Change implementation from function pointer to abstract base class us…

…ing shared pointers, minor fix for CMake build system #2717

libraries/plugins/chain/CMakeLists.txt

@@ -1,4 +1,4 @@
-file(GLOB HEADERS "include/steem/chain_plugin/*.hpp")
+file(GLOB HEADERS "include/steem/plugins/chain/*.hpp")
 add_library( chain_plugin
              chain_plugin.cpp
              ${HEADERS} )
@@ -20,4 +20,4 @@ install( TARGETS
    LIBRARY DESTINATION lib
    ARCHIVE DESTINATION lib
 )
-install( FILES ${HEADERS} DESTINATION "include/steem/chain_plugin" )
+install( FILES ${HEADERS} DESTINATION "include/steem/plugins/chain" )

libraries/plugins/chain/chain_plugin.cpp

@@ -1,5 +1,6 @@
 #include <steem/chain/database_exceptions.hpp>
 
+#include <steem/plugins/chain/abstract_block_producer.hpp>
 #include <steem/plugins/chain/chain_plugin.hpp>
 #include <steem/plugins/statsd/utility.hpp>
 
@@ -91,7 +92,7 @@ class chain_plugin_impl
 
       database  db;
       std::string block_generator_registrant;
-      fc::optional< chain_plugin::block_generator_func > block_generator;
+      std::shared_ptr< abstract_block_producer > block_generator;
 };
 
 struct write_request_visitor
@@ -101,7 +102,7 @@ struct write_request_visitor
    database* db;
    uint32_t  skip = 0;
    fc::optional< fc::exception >* except;
-   fc::optional< chain_plugin::block_generator_func > block_generator;
+   std::shared_ptr< abstract_block_producer > block_generator;
 
    typedef bool result_type;
 
@@ -159,11 +160,11 @@ struct write_request_visitor
 
       try
       {
-         if( !block_generator.valid() )
+         if( !block_generator )
             FC_THROW_EXCEPTION( chain_exception, "Received a generate block request, but no block generator has been registered." );
 
          STATSD_START_TIMER( "chain", "write_time", "generate_block", 1.0f )
-         req->block = (*block_generator)(
+         req->block = block_generator->generate_block(
             req->when,
             req->witness_owner,
             req->block_signing_private_key,
@@ -637,15 +638,15 @@ void chain_plugin::check_time_in_block( const steem::chain::signed_block& block
    FC_ASSERT( block.timestamp.sec_since_epoch() <= max_accept_time );
 }
 
-void chain_plugin::register_block_generator( const std::string& plugin_name, block_generator_func func )
+void chain_plugin::register_block_generator( const std::string& plugin_name, std::shared_ptr< abstract_block_producer > block_producer )
 {
-   FC_ASSERT( get_state() != appbase::abstract_plugin::state::started, "Can only register a block generator when the chain_plugin is not started." );
+   FC_ASSERT( get_state() == appbase::abstract_plugin::state::initialized, "Can only register a block generator when the chain_plugin is initialized." );
 
-   if ( my->block_generator.valid() )
+   if ( my->block_generator )
       wlog( "Overriding a previously registered block generator by: ${registrant}", ("registrant", my->block_generator_registrant) );
 
    my->block_generator_registrant = plugin_name;
-   my->block_generator = func;
+   my->block_generator = block_producer;
 }
 
 } } } // namespace steem::plugis::chain::chain_apis

libraries/plugins/chain/include/steem/plugins/chain/abstract_block_producer.hpp

@@ -0,0 +1,18 @@
+#pragma once
+
+#include <fc/time.hpp>
+
+#include <steem/chain/database.hpp>
+
+namespace steem { namespace plugins { namespace chain {
+
+class abstract_block_producer {
+public:
+   virtual steem::chain::signed_block generate_block(
+      fc::time_point_sec when,
+      const steem::chain::account_name_type& witness_owner,
+      const fc::ecc::private_key& block_signing_private_key,
+      uint32_t skip = steem::chain::database::skip_nothing) = 0;
+};
+
+} } } // steem::plugins::chain

libraries/plugins/chain/include/steem/plugins/chain/chain_plugin.hpp

@@ -1,9 +1,10 @@
 #pragma once
 #include <appbase/application.hpp>
 #include <steem/chain/database.hpp>
+#include <steem/plugins/chain/abstract_block_producer.hpp>
 
 #include <boost/signals2.hpp>
-#include <functional>
+
 #define STEEM_CHAIN_PLUGIN_NAME "chain"
 
 namespace steem { namespace plugins { namespace chain {
@@ -42,22 +43,14 @@ class chain_plugin : public plugin< chain_plugin >
       uint32_t skip = database::skip_nothing
       );
 
-   typedef std::function
-      < signed_block (
-         fc::time_point_sec,
-         const account_name_type&,
-         const fc::ecc::private_key&,
-         uint32_t ) >
-            block_generator_func;
-
    /**
-    * Set a function to be called for block generation.
+    * Set a class to be called for block generation.
     *
     * This function must be called during abtract_plugin::plugin_initialize().
     * Calling this during abstract_plugin::plugin_startup() will be too late
     * and will not take effect.
     */
-   void register_block_generator( const std::string& plugin_name, block_generator_func func );
+   void register_block_generator( const std::string& plugin_name, std::shared_ptr< abstract_block_producer > block_producer );
 
    /**
     * Sets the time (in ms) that the write thread will hold the lock for.

libraries/plugins/witness/include/steem/plugins/witness/block_producer.hpp

@@ -2,11 +2,12 @@
 
 #include <fc/time.hpp>
 
+#include <steem/plugins/chain/abstract_block_producer.hpp>
 #include <steem/plugins/chain/chain_plugin.hpp>
 
 namespace steem { namespace plugins { namespace witness {
 
-class block_producer {
+class block_producer : public chain::abstract_block_producer {
 public:
    block_producer( chain::database& db ) : _db( db ) {}
 

libraries/plugins/witness/witness_plugin.cpp

@@ -79,7 +79,7 @@ namespace detail {
          _timer(io),
          _chain_plugin( appbase::app().get_plugin< steem::plugins::chain::chain_plugin >() ),
          _db( appbase::app().get_plugin< steem::plugins::chain::chain_plugin >().db() ),
-         _block_producer( _db )
+         _block_producer( std::make_shared< witness::block_producer >( _db ) )
          {}
 
       void on_pre_apply_block( const chain::block_notification& note );
@@ -107,12 +107,13 @@ namespace detail {
 
       plugins::chain::chain_plugin& _chain_plugin;
       chain::database&              _db;
-      witness::block_producer       _block_producer;
       boost::signals2::connection   _pre_apply_block_conn;
       boost::signals2::connection   _post_apply_block_conn;
       boost::signals2::connection   _pre_apply_transaction_conn;
       boost::signals2::connection   _pre_apply_operation_conn;
       boost::signals2::connection   _post_apply_operation_conn;
+
+      std::shared_ptr< witness::block_producer >                         _block_producer;
    };
 
    struct comment_options_extension_visitor
@@ -648,15 +649,7 @@ void witness_plugin::plugin_initialize(const boost::program_options::variables_m
    ilog( "Initializing witness plugin" );
    my = std::make_unique< detail::witness_plugin_impl >( appbase::app().get_io_service() );
 
-   my->_chain_plugin.register_block_generator(
-      get_name(),
-      [this] (fc::time_point_sec when,
-              const chain::account_name_type& witness_owner,
-              const fc::ecc::private_key& block_signing_private_key,
-              uint32_t skip) -> chain::signed_block
-      {
-        return my->_block_producer.generate_block(when, witness_owner, block_signing_private_key, skip);
-      });
+   my->_chain_plugin.register_block_generator( get_name(), my->_block_producer );
 
    block_data_export_plugin* export_plugin = appbase::app().find_plugin< block_data_export_plugin >();
    if( export_plugin != nullptr )