src/comm/IoCallback.h

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