vss: Improve error diagnostics.
[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 * Open one instance of the receiver.
44 *
45 * This should allocate the output buffer of the given receiver node
46 * and prepare it for retrieving the audio stream according to the
47 * configuration stored in rn->lpr.
48 *
49 * \sa struct \ref receiver_node.
50 */
51 int (*open)(struct receiver_node *rn);
52 /**
53 * Close this instance of the receiver.
54 *
55 * It should free all resources associated with given receiver node
56 * that were allocated during the corresponding open call.
57 *
58 * \sa \ref receiver_node.
59 */
60 void (*close)(struct receiver_node *rn);
61 /**
62 * Add file descriptors to fd_sets and compute timeout for select(2).
63 *
64 * If this is not NULL, the function is called in each iteration of the
65 * scheduler's select loop. The receiver may define it to add file
66 * descriptors to the file descriptor sets given by s. Those will be
67 * monitored in the subsequent call to select(2). The function may also
68 * lower the timeout value of s to make select(2) return earlier if no
69 * file descriptors are ready for I/O.
70 *
71 * \sa select(2), \ref time.c, struct \ref sched.
72 */
73 void (*pre_select)(struct sched *s, void *context);
74 /**
75 * Evaluate the result from select(2).
76 *
77 * This is called after the call to select(2). It should check all file
78 * descriptors which were added to any of the fd sets in the previous
79 * call to ->pre_select() and perform (non-blocking) I/O operations on
80 * those fds which are ready for I/O, for example in order to establish
81 * a connection or to receive a part of the audio stream.
82 *
83 * \sa select(2), struct \ref receiver.
84 */
85 int (*post_select)(struct sched *s, void *context);
86 /**
87 * Answer a buffer tree query.
88 *
89 * This optional function pointer allows for inter node communication
90 * of the buffer tree nodes. See \ref btr_command_handler for details.
91 */
92 btr_command_handler execute;
93 };
94
95 #define RECV_CMD(_num) (lls_cmd(_num, recv_cmd_suite))
96
97 #define RECV_CMD_OPT_RESULT(_recv, _opt, _lpr) \
98 (lls_opt_result(LSG_RECV_CMD_ ## _recv ## _OPT_ ## _opt, _lpr))
99 #define RECV_CMD_OPT_GIVEN(_recv, _opt, _lpr) \
100 (lls_opt_given(RECV_CMD_OPT_RESULT(_recv, _opt, _lpr)))
101 #define RECV_CMD_OPT_STRING_VAL(_recv, _opt, _lpr) \
102 (lls_string_val(0, RECV_CMD_OPT_RESULT(_recv, _opt, _lpr)))
103 #define RECV_CMD_OPT_UINT32_VAL(_recv, _opt, _lpr) \
104 (lls_uint32_val(0, RECV_CMD_OPT_RESULT(_recv, _opt, _lpr)))
105 #define RECV_CMD_OPT_INT32_VAL(_recv, _opt, _lpr) \
106 (lls_int32_val(0, RECV_CMD_OPT_RESULT(_recv, _opt, _lpr)))
107
108 /** Iterate over all available receivers. */
109 #define FOR_EACH_RECEIVER(i) for (i = 1; lls_cmd(i, recv_cmd_suite); i++)
110
111 int check_receiver_arg(const char *ra, struct lls_parse_result **lprp);
112 void print_receiver_helps(bool detailed);
113 int generic_recv_pre_select(struct sched *s, struct receiver_node *rn);