DirAsDSK.hh

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#ifndef DIRASDSK_HH
#define DIRASDSK_HH
 
#include "DiskImageUtils.hh"
#include "EmuTime.hh"
#include "FileOperations.hh"
#include "SectorBasedDisk.hh"
 
#include "hash_map.hh"
 
#include <utility>
 
namespace openmsx {
 
class DiskChanger;
class CliComm;
 
class DirAsDSK final : public SectorBasedDisk
{
public:
        enum class SyncMode { READONLY, FULL };
        enum class BootSectorType { DOS1, 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;
        [[nodiscard]] bool isWriteProtectedImpl() const override;
        [[nodiscard]] bool hasChanged() const override;
        void checkCaches() override;
 
private:
        struct DirIndex {
                DirIndex() = default;
                DirIndex(unsigned sector_, unsigned idx_)
                        : sector(sector_), idx(idx_) {}
                [[nodiscard]] constexpr bool operator==(const DirIndex&) const = default;
 
                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.
        };
 
        [[nodiscard]] std::span<SectorBuffer> fat();
        [[nodiscard]] std::span<SectorBuffer> fat2();
        [[nodiscard]] 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, const FileOperations::Stat& fst);
        void addNewHostFile(const std::string& hostSubDir, const std::string& hostName,
                            unsigned msxDirSector, const FileOperations::Stat& fst);
        [[nodiscard]] DirIndex fillMSXDirEntry(
                const std::string& hostSubDir, const std::string& hostName,
                unsigned msxDirSector);
        [[nodiscard]] DirIndex getFreeDirEntry(unsigned msxDirSector);
        [[nodiscard]] DirIndex findHostFileInDSK(std::string_view hostName) const;
        [[nodiscard]] bool checkFileUsedInDSK(std::string_view hostName) const;
        [[nodiscard]] unsigned nextMsxDirSector(unsigned sector);
        [[nodiscard]] bool checkMSXFileExists(std::span<const char, 11> msxfilename,
                                              unsigned msxDirSector);
        void checkModifiedHostFiles();
        void setMSXTimeStamp(DirIndex dirIndex, const FileOperations::Stat& fst);
        void importHostFile(DirIndex dirIndex, const 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);
        [[nodiscard]] unsigned findNextFreeCluster(unsigned cluster);
        [[nodiscard]] unsigned findFirstFreeCluster();
        [[nodiscard]] unsigned getFreeCluster();
        [[nodiscard]] unsigned readFAT(unsigned cluster);
        void writeFAT12(unsigned cluster, unsigned val);
        void exportFileFromFATChange(unsigned cluster, std::span<SectorBuffer> oldFAT);
        std::pair<unsigned, unsigned> getChainStart(unsigned cluster);
        [[nodiscard]] std::optional<DirIndex> isDirSector(unsigned sector);
 
        struct DirEntryForClusterResult {
                DirIndex dirIndex;
                DirIndex dirDirIndex;
        };
        [[nodiscard]] std::optional<DirEntryForClusterResult> 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
        [[nodiscard]] unsigned readFATHelper(std::span<const SectorBuffer> fat, unsigned cluster) const;
        void writeFATHelper(std::span<SectorBuffer> fat, unsigned cluster, unsigned val) const;
        [[nodiscard]] unsigned clusterToSector(unsigned cluster) const;
        [[nodiscard]] std::pair<unsigned, unsigned> sectorToClusterOffset(unsigned sector) const;
        [[nodiscard]] 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 = EmuTime::zero(); // 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