FILE: BufferMsgs.h
Copyright (c) 1995-1997 by Be Incorporated. All Rights Reserved.
+++++ */
#ifndef _BUFFER_MSGS_H
#define _BUFFER_MSGS_H
#include <SupportDefs.h>
This file defines the messages sent between a Subscriber and a
Server. Changes to the protocol should be noted here and appropriate
modifications made to Subscriber.cpp and any servers (currently
the audio_server is the only one).
BufferMsgs defines a message-based interface, not a class
interface. A BufferMsgs receives messages from Subscribers via the
BMessenger class.
Here are the messages that must be supported for the base Subscriber
class and the replies that a server will send. Specific Servers
may support other messages as well.
====
Acquire a stream-id for subsequent operations.
'resource' is a server-specific value that specifies the resource
to which the client wants access.
Upon success, the server replies with 'stream_id' (used for
subsequent operations).
GET_STREAM_ID int32("resource")
=> GET_STREAM_ID int32("stream_id")
=> ERROR_RETURN int32("error")
====
Acquire access to a stream for subsequent operations.
'stream_id' specifies the stream to which the client wants access.
'will_wait' determines if the client will receive an immediate reply
or if it will block until access is granted. 'sem' is a semaphore
used to indicate that the stream has released a buffer.
Upon success, the server replies with 'subscriber_id' (used for
subsequent operations).
SUBSCRIBE String("name")
int32("stream_id")
int32("sem")
Bool("will_wait")
=> SUBSCRIBE int32("subscriber_id")
=> ERROR_RETURN int32("error")
====
Relinquish access to the stream.
UNSUBSCRIBE int32("subscriber_id")
=> UNSUBSCRIBE
=> ERROR_RETURN int32("error")
====
Join the stream at the specified position and start receiving buffers
of data.
ENTER_STREAM int32("subscriber_id")
int32("neighbor")
Bool("before")
=> ENTER_STREAM
=> ERROR_RETURN int32("error")
====
Issue a request to stop receiving buffers. More buffers may continue
to arrive, but you must keep acquiring_ and releasing_ them until you
get one for which is_last_buffer() is true. Then you can stop.
EXIT_STREAM int32("subscriber_id")
=> EXIT_STREAM
=> ERROR_RETURN int32("error")
====
Get information about a particular buffer stream.
GET_STREAM_PARAMS int32("stream_id")
=> GET_STREAM_PARAMS int32("buffer_size")
int32("buffer_count")
Bool("is_running")
int32("subscriber_count")
=> ERROR_RETURN int32("error")
====
Set information about a particular buffer stream.
SET_STREAM_PARAMS int32("stream_id")
int32("buffer_size") <<optional>>
int32("buffer_count") <<optional>>
Bool("is_running") <<optional>>
=> SET_STREAM_PARAMS int32("buffer_size")
int32("buffer_count")
Bool("is_running")
int32("subscriber_count")
=> ERROR_RETURN int32("error")
====
Return the subscriber id of the index'th subscriber sharing the
stream with the given subscriber.
SUBSCRIBER_INFO int32("subscriber_id")
=> SUBSCRIBER_INFO String("subscriber_name")
int32("stream_id") // granted access to
int32("position") // position (if active) or -1
=> ERROR_RETURN int32("error")
<end of long comment>
****************************************************************/
enum {
DEBUG_SERVER = 99,
SUBSCRIBE,
UNSUBSCRIBE,
ENTER_STREAM,
EXIT_STREAM,
GET_STREAM_PARAMETERS,
SET_STREAM_PARAMETERS,
GET_STREAM_ID,
SUBSCRIBER_INFO,
ERROR_RETURN
};
#endif
