Fasta kernel builders.

pkg/fasta/lib/src/kernel/kernel_mixin_application_builder.dart

+// Copyright (c) 2016, 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.
+
+library fasta.kernel_mixin_application_builder;
+
+import 'package:kernel/ast.dart' show
+    Class,
+    InterfaceType,
+    Supertype;
+
+import 'kernel_builder.dart' show
+    KernelTypeBuilder,
+    MixinApplicationBuilder;
+
+class KernelMixinApplicationBuilder
+    extends MixinApplicationBuilder<KernelTypeBuilder>
+    implements KernelTypeBuilder {
+  Supertype builtType;
+
+  KernelMixinApplicationBuilder(KernelTypeBuilder supertype,
+      List<KernelTypeBuilder> mixins)
+      : super(supertype, mixins);
+
+  InterfaceType build() => buildSupertype().asInterfaceType;
+
+  Supertype buildSupertype() {
+    if (builtType != null) return builtType;
+    Supertype supertype =
+        this.supertype.buildSupertype()?.classNode?.asRawSupertype;
+    if (supertype == null) {
+      return null;
+    }
+    for (KernelTypeBuilder builder in mixins) {
+      Supertype mixin = builder.buildSupertype()?.classNode?.asRawSupertype;
+      if (mixin == null) {
+        return null;
+      }
+      Class application = new Class(
+          name: "${supertype.classNode.name}&${mixin.classNode.name}",
+          isAbstract: true,
+          supertype: supertype,
+          mixedInType: mixin,
+          typeParameters: null); // TODO(ahe): Compute these.
+      // TODO(ahe): Use asThisSupertype instead and translate type variables.
+      supertype = application.asRawSupertype;
+    }
+    builtType = supertype;
+    return builtType;
+  }
+}