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