Initial support for generating client and server stubs for Dart.

lib/service_generator.dart

+// Copyright (c) 2015, 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.
+
+part of protoc;
+
+class ServiceGenerator extends ProtobufContainer {
+  final String classname;
+  final String fqname;
+
+  final ProtobufContainer _parent;
+  final GenerationContext _context;
+  final ServiceDescriptorProto _descriptor;
+  final List<MethodDescriptorProto> _methodDescriptors;
+
+  ServiceGenerator(ServiceDescriptorProto descriptor, ProtobufContainer parent,
+      this._context)
+      : _descriptor = descriptor,
+        _parent = parent,
+        classname = descriptor.name,
+        fqname = _qualifiedName(descriptor, parent),
+        _methodDescriptors = descriptor.method {
+    _context.register(this);
+  }
+
+  static String  _qualifiedName(ServiceDescriptorProto descriptor,
+      ProtobufContainer parent) {
+    if (parent == null || parent.fqname == null) {
+      return descriptor.name;
+    } else if (parent.fqname == '.') {
+      return '.${descriptor.name}';
+    } else {
+      return '${parent.fqname}.${descriptor.name}';
+    }
+  }
+
+  static String _serviceClassName(descriptor) {
+    if (descriptor.name.endsWith("Service")) {
+      return descriptor.name + "Base"; // avoid: ServiceServiceBase
+    } else {
+      return descriptor.name + "ServiceBase";
+    }
+  }
+
+  String get package => _parent.package;
+
+  String _shortType(String typename) {
+    return typename.substring(typename.lastIndexOf('.') + 1);
+  }
+
+  String _methodName(String name) =>
+      name.substring(0,1).toLowerCase() + name.substring(1);
+
+  void generate(IndentingWriter out) {
+    out.addBlock(
+        'abstract class ${_serviceClassName(_descriptor)} extends '
+        'GeneratedService {',
+        '}', () {
+      for (MethodDescriptorProto m in _methodDescriptors) {
+        var methodName = _methodName(m.name);
+        out.println('Future<${_shortType(m.outputType)}> $methodName('
+            'ServerContext ctx, ${_shortType(m.inputType)} request);');
+      }
+      out.println();
+
+      out.addBlock(
+          'GeneratedMessage createRequest(String method) {', '}', () {
+        out.addBlock("switch (method) {", "}", () {
+          for (MethodDescriptorProto m in _methodDescriptors) {
+            out.println(
+              "case '${m.name}': return new ${_shortType(m.inputType)}();");
+          }
+          out.println("default: "
+            "throw new ArgumentError('Unknown method: \$method');");
+        });
+      });
+      out.println();
+
+      out.addBlock(
+          'Future<GeneratedMessage> handleCall(ServerContext ctx, '
+          'String method, GeneratedMessage request) async {', '}', () {
+        out.addBlock("switch (method) {", "}", () {
+          for (MethodDescriptorProto m in _methodDescriptors) {
+            var methodName = _methodName(m.name);
+            out.println(
+              "case '${m.name}': return await $methodName(ctx, request);");
+          }
+          out.println("default: "
+            "throw new ArgumentError('Unknown method: \$method');");
+        });
+      });
+    });
+    out.println();
+  }
+}