Pass NodeContext, ConnMan, BanMan references more places

So g_connman and g_banman globals can be removed next commit.

src/node/context.cpp

@@ -0,0 +1,10 @@
+// Copyright (c) 2019 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <node/context.h>
+
+#include <interfaces/chain.h>
+
+NodeContext::NodeContext() {}
+NodeContext::~NodeContext() {}

src/node/context.h

@@ -13,11 +13,26 @@ class Chain;
 class ChainClient;
 } // namespace interfaces
 
-//! Pointers to interfaces used during init and destroyed on shutdown.
+//! NodeContext struct containing references to chain state and connection
+//! state.
+//!
+//! This is used by init, rpc, and test code to pass object references around
+//! without needing to declare the same variables and parameters repeatedly, or
+//! to use globals. More variables could be added to this struct (particularly
+//! references to validation and mempool objects) to eliminate use of globals
+//! and make code more modular and testable. The struct isn't intended to have
+//! any member functions. It should just be a collection of references that can
+//! be used without pulling in unwanted dependencies or functionality.
 struct NodeContext
 {
     std::unique_ptr<interfaces::Chain> chain;
     std::vector<std::unique_ptr<interfaces::ChainClient>> chain_clients;
+
+    //! Declare default constructor and destructor that are not inline, so code
+    //! instantiating the NodeContext struct doesn't need to #include class
+    //! definitions for all the unique_ptr members.
+    NodeContext();
+    ~NodeContext();
 };
 
 #endif // BITCOIN_NODE_CONTEXT_H

src/node/transaction.cpp

@@ -6,6 +6,7 @@
 #include <consensus/validation.h>
 #include <net.h>
 #include <net_processing.h>
+#include <node/context.h>
 #include <util/validation.h>
 #include <validation.h>
 #include <validationinterface.h>
@@ -13,7 +14,7 @@
 
 #include <future>
 
-TransactionError BroadcastTransaction(const CTransactionRef tx, std::string& err_string, const CAmount& max_tx_fee, bool relay, bool wait_callback)
+TransactionError BroadcastTransaction(NodeContext& node, const CTransactionRef tx, std::string& err_string, const CAmount& max_tx_fee, bool relay, bool wait_callback)
 {
     // BroadcastTransaction can be called by either sendrawtransaction RPC or wallet RPCs.
     // g_connman is assigned both before chain clients and before RPC server is accepting calls,

src/node/transaction.h

@@ -9,6 +9,8 @@
 #include <primitives/transaction.h>
 #include <util/error.h>
 
+struct NodeContext;
+
 /**
  * Submit a transaction to the mempool and (optionally) relay it to all P2P peers.
  *
@@ -18,6 +20,7 @@
  * NOT be set while cs_main, cs_mempool or cs_wallet are held to avoid
  * deadlock.
  *
+ * @param[in]  node reference to node context
  * @param[in]  tx the transaction to broadcast
  * @param[out] &err_string reference to std::string to fill with error string if available
  * @param[in]  max_tx_fee reject txs with fees higher than this (if 0, accept any fee)
@@ -25,6 +28,6 @@
  * @param[in]  wait_callback, wait until callbacks have been processed to avoid stale result due to a sequentially RPC.
  * return error
  */
-NODISCARD TransactionError BroadcastTransaction(CTransactionRef tx, std::string& err_string, const CAmount& max_tx_fee, bool relay, bool wait_callback);
+NODISCARD TransactionError BroadcastTransaction(NodeContext& node, CTransactionRef tx, std::string& err_string, const CAmount& max_tx_fee, bool relay, bool wait_callback);
 
 #endif // BITCOIN_NODE_TRANSACTION_H