Segment.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_IPC_MEM_SEGMENT_H
#define SQUID_IPC_MEM_SEGMENT_H
 
#include "base/RunnersRegistry.h"
#include "sbuf/forward.h"
#include "SquidString.h"
 
namespace Ipc
{
 
namespace Mem
{
 
class Segment
{
public:
    Segment(const char *const id);
    ~Segment();
 
    static bool Enabled();
 
    void create(const off_t aSize);
    void open(const bool unlinkWhenDone);
 
    const String &name() { return theName; } 
    off_t size() { return theSize; } 
    void *mem() { return reserve(0); } 
    void *reserve(size_t chunkSize); 
 
    static const char *BasePath;
 
    static SBuf Name(const SBuf &prefix, const char *suffix);
 
private:
 
    // not implemented
    Segment(const Segment &);
    Segment &operator =(const Segment &);
 
#if HAVE_SHM
 
    bool createFresh(int &err);
    void attach();
    void detach();
    void lock();
    void unlink(); 
    off_t statSize(const char *context) const;
 
    static String GenerateName(const char *id);
 
    int theFD; 
 
#else // HAVE_SHM
 
    void checkSupport(const char *const context);
 
#endif // HAVE_SHM
 
    const String theName; 
    void *theMem; 
    off_t theSize; 
    off_t theReserved; 
    bool doUnlink; 
};
 
class RegisteredRunner: public ::RegisteredRunner
{
public:
    /* RegisteredRunner API */
    void useConfig() override;
 
protected:
    virtual void create() = 0;
    virtual void open() {}
};
 
} // namespace Mem
 
} // namespace Ipc
 
#endif /* SQUID_IPC_MEM_SEGMENT_H */