public void RenameNode(BobFsNode node, string name)
{
DeleteNode(node);
LinkNode(name, node);
node.NumLinks--;
node.Commit();
}
// TODO: We should update the inode bitmap if necessary
public void DeleteNode(BobFsNode node)
{
if (!IsDirectory)
{
throw new InvalidOperationException("Current node is not a directory.");
}
int runner = 0;
DirEntry entry = new DirEntry();
while (runner < Size)
{
entry.ReadFrom(this, runner);
if (entry.Inum == node.Inum)
{
int read;
while ((read = ReadAll(runner + (8 + entry.Name.Length), _tmpBuffer, 0, BobFs.BlockSize)) != 0)
{
WriteAll(runner, _tmpBuffer, 0, read);
runner += read;
}
Size -= (uint)(8 + entry.Name.Length);
return;
}
runner += 8 + entry.Name.Length; // Point to next direntry's inum
}
throw new Exception("Node not found.");
}
public void Format()
{
// Setup superblock
Array.Clear(_tmpBuffer, 0, BlockSize);
Encoding.ASCII.GetBytes(HeaderMagic).CopyTo(_tmpBuffer, 0);
BitConverter.GetBytes((int)0).CopyTo(_tmpBuffer, HeaderMagic.Length);
Source.WriteAll(0, _tmpBuffer, 0, BlockSize);
_superBlock = Superblock.ReadFrom(_tmpBuffer);
// Setup block bitmap
byte[] tmpBuffer = new byte[BlockSize];
Source.WriteAll(BlockSize * 1, tmpBuffer, 0, BlockSize);
// Clear inode bitmap
BitArray inodeBitmap = new BitArray(tmpBuffer);
inodeBitmap[0] = true;
inodeBitmap.CopyTo(tmpBuffer, 0);
Source.WriteAll(BlockSize * 2, tmpBuffer, 0, BlockSize);
// Create root directory
BobFsNode root = new BobFsNode(this, 0);
root.Type = ENodeType.Directory;
root.NumLinks = 1;
root.Size = 0;
root.Commit();
}
public int WriteTo(BobFsNode node, int offset)
{
byte[] buf = new byte[Name.Length + 8];
BitConverter.GetBytes(Inum).CopyTo(buf, 0);
BitConverter.GetBytes((uint)Name.Length).CopyTo(buf, 4);
Encoding.ASCII.GetBytes(Name).CopyTo(buf, 8);
return(node.WriteAll(offset, buf, 0, buf.Length));
}
public void ReadFrom(BobFsNode node, int offset)
{
byte[] headBuf = new byte[8];
node.ReadAll(offset, headBuf, 0, 8);
Inum = BitConverter.ToUInt32(headBuf, 0);
uint nameLength = BitConverter.ToUInt32(headBuf, 4);
byte[] nameBuf = new byte[nameLength];
node.ReadAll(offset + 8, nameBuf, 0, (int)nameLength);
Name = Encoding.ASCII.GetString(nameBuf, 0, (int)nameLength);
}
private BobFsNode NewNode(string name, ENodeType type)
{
if (!IsDirectory)
{
throw new InvalidOperationException("Current node is not a directory.");
}
// Get free inum
// TODO: Can be optimized
// TODO: Implement caching
int freeInum = -1;
_bobFs.Source.ReadAll(BobFs.BlockSize * 2, _tmpBuffer, 0, BobFs.BlockSize);
BitArray inodeBitmap = new BitArray(_tmpBuffer);
for (int index = 0; index < BobFs.BlockSize * 8 && freeInum == -1; index++)
{
if (!inodeBitmap[index])
{
freeInum = index;
}
}
if (freeInum == -1)
{
throw new Exception("No free Inode.");
}
inodeBitmap[freeInum] = true;
inodeBitmap.CopyTo(_tmpBuffer, 0);
_bobFs.Source.WriteAll(BobFs.BlockSize * 2, _tmpBuffer, 0, BobFs.BlockSize);
// Add to directory
DirEntry newDirEntry = new DirEntry();
newDirEntry.Inum = (uint)freeInum;
newDirEntry.Name = name;
int bytesWritten = newDirEntry.WriteTo(this, (int)Size);
if (bytesWritten < 0)
{
throw new Exception("Current directory is full.");
}
// Create inode at inum
BobFsNode newInode = new BobFsNode(_bobFs, (uint)freeInum);
newInode.Type = type;
newInode.NumLinks = 1;
newInode.Size = 0;
newInode.Commit();
return(newInode);
}
public void LinkNode(string name, BobFsNode file)
{
if (!IsDirectory)
{
throw new InvalidOperationException("Current node is not a directory.");
}
// Add to directory
DirEntry newDirEntry = new DirEntry();
newDirEntry.Inum = file.Inum;
newDirEntry.Name = name;
int bytesWritten = newDirEntry.WriteTo(this, (int)Size);
if (bytesWritten < 0)
{
throw new Exception("Current directory is full.");
}
// Update nlinks in node
file.Node.NumLinks++;
file.Commit();
}
