// The following should be self-explanatory.
public void DeleteEntry(String tid)
{
lock (this) {
StoreEntry entry = null;
if (table.TryGetValue(tid, out entry))
{
table.Remove(tid);
bw.Seek(entry.index, SeekOrigin.Begin);
bw.Write(empty_id, 0, idSize);
bw.Flush();
freeEntries.Push(entry);
}
}
}
public TidStatus CreateEntry(String tid)
{
lock (this) {
if (tid == null || tid.Length != idSize)
{
throw new ArgumentException("Invalid TID");
}
StoreEntry entry = null;
table.TryGetValue(tid, out entry);
if (entry != null)
{
return(entry.status);
}
if (freeEntries.Count > 0)
{
entry = freeEntries.Pop();
}
else
{
entry = new StoreEntry();
entry.index = (int)fs.Length;
bw.Seek(0, SeekOrigin.Begin);
bw.Write(++slots);
}
entry.status = TidStatus.Created;
entry.tid = tid;
table.Add(tid, entry);
bw.Seek(entry.index, SeekOrigin.Begin);
bw.Write(tid.ToCharArray(), 0, idSize);
bw.Write((byte)TidStatus.Created);
bw.Write(EMPTY_REMAINDER, 0, REMAINDER_SIZE);
bw.Flush();
return(TidStatus.Created);
}
}
public TidStatus GetStatus(String tid, out String errorMessage)
{
TidStatus tidStatus = TidStatus.Created;
lock (this) {
errorMessage = "";
StoreEntry entry = null;
if (!table.TryGetValue(tid, out entry))
{
throw new ArgumentException("Invalid TID");
}
tidStatus = entry.status;
if (tidStatus == TidStatus.RolledBack)
{
br.BaseStream.Seek(entry.index + idSize + 1, SeekOrigin.Begin);
byte[] err = br.ReadBytes(REMAINDER_SIZE);
errorMessage = Encoding.UTF8.GetString(err);
}
}
return(tidStatus);
}
// Opens an existing TidStore, or creates a fresh one, if the given file does not yet exist.
public TidStore(String fileName, bool bgRFC)
{
idSize = bgRFC ? GUID_SIZE : TID_SIZE;
entrySize = idSize + REMAINDER_SIZE;
empty_id = new char[idSize];
if (string.IsNullOrEmpty(fileName))
{
fileName = "TIDStore.tid";
}
try {
fs = new FileStream(fileName, FileMode.OpenOrCreate, FileAccess.ReadWrite);
br = new BinaryReader(fs);
bw = new BinaryWriter(fs);
if (fs.Length < entrySize) // A newly created empty store file
{
slots = 0;
bw.Seek(0, SeekOrigin.Begin);
bw.Write(slots);
bw.Flush();
}
else
{
br.BaseStream.Seek(0, SeekOrigin.Begin);
slots = br.ReadInt32();
}
table = new Dictionary <String, StoreEntry>();
for (int i = 0; i < slots; ++i)
{
StoreEntry entry = new StoreEntry();
entry.index = (int)fs.Position;
// Read tid/uid
char[] tempId = br.ReadChars(idSize);
if (tempId == null || tempId.Length != idSize)
{
throw new IOException("Unable to read entry at position " + i);
}
// Read status
entry.status = (TidStatus)br.ReadByte();
// Skip REMAINDER
br.BaseStream.Seek(REMAINDER_SIZE, SeekOrigin.Current);
if (tempId[0] == 0)
{
freeEntries.Push(entry);
}
else
{
entry.tid = new String(tempId);
table[entry.tid] = entry;
}
}
}
catch (Exception) {
if (fs != null)
{
fs.Close();
}
br = null;
bw = null;
throw;
}
}
