workbench/libs/asyncio/src/WaitPacket.c

   1 #include "async.h"
   2
   3
   4 /* this function waits for a packet to come back from the file system. If no
   5  * packet is pending, state from the previous packet is returned. This ensures
   6  * that once an error occurs, it state is maintained for the rest of the life
   7  * of the file handle.
   8  *
   9  * This function also deals with IO errors, bringing up the needed DOS
  10  * requesters to let the user retry an operation or cancel it.
  11  */
  12 LONG
  13 AS_WaitPacket( AsyncFile *file )
  14 {
  15 #ifdef ASIO_NOEXTERNALS
  16         struct ExecBase         *SysBase = file->af_SysBase;
  17         struct DosLibrary       *DOSBase = file->af_DOSBase;
  18 #endif
  19         LONG bytes;
  20
  21         if( file->af_PacketPending )
  22         {
  23                 while( TRUE )
  24                 {
  25                         /* This enables signalling when a packet comes back to the port */
  26                         file->af_PacketPort.mp_Flags = PA_SIGNAL;
  27
  28                         /* Wait for the packet to come back, and remove it from the message
  29                          * list. Since we know no other packets can come in to the port, we can
  30                          * safely use Remove() instead of GetMsg(). If other packets could come in,
  31                          * we would have to use GetMsg(), which correctly arbitrates access in such
  32                          * a case
  33                          */
  34                         Remove( ( struct Node * ) WaitPort( &file->af_PacketPort ) );
  35
  36                         /* set the port type back to PA_IGNORE so we won't be bothered with
  37                          * spurious signals
  38                          */
  39                         file->af_PacketPort.mp_Flags = PA_IGNORE;
  40
  41                         /* mark packet as no longer pending since we removed it */
  42                         file->af_PacketPending = FALSE;
  43
  44                         bytes = file->af_Packet.sp_Pkt.dp_Res1;
  45
  46                         if( bytes >= 0 )
  47                         {
  48                                 /* packet didn't report an error, so bye... */
  49                                 return( bytes );
  50                         }
  51
  52                         /* see if the user wants to try again... */
  53                         if( ErrorReport( file->af_Packet.sp_Pkt.dp_Res2, REPORT_STREAM, file->af_File, NULL ) )
  54                         {
  55                                 return( -1 );
  56                         }
  57
  58                         /* user wants to try again, resend the packet */
  59                         AS_SendPacket( file,
  60                                 file->af_Buffers[ file->af_ReadMode ?
  61                                         file->af_CurrentBuf :
  62                                         1 - file->af_CurrentBuf ] );
  63                 }
  64         }
  65
  66         /* last packet's error code, or 0 if packet was never sent */
  67         SetIoErr( file->af_Packet.sp_Pkt.dp_Res2 );
  68
  69         return( file->af_Packet.sp_Pkt.dp_Res1 );
  70 }