recv.h

   1 /*
   2  * Copyright (C) 2005-2011 Andre Noll <maan@systemlinux.org>
   3  *
   4  * Licensed under the GPL v2. For licencing details see COPYING.
   5  */
   6
   7 /** \file recv.h Receiver-related structures and exported symbols of recv_common.c. */
   8
   9 /**
  10  * Describes one instance of a receiver.
  11  */
  12 struct receiver_node {
  13         /** Points to the corresponding receiver. */
  14         struct receiver *receiver;
  15         /** Receiver-specific data. */
  16         void *private_data;
  17         /** Pointer to the configuration data for this instance. */
  18         void *conf;
  19         /** The task associated with this instance. */
  20         struct task task;
  21         /** The receiver node is always the root of the buffer tree. */
  22         struct btr_node *btrn;
  23         /** Each receiver node maintains a buffer pool for the received data. */
  24         struct btr_pool *btrp;
  25         /**
  26          * The file descriptor to receive the stream.
  27          *
  28          * The pre_select function of the receiver adds this file descriptor to
  29          * the set of file descriptors which are watched for readability or
  30          * writability, depending on the state of the connection (if any).
  31          *
  32          * If \a fd is readable, the post_select function of the receiver reads
  33          * data from this fd into the buffer pool area of \a btrp.
  34          *
  35          * \sa \ref receiver.
  36          */
  37         int fd;
  38 };
  39
  40 /**
  41  * Describes one supported paraslash receiver.
  42  *
  43  * \sa http_recv.c, udp_recv.c
  44  */
  45 struct receiver {
  46         /**
  47          * The name of the receiver.
  48          */
  49         const char *name;
  50         /**
  51          * The receiver init function.
  52          *
  53          * It must fill in all other function pointers and is assumed to succeed.
  54          *
  55          * \sa http_recv_init udp_recv_init.
  56          */
  57         void (*init)(struct receiver *r);
  58         /**
  59          * The command line parser of the receiver.
  60          *
  61          * It should check whether the command line options given by \a argc and \a
  62          * argv are valid.  On success, it should return a pointer to the
  63          * receiver-specific configuration data determined by \a argc and \a argv.
  64          * Note that this might be called more than once with different values of
  65          * \a argc and \a argv.
  66          */
  67         void *(*parse_config)(int argc, char **argv);
  68         /**
  69          * Deallocate the configuration structure of a receiver node.
  70          *
  71          * This calls the receiver-specific cleanup function generated by
  72          * gengetopt.
  73          */
  74         void (*free_config)(void *conf);
  75         /**
  76          * Open one instance of the receiver.
  77          *
  78          * This should allocate the output buffer of \a rn. and may also
  79          * perform any other work necessary for retrieving the stream according
  80          * to the configuration stored in the \a conf member of \a rn which is
  81          * guaranteed to point to valid configuration data (as previously
  82          * obtained from the config parser).
  83          *
  84          * \sa receiver_node::conf, receiver_node::buf.
  85          */
  86         int (*open)(struct receiver_node *rn);
  87         /**
  88          * Close this instance of the receiver.
  89          *
  90          * It should free all resources associated with given receiver node
  91          * that were allocated during the corresponding open call.
  92          *
  93          * \sa receiver_node.
  94          */
  95         void (*close)(struct receiver_node *rn);
  96         /**
  97          * Add file descriptors to fd_sets and compute timeout for select(2).
  98          *
  99          * The pre_select function gets called from the driving application
 100          * before entering its select loop. The receiver may use this hook to
 101          * add any file descriptors to the sets of file descriptors given by \a
 102          * s.
 103          *
 104          * \sa select(2), time.c struct task, struct sched.
 105          */
 106         void (*pre_select)(struct sched *s, struct task *t);
 107         /**
 108          * Evaluate the result from select().
 109          *
 110          * This hook gets called after the call to select(). It should check
 111          * all file descriptors which were added to any of the the fd sets
 112          * during the previous call to pre_select. According to the result, it
 113          * may then use any non-blocking I/O to establish a connection or to
 114          * receive the audio data.
 115          *
 116          * \sa select(2), struct receiver.
 117          */
 118         void (*post_select)(struct sched *s, struct task *t);
 119
 120         /** The two help texts of this receiver. */
 121         struct ggo_help help;
 122 };
 123
 124 /** Define an array of all available receivers. */
 125 #define DEFINE_RECEIVER_ARRAY struct receiver receivers[] = { \
 126         HTTP_RECEIVER \
 127         DCCP_RECEIVER \
 128         UDP_RECEIVER \
 129         {.name = NULL}};
 130
 131 /** Iterate over all available receivers. */
 132 #define FOR_EACH_RECEIVER(i) for (i = 0; receivers[i].name; i++)
 133
 134 void recv_init(void);
 135 void *check_receiver_arg(char *ra, int *receiver_num);
 136 void print_receiver_helps(int detailed);
 137 int generic_recv_pre_select(struct sched *s, struct task *t);
 138
 139 /** \cond receiver */
 140 extern void http_recv_init(struct receiver *r);
 141 #define HTTP_RECEIVER {.name = "http", .init = http_recv_init},
 142 extern void dccp_recv_init(struct receiver *r);
 143 #define DCCP_RECEIVER {.name = "dccp", .init = dccp_recv_init},
 144 extern void udp_recv_init(struct receiver *r);
 145 #define UDP_RECEIVER {.name = "udp", .init = udp_recv_init},
 146
 147 extern struct receiver receivers[];
 148 /** \endcond receiver */
 149