public static IEnumerable <T> Find <T>(this DB db, ReadOptions options, Slice prefix, Func <Slice, Slice, T> resultSelector)
{
using (Iterator it = db.NewIterator(options))
{
for (it.Seek(prefix); it.Valid(); it.Next())
{
Slice key = it.Key();
byte[] x = key.ToArray();
byte[] y = prefix.ToArray();
if (x.Length < y.Length)
{
break;
}
if (!x.Take(y.Length).SequenceEqual(y))
{
break;
}
yield return(resultSelector(key, it.Value()));
}
}
}
public LevelDBBlockchain(string path)
{
header_index.Add(GenesisBlock.Hash);
Version version;
Slice value;
db = DB.Open(path, new Options {
CreateIfMissing = true
});
if (db.TryGet(ReadOptions.Default, SliceBuilder.Begin(DataEntryPrefix.SYS_Version), out value) && Version.TryParse(value.ToString(), out version) && version >= Version.Parse("1.5"))
{
ReadOptions options = new ReadOptions {
FillCache = false
};
value = db.Get(options, SliceBuilder.Begin(DataEntryPrefix.SYS_CurrentBlock));
UInt256 current_header_hash = new UInt256(value.ToArray().Take(32).ToArray());
this.current_block_height = value.ToArray().ToUInt32(32);
uint current_header_height = current_block_height;
if (db.TryGet(options, SliceBuilder.Begin(DataEntryPrefix.SYS_CurrentHeader), out value))
{
current_header_hash = new UInt256(value.ToArray().Take(32).ToArray());
current_header_height = value.ToArray().ToUInt32(32);
}
foreach (UInt256 hash in db.Find(options, SliceBuilder.Begin(DataEntryPrefix.IX_HeaderHashList), (k, v) =>
{
using (MemoryStream ms = new MemoryStream(v.ToArray(), false))
using (BinaryReader r = new BinaryReader(ms))
{
return(new
{
Index = k.ToArray().ToUInt32(1),
Hashes = r.ReadSerializableArray <UInt256>()
});
}
}).OrderBy(p => p.Index).SelectMany(p => p.Hashes).ToArray())
{
if (!hash.Equals(GenesisBlock.Hash))
{
header_index.Add(hash);
}
stored_header_count++;
}
if (stored_header_count == 0)
{
Header[] headers = db.Find(options, SliceBuilder.Begin(DataEntryPrefix.DATA_Block), (k, v) => Header.FromTrimmedData(v.ToArray(), sizeof(long))).OrderBy(p => p.Index).ToArray();
for (int i = 1; i < headers.Length; i++)
{
header_index.Add(headers[i].Hash);
}
}
else if (current_header_height >= stored_header_count)
{
for (UInt256 hash = current_header_hash; hash != header_index[(int)stored_header_count - 1];)
{
Header header = Header.FromTrimmedData(db.Get(options, SliceBuilder.Begin(DataEntryPrefix.DATA_Block).Add(hash)).ToArray(), sizeof(long));
header_index.Insert((int)stored_header_count, hash);
hash = header.PrevHash;
}
}
}
else
{
WriteBatch batch = new WriteBatch();
ReadOptions options = new ReadOptions {
FillCache = false
};
using (Iterator it = db.NewIterator(options))
{
for (it.SeekToFirst(); it.Valid(); it.Next())
{
batch.Delete(it.Key());
}
}
db.Write(WriteOptions.Default, batch);
Persist(GenesisBlock);
db.Put(WriteOptions.Default, SliceBuilder.Begin(DataEntryPrefix.SYS_Version), GetType().GetTypeInfo().Assembly.GetName().Version.ToString());
}
thread_persistence = new Thread(PersistBlocks);
thread_persistence.Name = "LevelDBBlockchain.PersistBlocks";
thread_persistence.Start();
}