins with the string found in "prefix" and then a
* "=" sign, then the "arg" parameter is set to "str + strlen(prefix) + 1"
* (i.e., to the point in the string right after the prefix and the "=" sign),
* and 1 is returned.
*
* Otherwise, return 0 and leave "arg" untouched.
*
* When we accept both a "--key" and a "--key=<val>" option, this function
* can be used instead of !strcmp(arg, "--key") and then
* skip_prefix(arg, "--key=", &arg) to parse such an option.
*/
int skip_to_optional_arg_default(const char *str, const char *prefix,
const char **arg, const char *def);
static inline int skip_to_optional_arg(const char *str, const char *prefix,
const char **arg)
{
return skip_to_optional_arg_default(str, prefix, arg, "");
}
/*
* Like skip_prefix, but promises never to read past "len" bytes of the input
* buffer, and returns the remaining number of bytes in "out" via "outlen".
......
......@@ -11,6 +11,28 @@ int starts_with(const char *str, const char *prefix)
return 0;
}
int skip_to_optional_arg_default(const char *str, const char *prefix,
const char **arg, const char *def)
{
const char *p;
if (!skip_prefix(str, prefix, &p))
return 0;
if (!*p) {
if (arg)
*arg = def;
return 1;
}
if (*p != '=')
return 0;
if (arg)
*arg = p + 1;
return 1;
}
/*
* Used as the default ->buf value, so that people can always assume
* buf is non NULL and ->buf is NUL terminated even for a freshly
......
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