Introduce code to generate summaries from an element model.

pkg/analyzer/tool/summary/generate.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.
 
 /**
  * This file contains code to generate serialization/deserialization logic for
  * summaries based on an "IDL" description of the summary format (written in
  * stylized Dart).
  *
  * For each class in the "IDL" input, two corresponding classes are generated:
@@ skipping 138 matching lines @@
   }
 
   /**
    * Process the AST in [idlParsed] and store the resulting semantic model in
    * [_idl].  Also perform some error checking.
    */
   void extractIdl(CompilationUnit idlParsed) {
     _idl = new idlModel.Idl();
     for (CompilationUnitMember decl in idlParsed.declarations) {
       if (decl is ClassDeclaration) {
-        idlModel.ClassDeclaration cls = new idlModel.ClassDeclaration();
+        bool isTopLevel = false;
+        for (Annotation annotation in decl.metadata) {
+          if (annotation.arguments == null &&
+              annotation.name.name == 'topLevel') {
+            isTopLevel = true;
+          }
+        }
+        idlModel.ClassDeclaration cls =
+            new idlModel.ClassDeclaration(isTopLevel);
         _idl.classes[decl.name.name] = cls;
         for (ClassMember classMember in decl.members) {
           if (classMember is FieldDeclaration) {
             TypeName type = classMember.fields.type;
             bool isList = false;
             if (type.name.name == 'List' &&
                 type.typeArguments != null &&
                 type.typeArguments.arguments.length == 1) {
               isList = true;
               type = type.typeArguments.arguments[0];
@@ skipping 59 matching lines @@
     checkIdl();
     out('// Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file');
     out('// for details. All rights reserved. Use of this source code is governed by a');
     out('// BSD-style license that can be found in the LICENSE file.');
     out('//');
     out('// This file has been automatically generated.  Please do not edit it manually.');
     out('// To regenerate the file, use the script "pkg/analyzer/tool/generate_files".');
     out();
     out('library analyzer.src.summary.format;');
     out();
+    out("import 'dart:convert';");
     out("import 'builder.dart' as builder;");
     out();
     _idl.enums.forEach((String name, idlModel.EnumDeclaration enm) {
       out('enum $name {');
       indent(() {
         for (String value in enm.values) {
           out('$value,');
         }
       });
       out('}');
@@ skipping 25 matching lines @@
             }
             initializers.add('_$fieldName = $convert');
           });
           for (int i = 0; i < initializers.length; i++) {
             String prefix = i == 0 ? ': ' : '  ';
             String suffix = i == initializers.length - 1 ? ';' : ',';
             out('$prefix${initializers[i]}$suffix');
           }
         });
         out();
+        if (cls.isTopLevel) {
+          out('$name.fromBuffer(List<int> buffer) : this.fromJson(JSON.decode(UTF8.decode(buffer)));');
+          out();
+        }
         cls.fields.forEach((String fieldName, idlModel.FieldType type) {
           String def = defaultValue(type);
           String defaultSuffix = def == null ? '' : ' ?? $def';
           out('${dartType(type)} get $fieldName => _$fieldName$defaultSuffix;');
         });
       });
       out('}');
       out();
       List<String> builderParams = <String>[];
       out('class ${name}Builder {');
@@ skipping 42 matching lines @@
     });
   }
 
   /**
    * Enclose [s] in quotes, escaping as necessary.
    */
   String quoted(String s) {
     return JSON.encode(s);
   }
 }