public static NODE CreateFromBytes(byte[] raw)
{
switch (GetTypeFromBytes(raw))
{
case SectorType.DIR_NODE:
return(DIR_NODE.CreateFromBytes(raw));
case SectorType.FILE_NODE:
return(FILE_NODE.CreateFromBytes(raw));
}
throw new Exception("Expected a DIR_NODE or FILE_NODE!");
}
private void LoadChildren()
{
// Ensure that the children cache is correctly put in memory (i.e. reflects what's on the disk)
// Assume if the cache exsists, it is correct at the moment
// So, we need to call CommitChildren()
if (children == null)
{
// Create the cache itself
children = new Dictionary <string, VirtualNode>();
// Read the list of children for this directory from disk
// Instantiate a VirtualNode for each [child?] and add them to the children cache.
// Read the data sector for this directory
DATA_SECTOR dataSector = DATA_SECTOR.CreateFromBytes(drive.Disk.ReadSector(sector.FirstDataAt));
// Extract the list of children from the sata sector
byte[] rawList = dataSector.DataBytes;
// Foreach child in the list...
for (int i = 0; i < ChildCount; i++)
{
// Getthe child's sector address
int childSectorAt = BitConverter.ToInt32(rawList, i * 4);
// Read its sector from disk
// Check if it's a file or directory
byte[] childNodeBytes = drive.Disk.ReadSector(childSectorAt);
NODE childSector;
if (SECTOR.GetTypeFromBytes(childNodeBytes) == SECTOR.SectorType.DIR_NODE)
{
childSector = DIR_NODE.CreateFromBytes(drive.Disk.ReadSector(childSectorAt));
}
else if (SECTOR.GetTypeFromBytes(childNodeBytes) == SECTOR.SectorType.FILE_NODE)
{
childSector = FILE_NODE.CreateFromBytes(drive.Disk.ReadSector(childSectorAt));
}
else
{
throw new Exception("Unexpected sector type whe reading directory's children!");
}
// Construct a VirtualNode
VirtualNode childNode = new VirtualNode(drive, childSectorAt, childSector, this);
// Add the VirtualNode to the children cache
children.Add(childNode.Name, childNode);
}
}
}
public void Mount(DiskDriver disk, string mountPoint)
{
// for the first mounted drive, expect mountPoint to be named FSConstants.PATH_SEPARATOR as the root
if (drives.Count == 0 && mountPoint != FSConstants.PATH_SEPARATOR.ToString())
{
throw new Exception("Expected first mounted dist to be at root directory!");
}
// read drive info from disk, load root node and connect to mountPoint
DRIVE_INFO driveInfo = DRIVE_INFO.CreateFromBytes(disk.ReadSector(DRIVE_INFO_SECTOR));
VirtualDrive drive = new VirtualDrive(disk, DRIVE_INFO_SECTOR, driveInfo);
DIR_NODE rootSector = DIR_NODE.CreateFromBytes(disk.ReadSector(ROOT_DIR_SECTOR));
rootNode = new VirtualNode(drive, ROOT_DIR_SECTOR, rootSector, null);
drives.Add(mountPoint, drive);
}
public void Mount(DiskDriver disk, string mountPoint)
{
// read drive info from disk, load root node and connect to mountPoint
// for the first mounted drive, expect mountPoint to be named FSConstants.ROOT_DIR_NAME as the root
//read drive info for disk to determin what sector contains its root node
DRIVE_INFO diSector = DRIVE_INFO.CreateFromBytes(disk.ReadSector(DRIVE_INFO_SECTOR));
int rootNodeAt = diSector.RootNodeAt;
VirtualDrive drive = new VirtualDrive(disk, DRIVE_INFO_SECTOR, diSector);
DIR_NODE rootNodeSector = DIR_NODE.CreateFromBytes(disk.ReadSector(rootNodeAt));
if (rootNode == null)
{
rootNode = new VirtualNode(drive, rootNodeAt, rootNodeSector, null);
}
drives.Add(mountPoint, drive);
}
public void Mount(DiskDriver disk, string mountPoint)
{
// read drive info from disk, load root node and connect to mountPoint
// for the first mounted drive, expect mountPoint to be named "/", FSConstants.ROOT_DIR_NAME, as the root
try
{
// Step 1: Read infor from the disk to understand it's directory structure
// Read DRIVE_INFO from FRIVE_INFO_SECTOR
DRIVE_INFO di = DRIVE_INFO.CreateFromBytes(disk.ReadSector(DRIVE_INFO_SECTOR));
DIR_NODE dn = DIR_NODE.CreateFromBytes(disk.ReadSector(di.RootNodeAt));
DATA_SECTOR ds = DATA_SECTOR.CreateFromBytes(disk.ReadSector(dn.FirstDataAt));
// Step 2: Join th new disk into the virtual file system structure, at the mount point.
// Create a VistualDrive for the disk
VirtualDrive vd = new VirtualDrive(disk, DRIVE_INFO_SECTOR, di);
if (rootNode == null)
{
// Create a VirtualNode to represent the root dictionaru, at the mount point.
// Set the VFS's root node, if this is the first disk to be mounted.
rootNode = new VirtualNode(vd, di.RootNodeAt, dn, null);
}
else
{
// TODO: Extra Credit: Handle 2nd dick mounted to exsisting VFS
// Create a virtual node for this new disk's root
// "join" the new node to the exsisting node structure at the mount point
}
// Add a new VirtualDrive to drives dictionary, using te mountPoint as the key
drives.Add(mountPoint, vd);
}
catch (Exception ex)
{
throw new Exception("Failed to mount disk");
}
}
