Reduce the scope of the mutex lock and other minor changes.

Author: greg7mdp

libraries/chain/include/eosio/chain/peer_keys_db.hpp

@@ -1,8 +1,8 @@
 #pragma once
 
 #include <eosio/chain/controller.hpp>
-#include <boost/smart_ptr/atomic_shared_ptr.hpp>
 #include <boost/unordered/unordered_flat_map.hpp>
+#include <fc/mutex.hpp>
 
 namespace eosio::chain {
 
@@ -21,15 +21,17 @@ class peer_keys_db_t {
    size_t update_peer_keys(const controller& chain, uint32_t lib_number);
 
    // safe to be called from any thread
-   std::optional<public_key_type> operator[](name n) const;
+   std::optional<public_key_type> get_peer_key(name n) const;
+
+   // safe to be called from any thread
    size_t size() const;
 
 private:
    std::optional<uint64_t> _get_version(const chainbase::database& db);
 
-   mutable std::mutex _m;
+   mutable fc::mutex  _m;
    uint32_t           _block_num = 0; // below map includes keys registered up to _block_num (inclusive)
-   peer_key_map_t     _peer_key_map;
+   peer_key_map_t     _peer_key_map GUARDED_BY(_m);
 };
 
 } // namespace eosio::chain

libraries/chain/peer_keys_db.cpp

@@ -5,7 +5,7 @@ namespace eosio::chain {
 
 peer_keys_db_t::peer_keys_db_t() {}
 
-std::optional<public_key_type> peer_keys_db_t::operator[](name n) const {
+std::optional<public_key_type> peer_keys_db_t::get_peer_key(name n) const {
    std::lock_guard g(_m);
    if (auto it = _peer_key_map.find(n); it != _peer_key_map.end())
       return std::optional<public_key_type>(it->second);
@@ -20,7 +20,6 @@ size_t peer_keys_db_t::size() const {
 // we update the keys that were registered up to lib_number (inclusive)
 // --------------------------------------------------------------------
 size_t peer_keys_db_t::update_peer_keys(const controller& chain, uint32_t lib_number) {
-   std::lock_guard g(_m);
    size_t num_updated = 0;
    try {
       if (lib_number <= _block_num)
@@ -42,6 +41,8 @@ size_t peer_keys_db_t::update_peer_keys(const controller& chain, uint32_t lib_nu
          return num_updated;
       }
 
+      std::lock_guard g(_m); // we only need to protect access to _peer_key_map
+
       for (auto itr = lower; itr != upper; ++itr) {
          try {
             const auto* itr2 =