Aaru/Aaru.Filesystems/CPM/File.cs

// /***************************************************************************
// Aaru Data Preservation Suite
// ----------------------------------------------------------------------------
//
// Filename       : File.cs
// Author(s)      : Natalia Portillo <claunia@claunia.com>
//
// Component      : CP/M filesystem plugin.
//
// --[ Description ] ----------------------------------------------------------
//
//     Methods to handle files.
//
// --[ License ] --------------------------------------------------------------
//
//     This library is free software; you can redistribute it and/or modify
//     it under the terms of the GNU Lesser General Public License as
//     published by the Free Software Foundation; either version 2.1 of the
//     License, or (at your option) any later version.
//
//     This library is distributed in the hope that it will be useful, but
//     WITHOUT ANY WARRANTY; without even the implied warranty of
//     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
//     Lesser General Public License for more details.
//
//     You should have received a copy of the GNU Lesser General Public
//     License along with this library; if not, see <http://www.gnu.org/licenses/>.
//
// ----------------------------------------------------------------------------
// Copyright © 2011-2022 Natalia Portillo
// ****************************************************************************/

using System;
using Aaru.CommonTypes.Enums;
using Aaru.CommonTypes.Structs;
using Aaru.Helpers;

namespace Aaru.Filesystems;

public sealed partial class CPM
{
    /// <inheritdoc />
    public ErrorNumber GetAttributes(string path, out FileAttributes attributes)
    {
        attributes = new FileAttributes();

        if(!_mounted)
            return ErrorNumber.AccessDenied;

        string[] pathElements = path.Split(new[]
        {
            '/'
        }, StringSplitOptions.RemoveEmptyEntries);

        if(pathElements.Length != 1)
            return ErrorNumber.NotSupported;

        if(string.IsNullOrEmpty(pathElements[0]) ||
           string.Compare(pathElements[0], "/", StringComparison.OrdinalIgnoreCase) == 0)
        {
            attributes = new FileAttributes();
            attributes = FileAttributes.Directory;

            return ErrorNumber.NoError;
        }

        if(!_statCache.TryGetValue(pathElements[0].ToUpperInvariant(), out FileEntryInfo fInfo))
            return ErrorNumber.NoSuchFile;

        attributes = fInfo.Attributes;

        return ErrorNumber.NoError;
    }

    // TODO: Implementing this would require storing the interleaving
    /// <inheritdoc />
    public ErrorNumber MapBlock(string path, long fileBlock, out long deviceBlock)
    {
        deviceBlock = 0;

        return !_mounted ? ErrorNumber.AccessDenied : ErrorNumber.NotImplemented;
    }

    /// <inheritdoc />
    public ErrorNumber Read(string path, long offset, long size, ref byte[] buf)
    {
        if(!_mounted)
            return ErrorNumber.AccessDenied;

        if(size == 0)
        {
            buf = Array.Empty<byte>();

            return ErrorNumber.NoError;
        }

        if(offset < 0)
            return ErrorNumber.InvalidArgument;

        string[] pathElements = path.Split(new[]
        {
            '/'
        }, StringSplitOptions.RemoveEmptyEntries);

        if(pathElements.Length != 1)
            return ErrorNumber.NotSupported;

        if(!_fileCache.TryGetValue(pathElements[0].ToUpperInvariant(), out byte[] file))
            return ErrorNumber.NoSuchFile;

        if(offset >= file.Length)
            return ErrorNumber.EINVAL;

        if(size + offset >= file.Length)
            size = file.Length - offset;

        buf = new byte[size];
        Array.Copy(file, offset, buf, 0, size);

        return ErrorNumber.NoError;
    }

    /// <inheritdoc />
    public ErrorNumber ReadLink(string path, out string dest)
    {
        dest = null;

        return !_mounted ? ErrorNumber.AccessDenied : ErrorNumber.NotSupported;
    }

    /// <inheritdoc />
    public ErrorNumber Stat(string path, out FileEntryInfo stat)
    {
        stat = null;

        if(!_mounted)
            return ErrorNumber.AccessDenied;

        string[] pathElements = path.Split(new[]
        {
            '/'
        }, StringSplitOptions.RemoveEmptyEntries);

        if(pathElements.Length != 1)
            return ErrorNumber.NotSupported;

        if(!string.IsNullOrEmpty(path) &&
           string.Compare(path, "/", StringComparison.OrdinalIgnoreCase) != 0)
            return _statCache.TryGetValue(pathElements[0].ToUpperInvariant(), out stat) ? ErrorNumber.NoError
                       : ErrorNumber.NoSuchFile;

        stat = new FileEntryInfo
        {
            Attributes = FileAttributes.Directory,
            BlockSize  = XmlFsType.ClusterSize
        };

        if(_labelCreationDate != null)
            stat.CreationTime = DateHandlers.CpmToDateTime(_labelCreationDate);

        if(_labelUpdateDate != null)
            stat.StatusChangeTime = DateHandlers.CpmToDateTime(_labelUpdateDate);

        return ErrorNumber.NoError;
    }
}