Re: [Libguestfs] [PATCH] inspect: improve canonical_mountpoint implementation

Use a simplier version using a loop, skipping multiple '/' at once, reducing the amount of memmove and strlen needed. Updates commit 865d070ddcbb071a919614f45c8eef8fcb4497ff. --- src/inspect-fs-unix.c | 56 ++++++++++++++++++--------------------------------- 1 file changed, 20 insertions(+), 36 deletions(-) diff --git a/src/inspect-fs-unix.c b/src/inspect-fs-unix.c index 49ac3f9..7e940d6 100644 --- a/src/inspect-fs-unix.c +++ b/src/inspect-fs-unix.c @@ -2130,44 +2130,28 @@ make_augeas_path_expression (guestfs_h *g, const char **configfiles) * the same length or shorter than the argument passed. */ static void -drop_char (char *mp) +canonical_mountpoint (char *s) { - size_t len = strlen (mp); - memmove (&mp[0], &mp[1], len); -} + size_t len = strlen (s); + char *orig = s; -static void -canonical_mountpoint_recursive (char *mp) -{ - if (mp[0] == '\0') - return; + s = strchr (s, '/'); + while (s != NULL && *s != 0) { + char *pos = s + 1; + char *p = pos; + /* Find how many consecutive slashes are there after the one found, + * and shift the characters after them accordingly. */ + while (*p == '/') + ++p; + if (p - pos > 0) { + memmove (pos, p, len - (p - orig) + 1); + len -= p - pos; + } - /* Remove trailing slashes. */ - if (mp[0] == '/' && mp[1] == '\0') { - mp[0] = '\0'; - return; + s = strchr (pos, '/'); } - - /* Replace multiple slashes with single slashes. */ - if (mp[0] == '/' && mp[1] == '/') { - drop_char (mp); - canonical_mountpoint_recursive (mp); - return; - } - - canonical_mountpoint_recursive (&mp[1]); -} - -static void -canonical_mountpoint (char *mp) -{ - /* Collapse multiple leading slashes into a single slash ... */ - while (mp[0] == '/' && mp[1] == '/') - drop_char (mp); - - /* ... and then continue, skipping the leading slash. */ - if (mp[0] == '/') - canonical_mountpoint_recursive (&mp[1]); - else - canonical_mountpoint_recursive (mp); + /* Ignore the trailing slash, but avoid removing it for "/". */ + if (len > 1 && orig[len-1] == '/') + --len; + orig[len] = 0; }