DirAsDSK.hh

Go to the documentation of this file.

#ifndef DIRASDSK_HH
#define DIRASDSK_HH

#include "SectorBasedDisk.hh"
#include "DiskImageUtils.hh"
#include "FileOperations.hh"
#include "EmuTime.hh"
#include "hash_map.hh"

namespace openmsx {

class DiskChanger;
class CliComm;

class DirAsDSK final : public SectorBasedDisk
{
public:
        enum SyncMode { SYNC_READONLY, SYNC_FULL };
        enum BootSectorType { BOOTSECTOR_DOS1, BOOTSECTOR_DOS2 };

public:
        DirAsDSK(DiskChanger& diskChanger, CliComm& cliComm,
                 const Filename& hostDir, SyncMode syncMode,
                 BootSectorType bootSectorType);

        // SectorBasedDisk
        void readSectorImpl (size_t sector,       SectorBuffer& buf) override;
        void writeSectorImpl(size_t sector, const SectorBuffer& buf) override;
        bool isWriteProtectedImpl() const override;
        void checkCaches() override;

private:
        struct DirIndex {
                DirIndex() = default;
                DirIndex(unsigned sector_, unsigned idx_)
                        : sector(sector_), idx(idx_) {}
                friend bool operator==(const DirIndex& x, const DirIndex& y) {
                        return (x.sector == y.sector) &&
                               (x.idx    == y.idx);
                }
                unsigned sector;
                unsigned idx;
        };
        struct HashDirIndex {
                auto operator()(const DirIndex& d) const {
                        std::hash<unsigned> subHasher;
                        return 31 * subHasher(d.sector)
                                  + subHasher(d.idx);
                }
        };
        struct MapDir {
                std::string hostName; // path relative to 'hostDir'
                // The following two are used to detect changes in the host
                // file compared to the last host->virtual-disk sync.
                time_t mtime; // Modification time of host file at the time of
                              // the last sync.
                size_t filesize; // Host file size, normally the same as msx
                                 // filesize, except when the host file was
                                 // truncated.
        };

        SectorBuffer* fat();
        SectorBuffer* fat2();
        MSXDirEntry& msxDir(DirIndex dirIndex);
        void writeFATSector (unsigned sector, const SectorBuffer& buf);
        void writeDIRSector (unsigned sector, DirIndex dirDirIndex,
                             const SectorBuffer& buf);
        void writeDataSector(unsigned sector, const SectorBuffer& buf);
        void writeDIREntry(DirIndex dirIndex, DirIndex dirDirIndex,
                           const MSXDirEntry& newEntry);
        void syncWithHost();
        void checkDeletedHostFiles();
        void deleteMSXFile(DirIndex dirIndex);
        void deleteMSXFilesInDir(unsigned msxDirSector);
        void freeFATChain(unsigned cluster);
        void addNewHostFiles(const std::string& hostSubDir, unsigned msxDirSector);
        void addNewDirectory(const std::string& hostSubDir, const std::string& hostName,
                             unsigned msxDirSector, FileOperations::Stat& fst);
        void addNewHostFile(const std::string& hostSubDir, const std::string& hostName,
                            unsigned msxDirSector, FileOperations::Stat& fst);
        DirIndex fillMSXDirEntry(
                const std::string& hostSubDir, const std::string& hostName,
                unsigned msxDirSector);
        DirIndex getFreeDirEntry(unsigned msxDirSector);
        DirIndex findHostFileInDSK(const std::string& hostName);
        bool checkFileUsedInDSK(const std::string& hostName);
        unsigned nextMsxDirSector(unsigned sector);
        bool checkMSXFileExists(const std::string& msxfilename,
                                unsigned msxDirSector);
        void checkModifiedHostFiles();
        void setMSXTimeStamp(DirIndex dirIndex, FileOperations::Stat& fst);
        void importHostFile(DirIndex dirIndex, FileOperations::Stat& fst);
        void exportToHost(DirIndex dirIndex, DirIndex dirDirIndex);
        void exportToHostDir (DirIndex dirIndex, const std::string& hostName);
        void exportToHostFile(DirIndex dirIndex, const std::string& hostName);
        unsigned findNextFreeCluster(unsigned cluster);
        unsigned findFirstFreeCluster();
        unsigned getFreeCluster();
        unsigned readFAT(unsigned cluster);
        void writeFAT12(unsigned cluster, unsigned val);
        void exportFileFromFATChange(unsigned cluster, SectorBuffer* oldFAT);
        unsigned getChainStart(unsigned cluster, unsigned& chainLength);
        bool isDirSector(unsigned sector, DirIndex& dirDirIndex);
        bool getDirEntryForCluster(unsigned cluster,
                                   DirIndex& dirIndex, DirIndex& dirDirIndex);
        DirIndex getDirEntryForCluster(unsigned cluster);
        void unmapHostFiles(unsigned msxDirSector);
        template<typename FUNC> bool scanMsxDirs(
                FUNC func, unsigned msxDirSector);
        friend struct NullScanner;
        friend struct DirScanner;
        friend struct IsDirSector;
        friend struct DirEntryForCluster;
        friend struct UnmapHostFiles;

        // internal helper functions
        unsigned readFATHelper(const SectorBuffer* fat, unsigned cluster) const;
        void writeFATHelper(SectorBuffer* fat, unsigned cluster, unsigned val) const;
        unsigned clusterToSector(unsigned cluster) const;
        void sectorToCluster(unsigned sector, unsigned& cluster, unsigned& offset) const;
        unsigned sectorToCluster(unsigned sector) const;

private:
        DiskChanger& diskChanger; // used to query time / report disk change
        CliComm& cliComm; // TODO don't use CliComm to report errors/warnings
        const std::string hostDir;
        const SyncMode syncMode;

        EmuTime lastAccess; // last time there was a sector read/write

        // For each directory entry that has a mapped host file/directory we
        // store the name, last modification time and size of the corresponding
        // host file/dir.
        using MapDirs = hash_map<DirIndex, MapDir, HashDirIndex>;
        MapDirs mapDirs;

        // format parameters which depend on single/double sided
        // varying root parameters
        const unsigned nofSectors;
        const unsigned nofSectorsPerFat;
        // parameters that depend on these and thus also vary
        const unsigned firstSector2ndFAT;
        const unsigned firstDirSector;
        const unsigned firstDataSector;
        const unsigned maxCluster; // First cluster number that can NOT be used anymore.

        // Storage for the whole virtual disk.
        std::vector<SectorBuffer> sectors;
};

} // namespace openmsx

#endif