public FragmentWriter(BuilderContext context)
{
_context = context;
_currentBlock = new byte[context.DataBlockSize];
_currentOffset = 0;
_fragmentBlocks = new List<FragmentRecord>();
}
protected void FillCommonInodeData(BuilderContext context)
{
Inode.Mode = (ushort)Mode;
Inode.UidKey = context.AllocateId(UserId);
Inode.GidKey = context.AllocateId(GroupId);
Inode.ModificationTime = ModificationTime;
InodeNumber = (int)context.AllocateInode();
Inode.InodeNumber = (uint)InodeNumber;
Inode.NumLinks = NumLinks;
}
public override void Write(BuilderContext context)
{
if (!_written)
{
WriteFileData(context);
WriteInode(context);
_written = true;
}
}
private void WriteFileData(BuilderContext context)
{
Stream outStream = context.RawStream;
bool disposeSource = false;
try
{
if (_source == null)
{
_source = new FileStream(_sourcePath, FileMode.Open, FileAccess.Read, FileShare.Read);
disposeSource = true;
}
if (_source.Position != 0)
{
_source.Position = 0;
}
long startPos = outStream.Position;
int bufferedBytes = Utilities.ReadFully(_source, context.IoBuffer, 0, context.DataBlockSize);
if (bufferedBytes < context.DataBlockSize)
{
// Fragment - less than one complete block of data
_inode.StartBlock = 0xFFFFFFFF;
_inode.FragmentKey = context.WriteFragment(bufferedBytes, out _inode.FragmentOffset);
_inode.FileSize = (uint)bufferedBytes;
}
else
{
// At least one full block, no fragments used
_inode.FragmentKey = 0xFFFFFFFF;
_lengths = new List<uint>();
_inode.StartBlock = (uint)startPos;
_inode.FileSize = bufferedBytes;
while (bufferedBytes > 0)
{
_lengths.Add(context.WriteDataBlock(context.IoBuffer, 0, bufferedBytes));
bufferedBytes = Utilities.ReadFully(_source, context.IoBuffer, 0, context.DataBlockSize);
_inode.FileSize += (uint)bufferedBytes;
}
}
}
finally
{
if (disposeSource)
{
_source.Dispose();
}
}
}
/// <summary>
/// Writes the file system to an existing stream.
/// </summary>
/// <param name="output">The stream to write to.</param>
/// <remarks>The <c>output</c> stream must support seeking and writing.</remarks>
public void Build(Stream output)
{
if (output == null)
{
throw new ArgumentNullException("output");
}
if (!output.CanWrite)
{
throw new ArgumentException("Output stream must be writable", "output");
}
if (!output.CanSeek)
{
throw new ArgumentException("Output stream must support seeking", "output");
}
_context = new BuilderContext()
{
RawStream = output,
DataBlockSize = DefaultBlockSize,
IoBuffer = new byte[DefaultBlockSize],
};
MetablockWriter inodeWriter = new MetablockWriter();
MetablockWriter dirWriter = new MetablockWriter();
FragmentWriter fragWriter = new FragmentWriter(_context);
IdTableWriter idWriter = new IdTableWriter(_context);
_context.AllocateInode = AllocateInode;
_context.AllocateId = idWriter.AllocateId;
_context.WriteDataBlock = WriteDataBlock;
_context.WriteFragment = fragWriter.WriteFragment;
_context.InodeWriter = inodeWriter;
_context.DirectoryWriter = dirWriter;
_nextInode = 1;
SuperBlock superBlock = new SuperBlock();
superBlock.Magic = SuperBlock.SquashFsMagic;
superBlock.CreationTime = DateTime.Now;
superBlock.BlockSize = (uint)_context.DataBlockSize;
superBlock.Compression = 1; // DEFLATE
superBlock.BlockSizeLog2 = (ushort)Utilities.Log2(superBlock.BlockSize);
superBlock.MajorVersion = 4;
superBlock.MinorVersion = 0;
output.Position = superBlock.Size;
GetRoot().Reset();
GetRoot().Write(_context);
fragWriter.Flush();
superBlock.RootInode = GetRoot().InodeRef;
superBlock.InodesCount = _nextInode - 1;
superBlock.FragmentsCount = (uint)fragWriter.FragmentCount;
superBlock.UidGidCount = (ushort)idWriter.IdCount;
superBlock.InodeTableStart = output.Position;
inodeWriter.Persist(output);
superBlock.DirectoryTableStart = output.Position;
dirWriter.Persist(output);
if (fragWriter.FragmentCount > 0)
{
superBlock.FragmentTableStart = output.Position;
fragWriter.Persist();
}
else
{
superBlock.FragmentTableStart = -1;
}
superBlock.LookupTableStart = -1;
if (idWriter.IdCount > 0)
{
superBlock.UidGidTableStart = output.Position;
idWriter.Persist();
}
else
{
superBlock.UidGidTableStart = -1;
}
superBlock.ExtendedAttrsTableStart = -1;
superBlock.BytesUsed = output.Position;
// Pad to 4KB
long end = Utilities.RoundUp(output.Position, 4 * Sizes.OneKiB);
if (end != output.Position)
{
byte[] padding = new byte[(int)(end - output.Position)];
output.Write(padding, 0, padding.Length);
}
// Go back and write the superblock
output.Position = 0;
byte[] buffer = new byte[superBlock.Size];
superBlock.WriteTo(buffer, 0);
output.Write(buffer, 0, buffer.Length);
output.Position = end;
}
public abstract void Write(BuilderContext context);
public IdTableWriter(BuilderContext context)
{
_context = context;
_ids = new List<int>();
}
private void WriteInode(BuilderContext context)
{
if (NumLinks != 1)
{
throw new IOException("Extended file records (with multiple hard links) not supported");
}
FillCommonInodeData(context);
_inode.Type = InodeType.File;
InodeRef = context.InodeWriter.Position;
int totalSize = _inode.Size;
_inode.WriteTo(context.IoBuffer, 0);
if (_lengths != null && _lengths.Count > 0)
{
for (int i = 0; i < _lengths.Count; ++i)
{
Utilities.WriteBytesLittleEndian(_lengths[i], context.IoBuffer, _inode.Size + (i * 4));
}
totalSize += _lengths.Count * 4;
}
context.InodeWriter.Write(context.IoBuffer, 0, totalSize);
}
