/// <summary>
/// Creates an instance of <see cref="ICompressedArchiveAccess"/> that can be used to access a nested archive.
/// </summary>
/// <param name="parentArchiveAccess">The parent archive, which contains the nested archive indicated by <paramref name="entry"/>.</param>
/// <param name="entry">The entry within <paramref name="parentArchiveAccess"/> that indicates a nested archive.</param>
/// <returns>An instance of <see cref="NestedCompressedArchiveAccess"/>, which provides access to the nested archive.</returns>
/// <remarks>This wrapper type takes care of cleaning up any temporary files that may be required to access the nested archive.
/// For example, some data streams used to access an archive are not navigable from the parent stream (GZIP).</remarks>
public static NestedCompressedArchiveAccess Create(ICompressedArchiveAccess parentArchiveAccess, ICompressedArchiveEntry entry)
{
NestedCompressedArchiveAccess nestedCompressedArchive = null;
var entryName = entry.Name;
var nestedArchiveFormats = Path.GetExtension(entryName).GetCompressedArchiveFormatsFromFileExtension();
var nestedArchiveFormat = nestedArchiveFormats.FirstOrDefault();
if (nestedArchiveFormat.IsCompressedArchiveFormatSupported())
{
TemporaryDirectory temporaryLocation = null;
var entryData = parentArchiveAccess.OpenEntry(entry);
if (FormatMustBeExtracted(parentArchiveAccess.Format) || FormatMustBeExtracted(nestedArchiveFormat))
{
// We can't fully navigate the nested stream, so extract to disk, then proceed.
temporaryLocation = new TemporaryDirectory();
var temporaryEntryFilePath = Path.Combine(temporaryLocation.Path, entryName);
if (Directory.CreateDirectory(Path.GetDirectoryName(temporaryEntryFilePath)).Exists)
{
System.Diagnostics.Debug.WriteLine("Extracted entry " + entryName + " to " + temporaryLocation.Path);
var fileStream = new FileStream(temporaryEntryFilePath, FileMode.Create, FileAccess.ReadWrite);
entryData.CopyTo(fileStream);
fileStream.Seek(0, SeekOrigin.Begin);
entryData.Dispose();
entryData = fileStream;
}
}
var compressedArchive = CompressedArchiveAccess.Open(entryData, nestedArchiveFormat, CompressedArchiveAccessMode.Read);
nestedCompressedArchive = new NestedCompressedArchiveAccess(parentArchiveAccess, compressedArchive, temporaryLocation);
nestedCompressedArchive.NestedArchiveFormats = nestedArchiveFormats;
}
return(nestedCompressedArchive);
}
/// <inheritdoc />
protected override void Dispose(bool disposing)
{
lock (_lock)
{
if (CompressedArchiveAccess != null)
{
CompressedArchiveAccess.Dispose();
CompressedArchiveAccess = null;
}
if (Stream != null)
{
Stream.Dispose();
Stream = null;
}
}
}
/// <inheritdoc />
public override ICompressedArchiveEntry CreateEntry(string name)
{
return(CompressedArchiveAccess.CreateEntry(name));
}
/// <inheritdoc />
protected override bool DeleteEntry(ICompressedArchiveEntry entry)
{
return(CompressedArchiveAccess.DeleteEntry(entry.Name));
}
/// <inheritdoc />
public override Stream OpenEntry(ICompressedArchiveEntry entry)
{
return(CompressedArchiveAccess.OpenEntry(entry));
}