private static List <HeadCandidate> AssembleBlockchain(Database db, HeadSelector selector)
{
var blocks = BuildBlocks(db);
var ret = new List <HeadCandidate>(blocks.Blocks.Count);
if (blocks.Blocks.Count == 0)
{
return(ret);
}
for (var current = SelectHead(db, blocks, selector); current != null; current = current.Previous)
{
ret.Add(current);
var back = ret[ret.Count - 1];
if (current.Previous != null)
{
back.PreviousBlockId = current.Previous.DbId;
}
else
{
back.PreviousBlockId = long.MaxValue;
}
}
ret.Reverse();
return(ret);
}
private static HeadCandidate SelectHead(Database db, BlocksTemp blocks, HeadSelector selector)
{
var heads = blocks.Blocks.Where(block => !block.HasChildren).ToList();
if (heads.Count == 0)
{
throw new Exception("Invalid blockchain. Circular topologies are invalid.");
}
if (heads.Count == 1)
{
return(heads[0]);
}
var hash = db.BlockchainHead;
if (hash == null)
{
if (selector == null)
{
throw new Exception("Can't read blockchain head from DB.");
}
hash = selector(heads).Hash;
}
HeadCandidate ret;
if (!blocks.BlockMap.TryGetValue(hash, out ret))
{
throw new Exception(
$"DB states that the blockchain head is {hash}, but no such block exists in the DB.");
}
return(ret);
}
public Blockchain(Database db, HeadSelector selector = null) : base(db, Configuration.Get().Network)
{
var blocks = AssembleBlockchain(db, selector);
_blockchain = new List <Block>(blocks.Count);
foreach (var block in blocks)
{
var height = _blockchain.Count;
var block2 = new Block
{
Hash = block.Hash,
PreviousHash = block.PreviousHash,
Height = height,
DbId = block.DbId,
PreviousBlockId = block.PreviousBlockId
};
_blockMap[block2.Hash] = height;
_blockchain.Add(block2);
}
UpdateDb();
}