[PATCH v3 05/17] tools/xenstore: replace watch->relative_path with a prefix length

[Juergen Gross <jgross@suse.com>]

Instead of storing a pointer to the path which is prepended to
relative paths in struct watch, just use the length of the prepended
path.

It should be noted that the now removed special case of the
relative path being "" in get_watch_path() can't happen at all.

Signed-off-by: Juergen Gross <jgross@suse.com>
---
V2:
- don't open code get_watch_path() (Julien Grall)
V3:
- drop needless modification of dump_state_watches() (Julien Grall)
---
 tools/xenstore/xenstored_watch.c | 19 ++++---------------
 1 file changed, 4 insertions(+), 15 deletions(-)

diff --git a/tools/xenstore/xenstored_watch.c b/tools/xenstore/xenstored_watch.c
index 75748ac109..8ad0229df6 100644
--- a/tools/xenstore/xenstored_watch.c
+++ b/tools/xenstore/xenstored_watch.c
@@ -39,8 +39,8 @@ struct watch
 	/* Current outstanding events applying to this watch. */
 	struct list_head events;
 
-	/* Is this relative to connnection's implicit path? */
-	const char *relative_path;
+	/* Offset into path for skipping prefix (used for relative paths). */
+	unsigned int prefix_len;
 
 	char *token;
 	char *node;
@@ -66,15 +66,7 @@ static bool is_child(const char *child, const char *parent)
 
 static const char *get_watch_path(const struct watch *watch, const char *name)
 {
-	const char *path = name;
-
-	if (watch->relative_path) {
-		path += strlen(watch->relative_path);
-		if (*path == '/') /* Could be "" */
-			path++;
-	}
-
-	return path;
+	return name + watch->prefix_len;
 }
 
 /*
@@ -211,10 +203,7 @@ static struct watch *add_watch(struct connection *conn, char *path, char *token,
 			      no_quota_check))
 		goto nomem;
 
-	if (relative)
-		watch->relative_path = get_implicit_path(conn);
-	else
-		watch->relative_path = NULL;
+	watch->prefix_len = relative ? strlen(get_implicit_path(conn)) + 1 : 0;
 
 	INIT_LIST_HEAD(&watch->events);
 
-- 
2.35.3