Protocol Buffer runtime library and 'protoc' plugin

lib/protobuf/plugin/ExtensionGenerator.dart

+// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+class ExtensionGenerator implements ProtobufContainer {
+
+  // Whitespace
+  static final String sp = MessageGenerator.sp;
+
+  // List of all ExtensionGenerators encountered during a compilation run
+  static List<ExtensionGenerator> allExtensions;
+
+  ExtensionGenerator(GoogleProtobuf_FieldDescriptorProto descriptor,
+      ProtobufContainer parent, GenerationContext context)
+      : this._descriptor = descriptor,
+        this._parent = parent,
+        this._context = context,
+        fqname = parent.fqname == "." ?
+            ".${descriptor.name}" :
+            "${parent.fqname}.${descriptor.name}" {
+    if (allExtensions == null) {
+      allExtensions = new List<ExtensionGenerator>();
+    }
+    allExtensions.add(this);
+  }
+
+  String get classname() {
+    if (_classname == null) {
+      String name = new ProtobufField(_descriptor, _context).externalFieldName;
+      if (_parent is MessageGenerator) {
+        MessageGenerator mg = _parent;
+        _classname = "${mg._classname}.$name";
+      } else {
+        _classname = name;
+      }
+    }
+    return _classname;
+  }
+
+  void generate(IndentingWriter out) {
+    ProtobufField field = new ProtobufField(_descriptor, _context);
+    String baseType = field.baseType;
+
+    String name = field.externalFieldName;
+    String type = field.shortTypeName;
+
+    String typeName = "";
+    ProtobufContainer typeNameContainer = _context[_descriptor.typeName];
+    if (typeNameContainer != null) {
+      typeName = typeNameContainer.classname;
+    }
+
+    String extendee = "";
+    ProtobufContainer extendeeContainer = _context[_descriptor.extendee];
+    if (extendeeContainer != null) {
+      extendee = extendeeContainer.classname;
+    }
+
+    out.println("static Extension _$name${sp}=${sp}null;");
+    out.println("static Extension get $name()${sp}{");
+    out.println("${sp}${sp}if${sp}(null${sp}==${sp}_$name${sp}) {");
+
+    String initializer = "";
+    String builder = "";
+    String valueOf = "";
+
+    if (_descriptor.type == GoogleProtobuf_FieldDescriptorProto_Type.TYPE_MESSAGE ||
+        _descriptor.type == GoogleProtobuf_FieldDescriptorProto_Type.TYPE_GROUP) {
+      if (_descriptor.label ==
+          GoogleProtobuf_FieldDescriptorProto_Label.LABEL_REPEATED) {
+        initializer = ",${sp}()${sp}=>${sp}new PbList<${typeName}>(null)";
+        builder = ",${sp}()${sp}=>${sp}new ${typeName}_Builder()";
+      } else {
+        initializer = ",${sp}()${sp}=>${sp}${typeName}.defaultInstance";
+        builder = ",${sp}()${sp}=>${sp}new ${typeName}_Builder()";
+      }
+    } else {
+      if (_descriptor.label ==
+          GoogleProtobuf_FieldDescriptorProto_Label.LABEL_REPEATED) {
+        initializer = ",${sp}()${sp}=>${sp}new PbList<${baseType}>(null)";
+      } else if (field.hasInitialization) {
+        initializer = ",${sp}${field.initialization}";
+      }
+    }
+
+    if (field.enum) {
+      if (initializer.isEmpty()) {
+        initializer = ",${sp}null";
+      }
+      if (builder.isEmpty()) {
+        builder = ",${sp}null";
+      }
+      valueOf = ",${sp}(var v)${sp}=>${sp}${field.baseType}.valueOf(v)";
+    }
+
+    out.println("${sp}${sp}${sp}${sp}_$name${sp}="
+      "${sp}new Extension(\"$extendee\",${sp}\"$name\",${sp}"
+      "${_descriptor.number},${sp}Builder.$type"
+      "${initializer}${builder}${valueOf}"
+      ");");
+
+    out.println("${sp}${sp}}");
+    out.println("${sp}${sp}return _$name;");
+    out.println("}");
+  }
+
+  String get name() => classname;
+  GoogleProtobuf_FileOptions_OptimizeMode get optimizeFor() => _parent.optimizeFor;
+
+  final String fqname;
+  String _classname;
+  GoogleProtobuf_FieldDescriptorProto _descriptor;
+  ProtobufContainer _parent;
+  GenerationContext _context;
+}