Many command arguments must not be negative; add a separate
parser/checker function for that. For the same reason, add
check_bool(). This eliminates two strange special cases handlers from
check_int().
There are some integers which have a "magic" -1 value which means
"undefined" or "nothing". All others can be converted to unsigned,
since they must not contain a negative number.
Also add names for "error" and "ok". I don't like passing anonymous
integer codes around.
This is not yet complete: lots of functions (e.g. in playlist.c)
follow the same convention of -1/0, and these have to be adapted, too.
The list of commands is known at compile time. Instead of creating a
linked list on startup, we can just register all commands in a static
sorted array.
The command pointers which are passed around aren't being modified -
in fact, no command pointer must be modified once it has been added to
the commandList.
When adding a local file, clients have to use the "file" URI schema
described in RFC 1738 3.10. By adding this schema to "urlhandlers", a
client can detect whether this feature is available.
"idle" waits until something noteworthy happens on the server,
e.g. song change, playlist modified, database updated. This allows
clients to keep up to date without polling.
The documentation for directory_update_init() was incorrect: a job ID
must be positive, not non-negative. If the update queue is full and
no job was created, it makes more sense to return 0 instead of -1,
because it is more consistent with the return value of isUpdatingDB().
Remove clutter from directory.c. Everything which saves or loads
to/from the hard disk goes to directory_save.c, and code which sends
directory information to the client is moved into directory_print.c.
With commit 6dcd7fea (if I am not mistaken) the error returned when
you try to save to an existing playlist is wrong. Instead of
MPD_ACK_ERROR_EXIST, MPD_ACK_ERROR_NO_EXIST is returned. This is
obviously wrong and breaks gmpc.
Taming the directory.c monster, part II: move the database management
stuff to database. directory.c should only contain code which works
on directory objects.
The source directory.c mixes several libraries: directory object
management, database management and database update, resulting in a
1000+ line monster. Move the whole database update code to update.c.
This got broken when listHandlerFunc was removed. Since we no
longer need it and it's confusing, remove processCommandInternal
and just use process_command.
commands should really not behave differently if they're issued
inside a command list or not; so stop having special handler
functions to deal with them. "update" was the only command
that used this functionality and I changed that in the last
commit to serialize access.
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.
