--- a/lib/Protobuf-PHP/library/DrSlump/Protobuf/Compiler/AbstractGenerator.php
+++ b/lib/Protobuf-PHP/library/DrSlump/Protobuf/Compiler/AbstractGenerator.php
@@ -1,1 +1,41 @@
+<?php
 
+namespace DrSlump\Protobuf\Compiler;
+
+use google\protobuf as proto;
+
+abstract class AbstractGenerator
+{
+    /** @var \DrSlump\Protobuf\Compiler */
+    protected $compiler;
+    /** @var \google\protobuf\FileDescriptorProto */
+    protected $proto;
+
+    /** @var array */
+    protected $extensions = array();
+
+    public function __construct(\DrSlump\Protobuf\Compiler $compiler)
+    {
+        $this->compiler = $compiler;
+    }
+
+    public function getNamespace(proto\FileDescriptorProto $proto = NULL)
+    {
+        return NULL === $proto
+               ? $this->proto->getPackage()
+               : $proto->getPackage();
+    }
+
+    public function generate(proto\FileDescriptorProto $proto)
+    {
+        $this->proto = $proto;
+    }
+
+
+    abstract protected function compileEnum(proto\EnumDescriptorProto $enum, $namespace);
+
+    abstract protected function compileMessage(proto\DescriptorProto $msg, $namespace);
+
+    abstract protected function compileExtension(proto\FieldDescriptorProto $field, $ns, $indent);
+}
+