FileMeta.h

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#pragma once

#include "../Access.h"
#include "../FileAttributes.h"
#include "../Compression.h"

namespace IFS
{
namespace SPIFFS
{
struct FileMeta {
    static constexpr uint32_t Magic{0xE3457A77};

    // Magic
    uint32_t magic;
    // Modification time
    TimeStamp mtime;
    // FileAttributes - default indicates content has changed
    FileAttributes attr;
    // Security
    ACL acl;
    // Compression
    struct __attribute__((packed)) {
        Compression::Type type;
        uint32_t originalSize;
    } compression;

    void init()
    {
        *this = FileMeta{};
        magic = Magic;
        mtime = fsGetTimeUTC();
        acl.readAccess = UserRole::Admin;
        acl.writeAccess = UserRole::Admin;
    }
};

#define FILEMETA_SIZE 16
static_assert(sizeof(FileMeta) == FILEMETA_SIZE, "FileMeta wrong size");

#if SPIFFS_OBJ_META_LEN >= FILEMETA_SIZE
#define SPIFFS_STORE_META
#define SPIFFS_USER_METALEN (SPIFFS_OBJ_META_LEN - FILEMETA_SIZE)
#else
#define SPIFFS_USER_METALEN 0
#endif

struct SpiffsMetaBuffer {
    FileMeta meta;
    uint8_t user[SPIFFS_USER_METALEN];

    enum class Flag {
        dirty,
    };
    BitSet<uint8_t, Flag> flags;

    void init()
    {
        meta.init();
        memset(user, 0xFF, sizeof(user));
    }

    template <typename T> void assign(const T& data)
    {
        static_assert(sizeof(data) == offsetof(SpiffsMetaBuffer, flags), "SPIFFS metadata assign() size incorrect");
        memcpy(reinterpret_cast<void*>(this), data, sizeof(data));

        // If metadata uninitialised, then initialise it now
        if(meta.magic != FileMeta::Magic) {
            meta.init();
            flags[Flag::dirty] = true;
        }
    }

    void copyTo(Stat& stat)
    {
        stat.acl = meta.acl;
        stat.attr = meta.attr;
        stat.mtime = meta.mtime;
        stat.compression = Compression{meta.compression.type, meta.compression.originalSize};
    }

    void setAcl(const ACL& newAcl)
    {
        if(meta.acl != newAcl) {
            meta.acl = newAcl;
            flags[Flag::dirty] = true;
        }
    }

    void setFileTime(time_t t)
    {
        if(meta.mtime != t) {
            meta.mtime = t;
            flags[Flag::dirty] = true;
        }
    }

    void setCompression(const Compression& c)
    {
        if(meta.compression.type != c.type || meta.compression.originalSize != c.originalSize) {
            meta.compression.type = c.type;
            meta.compression.originalSize = c.originalSize;
            meta.attr[FileAttribute::Compressed] = (c.type != Compression::Type::None);
            flags[Flag::dirty] = true;
        }
    }

    void setattr(FileAttributes newAttr)
    {
        if(meta.attr != newAttr) {
            meta.attr = newAttr;
            flags[Flag::dirty] = true;
        }
    }
};

} // namespace SPIFFS
} // namespace IFS