Merge branch 'dbtool_preselect'
[paraslash.git] / db.h
1 /*
2 * Copyright (C) 2005-2006 Andre Noll <maan@systemlinux.org>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
17 */
18
19 /** \file db.h data structures common to all database tools */
20
21 #include <sys/select.h>
22
23 int find_audio_files(const char *dirname, int (*f)(const char *, const char *));
24
25 /**
26 * describes one of para_server's supported database tools
27 *
28 * There is exactly one such struct for each supported database tool. During
29 * the startup part of para_server the \a init() function of the activated
30 * database tool gets called which fills in the other members.
31
32 *
33 *
34 */
35 struct dbtool {
36 /**
37 * name name of this database tool
38 */
39 const char *name;
40 /**
41 * the database init routine
42 *
43 * It should check its command line options and do all necessary initialization
44 * like connecting to a database server.
45 *
46 * A negative return value indicates an initialization error and means that
47 * this database tool should be ignored for now (it may later be activated
48 * again via the cdt command).
49 *
50 * If \a init() returns success (non-negative return value), it must have
51 * initialized in all non-optional function pointers of the given dbtool
52 * struct. Moreover, \a cmd_list must point to a NULL-terminated array which
53 * holds the list of all commands that are supported by this database tool.
54 */
55 int (*init)(struct dbtool *self);
56 /**
57 * list of commands supported by this dbtool
58 */
59 struct server_command *cmd_list;
60 /**
61 * pointer to function returning list of at most \a num audio files to be
62 * streamed next
63 *
64 * \a get_audio_file_list() must return a pointer to a array of at most \a num
65 * char* pointers (terminated by a NULL pointer), or NULL on errors. Both the
66 * array and its contents must be dynamically allocated and are freed by the
67 * caller.
68 *
69 */
70 char **(*get_audio_file_list)(unsigned int num);
71 /**
72 *
73 * the update hook
74 *
75 * The \a update_audio_file pointer is optional and need not be supplied. In this
76 * case it is not neccessary to init this pointer from within init(). If
77 * \a update_audio_file is non-NULL, the function it points to gets called
78 * whenever a new audio file was successfully loaded and is going to be
79 * streamed by any of paraslash's senders. The full path of the audio file is
80 * passed \a update_audio_file().
81 *
82 */
83 void (*update_audio_file)(char *audio_file);
84 /**
85 *
86 * shutdown this database tool and free all resources
87 *
88 * This gets called whenever the database tool changes (via the cdt command),
89 * or when para_server receives the HUP signal, or when para_server shuts down.
90 * It is assumed to succeed.
91 */
92 void (*shutdown)(void);
93 /**
94 *
95 * add file descriptors to fd_sets
96 *
97 * The pre_select function of the activated database tool gets called just
98 * before para_server enters its main select loop. The dbtool may add its own
99 * file descriptors to the \a rfds or the \a wfds set.
100 *
101 * If a file descriptor was added, \a max_fileno must be increased by
102 * this function, if neccessary.
103 *
104 * \sa select(2)
105 */
106 int (*pre_select)(fd_set *rfds, fd_set *wfds);
107 /**
108 * handle the file descriptors which are ready for I/O
109 *
110 * If the pre_select hook added one ore more file descriptors to the read or write
111 * set, this is the hook to check the result and do any I/O on those descriptors
112 * which are ready for reading/writing.
113 */
114 void (*post_select)(fd_set *rfds, fd_set *wfds);
115 };
116
117 int mysql_dbtool_init(struct dbtool*);
118 int plm_dbtool_init(struct dbtool*);
119 int random_dbtool_init(struct dbtool*);
120