Refactor database for RAII compliance

Make chainbase::database implement RAII by having the constructor open and the destructor close.
As long as the database is constructed, it should be properly open and ready to use.

include/chainbase/chainbase.hpp

@@ -656,11 +656,12 @@ namespace chainbase {
             read_write    = 1
          };
 
-         void open( const bfs::path& dir, uint32_t write = read_only, uint64_t shared_file_size = 0 );
-         bool is_open()const;
-         void close();
+         database(const bfs::path& dir, open_flags write = read_only, uint64_t shared_file_size = 0);
+         ~database();
+         database(database&&) = default;
+         database& operator=(database&&) = default;
+         bool is_read_only() const { return _read_only; }
          void flush();
-         void wipe( const bfs::path& dir );
          void set_require_locking( bool enable_require_locking );
 
 #ifdef CHAINBASE_CHECK_LOCKING

src/chainbase.cpp

@@ -30,16 +30,14 @@ namespace chainbase {
       bool                    windows = false;
    };
 
-   void database::open( const bfs::path& dir, uint32_t flags, uint64_t shared_file_size ) {
-
+   database::database(const bfs::path& dir, open_flags flags, uint64_t shared_file_size) {
       bool write = flags & database::read_write;
 
-      if( !bfs::exists( dir ) ) {
-         if( !write ) BOOST_THROW_EXCEPTION( std::runtime_error( "database file not found at " + dir.native() ) );
+      if (!bfs::exists(dir)) {
+         if(!write) BOOST_THROW_EXCEPTION( std::runtime_error( "database file not found at " + dir.native() ) );
       }
 
-      bfs::create_directories( dir );
-      if( _data_dir != dir ) close();
+      bfs::create_directories(dir);
 
       _data_dir = dir;
       auto abs_path = bfs::absolute( dir / "shared_memory.bin" );
@@ -105,19 +103,7 @@ namespace chainbase {
       }
    }
 
-   bool database::is_open() const
-   {
-      return _segment && _meta && !_data_dir.empty();
-   }
-
-   void database::flush() {
-      if( _segment )
-         _segment->flush();
-      if( _meta )
-         _meta->flush();
-   }
-
-   void database::close()
+   database::~database()
    {
       _segment.reset();
       _meta.reset();
@@ -126,15 +112,11 @@ namespace chainbase {
       _data_dir = bfs::path();
    }
 
-   void database::wipe( const bfs::path& dir )
-   {
-      _segment.reset();
-      _meta.reset();
-      bfs::remove_all( dir / "shared_memory.bin" );
-      bfs::remove_all( dir / "shared_memory.meta" );
-      _data_dir = bfs::path();
-      _index_list.clear();
-      _index_map.clear();
+   void database::flush() {
+      if( _segment )
+         _segment->flush();
+      if( _meta )
+         _meta->flush();
    }
 
    void database::set_require_locking( bool enable_require_locking )

test/test.cpp

@@ -44,13 +44,8 @@ BOOST_AUTO_TEST_CASE( open_and_create ) {
    try {
       std::cerr << temp.native() << " \n";
 
-      chainbase::database db;
-      BOOST_CHECK_THROW( db.open( temp ), std::runtime_error ); /// temp does not exist
-
-      db.open( temp, database::read_write, 1024*1024*8 );
-
-      chainbase::database db2; /// open an already created db
-      db2.open( temp );
+      chainbase::database db(temp, database::read_write, 1024*1024*8);
+      chainbase::database db2(temp); /// open an already created db
       BOOST_CHECK_THROW( db2.add_index< book_index >(), std::runtime_error ); /// index does not exist in read only database
 
       db.add_index< book_index >();