RockIoState.h

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/*
 * Copyright (C) 1996-2023 The Squid Software Foundation and contributors
 *
 * Squid software is distributed under GPLv2+ license and includes
 * contributions from numerous individuals and organizations.
 * Please see the COPYING and CONTRIBUTORS files for details.
 */
 
#ifndef SQUID_FS_ROCK_IO_STATE_H
#define SQUID_FS_ROCK_IO_STATE_H
 
#include "fs/rock/forward.h"
#include "fs/rock/RockSwapDir.h"
#include "sbuf/MemBlob.h"
 
class DiskFile;
 
namespace Rock
{
 
class DbCellHeader;
class SwapDir;
 
class IoState: public ::StoreIOState
{
    MEMPROXY_CLASS(IoState);
 
public:
    typedef RefCount<IoState> Pointer;
 
    IoState(Rock::SwapDir::Pointer &, StoreEntry *, StoreIOState::STIOCB *, void *cbData);
    ~IoState() override;
 
    void file(const RefCount<DiskFile> &aFile);
 
    // ::StoreIOState API
    void read_(char *buf, size_t size, off_t offset, STRCB * callback, void *callback_data) override;
    bool write(char const *buf, size_t size, off_t offset, FREE * free_func) override;
    void close(int how) override;
 
    bool stillWaiting() const { return theFile != nullptr; }
 
    void handleReadCompletion(Rock::ReadRequest &request, const int rlen, const int errFlag);
 
    void finishedWriting(const int errFlag);
 
    bool expectedReply(const IoXactionId receivedId);
 
    /* one and only one of these will be set and locked; access via *Anchor() */
    const Ipc::StoreMapAnchor *readableAnchor_; 
    Ipc::StoreMapAnchor *writeableAnchor_; 
 
    SlotId splicingPoint;
    SlotId staleSplicingPointNext;
 
private:
    const Ipc::StoreMapAnchor &readAnchor() const;
    Ipc::StoreMapAnchor &writeAnchor();
    const Ipc::StoreMapSlice &currentReadableSlice() const;
 
    void tryWrite(char const *buf, size_t size, off_t offset);
    size_t writeToBuffer(char const *buf, size_t size);
    void writeToDisk();
 
    void callReaderBack(const char *buf, int rlen);
    void callBack(int errflag);
 
    Rock::SwapDir::Pointer dir; 
    const size_t slotSize; 
    int64_t objOffset; 
 
    SlotId sidFirst;
 
    SlotId sidPrevious;
 
    SlotId sidCurrent;
 
    SlotId sidNext;
 
    uint64_t requestsSent;
 
    uint64_t repliesReceived;
 
    RefCount<DiskFile> theFile; // "file" responsible for this I/O
    MemBlob theBuf; // use for write content accumulation only
};
 
} // namespace Rock
 
#endif /* SQUID_FS_ROCK_IO_STATE_H */