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[paraslash.git] / recv.h
1 /* Copyright (C) 2005 Andre Noll <maan@tuebingen.mpg.de>, see file COPYING. */
2
3 /** \file recv.h Receiver-related structures and exported symbols of recv_common.c. */
4
5 /**
6 * Describes one instance of a receiver.
7 */
8 struct receiver_node {
9 /** Points to the corresponding receiver. */
10 const struct receiver *receiver;
11 /** Receiver-specific data. */
12 void *private_data;
13 /** The parsed command line options for this instance. */
14 struct lls_parse_result *lpr;
15 /** The task associated with this instance. */
16 struct task *task;
17 /** The receiver node is always the root of the buffer tree. */
18 struct btr_node *btrn;
19 /** Each receiver node maintains a buffer pool for the received data. */
20 struct btr_pool *btrp;
21 /**
22 * The file descriptor to receive the stream.
23 *
24 * The pre_select function of the receiver adds this file descriptor to
25 * the set of file descriptors which are watched for readability or
26 * writability, depending on the state of the connection (if any).
27 *
28 * If \a fd is readable, the post_select function of the receiver reads
29 * data from this fd into the buffer pool area of \a btrp.
30 *
31 * \sa \ref receiver.
32 */
33 int fd;
34 };
35
36 /**
37 * Describes one supported paraslash receiver.
38 *
39 * \sa \ref http_recv.c, \ref udp_recv.c.
40 */
41 struct receiver {
42 /**
43 * The optional receiver init function.
44 *
45 * Performs any initialization needed before the receiver can be opened.
46 */
47 void (*init)(void);
48 /**
49 * Open one instance of the receiver.
50 *
51 * This should allocate the output buffer of the given receiver node
52 * and prepare it for retrieving the audio stream according to the
53 * configuration stored in rn->lpr.
54 *
55 * \sa struct \ref receiver_node.
56 */
57 int (*open)(struct receiver_node *rn);
58 /**
59 * Close this instance of the receiver.
60 *
61 * It should free all resources associated with given receiver node
62 * that were allocated during the corresponding open call.
63 *
64 * \sa \ref receiver_node.
65 */
66 void (*close)(struct receiver_node *rn);
67 /**
68 * Add file descriptors to fd_sets and compute timeout for select(2).
69 *
70 * If this is not NULL, the function is called in each iteration of the
71 * scheduler's select loop. The receiver may define it to add file
72 * descriptors to the file descriptor sets given by s. Those will be
73 * monitored in the subsequent call to select(2). The function may also
74 * lower the timeout value of s to make select(2) return earlier if no
75 * file descriptors are ready for I/O.
76 *
77 * \sa select(2), \ref time.c, struct \ref sched.
78 */
79 void (*pre_select)(struct sched *s, void *context);
80 /**
81 * Evaluate the result from select(2).
82 *
83 * This is called after the call to select(2). It should check all file
84 * descriptors which were added to any of the fd sets in the previous
85 * call to ->pre_select() and perform (non-blocking) I/O operations on
86 * those fds which are ready for I/O, for example in order to establish
87 * a connection or to receive a part of the audio stream.
88 *
89 * \sa select(2), struct \ref receiver.
90 */
91 int (*post_select)(struct sched *s, void *context);
92 /**
93 * Answer a buffer tree query.
94 *
95 * This optional function pointer allows for inter node communication
96 * of the buffer tree nodes. See \ref btr_command_handler for details.
97 */
98 btr_command_handler execute;
99 };
100
101 #define RECV_CMD(_num) (lls_cmd(_num, recv_cmd_suite))
102
103 #define RECV_CMD_OPT_RESULT(_recv, _opt, _lpr) \
104 (lls_opt_result(LSG_RECV_CMD_ ## _recv ## _OPT_ ## _opt, _lpr))
105 #define RECV_CMD_OPT_GIVEN(_recv, _opt, _lpr) \
106 (lls_opt_given(RECV_CMD_OPT_RESULT(_recv, _opt, _lpr)))
107 #define RECV_CMD_OPT_STRING_VAL(_recv, _opt, _lpr) \
108 (lls_string_val(0, RECV_CMD_OPT_RESULT(_recv, _opt, _lpr)))
109 #define RECV_CMD_OPT_UINT32_VAL(_recv, _opt, _lpr) \
110 (lls_uint32_val(0, RECV_CMD_OPT_RESULT(_recv, _opt, _lpr)))
111 #define RECV_CMD_OPT_INT32_VAL(_recv, _opt, _lpr) \
112 (lls_int32_val(0, RECV_CMD_OPT_RESULT(_recv, _opt, _lpr)))
113
114 /** Iterate over all available receivers. */
115 #define FOR_EACH_RECEIVER(i) for (i = 1; lls_cmd(i, recv_cmd_suite); i++)
116
117 void recv_init(void);
118 int check_receiver_arg(const char *ra, struct lls_parse_result **lprp);
119 void print_receiver_helps(bool detailed);
120 int generic_recv_pre_select(struct sched *s, struct receiver_node *rn);