afs_common.h

   1 /*
   2  * Copyright (C) 2005-2007 Andre Noll <maan@systemlinux.org>
   3  *
   4  * Licensed under the GPL v2. For licencing details see COPYING.
   5  */
   6
   7 /** \file afs_common.h data structures common to all audio file selectors */
   8
   9 #include <sys/select.h>
  10
  11
  12 int find_audio_files(const char *dirname, int (*f)(const char *, const char *));
  13
  14 /**
  15  * describes one supported audio file selector
  16  *
  17  * There is one such struct for each supported selector.  During the startup
  18  * part of para_server the \a init() function of the activated selector gets
  19  * called which fills in all other function pointers.
  20  *
  21  */
  22 struct audio_file_selector {
  23 /**
  24  * name name of this selector
  25  */
  26 const char *name;
  27 /**
  28  * the init routine of the selector
  29  *
  30  * It should check its command line options and do all necessary initialization
  31  * like connecting to a database server.
  32  *
  33  * A negative return value indicates an initialization error and means that
  34  * this selector should be ignored for now (it may later be activated again via
  35  * the chs command).
  36  *
  37  * If \a init() returns success (non-negative return value), it must have
  38  * initialized in all non-optional function pointers of the given selector
  39  * struct. Moreover, \a cmd_list must point to a NULL-terminated array which
  40  * holds the list of all commands that are supported by this selector.
  41  */
  42 int (*init)(struct audio_file_selector *self);
  43 /**
  44  * list of commands supported by this selector
  45  */
  46 struct server_command *cmd_list;
  47 /**
  48  * pointer to function returning list of at most \a num audio files to be
  49  * streamed next
  50  *
  51  * \a get_audio_file_list() must return a pointer to a array of at most \a num
  52  * char* pointers (terminated by a NULL pointer), or NULL on errors.  Both the
  53  * array and its contents must be dynamically allocated and are freed by the
  54  * caller.
  55  *
  56 */
  57 char **(*get_audio_file_list)(unsigned int num);
  58 /**
  59  *
  60  * the update hook
  61  *
  62  * The \a update_audio_file pointer is optional and need not be supplied. In this
  63  * case it is not necessary to init this pointer from within init(). If
  64  * \a update_audio_file is non-NULL, the function it points to gets called
  65  * whenever a new audio file was successfully loaded and is going to be
  66  * streamed by any of paraslash's senders. The full path of the audio file is
  67  * passed \a update_audio_file().
  68  *
  69  */
  70 void (*update_audio_file)(char *audio_file);
  71 /**
  72  *
  73  * shutdown this selector and free all resources
  74  *
  75  * This gets called whenever the audio file selector changes. The reason for
  76  * this change might be that some user sent the chs command, that para_server
  77  * receives the HUP signal, or that para_server shuts down. It is assumed to
  78  * succeed.
  79  */
  80 void (*shutdown)(void);
  81 /**
  82  *
  83  * add file descriptors to fd_sets
  84  *
  85  * The pre_select function of the activated selector gets called just before
  86  * para_server enters its main select loop. The selector may add its own file
  87  * descriptors to the \a rfds or the \a wfds set.
  88  *
  89  * \return The highest-numbered file descriptor which was added to either of
  90  * the two fd sets (or -1 if no file descriptors were added).
  91  *
  92  * \sa select(2)
  93  */
  94 int (*pre_select)(fd_set *rfds, fd_set *wfds);
  95 /**
  96  * handle the file descriptors which are ready for I/O
  97  *
  98  * If the pre_select hook added one ore more file descriptors to the read or write
  99  * set, this is the hook to check the result and do any I/O on those descriptors
 100  * which are ready for reading/writing.
 101  */
 102 void (*post_select)(fd_set *rfds, fd_set *wfds);
 103 /**
 104  * each selector has its private data pointer */
 105 void *private_data;
 106 };
 107
 108 int mysql_selector_init(struct audio_file_selector*);
 109 int playlist_selector_init(struct audio_file_selector*);
 110 int random_selector_init(struct audio_file_selector*);
 111