Christian CouderFrom: Christian Couder <christian.couder@gmail.com>
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_val(arg, "--key", &arg)) {
/* do something with arg */
}This also introduces skip_to_optional_val_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_val() should be encouraged compared to skip_to_optional_val_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 <chriscool@tuxfamily.org> --- git-compat-util.h | 23 +++++++++++++++++++++++ strbuf.c | 20 ++++++++++++++++++++ 2 files changed, 43 insertions(+)
After thinking about it a bit more and taking a look at the current code, I thought that it was probably best to have both skip_to_optional_val() and skip_to_optional_val_default().
The changes compared to previous version are:
- 2 new functions instead of 1 - "optional" instead of "opt" in the function names - the big function is not inlined - more code in diff.c is simplified using the functions
Show changes to 2 files +43 −0
git-compat-util.h, strbuf.c
diff --git a/git-compat-util.h b/git-compat-util.h index cedad4d581..2858d66f85 100644 --- a/git-compat-util.h +++ b/git-compat-util.h @@ -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 "val" + * 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 "val" 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 "val" 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_val_default(const char *str, const char *prefix, + const char **val, const char *def); + +static inline int skip_to_optional_val(const char *str, const char *prefix, + const char **val) +{ + return skip_to_optional_val_default(str, prefix, val, ""); +} + /* * 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". diff --git a/strbuf.c b/strbuf.c index 323c49ceb3..3430499f9e 100644 --- a/strbuf.c +++ b/strbuf.c @@ -11,6 +11,26 @@ int starts_with(const char *str, const char *prefix) return 0; } +int skip_to_optional_val_default(const char *str, const char *prefix, + const char **val, const char *def) +{ + const char *p; + + if (!skip_prefix(str, prefix, &p)) + return 0; + + if (!*p) { + *val = def; + return 1; + } + + if (*p != '=') + return 0; + + *val = 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
-- 2.15.1.274.g3f22e311ce.dirty
