src/comm/IoCallback.h

   1 #ifndef _SQUID_COMM_IOCALLBACK_H
   2 #define _SQUID_COMM_IOCALLBACK_H
   3
   4 #include "base/AsyncCall.h"
   5 #include "comm/Flag.h"
   6 #include "comm/forward.h"
   7 #include "typedefs.h"
   8
   9 class SBuf;
  10
  11 namespace Comm
  12 {
  13
  14 /// Type of IO callbacks the Comm layer deals with.
  15 typedef enum {
  16     IOCB_NONE,
  17     IOCB_READ,
  18     IOCB_WRITE
  19 } iocb_type;
  20
  21 /// Details about a particular Comm IO callback event.
  22 class IoCallback
  23 {
  24 public:
  25     iocb_type type;
  26     Comm::ConnectionPointer conn;
  27     AsyncCall::Pointer callback;
  28     char *buf;
  29     FREE *freefunc;
  30     int size;
  31     int offset;
  32     Comm::Flag errcode;
  33     int xerrno;
  34 #if USE_DELAY_POOLS
  35     unsigned int quotaQueueReserv; ///< reservation ID from CommQuotaQueue
  36 #endif
  37
  38     bool active() const { return callback != NULL; }
  39     void setCallback(iocb_type type, AsyncCall::Pointer &cb, char *buf, FREE *func, int sz);
  40
  41     /// called when fd needs to write but may need to wait in line for its quota
  42     void selectOrQueueWrite();
  43
  44     /// Actively cancel the given callback
  45     void cancel(const char *reason);
  46
  47     /// finish the IO operation imediately and schedule the callback with the current state.
  48     void finish(Comm::Flag code, int xerrn);
  49
  50 private:
  51     void reset();
  52 };
  53
  54 /// Entry nodes for the IO callback table: iocb_table
  55 /// Keyed off the FD which the event applies to.
  56 class CbEntry
  57 {
  58 public:
  59     int fd;
  60     IoCallback  readcb;
  61     IoCallback  writecb;
  62 };
  63
  64 /// Table of scheduled IO events which have yet to be processed ??
  65 /// Callbacks which might be scheduled in future are stored in fd_table.
  66 extern CbEntry *iocb_table;
  67
  68 void CallbackTableInit();
  69 void CallbackTableDestruct();
  70
  71 #define COMMIO_FD_READCB(fd)    (&Comm::iocb_table[(fd)].readcb)
  72 #define COMMIO_FD_WRITECB(fd)   (&Comm::iocb_table[(fd)].writecb)
  73
  74 } // namespace Comm
  75
  76 #endif /* _SQUID_COMM_IOCALLBACK_H */