1 files changed, 133 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb b/activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb
new file mode 100644
index 0000000000..9bdaa00336
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/mysql2_adapter.rb
@@ -0,0 +1,133 @@
+# frozen_string_literal: true
+
+require "active_record/connection_adapters/abstract_mysql_adapter"
+require "active_record/connection_adapters/mysql/database_statements"
+
+gem "mysql2", ">= 0.4.4"
+require "mysql2"
+
+module ActiveRecord
+  module ConnectionHandling # :nodoc:
+    # Establishes a connection to the database that's used by all Active Record objects.
+    def mysql2_connection(config)
+      config = config.symbolize_keys
+      config[:flags] ||= 0
+
+      if config[:flags].kind_of? Array
+        config[:flags].push "FOUND_ROWS"
+      else
+        config[:flags] |= Mysql2::Client::FOUND_ROWS
+      end
+
+      client = Mysql2::Client.new(config)
+      ConnectionAdapters::Mysql2Adapter.new(client, logger, nil, config)
+    rescue Mysql2::Error => error
+      if error.message.include?("Unknown database")
+        raise ActiveRecord::NoDatabaseError
+      else
+        raise
+      end
+    end
+  end
+
+  module ConnectionAdapters
+    class Mysql2Adapter < AbstractMysqlAdapter
+      ADAPTER_NAME = "Mysql2"
+
+      include MySQL::DatabaseStatements
+
+      def initialize(connection, logger, connection_options, config)
+        super
+        @prepared_statements = false unless config.key?(:prepared_statements)
+        configure_connection
+      end
+
+      def supports_json?
+        !mariadb? && version >= "5.7.8"
+      end
+
+      def supports_comments?
+        true
+      end
+
+      def supports_comments_in_create?
+        true
+      end
+
+      def supports_savepoints?
+        true
+      end
+
+      def supports_lazy_transactions?
+        true
+      end
+
+      # HELPER METHODS ===========================================
+
+      def each_hash(result) # :nodoc:
+        if block_given?
+          result.each(as: :hash, symbolize_keys: true) do |row|
+            yield row
+          end
+        else
+          to_enum(:each_hash, result)
+        end
+      end
+
+      def error_number(exception)
+        exception.error_number if exception.respond_to?(:error_number)
+      end
+
+      #--
+      # QUOTING ==================================================
+      #++
+
+      def quote_string(string)
+        @connection.escape(string)
+      end
+
+      #--
+      # CONNECTION MANAGEMENT ====================================
+      #++
+
+      def active?
+        @connection.ping
+      end
+
+      def reconnect!
+        super
+        disconnect!
+        connect
+      end
+      alias :reset! :reconnect!
+
+      # Disconnects from the database if already connected.
+      # Otherwise, this method does nothing.
+      def disconnect!
+        super
+        @connection.close
+      end
+
+      def discard! # :nodoc:
+        @connection.automatic_close = false
+        @connection = nil
+      end
+
+      private
+
+        def connect
+          @connection = Mysql2::Client.new(@config)
+          configure_connection
+        end
+
+        def configure_connection
+          @connection.query_options[:as] = :array
+          super
+        end
+
+        def full_version
+          @full_version ||= @connection.server_info[:version]
+        end
+    end
+  end
+end