diff options
| -rw-r--r-- | merge-ort.c | 104 |
1 files changed, 104 insertions, 0 deletions
diff --git a/merge-ort.c b/merge-ort.c index 2a1c62c533..eb609ab006 100644 --- a/merge-ort.c +++ b/merge-ort.c @@ -721,6 +721,110 @@ static int handle_content_merge(struct merge_options *opt, /*** Function Grouping: functions related to directory rename detection ***/ +MAYBE_UNUSED +static void get_renamed_dir_portion(const char *old_path, const char *new_path, + char **old_dir, char **new_dir) +{ + char *end_of_old, *end_of_new; + + /* Default return values: NULL, meaning no rename */ + *old_dir = NULL; + *new_dir = NULL; + + /* + * For + * "a/b/c/d/e/foo.c" -> "a/b/some/thing/else/e/foo.c" + * the "e/foo.c" part is the same, we just want to know that + * "a/b/c/d" was renamed to "a/b/some/thing/else" + * so, for this example, this function returns "a/b/c/d" in + * *old_dir and "a/b/some/thing/else" in *new_dir. + */ + + /* + * If the basename of the file changed, we don't care. We want + * to know which portion of the directory, if any, changed. + */ + end_of_old = strrchr(old_path, '/'); + end_of_new = strrchr(new_path, '/'); + + /* + * If end_of_old is NULL, old_path wasn't in a directory, so there + * could not be a directory rename (our rule elsewhere that a + * directory which still exists is not considered to have been + * renamed means the root directory can never be renamed -- because + * the root directory always exists). + */ + if (end_of_old == NULL) + return; /* Note: *old_dir and *new_dir are still NULL */ + + /* + * If new_path contains no directory (end_of_new is NULL), then we + * have a rename of old_path's directory to the root directory. + */ + if (end_of_new == NULL) { + *old_dir = xstrndup(old_path, end_of_old - old_path); + *new_dir = xstrdup(""); + return; + } + + /* Find the first non-matching character traversing backwards */ + while (*--end_of_new == *--end_of_old && + end_of_old != old_path && + end_of_new != new_path) + ; /* Do nothing; all in the while loop */ + + /* + * If both got back to the beginning of their strings, then the + * directory didn't change at all, only the basename did. + */ + if (end_of_old == old_path && end_of_new == new_path && + *end_of_old == *end_of_new) + return; /* Note: *old_dir and *new_dir are still NULL */ + + /* + * If end_of_new got back to the beginning of its string, and + * end_of_old got back to the beginning of some subdirectory, then + * we have a rename/merge of a subdirectory into the root, which + * needs slightly special handling. + * + * Note: There is no need to consider the opposite case, with a + * rename/merge of the root directory into some subdirectory + * because as noted above the root directory always exists so it + * cannot be considered to be renamed. + */ + if (end_of_new == new_path && + end_of_old != old_path && end_of_old[-1] == '/') { + *old_dir = xstrndup(old_path, --end_of_old - old_path); + *new_dir = xstrdup(""); + return; + } + + /* + * We've found the first non-matching character in the directory + * paths. That means the current characters we were looking at + * were part of the first non-matching subdir name going back from + * the end of the strings. Get the whole name by advancing both + * end_of_old and end_of_new to the NEXT '/' character. That will + * represent the entire directory rename. + * + * The reason for the increment is cases like + * a/b/star/foo/whatever.c -> a/b/tar/foo/random.c + * After dropping the basename and going back to the first + * non-matching character, we're now comparing: + * a/b/s and a/b/ + * and we want to be comparing: + * a/b/star/ and a/b/tar/ + * but without the pre-increment, the one on the right would stay + * a/b/. + */ + end_of_old = strchr(++end_of_old, '/'); + end_of_new = strchr(++end_of_new, '/'); + + /* Copy the old and new directories into *old_dir and *new_dir. */ + *old_dir = xstrndup(old_path, end_of_old - old_path); + *new_dir = xstrndup(new_path, end_of_new - new_path); +} + static void compute_rename_counts(struct diff_queue_struct *pairs, struct strmap *dir_rename_count, struct strset *dirs_removed) |