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| #include "cache.h" | |
| static int threaded_check_leading_path(struct cache_def *cache, const char *name, int len); | |
| static int threaded_has_dirs_only_path(struct cache_def *cache, const char *name, int len, int prefix_len); | |
| /* | |
| * Returns the length (on a path component basis) of the longest | |
| * common prefix match of 'name_a' and 'name_b'. | |
| */ | |
| static int longest_path_match(const char *name_a, int len_a, | |
| const char *name_b, int len_b, | |
| int *previous_slash) | |
| { | |
| int max_len, match_len = 0, match_len_prev = 0, i = 0; | |
| max_len = len_a < len_b ? len_a : len_b; | |
| while (i < max_len && name_a[i] == name_b[i]) { | |
| if (name_a[i] == '/') { | |
| match_len_prev = match_len; | |
| match_len = i; | |
| } | |
| i++; | |
| } | |
| /* | |
| * Is 'name_b' a substring of 'name_a', the other way around, | |
| * or is 'name_a' and 'name_b' the exact same string? | |
| */ | |
| if (i >= max_len && ((len_a > len_b && name_a[len_b] == '/') || | |
| (len_a < len_b && name_b[len_a] == '/') || | |
| (len_a == len_b))) { | |
| match_len_prev = match_len; | |
| match_len = i; | |
| } | |
| *previous_slash = match_len_prev; | |
| return match_len; | |
| } | |
| static struct cache_def default_cache = CACHE_DEF_INIT; | |
| static inline void reset_lstat_cache(struct cache_def *cache) | |
| { | |
| strbuf_reset(&cache->path); | |
| cache->flags = 0; | |
| /* | |
| * The track_flags and prefix_len_stat_func members is only | |
| * set by the safeguard rule inside lstat_cache() | |
| */ | |
| } | |
| #define FL_DIR (1 << 0) | |
| #define FL_NOENT (1 << 1) | |
| #define FL_SYMLINK (1 << 2) | |
| #define FL_LSTATERR (1 << 3) | |
| #define FL_ERR (1 << 4) | |
| #define FL_FULLPATH (1 << 5) | |
| /* | |
| * Check if name 'name' of length 'len' has a symlink leading | |
| * component, or if the directory exists and is real, or not. | |
| * | |
| * To speed up the check, some information is allowed to be cached. | |
| * This can be indicated by the 'track_flags' argument, which also can | |
| * be used to indicate that we should check the full path. | |
| * | |
| * The 'prefix_len_stat_func' parameter can be used to set the length | |
| * of the prefix, where the cache should use the stat() function | |
| * instead of the lstat() function to test each path component. | |
| */ | |
| static int lstat_cache_matchlen(struct cache_def *cache, | |
| const char *name, int len, | |
| int *ret_flags, int track_flags, | |
| int prefix_len_stat_func) | |
| { | |
| int match_len, last_slash, last_slash_dir, previous_slash; | |
| int save_flags, ret; | |
| struct stat st; | |
| if (cache->track_flags != track_flags || | |
| cache->prefix_len_stat_func != prefix_len_stat_func) { | |
| /* | |
| * As a safeguard rule we clear the cache if the | |
| * values of track_flags and/or prefix_len_stat_func | |
| * does not match with the last supplied values. | |
| */ | |
| reset_lstat_cache(cache); | |
| cache->track_flags = track_flags; | |
| cache->prefix_len_stat_func = prefix_len_stat_func; | |
| match_len = last_slash = 0; | |
| } else { | |
| /* | |
| * Check to see if we have a match from the cache for | |
| * the 2 "excluding" path types. | |
| */ | |
| match_len = last_slash = | |
| longest_path_match(name, len, cache->path.buf, | |
| cache->path.len, &previous_slash); | |
| *ret_flags = cache->flags & track_flags & (FL_NOENT|FL_SYMLINK); | |
| if (!(track_flags & FL_FULLPATH) && match_len == len) | |
| match_len = last_slash = previous_slash; | |
| if (*ret_flags && match_len == cache->path.len) | |
| return match_len; | |
| /* | |
| * If we now have match_len > 0, we would know that | |
| * the matched part will always be a directory. | |
| * | |
| * Also, if we are tracking directories and 'name' is | |
| * a substring of the cache on a path component basis, | |
| * we can return immediately. | |
| */ | |
| *ret_flags = track_flags & FL_DIR; | |
| if (*ret_flags && len == match_len) | |
| return match_len; | |
| } | |
| /* | |
| * Okay, no match from the cache so far, so now we have to | |
| * check the rest of the path components. | |
| */ | |
| *ret_flags = FL_DIR; | |
| last_slash_dir = last_slash; | |
| if (len > cache->path.len) | |
| strbuf_grow(&cache->path, len - cache->path.len); | |
| while (match_len < len) { | |
| do { | |
| cache->path.buf[match_len] = name[match_len]; | |
| match_len++; | |
| } while (match_len < len && name[match_len] != '/'); | |
| if (match_len >= len && !(track_flags & FL_FULLPATH)) | |
| break; | |
| last_slash = match_len; | |
| cache->path.buf[last_slash] = '\0'; | |
| if (last_slash <= prefix_len_stat_func) | |
| ret = stat(cache->path.buf, &st); | |
| else | |
| ret = lstat(cache->path.buf, &st); | |
| if (ret) { | |
| *ret_flags = FL_LSTATERR; | |
| if (errno == ENOENT) | |
| *ret_flags |= FL_NOENT; | |
| } else if (S_ISDIR(st.st_mode)) { | |
| last_slash_dir = last_slash; | |
| continue; | |
| } else if (S_ISLNK(st.st_mode)) { | |
| *ret_flags = FL_SYMLINK; | |
| } else { | |
| *ret_flags = FL_ERR; | |
| } | |
| break; | |
| } | |
| /* | |
| * At the end update the cache. Note that max 3 different | |
| * path types, FL_NOENT, FL_SYMLINK and FL_DIR, can be cached | |
| * for the moment! | |
| */ | |
| save_flags = *ret_flags & track_flags & (FL_NOENT|FL_SYMLINK); | |
| if (save_flags && last_slash > 0) { | |
| cache->path.buf[last_slash] = '\0'; | |
| cache->path.len = last_slash; | |
| cache->flags = save_flags; | |
| } else if ((track_flags & FL_DIR) && last_slash_dir > 0) { | |
| /* | |
| * We have a separate test for the directory case, | |
| * since it could be that we have found a symlink or a | |
| * non-existing directory and the track_flags says | |
| * that we cannot cache this fact, so the cache would | |
| * then have been left empty in this case. | |
| * | |
| * But if we are allowed to track real directories, we | |
| * can still cache the path components before the last | |
| * one (the found symlink or non-existing component). | |
| */ | |
| cache->path.buf[last_slash_dir] = '\0'; | |
| cache->path.len = last_slash_dir; | |
| cache->flags = FL_DIR; | |
| } else { | |
| reset_lstat_cache(cache); | |
| } | |
| return match_len; | |
| } | |
| static int lstat_cache(struct cache_def *cache, const char *name, int len, | |
| int track_flags, int prefix_len_stat_func) | |
| { | |
| int flags; | |
| (void)lstat_cache_matchlen(cache, name, len, &flags, track_flags, | |
| prefix_len_stat_func); | |
| return flags; | |
| } | |
| #define USE_ONLY_LSTAT 0 | |
| /* | |
| * Return non-zero if path 'name' has a leading symlink component | |
| */ | |
| int threaded_has_symlink_leading_path(struct cache_def *cache, const char *name, int len) | |
| { | |
| return lstat_cache(cache, name, len, FL_SYMLINK|FL_DIR, USE_ONLY_LSTAT) & FL_SYMLINK; | |
| } | |
| /* | |
| * Return non-zero if path 'name' has a leading symlink component | |
| */ | |
| int has_symlink_leading_path(const char *name, int len) | |
| { | |
| return threaded_has_symlink_leading_path(&default_cache, name, len); | |
| } | |
| /* | |
| * Return zero if path 'name' has a leading symlink component or | |
| * if some leading path component does not exists. | |
| * | |
| * Return -1 if leading path exists and is a directory. | |
| * | |
| * Return path length if leading path exists and is neither a | |
| * directory nor a symlink. | |
| */ | |
| int check_leading_path(const char *name, int len) | |
| { | |
| return threaded_check_leading_path(&default_cache, name, len); | |
| } | |
| /* | |
| * Return zero if path 'name' has a leading symlink component or | |
| * if some leading path component does not exists. | |
| * | |
| * Return -1 if leading path exists and is a directory. | |
| * | |
| * Return path length if leading path exists and is neither a | |
| * directory nor a symlink. | |
| */ | |
| static int threaded_check_leading_path(struct cache_def *cache, const char *name, int len) | |
| { | |
| int flags; | |
| int match_len = lstat_cache_matchlen(cache, name, len, &flags, | |
| FL_SYMLINK|FL_NOENT|FL_DIR, USE_ONLY_LSTAT); | |
| if (flags & FL_NOENT) | |
| return 0; | |
| else if (flags & FL_DIR) | |
| return -1; | |
| else | |
| return match_len; | |
| } | |
| /* | |
| * Return non-zero if all path components of 'name' exists as a | |
| * directory. If prefix_len > 0, we will test with the stat() | |
| * function instead of the lstat() function for a prefix length of | |
| * 'prefix_len', thus we then allow for symlinks in the prefix part as | |
| * long as those points to real existing directories. | |
| */ | |
| int has_dirs_only_path(const char *name, int len, int prefix_len) | |
| { | |
| return threaded_has_dirs_only_path(&default_cache, name, len, prefix_len); | |
| } | |
| /* | |
| * Return non-zero if all path components of 'name' exists as a | |
| * directory. If prefix_len > 0, we will test with the stat() | |
| * function instead of the lstat() function for a prefix length of | |
| * 'prefix_len', thus we then allow for symlinks in the prefix part as | |
| * long as those points to real existing directories. | |
| */ | |
| static int threaded_has_dirs_only_path(struct cache_def *cache, const char *name, int len, int prefix_len) | |
| { | |
| return lstat_cache(cache, name, len, | |
| FL_DIR|FL_FULLPATH, prefix_len) & | |
| FL_DIR; | |
| } | |
| static struct strbuf removal = STRBUF_INIT; | |
| static void do_remove_scheduled_dirs(int new_len) | |
| { | |
| while (removal.len > new_len) { | |
| removal.buf[removal.len] = '\0'; | |
| if (rmdir(removal.buf)) | |
| break; | |
| do { | |
| removal.len--; | |
| } while (removal.len > new_len && | |
| removal.buf[removal.len] != '/'); | |
| } | |
| removal.len = new_len; | |
| } | |
| void schedule_dir_for_removal(const char *name, int len) | |
| { | |
| int match_len, last_slash, i, previous_slash; | |
| match_len = last_slash = i = | |
| longest_path_match(name, len, removal.buf, removal.len, | |
| &previous_slash); | |
| /* Find last slash inside 'name' */ | |
| while (i < len) { | |
| if (name[i] == '/') | |
| last_slash = i; | |
| i++; | |
| } | |
| /* | |
| * If we are about to go down the directory tree, we check if | |
| * we must first go upwards the tree, such that we then can | |
| * remove possible empty directories as we go upwards. | |
| */ | |
| if (match_len < last_slash && match_len < removal.len) | |
| do_remove_scheduled_dirs(match_len); | |
| /* | |
| * If we go deeper down the directory tree, we only need to | |
| * save the new path components as we go down. | |
| */ | |
| if (match_len < last_slash) | |
| strbuf_add(&removal, &name[match_len], last_slash - match_len); | |
| } | |
| void remove_scheduled_dirs(void) | |
| { | |
| do_remove_scheduled_dirs(0); | |
| } |