Remove g_rpc_chain global

Replace with RPC request reference to new WalletContext struct similar to the
existing NodeContext struct and reference.

This PR is a followup to 25ad2c623af30056ffb36dcd203a52edda2b170f
https://github.com/bitcoin/bitcoin/pull/18740 removing the g_rpc_node global.

Some later PRs will follow this up and move more wallet globals to the
WalletContext struct.

Co-authored-by: João Barbosa <joao.paulo.barbosa@gmail.com>

1 files changed, 32 insertions, 0 deletions

diff --git a/src/wallet/context.h b/src/wallet/context.h
new file mode 100644
index 0000000000..3c8fdd1c59
--- /dev/null
+++ b/src/wallet/context.h
@@ -0,0 +1,32 @@
+// Copyright (c) 2020 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_WALLET_CONTEXT_H
+#define BITCOIN_WALLET_CONTEXT_H
+
+namespace interfaces {
+class Chain;
+} // namespace interfaces
+
+//! WalletContext struct containing references to state shared between CWallet
+//! instances, like the reference to the chain interface, and the list of opened
+//! wallets.
+//!
+//! Future shared state can be added here as an alternative to adding global
+//! variables.
+//!
+//! The struct isn't intended to have any member functions. It should just be a
+//! collection of state pointers that doesn't pull in dependencies or implement
+//! behavior.
+struct WalletContext {
+    interfaces::Chain* chain{nullptr};
+
+    //! Declare default constructor and destructor that are not inline, so code
+    //! instantiating the WalletContext struct doesn't need to #include class
+    //! definitions for smart pointer and container members.
+    WalletContext();
+    ~WalletContext();
+};
+
+#endif // BITCOIN_WALLET_CONTEXT_H