directory: simplify list update handling logic

Now the "update" command can be issued multiple times regardless
of whether the client is in list mode or not.

We serialize the update tasks to prevent updates from trampling
over each other and will spawn another update task
once the current one is finished updating and reaped.

Right now we cap the queue size to 32 which is probably enough (I
bet most people usually run update with no argument anyways);
but we can make it grow/shrink dynamically if needed.  There'll
still be a hard-coded limit to prevent DoS attacks, though.

1 files changed, 5 insertions, 5 deletions

diff --git a/src/directory.h b/src/directory.h
index 42d0e2bb6..764902071 100644
--- a/src/directory.h
+++ b/src/directory.h
@@ -42,12 +42,12 @@ void reap_update_task(void);
 
 int isUpdatingDB(void);
 
-/**
- * Starts the tag cache update in the specified location(s).  Returns
- * the job id on success, -1 on error or 0 if an update is already
- * running.
+/*
+ * returns the non-negative update job ID on success,
+ * returns -1 if busy
+ * @path will be freed by this function and should not be reused
  */
-int updateInit(List * pathList);
+int directory_update_init(char *path);
 
 void directory_init(void);