Fix duplication of private messages on filtering. #806

Author: afalaleev

libraries/chain/database.cpp

@@ -1145,7 +1145,7 @@ namespace golos { namespace chain {
 
             signed_block pending_block;
 
-            with_strong_write_lock([&]() {
+            with_strong_write_lock([&]() { detail::with_generating(*this, [&]() {
                 //
                 // The following code throws away existing pending_tx_session and
                 // rebuilds it by re-applying pending transactions.
@@ -1198,7 +1198,7 @@ namespace golos { namespace chain {
                 }
 
                 _pending_tx_session.reset();
-            });
+            }); });
 
             // We have temporarily broken the invariant that
             // _pending_tx_session is the result of applying _pending_tx, as

libraries/chain/include/golos/chain/database.hpp

@@ -48,7 +48,16 @@ namespace golos { namespace chain {
                 _is_producing = p;
             }
 
+            bool is_generating() const {
+                return _is_generating;
+            }
+
+            void set_generating(bool p) {
+                _is_generating = p;
+            }
+
             bool _is_producing = false;
+            bool _is_generating = false;
             bool _is_testing = false;           ///< set for tests to avoid low free memory spam
             bool _log_hardforks = true;
 

libraries/chain/include/golos/chain/db_with.hpp

@@ -82,6 +82,21 @@ namespace golos {
                 database &_db;
             };
 
+            /**
+             * Class is used to help the with_generating implementation
+             */
+            struct generating_helper final {
+                generating_helper(database& db): _db(db) {
+                    _db.set_generating(true);
+                }
+
+                ~generating_helper() {
+                    _db.set_generating(false);
+                }
+
+                database &_db;
+            };
+
             /**
              * Empty pending_transactions, call callback,
              * then reset pending_transactions after callback is done.
@@ -111,6 +126,19 @@ namespace golos {
                  producing_helper restorer(db);
                  callback();
              }
+
+             /**
+              * Set generating flag to true, call callback, then set generating flag to false
+              */
+             template <typename Lambda>
+             void with_generating(
+                 database& db,
+                 Lambda callback
+             ) {
+                 generating_helper restorer(db);
+                 callback();
+             }
+
         }
     }
 } // golos::chain::detail

plugins/private_message/private_message_plugin.cpp

@@ -286,7 +286,7 @@ namespace golos { namespace plugins { namespace private_message {
     }
 
     bool private_message_plugin::private_message_plugin_impl::can_call_callbacks() const {
-        return !db_.is_producing() && !callbacks_.empty();
+        return !db_.is_producing() && !db_.is_generating() && !callbacks_.empty();
     }
 
     void private_message_plugin::private_message_plugin_impl::call_callbacks(