path: add a function to check for path suffix

We have a function to strip the path suffix from a commit, but we don't
have one to check for a path suffix. For a plain filename, we can use
basename, but that requires an allocation, since POSIX allows it to
modify its argument. Refactor strip_path_suffix into a helper function
and a new function, ends_with_path_components, to meet this need.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
brian m. carlson 2019-08-25 23:33:39 +00:00 коммит произвёл Junio C Hamano
Родитель 75b2f01a0f
Коммит ce17feb1b3
2 изменённых файлов: 42 добавлений и 18 удалений

57
path.c
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@ -1220,6 +1220,43 @@ static inline int chomp_trailing_dir_sep(const char *path, int len)
return len;
}
/*
* If path ends with suffix (complete path components), returns the offset of
* the last character in the path before the suffix (sans trailing directory
* separators), and -1 otherwise.
*/
static ssize_t stripped_path_suffix_offset(const char *path, const char *suffix)
{
int path_len = strlen(path), suffix_len = strlen(suffix);
while (suffix_len) {
if (!path_len)
return -1;
if (is_dir_sep(path[path_len - 1])) {
if (!is_dir_sep(suffix[suffix_len - 1]))
return -1;
path_len = chomp_trailing_dir_sep(path, path_len);
suffix_len = chomp_trailing_dir_sep(suffix, suffix_len);
}
else if (path[--path_len] != suffix[--suffix_len])
return -1;
}
if (path_len && !is_dir_sep(path[path_len - 1]))
return -1;
return chomp_trailing_dir_sep(path, path_len);
}
/*
* Returns true if the path ends with components, considering only complete path
* components, and false otherwise.
*/
int ends_with_path_components(const char *path, const char *components)
{
return stripped_path_suffix_offset(path, components) != -1;
}
/*
* If path ends with suffix (complete path components), returns the
* part before suffix (sans trailing directory separators).
@ -1227,25 +1264,9 @@ static inline int chomp_trailing_dir_sep(const char *path, int len)
*/
char *strip_path_suffix(const char *path, const char *suffix)
{
int path_len = strlen(path), suffix_len = strlen(suffix);
ssize_t offset = stripped_path_suffix_offset(path, suffix);
while (suffix_len) {
if (!path_len)
return NULL;
if (is_dir_sep(path[path_len - 1])) {
if (!is_dir_sep(suffix[suffix_len - 1]))
return NULL;
path_len = chomp_trailing_dir_sep(path, path_len);
suffix_len = chomp_trailing_dir_sep(suffix, suffix_len);
}
else if (path[--path_len] != suffix[--suffix_len])
return NULL;
}
if (path_len && !is_dir_sep(path[path_len - 1]))
return NULL;
return xstrndup(path, chomp_trailing_dir_sep(path, path_len));
return offset == -1 ? NULL : xstrndup(path, offset);
}
int daemon_avoid_alias(const char *p)

3
path.h
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@ -193,4 +193,7 @@ const char *git_path_merge_head(struct repository *r);
const char *git_path_fetch_head(struct repository *r);
const char *git_path_shallow(struct repository *r);
int ends_with_path_components(const char *path, const char *components);
#endif /* PATH_H */