Cross Chain Transfer Store (stratisproject#161)

* Cross Chain Transfer Store

* Respect -mainchain / -sidechain argument

* Refactor

* Implement RecordLatestMatureDeposits method

* Implement MergeTransactionSignaturesAsync

* Refactor

* Fix xml documentation

* Add Guard

* Update DeleteAsync

* Add mainchain argument to test case

* Add GetTransactionsToBroadcastAsync

* Add comment

* Implement SetRejectedStatus

* Fix InitializeAsync

src/Stratis.FederatedPeg.Features.FederationGateway/CrossChainTransfer.cs

@@ -0,0 +1,191 @@
+using NBitcoin;
+using Stratis.Bitcoin.Utilities;
+
+namespace Stratis.FederatedPeg.Features.FederationGateway
+{
+    /// <summary>
+    /// Cross-chain transfer statuses.
+    /// </summary>
+    public enum CrossChainTransferStatus
+    {
+        Partial = 'P',
+        FullySigned = 'F',
+        SeenInBlock = 'S',
+        Rejected = 'R'
+    }
+
+    /// <summary>
+    /// Tracks the status of the cross-chain transfer.
+    /// </summary>
+    public class CrossChainTransfer : IBitcoinSerializable
+    {
+        /// <summary>
+        /// The transaction id of the deposit transaction.
+        /// </summary>
+        private uint256 depositTransactionId;
+        public uint256 DepositTransactionId => this.depositTransactionId;
+
+        /// <summary>
+        /// Indicated whether the deposit fields contain information.
+        /// </summary>
+        private bool depositPresent => this.depositTargetAddress != null;
+        public bool DepositPresent => this.depositPresent;
+
+        /// <summary>
+        /// The block height of the deposit transaction.
+        /// </summary>
+        public long DepositBlockHeight => this.depositBlockHeight;
+        private long depositBlockHeight;
+
+        /// <summary>
+        /// The target address of the deposit transaction.
+        /// </summary>
+        public Script DepositTargetAddress => this.depositTargetAddress;
+        private Script depositTargetAddress;
+
+        /// <summary>
+        /// The amount (in satoshis) of the deposit transaction.
+        /// </summary>
+        public long DepositAmount => this.depositAmount;
+        private long depositAmount;
+
+        /// <summary>
+        /// The unsigned partial transaction containing a full set of available UTXO's.
+        /// </summary>
+        public Transaction PartialTransaction => this.partialTransaction;
+        private Transaction partialTransaction;
+
+        /// <summary>
+        /// The hash of the block where the transaction resides on our chain.
+        /// </summary>
+        public uint256 BlockHash => this.blockHash;
+        private uint256 blockHash;
+
+        /// <summary>
+        /// The height of the block where the transaction resides on our chain.
+        /// </summary>
+        public int BlockHeight => this.blockHeight;
+        private int blockHeight;
+
+        /// <summary>
+        /// The status of the cross chain transfer transaction.
+        /// </summary>
+        private CrossChainTransferStatus status;
+        public CrossChainTransferStatus Status => this.status;
+
+        /// <summary>
+        /// Parameter-less constructor for (de)serialization.
+        /// </summary>
+        public CrossChainTransfer()
+        {
+        }
+
+        /// <summary>
+        /// Constructs this object from passed parameters.
+        /// </summary>
+        /// <param name="status">The status of the cross chain transfer transaction.</param>
+        /// <param name="depositTransactionId">The transaction id of the deposit transaction.</param>
+        /// <param name="depositBlockHeight">The block height of the deposit transaction.</param>
+        /// <param name="depositTargetAddress">The target address of the deposit transaction.</param>
+        /// <param name="depositAmount">The amount (in satoshis) of the deposit transaction.</param>
+        /// <param name="partialTransaction">The unsigned partial transaction containing a full set of available UTXO's.</param>
+        /// <param name="blockHash">The hash of the block where the transaction resides.</param>
+        /// <param name="blockHeight">The height (in our chain) of the block where the transaction resides.</param>
+        public CrossChainTransfer(CrossChainTransferStatus status, uint256 depositTransactionId, long depositBlockHeight, Script depositTargetAddress, Money depositAmount,
+            Transaction partialTransaction, uint256 blockHash, int blockHeight)
+        {
+            this.status = status;
+            this.depositTransactionId = depositTransactionId;
+            this.depositBlockHeight = depositBlockHeight;
+            this.depositTargetAddress = depositTargetAddress;
+            this.depositAmount = depositAmount;
+            this.partialTransaction = partialTransaction;
+            this.blockHash = blockHash;
+            this.blockHeight = blockHeight;
+
+            Guard.Assert(this.IsValid());
+        }
+
+        /// <summary>
+        /// (De)serializes this object.
+        /// </summary>
+        /// <param name="stream">Stream to use for (de)serialization.</param>
+        public void ReadWrite(BitcoinStream stream)
+        {
+            if (stream.Serializing)
+            {
+                Guard.Assert(this.IsValid());
+            }
+
+            byte status = (byte)this.status;
+            stream.ReadWrite(ref status);
+            this.status = (CrossChainTransferStatus)status;
+            stream.ReadWrite(ref this.depositTransactionId);
+
+            bool depositPresent = this.depositPresent;
+            stream.ReadWrite(ref depositPresent);
+
+            if (depositPresent)
+            {
+                stream.ReadWrite(ref this.depositBlockHeight);
+                stream.ReadWrite(ref this.depositTargetAddress);
+                stream.ReadWrite(ref this.depositAmount);
+            }
+
+            if (this.status == CrossChainTransferStatus.Partial || this.status == CrossChainTransferStatus.SeenInBlock)
+            {
+                stream.ReadWrite(ref this.partialTransaction);
+                if (this.status != CrossChainTransferStatus.Partial)
+                    stream.ReadWrite(ref this.blockHash);
+            }
+        }
+
+        /// <summary>
+        /// Depending on the status some fields can't be null.
+        /// </summary>
+        /// <returns><c>false</c> if the object is invalid and <c>true</c> otherwise.</returns>
+        public bool IsValid()
+        {
+            if (this.status == CrossChainTransferStatus.Partial || this.status == CrossChainTransferStatus.SeenInBlock)
+            {
+                if (this.status != CrossChainTransferStatus.Partial)
+                {
+                    return this.blockHash != null;
+                }
+
+                return this.partialTransaction != null;
+            }
+
+            return this.depositTransactionId != null;
+        }
+
+        /// <summary>
+        /// Sets the status and verifies that the status is valid given the available fields.
+        /// </summary>
+        /// <param name="status">The new status.</param>
+        public void SetStatus(CrossChainTransferStatus status)
+        {
+            this.status = status;
+
+            Guard.Assert(IsValid());
+        }
+
+        /// <summary>
+        /// Combines signatures from partial transactions received from other federation members.
+        /// </summary>
+        /// <param name="network">The network targeted by the transactions.</param>
+        /// <param name="partials">Partial transactions received from other federation members.</param>
+        public void CombineSignatures(Network network, Transaction[] partials)
+        {
+            Guard.Assert(this.status == CrossChainTransferStatus.Partial);
+
+            TransactionBuilder builder = new TransactionBuilder(network);
+
+            Transaction[] allPartials = new Transaction[partials.Length + 1];
+            allPartials[0] = this.partialTransaction;
+            partials.CopyTo(allPartials, 1);
+
+            this.partialTransaction = builder.CombineSignatures(allPartials);
+        }
+    }
+}