private static void UnpackArchiveStructure(ManagedLzma.SevenZip.FileModel.ArchivedFolder folder, string targetDirectory)
{
if (folder.Items.IsEmpty)
{
// Empty folders need to be created manually since the unpacking code doesn't try to write into it.
Directory.CreateDirectory(targetDirectory);
}
else
{
foreach (var item in folder.Items)
{
var file = item as ManagedLzma.SevenZip.FileModel.ArchivedFile;
if (file != null)
{
// Files without content are not iterated during normal unpacking so we need to create them manually.
if (file.Stream.IsUndefined)
{
System.Diagnostics.Debug.Assert(file.Length == 0); // If the file has no content then its length should be zero, otherwise something is wrong.
var filename = Path.Combine(targetDirectory, file.Name);
using (var stream = new FileStream(filename, FileMode.Create, FileAccess.Write, FileShare.Delete))
{
// Nothing to do, FileMode.Create already truncates the file on opening.
}
SetFileAttributes(filename, file);
}
}
var subfolder = item as ManagedLzma.SevenZip.FileModel.ArchivedFolder;
if (subfolder != null)
UnpackArchiveStructure(subfolder, Path.Combine(targetDirectory, subfolder.Name));
}
}
}
private static void SetFileAttributes(string path, ManagedLzma.SevenZip.FileModel.ArchivedFile file)
{
if (file.Attributes.HasValue)
{
// When calling File.SetAttributes we need to preserve existing attributes which are not part of the archive
var attr = File.GetAttributes(path);
const FileAttributes kAttrMask = ArchivedAttributesExtensions.FileAttributeMask;
attr = (attr & ~kAttrMask) | (file.Attributes.Value.ToFileAttributes() & kAttrMask);
File.SetAttributes(path, attr);
}
}
private static void UnpackArchive(string archiveFileName, string targetDirectory, ManagedLzma.PasswordStorage password)
{
if (!File.Exists(archiveFileName))
throw new FileNotFoundException("Archive not found.", archiveFileName);
// Ensure that the target directory exists.
Directory.CreateDirectory(targetDirectory);
using (var archiveStream = new FileStream(archiveFileName, FileMode.Open, FileAccess.Read, FileShare.Read | FileShare.Delete))
{
var archiveMetadataReader = new ManagedLzma.SevenZip.FileModel.ArchiveFileModelMetadataReader();
var archiveFileModel = archiveMetadataReader.ReadMetadata(archiveStream, password);
var archiveMetadata = archiveFileModel.Metadata;
for (int sectionIndex = 0; sectionIndex < archiveMetadata.DecoderSections.Length; sectionIndex++)
{
var sectionReader = new ManagedLzma.SevenZip.Reader.DecodedSectionReader(archiveStream, archiveMetadata, sectionIndex, password);
var sectionFiles = archiveFileModel.GetFilesInSection(sectionIndex);
// The section reader is constructed from metadata, if the counts do not match there must be a bug somewhere.
System.Diagnostics.Debug.Assert(sectionFiles.Count == sectionReader.StreamCount);
// The section reader iterates over all files in the section. NextStream advances the iterator.
for (; sectionReader.CurrentStreamIndex < sectionReader.StreamCount; sectionReader.NextStream())
{
var fileMetadata = sectionFiles[sectionReader.CurrentStreamIndex];
// The ArchiveFileModelMetadataReader we used above processes special marker nodes and resolves some conflicts
// in the archive metadata so we don't have to deal with them. In these cases there will be no file metadata
// produced and we should skip the stream. If you want to process these cases manually you should use a different
// MetadataReader subclass or write your own subclass.
if (fileMetadata == null)
continue;
// These asserts need to hold, otherwise there's a bug in the mapping the metadata reader produced.
System.Diagnostics.Debug.Assert(fileMetadata.Stream.SectionIndex == sectionIndex);
System.Diagnostics.Debug.Assert(fileMetadata.Stream.StreamIndex == sectionReader.CurrentStreamIndex);
// Ensure that the target directory is created.
var filename = Path.Combine(targetDirectory, fileMetadata.FullName);
Directory.CreateDirectory(Path.GetDirectoryName(filename));
// NOTE: you can have two using-statements here if you want to be explicit about it, but disposing the
// stream provided by the section reader is not mandatory, it is owned by the the section reader
// and will be auto-closed when moving to the next stream or when disposing the section reader.
using (var stream = new FileStream(filename, FileMode.Create, FileAccess.Write, FileShare.Delete))
sectionReader.OpenStream().CopyTo(stream);
SetFileAttributes(filename, fileMetadata);
}
}
// Create empty files and empty directories.
UnpackArchiveStructure(archiveFileModel.RootFolder, targetDirectory);
}
}
