public void Remove(Urn urn)
{
if (!DoesCacheExist())
{
return;
}
using FileStream cache = CacheDatabase.Open(FileMode.Open);
using BinaryReader reader = new(cache);
using BinaryWriter writer = new(cache);
// Skip file header
reader.BaseStream.Seek(FILE_MAGIC.Length, SeekOrigin.Begin);
// Loop through items in cache until target URN is found
byte[] targetUrnBytes = Encoding.Default.GetBytes(urn.ToString());
while (reader.BaseStream.Position < reader.BaseStream.Length)
{
// Read entry
long entryPos = writer.BaseStream.Position;
if (reader.ReadByte() != byte.MaxValue)
{
continue;
}
CacheEntry entry = CacheEntry.ReadFromStream(reader);
// Check for equality
if (entry.urnBytes.SequenceEqual(targetUrnBytes))
{
// Delete cached file, if it exists
var downloadItem = entry.GetDownloadItem();
if (downloadItem.Exists)
{
downloadItem.RecursiveDelete();
}
// Zero out entry, acts like a NOP slide
writer.BaseStream.Seek(entryPos, SeekOrigin.Begin);
for (int i = 0; i < entry.Length; i++)
{
writer.Write(byte.MinValue);
}
break;
}
}
}