Add skeleton chain and client classes

This commit does not change behavior. It just adds new skeleton classes that
don't do anything and aren't instantiated yet.

1 files changed, 44 insertions, 0 deletions

diff --git a/src/interfaces/chain.h b/src/interfaces/chain.h
new file mode 100644
index 0000000000..8a40cb4cda
--- /dev/null
+++ b/src/interfaces/chain.h
@@ -0,0 +1,44 @@
+// Copyright (c) 2018 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_INTERFACES_CHAIN_H
+#define BITCOIN_INTERFACES_CHAIN_H
+
+#include <memory>
+#include <string>
+#include <vector>
+
+namespace interfaces {
+
+//! Interface for giving wallet processes access to blockchain state.
+class Chain
+{
+public:
+    virtual ~Chain() {}
+};
+
+//! Interface to let node manage chain clients (wallets, or maybe tools for
+//! monitoring and analysis in the future).
+class ChainClient
+{
+public:
+    virtual ~ChainClient() {}
+};
+
+//! Return implementation of Chain interface.
+std::unique_ptr<Chain> MakeChain();
+
+//! Return implementation of ChainClient interface for a wallet client. This
+//! function will be undefined in builds where ENABLE_WALLET is false.
+//!
+//! Currently, wallets are the only chain clients. But in the future, other
+//! types of chain clients could be added, such as tools for monitoring,
+//! analysis, or fee estimation. These clients need to expose their own
+//! MakeXXXClient functions returning their implementations of the ChainClient
+//! interface.
+std::unique_ptr<ChainClient> MakeWalletClient(Chain& chain, std::vector<std::string> wallet_filenames);
+
+} // namespace interfaces
+
+#endif // BITCOIN_INTERFACES_CHAIN_H