AttachmentBase.cs

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using System.Diagnostics.CodeAnalysis;
using System.IO;
using System.Net.Mime;
using System.Text;
 
namespace System.Net.Mail;
 
public abstract class AttachmentBase : IDisposable
{
    internal bool disposed;
 
    private readonly MimePart _part = new MimePart();
 
    private static readonly char[] s_contentCIDInvalidChars = new char[2] { '<', '>' };
 
    public Stream ContentStream
    {
        get
        {
            if (disposed)
            {
                throw new ObjectDisposedException(GetType().FullName);
            }
            return _part.Stream;
        }
    }
 
    public string ContentId
    {
        get
        {
            string contentID = _part.ContentID;
            if (string.IsNullOrEmpty(contentID))
            {
                return ContentId = Guid.NewGuid().ToString();
            }
            if (contentID.Length >= 2 && contentID[0] == '<' && contentID[contentID.Length - 1] == '>')
            {
                return contentID.Substring(1, contentID.Length - 2);
            }
            return contentID;
        }
        [param: AllowNull]
        set
        {
            if (string.IsNullOrEmpty(value))
            {
                _part.ContentID = null;
                return;
            }
            if (value.IndexOfAny(s_contentCIDInvalidChars) != -1)
            {
                throw new ArgumentException(System.SR.MailHeaderInvalidCID, "value");
            }
            _part.ContentID = "<" + value + ">";
        }
    }
 
    public ContentType ContentType
    {
        get
        {
            return _part.ContentType;
        }
        set
        {
            _part.ContentType = value;
        }
    }
 
    public TransferEncoding TransferEncoding
    {
        get
        {
            return _part.TransferEncoding;
        }
        set
        {
            _part.TransferEncoding = value;
        }
    }
 
    internal Uri? ContentLocation
    {
        get
        {
            if (!Uri.TryCreate(_part.ContentLocation, UriKind.RelativeOrAbsolute, out Uri result))
            {
                return null;
            }
            return result;
        }
        set
        {
            _part.ContentLocation = ((value == null) ? null : (value.IsAbsoluteUri ? value.AbsoluteUri : value.OriginalString));
        }
    }
 
    internal MimePart MimePart => _part;
 
    internal AttachmentBase()
    {
    }
 
    protected AttachmentBase(string fileName)
    {
        SetContentFromFile(fileName, string.Empty);
    }
 
    protected AttachmentBase(string fileName, string? mediaType)
    {
        SetContentFromFile(fileName, mediaType);
    }
 
    protected AttachmentBase(string fileName, ContentType? contentType)
    {
        SetContentFromFile(fileName, contentType);
    }
 
    protected AttachmentBase(Stream contentStream)
    {
        _part.SetContent(contentStream);
    }
 
    protected AttachmentBase(Stream contentStream, string? mediaType)
    {
        _part.SetContent(contentStream, null, mediaType);
    }
 
    internal AttachmentBase(Stream contentStream, string name, string mediaType)
    {
        _part.SetContent(contentStream, name, mediaType);
    }
 
    protected AttachmentBase(Stream contentStream, ContentType? contentType)
    {
        _part.SetContent(contentStream, contentType);
    }
 
    public void Dispose()
    {
        Dispose(disposing: true);
    }
 
    protected virtual void Dispose(bool disposing)
    {
        if (disposing && !disposed)
        {
            disposed = true;
            _part.Dispose();
        }
    }
 
    internal void SetContentFromFile(string fileName, ContentType contentType)
    {
        if (fileName == null)
        {
            throw new ArgumentNullException("fileName");
        }
        if (fileName.Length == 0)
        {
            throw new ArgumentException(System.SR.Format(System.SR.net_emptystringcall, "fileName"), "fileName");
        }
        Stream stream = new FileStream(fileName, FileMode.Open, FileAccess.Read, FileShare.Read);
        _part.SetContent(stream, contentType);
    }
 
    internal void SetContentFromFile(string fileName, string mediaType)
    {
        if (fileName == null)
        {
            throw new ArgumentNullException("fileName");
        }
        if (fileName.Length == 0)
        {
            throw new ArgumentException(System.SR.Format(System.SR.net_emptystringcall, "fileName"), "fileName");
        }
        Stream stream = new FileStream(fileName, FileMode.Open, FileAccess.Read, FileShare.Read);
        _part.SetContent(stream, null, mediaType);
    }
 
    internal void SetContentFromString(string content, ContentType contentType)
    {
        if (content == null)
        {
            throw new ArgumentNullException("content");
        }
        if (_part.Stream != null)
        {
            _part.Stream.Close();
        }
        Encoding encoding = ((contentType != null && contentType.CharSet != null) ? Encoding.GetEncoding(contentType.CharSet) : ((!MimeBasePart.IsAscii(content, permitCROrLF: false)) ? Encoding.GetEncoding("utf-8") : Encoding.ASCII));
        byte[] bytes = encoding.GetBytes(content);
        _part.SetContent(new MemoryStream(bytes), contentType);
        if (MimeBasePart.ShouldUseBase64Encoding(encoding))
        {
            _part.TransferEncoding = TransferEncoding.Base64;
        }
        else
        {
            _part.TransferEncoding = TransferEncoding.QuotedPrintable;
        }
    }
 
    internal void SetContentFromString(string content, Encoding encoding, string mediaType)
    {
        if (content == null)
        {
            throw new ArgumentNullException("content");
        }
        if (_part.Stream != null)
        {
            _part.Stream.Close();
        }
        if (string.IsNullOrEmpty(mediaType))
        {
            mediaType = "text/plain";
        }
        int offset = 0;
        try
        {
            string text = MailBnfHelper.ReadToken(mediaType, ref offset, null);
            if (text.Length == 0 || offset >= mediaType.Length || mediaType[offset++] != '/')
            {
                throw new ArgumentException(System.SR.MediaTypeInvalid, "mediaType");
            }
            text = MailBnfHelper.ReadToken(mediaType, ref offset, null);
            if (text.Length == 0 || offset < mediaType.Length)
            {
                throw new ArgumentException(System.SR.MediaTypeInvalid, "mediaType");
            }
        }
        catch (FormatException)
        {
            throw new ArgumentException(System.SR.MediaTypeInvalid, "mediaType");
        }
        ContentType contentType = new ContentType(mediaType);
        if (encoding == null)
        {
            encoding = ((!MimeBasePart.IsAscii(content, permitCROrLF: false)) ? Encoding.GetEncoding("utf-8") : Encoding.ASCII);
        }
        contentType.CharSet = encoding.BodyName;
        byte[] bytes = encoding.GetBytes(content);
        _part.SetContent(new MemoryStream(bytes), contentType);
        if (MimeBasePart.ShouldUseBase64Encoding(encoding))
        {
            _part.TransferEncoding = TransferEncoding.Base64;
        }
        else
        {
            _part.TransferEncoding = TransferEncoding.QuotedPrintable;
        }
    }
 
    internal virtual void PrepareForSending(bool allowUnicode)
    {
        _part.ResetStream();
    }
}