FilePoolCore.hh

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#ifndef FILEPOOLCORE_HH
#define FILEPOOLCORE_HH
 
#include "FileOperations.hh"
#include "ObjectPool.hh"
#include "MemBuffer.hh"
#include "SimpleHashSet.hh"
#include "sha1.hh"
#include "xxhash.hh"
#include <cassert>
#include <cstdint>
#include <ctime>
#include <functional>
#include <string>
#include <string_view>
#include <vector>
 
namespace openmsx {
 
class File;
 
enum class FileType {
        NONE = 0,
        SYSTEM_ROM = 1, ROM = 2, DISK = 4, TAPE = 8
};
inline FileType operator|(FileType x, FileType y) {
        return static_cast<FileType>(int(x) | int(y));
}
inline FileType operator&(FileType x, FileType y) {
        return static_cast<FileType>(int(x) & int(y));
}
inline FileType& operator|=(FileType& x, FileType y) {
        x = x | y;
        return x;
}
 
class FilePoolCore
{
public:
        struct Dir {
                std::string_view path;
                FileType types;
        };
        using Directories = std::vector<Dir>;
 
public:
        FilePoolCore(std::string fileCache,
                     std::function<Directories()> getDirectories,
                     std::function<void(std::string_view)> reportProgress);
        ~FilePoolCore();
 
        [[nodiscard]] File getFile(FileType fileType, const Sha1Sum& sha1sum);
 
        [[nodiscard]] Sha1Sum getSha1Sum(File& file);
 
        void abort() { stop = true; }
 
private:
        struct ScanProgress {
                uint64_t lastTime;
                unsigned amountScanned;
        };
 
        struct Entry {
                Entry(const Sha1Sum& s, time_t t, std::string_view f)
                        : filename(f), time(t), sum(s)
                {
                        assert(time != Date::INVALID_TIME_T);
                }
                Entry(const Sha1Sum& s, const char* t, std::string_view f)
                        : filename(f), timeStr(t), sum(s)
                {
                        assert(timeStr != nullptr);
                }
 
                [[nodiscard]] time_t getTime();
                void setTime(time_t t);
 
                // - At least one of 'timeStr' or 'time' is valid.
                // - 'filename' and 'timeStr' are non-owning pointers.
                std::string_view filename;
                const char* timeStr = nullptr; // might be nullptr
                time_t time = Date::INVALID_TIME_T;
                Sha1Sum sum;
        };
 
        using Pool = ObjectPool<Entry>;
        using Index = Pool::Index;
        using Sha1Index = std::vector<Index>; // sorted on sha1sum
 
        class FilenameIndexHelper {
        public:
                FilenameIndexHelper(const Pool& p) : pool(p) {}
                [[nodiscard]] std::string_view get(std::string_view s) const { return s; }
                [[nodiscard]] std::string_view get(Index idx) const { return pool[idx].filename; }
        private:
                const Pool& pool;
        };
        struct FilenameIndexHash : FilenameIndexHelper {
                FilenameIndexHash(const Pool& p) : FilenameIndexHelper(p) {}
                template<typename T> [[nodiscard]] auto operator()(T t) const {
                        XXHasher hasher;
                        return hasher(get(t));
                }
        };
        struct FilenameIndexEqual : FilenameIndexHelper {
                FilenameIndexEqual(const Pool& p) : FilenameIndexHelper(p) {}
                template<typename T1, typename T2>
                [[nodiscard]] bool operator()(T1 x, T2 y) const {
                        return get(x) == get(y);
                }
        };
        // Hash indexed by filename, points to a full object in 'pool'
        using FilenameIndex = SimpleHashSet<Index, Index(-1), FilenameIndexHash, FilenameIndexEqual>;
 
private:
        void insert(const Sha1Sum& sum, time_t time, const std::string& filename);
        [[nodiscard]] Sha1Index::iterator getSha1Iterator(Index idx, Entry& entry);
        void remove(Sha1Index::iterator it);
        void remove(Index idx);
        void remove(Index idx, Entry& entry);
        bool adjustSha1(Sha1Index::iterator it, Entry& entry, const Sha1Sum& newSum);
        bool adjustSha1(Index idx,              Entry& entry, const Sha1Sum& newSum);
 
        void readSha1sums();
        void writeSha1sums();
 
        [[nodiscard]] File getFromPool(const Sha1Sum& sha1sum);
        [[nodiscard]] File scanDirectory(
                const Sha1Sum& sha1sum,
                const std::string& directory,
                std::string_view poolPath,
                ScanProgress& progress);
        [[nodiscard]] File scanFile(
                const Sha1Sum& sha1sum,
                const std::string& filename,
                const FileOperations::Stat& st,
                std::string_view poolPath,
                ScanProgress& progress);
        [[nodiscard]] Sha1Sum calcSha1sum(File& file);
        [[nodiscard]] std::pair<Index, Entry*> findInDatabase(std::string_view filename);
 
private:
        std::string fileCache; // path of the '.filecache' file.
        std::function<Directories()> getDirectories;
        std::function<void(std::string_view)> reportProgress;
 
        MemBuffer<char> fileMem; // content of initial .filecache
        std::vector<std::string> stringBuffer; // owns strings that are not in 'fileMem'
 
        Pool pool; // the actual entries
        Sha1Index sha1Index; // entries accessible via sha1, sorted on 'CompareSha1'
        FilenameIndex filenameIndex{FilenameIndexHash(pool), FilenameIndexEqual(pool)}; // accessible via filename
 
        bool stop = false; // abort long search (set via reportProgress callback)
        bool needWrite = false; // dirty '.filecache'? write on exit
 
        friend struct GetSha1;
};
 
} // namespace openmsx
 
#endif