xref: /openbmc/qemu/include/hw/stream.h (revision b3c818a4)
1 #ifndef STREAM_H
2 #define STREAM_H
3 
4 #include "qom/object.h"
5 
6 #define TYPE_STREAM_SINK "stream-sink"
7 
8 typedef struct StreamSinkClass StreamSinkClass;
9 DECLARE_CLASS_CHECKERS(StreamSinkClass, STREAM_SINK,
10                        TYPE_STREAM_SINK)
11 #define STREAM_SINK(obj) \
12      INTERFACE_CHECK(StreamSink, (obj), TYPE_STREAM_SINK)
13 
14 typedef struct StreamSink StreamSink;
15 
16 typedef void (*StreamCanPushNotifyFn)(void *opaque);
17 
18 struct StreamSinkClass {
19     InterfaceClass parent;
20     /**
21      * can push - determine if a stream sink is capable of accepting at least
22      * one byte of data. Returns false if cannot accept. If not implemented, the
23      * sink is assumed to always be capable of receiving.
24      * @notify: Optional callback that the sink will call when the sink is
25      * capable of receiving again. Only called if false is returned.
26      * @notify_opaque: opaque data to pass to notify call.
27      */
28     bool (*can_push)(StreamSink *obj, StreamCanPushNotifyFn notify,
29                      void *notify_opaque);
30     /**
31      * push - push data to a Stream sink. The number of bytes pushed is
32      * returned. If the sink short returns, the master must wait before trying
33      * again, the sink may continue to just return 0 waiting for the vm time to
34      * advance. The can_push() function can be used to trap the point in time
35      * where the sink is ready to receive again, otherwise polling on a QEMU
36      * timer will work.
37      * @obj: Stream sink to push to
38      * @buf: Data to write
39      * @len: Maximum number of bytes to write
40      * @eop: End of packet flag
41      */
42     size_t (*push)(StreamSink *obj, unsigned char *buf, size_t len, bool eop);
43 };
44 
45 size_t
46 stream_push(StreamSink *sink, uint8_t *buf, size_t len, bool eop);
47 
48 bool
49 stream_can_push(StreamSink *sink, StreamCanPushNotifyFn notify,
50                 void *notify_opaque);
51 
52 
53 #endif /* STREAM_H */
54