Policy: use USE_* from code wrappers and ENABLE_* for conditionals.

[thirdparty/squid.git] / src / comm / IoCallback.h

#ifndef _SQUID_COMM_IOCALLBACK_H
#define _SQUID_COMM_IOCALLBACK_H

#include "config.h"
#include "base/AsyncCall.h"
#include "comm_err_t.h"

namespace Comm {

/// Type of IO callbacks the Comm layer deals with.
typedef enum {
    IOCB_NONE,
    IOCB_READ,
    IOCB_WRITE
} iocb_type;

/// Details about a particular Comm IO callback event.
class IoCallback {
public:
    iocb_type type;
    int fd;
    AsyncCall::Pointer callback;
    char *buf;
    FREE *freefunc;
    int size;
    int offset;
    comm_err_t errcode;
    int xerrno;
#if USE_DELAY_POOLS
    unsigned int quotaQueueReserv; ///< reservation ID from CommQuotaQueue
#endif

    bool active() const { return callback != NULL; }
    void setCallback(iocb_type type, AsyncCall::Pointer &cb, char *buf, FREE *func, int sz);

    /// called when fd needs to write but may need to wait in line for its quota
    void selectOrQueueWrite();

    /// Actively cancel the given callback
    void cancel(const char *reason);

    /// finish the IO operation imediately and schedule the callback with the current state.
    void finish(comm_err_t code, int xerrn);

private:
    void reset();
};

/// Entry nodes for the IO callback table: iocb_table
/// Keyed off the FD which the event applies to.
class CbEntry {
public:
    int fd;
    IoCallback  readcb;
    IoCallback  writecb;
};

/// Table of scheduled IO events which have yet to be processed ??
/// Callbacks which might be scheduled in future are stored in fd_table.
extern CbEntry *iocb_table;

extern void CallbackTableInit();
extern void CallbackTableDestruct();

#define COMMIO_FD_READCB(fd)    (&Comm::iocb_table[(fd)].readcb)
#define COMMIO_FD_WRITECB(fd)   (&Comm::iocb_table[(fd)].writecb)

} // namespace Comm

#endif /* _SQUID_COMM_IOCALLBACK_H */