src/kits/media/legacy/OldBufferStreamManager.h

   1 /******************************************************************************
   2
   3         File:   BufferStreamManager.h
   4
   5         Copyright 1995-97, Be Incorporated
   6
   7 ******************************************************************************/
   8 #ifndef _BUFFER_STREAM_MANAGER_H
   9 #define _BUFFER_STREAM_MANAGER_H
  10
  11
  12 #include <OS.h>
  13 #include <SupportDefs.h>
  14 #include <Locker.h>
  15
  16 #include "OldBufferStream.h"
  17
  18
  19 /* ================
  20    Local Declarations
  21    ================ */
  22
  23 #define B_DEFAULT_BSTREAM_COUNT                 3
  24 #define B_DEFAULT_BSTREAM_SIZE                  B_PAGE_SIZE
  25 #define B_DEFAULT_BSTREAM_DELAY                 10000
  26 #define B_DEFAULT_BSTREAM_TIMEOUT               5000000
  27
  28
  29 enum stream_state {
  30   B_IDLE = 100,         /* stream is shut down */
  31   B_RUNNING,            /* stream is running */
  32   B_STOPPING            /* waiting for final buffer to return */
  33   };
  34
  35
  36 /* ================
  37    Class definition for BBufferStreamManager
  38    ================ */
  39
  40
  41 class BBufferStreamManager {
  42
  43 public:
  44
  45                                         BBufferStreamManager(char* name);
  46         virtual                 ~BBufferStreamManager();
  47
  48
  49         char                    *Name() const;
  50         BBufferStream   *Stream() const;
  51
  52         int32                   BufferCount() const;
  53         void                    SetBufferCount(int32 count);
  54
  55         int32                   BufferSize() const;
  56         void                    SetBufferSize(int32 bytes);
  57
  58   /* Get or set the minimum delay between sending out successive buffers.
  59    * Although the StreamManager automatically shuts down when there
  60    * are no more subscribers, setting the minimum delay can prevent
  61    * prevent runaway streams.  A zero or negative value means no
  62    * delay.
  63    */
  64         bigtime_t               BufferDelay() const;
  65         void                    SetBufferDelay(bigtime_t usecs);
  66
  67   /* If no Buffers return to the StreamManager within a period of time, the
  68    * StreamManager will decide that one of the subscribers is broken and
  69    * will go hunting for it.  When it finds the offending subscriber,
  70    * it will be removed from the chain with impunity.
  71    *
  72    * The default is B_DEFAULT_TIMEOUT.  Setting the timeout to 0 or a
  73    * negative number will disable this.
  74    */
  75         bigtime_t               Timeout() const;
  76         void                    SetTimeout(bigtime_t usecs);
  77
  78   /****************************************************************
  79    * Control the running of the stream.
  80    *
  81    */
  82
  83   /* Set the pending state to B_RUNNING and, if required, start up
  84    * the processing thread.  The processing thread will start
  85    * emitting buffers to the stream.
  86    */
  87         stream_state    Start();
  88
  89   /* Set the pending state to B_STOPPING.  The processing thread will
  90    * stop emitting new buffers to the stream, and when all buffers
  91    * are accounted for, will automatically set the desired state
  92    * to B_IDLE.
  93    */
  94         stream_state    Stop();
  95
  96   /* Set the desired state to B_IDLE.  The processing thread will
  97    * stop immediately and all buffers will be "reclaimed" back
  98    * to the StreamManager.
  99    */
 100         stream_state    Abort();
 101
 102   /* Return the current state of the stream (B_RUNNING, B_STOPPING, or B_IDLE).
 103    */
 104         stream_state    State() const;
 105
 106   /* When NotificationPort is set, the receiver will get a message
 107    * whenever the state of the StreamManager changes.  The msg_id of the
 108    * message will be the new state of the StreamManager.
 109    */
 110         port_id                 NotificationPort() const;
 111         void                    SetNotificationPort(port_id port);
 112
 113   /* Lock the data structures associated with this StreamManager
 114    */
 115         bool                    Lock();
 116         void                    Unlock();
 117
 118   /****************************************************************
 119    * Subscribe functions
 120    */
 121
 122         status_t                Subscribe(BBufferStream *stream);
 123         status_t                Unsubscribe();
 124         subscriber_id   ID() const;
 125
 126
 127 /* ================
 128    Protected member functions.
 129    ================ */
 130
 131 protected:
 132
 133   /****************************************************************
 134    *
 135    * The processing thread.  This thread waits to acquire a Buffer
 136    * (or for the timeout to expire) and takes appropriate action.
 137    */
 138         virtual void                    StartProcessing();
 139         virtual void                    StopProcessing();
 140         static status_t                 _ProcessingThread(void *arg);
 141         virtual void                    ProcessingThread();
 142
 143   /* Set the state of the stream.  If newState is the same as the
 144    * current state, this is a no-op.  Otherwise, this method will
 145    * notify anyone listening on the notification port about the
 146    * changed state and will send a StateChange buffer through the
 147    * stream.
 148    */
 149         virtual void                    SetState(stream_state newState);
 150
 151   /* Snooze until the desired time arrives.  Returns the
 152    * current time upon returning.
 153    */
 154         bigtime_t                               SnoozeUntil(bigtime_t sys_time);
 155
 156 /* ================
 157    Private data.
 158    ================ */
 159
 160 private:
 161
 162 virtual void            _ReservedBufferStreamManager1();
 163 virtual void            _ReservedBufferStreamManager2();
 164 virtual void            _ReservedBufferStreamManager3();
 165
 166   /****************************************************************
 167    *
 168    * Private fields.
 169    *
 170    */
 171
 172   BBufferStream *fStream;                       /* a BBufferStream object */
 173   stream_state  fState;                         /* running, stopping, etc. */
 174   sem_id                fSem;
 175
 176   int32                 fBufferCount;           /* desired # of buffers */
 177   int32                 fBufferSize;            /* desired size of each buffer */
 178   bigtime_t             fBufferDelay;           /* minimum time between sends */
 179   bigtime_t             fTimeout;                       /* watchdog timer */
 180
 181   port_id               fNotifyPort;            /* when set, send change of state msgs */
 182   thread_id             fProcessingThread;      /* thread to dispatch buffers */
 183   subscriber_id fManagerID;                     /* StreamManager's subID in fStream */
 184
 185   BLocker               fLock;
 186   char*                 fName;
 187   uint32                _reserved[4];
 188 };
 189
 190 #endif                  // #ifdef _BUFFER_STREAM_MANAGER_H