/// <summary>
/// Starts a new blockchain with one block.
/// All data possibly in the committedBlocks
/// before the call of this method is going to be deleted.
/// </summary>
/// <returns>The alias of the added block.</returns>
public UncommittedBlock OpenFirstBlock()
{
_committed.Clear();
_uncommitted.Clear();
var newBlockIdentifier = TempBlockId.Create();
var newBlock = new UncommittedBlock(0, newBlockIdentifier, BlockAlias.Genesis, BlockAlias.GenesisParent);
_uncommitted.Add(newBlock);
return(newBlock);
}
/// <summary>
/// Appends a new block to the end of the current committedBlocks.
/// The first block cannot be added via this method,
/// <see cref="OpenFirstBlock"/> will have to be used instead.
/// </summary>
/// <returns>The alias of the added block.</returns>
public UncommittedBlock OpenBlock(BlockAlias parentAlias)
{
// Verify if block to add is empty
if (parentAlias == BlockAlias.GenesisParent)
{
throw new ArgumentException("Blocks cannot have GenesisParent as parent.");
}
var parentIsNotInCBlock = !FindCommitted(block => block.Alias == parentAlias, out var parent);
// Parent has to be a valid block.
var parentIsNotInUBlock = !FindUncommitted(block => block.Alias == parentAlias, out var parentUnc);
if (parentIsNotInCBlock && parentIsNotInUBlock)
{
throw new ArgumentException($"{parentAlias} does not exist.");
}
// TOOD: [vermorel] Why do we have this small forest of tests? Comment needed
// TODO: [vermorel] Introduce a Linq-like helper 'QuickLast' to avoid the pattern '_array[_array.Length - 1]'.
BlockAlias newBlockAlias;
if (_uncommitted.Count == 0)
{
newBlockAlias = _committed[_committed.Count - 1].Alias.GetNext();
}
else if (_committed.Count == 0)
{
newBlockAlias = _uncommitted[_uncommitted.Count - 1].Alias.GetNext();
}
else // a committed block can have a higher alias than a non-committed one if they are on different forked chains
{
newBlockAlias = BlockAlias.GetJoinNext(_committed[_committed.Count - 1].Alias,
_uncommitted[_uncommitted.Count - 1].Alias);
}
var newBlockIdentifier = TempBlockId.Create();
int newBlockBlockHeight = 1 + (parentIsNotInCBlock ? parentUnc.BlockHeight : parent.BlockHeight);
var newBlock = new UncommittedBlock(newBlockBlockHeight, newBlockIdentifier, newBlockAlias, parentAlias);
_uncommitted.Add(newBlock);
if (newBlockBlockHeight > BlockchainHeight)
{
BlockchainHeight = newBlockBlockHeight;
}
return(newBlock);
}
private bool FindUncommitted(Predicate <UncommittedBlock> p, out UncommittedBlock foundBlock)
{
foundBlock = _uncommitted.FindLast(p);
return(!foundBlock.Equals(default(UncommittedBlock)));
}
/// <summary>
/// Returns the block metadata of the uncommitted block
/// identified by the alias given as argument.
/// </summary>
public bool RetrieveUncommittedBlock(BlockAlias alias, out UncommittedBlock block)
{
return(FindUncommitted(b => b.Alias == alias, out block));
}