Implement part-of directive.

dart/tests/utils/recursive_import_test.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.
+
+// Test of "recursive" imports using the dart2js compiler API.
+
+#import('../../lib/compiler/compiler.dart');
+#import('dart:uri');
+
+const CORE_LIB = """
+library core;
+class Object{}
+class bool {}
+class num {}
+class int {}
+class double{}
+class String{}
+class Function{}
+class List {}
+class Closure {}
+class Dynamic_ {}
+class Null {}
+getRuntimeTypeInfo(o) {}
+setRuntimeTypeInfo(o, i) {}
+eqNull(a) {}
+eqNullB(a) {}
+""";
+
+const String RECURSIVE_MAIN = """
+library fisk;
+import 'recurse/fisk.dart';
+main() {}
+""";
+
+
+main() {
+  int count = 0;
+  Future<String> provider(Uri uri) {
+    Completer<String> completer = new Completer<String>();
+    String source;
+    if (uri.path.length > 100) {
+      // Simulate an OS error.
+      throw 'Path length exceeded';
+    } else if (uri.scheme == "main") {
+      count++;
+      source = RECURSIVE_MAIN;
+    } else if (uri.scheme == "lib") {
+      if (uri.path.endsWith("/core.dart")) {
+        source = CORE_LIB;
+      } else if (uri.path.endsWith('_patch.dart')) {
+        source = '';
+      } else {
+        source = "library lib${uri.path.replaceAll('/', '.')};";
+      }
+    } else {
+     throw "unexpected URI $uri";
+    }
+    completer.complete(source);
+    return completer.future;
+  }
+
+  int warningCount = 0;
+  int errorCount = 0;
+  void handler(Uri uri, int begin, int end, String message, Diagnostic kind) {
+    if (uri != null) {
+      // print('$uri:$begin:$end: $kind: $message');
+      Expect.equals('main', uri.scheme);
+      if (kind == Diagnostic.WARNING) {
+        warningCount++;
+      } else if (kind == Diagnostic.ERROR) {
+        errorCount++;
+      } else {
+        throw kind;
+      }
+    }
+  }
+
+  String code = compile(new Uri.fromComponents(scheme: 'main'),
+                        new Uri.fromComponents(scheme: 'lib'),
+                        new Uri.fromComponents(scheme: 'package'),
+                        provider, handler).value;
+  Expect.isNull(code);
+  Expect.isTrue(10 < count);
+  // Two warnings for each time RECURSIVE_MAIN is read, except the
+  // first time.
+  Expect.equals(2 * (count - 1), warningCount);
+  Expect.equals(1, errorCount);
+}