Reimplement devfs in dart. Implementation now writes to disk.

runtime/observatory/tests/service/dev_fs_test.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.
 // VMOptions=--error_on_bad_type --error_on_bad_override
 
 import 'dart:convert';
 import 'package:observatory/service_io.dart';
 import 'package:unittest/unittest.dart';
 import 'test_helper.dart';
 
 var tests = [
   (VM vm) async {
     var result = await vm.invokeRpcNoUpgrade('_listDevFS', {});
-    expect(result['type'], equals('FSList'));
+    expect(result['type'], equals('FileSystemList'));
     expect(result['fsNames'].toString(), equals("[]"));
 
     var params = {
       'fsName': 'alpha'
     };
     result = await vm.invokeRpcNoUpgrade('_createDevFS', params);
-    expect(result['type'], equals('Success'));
+    expect(result['type'], equals('FileSystem'));
+    expect(result['name'], equals('alpha'));
+    expect(result['uri'], new isInstanceOf<String>());
 
     result = await vm.invokeRpcNoUpgrade('_listDevFS', {});
-    expect(result['type'], equals('FSList'));
+    expect(result['type'], equals('FileSystemList'));
     expect(result['fsNames'].toString(), equals('[alpha]'));
 
     bool caughtException;
     try {
       await vm.invokeRpcNoUpgrade('_createDevFS', params);
       expect(false, isTrue, reason:'Unreachable');
     } on ServerRpcException catch(e) {
       caughtException = true;
       expect(e.code, equals(ServerRpcException.kFileSystemAlreadyExists));
       expect(e.message, "_createDevFS: file system 'alpha' already exists");
     }
     expect(caughtException, isTrue);
 
     result = await vm.invokeRpcNoUpgrade('_deleteDevFS', params);
     expect(result['type'], equals('Success'));
 
     result = await vm.invokeRpcNoUpgrade('_listDevFS', {});
-    expect(result['type'], equals('FSList'));
+    expect(result['type'], equals('FileSystemList'));
     expect(result['fsNames'].toString(), equals("[]"));
 
     caughtException = false;
     try {
       await vm.invokeRpcNoUpgrade('_deleteDevFS', params);
       expect(false, isTrue, reason:'Unreachable');
     } on ServerRpcException catch(e) {
       caughtException = true;
       expect(e.code, equals(ServerRpcException.kFileSystemDoesNotExist));
       expect(e.message, "_deleteDevFS: file system 'alpha' does not exist");
     }
     expect(caughtException, isTrue);
   },
 
   (VM vm) async {
     var fsId = 'banana';
     var filePath = '/foobar.dat';
     var fileContents = BASE64.encode(UTF8.encode('fileContents'));
 
     var result;
     // Create DevFS.
-    result = await vm.invokeRpcNoUpgrade('_createDevFS', {
-        'fsName': fsId
-            });
-    expect(result['type'], equals('Success'));
+    result = await vm.invokeRpcNoUpgrade('_createDevFS', { 'fsName': fsId });
+    expect(result['type'], equals('FileSystem'));
+    expect(result['name'], equals(fsId));
+    expect(result['uri'], new isInstanceOf<String>());
 
     bool caughtException = false;
     try {
       await vm.invokeRpcNoUpgrade('_readDevFSFile', {
         'fsName': fsId,
         'path': filePath,
       });
       expect(false, isTrue, reason:'Unreachable');
     } on ServerRpcException catch(e) {
       caughtException = true;
       expect(e.code, equals(ServerRpcException.kFileDoesNotExist));
-      expect(e.message,
-             "_readDevFSFile: file 'dart-devfs://banana//foobar.dat' "
-             "does not exist");
+      expect(e.message, startsWith("_readDevFSFile: FileSystemException: "));
     }
     expect(caughtException, isTrue);
 
     // Write a file.
     result = await vm.invokeRpcNoUpgrade('_writeDevFSFile', {
         'fsName': fsId,
         'path': filePath,
         'fileContents': fileContents
     });
     expect(result['type'], equals('Success'));
 
     // Read the file back.
     result = await vm.invokeRpcNoUpgrade('_readDevFSFile', {
         'fsName': fsId,
         'path': filePath,
     });
     expect(result['type'], equals('FSFile'));
     expect(result['fileContents'], equals(fileContents));
 
-    // Read a malformed path back.
+    // The leading '/' is optional.
+    result = await vm.invokeRpcNoUpgrade('_readDevFSFile', {
+        'fsName': fsId,
+        'path': filePath.substring(1),
+    });
+    expect(result['type'], equals('FSFile'));
+    expect(result['fileContents'], equals(fileContents));
+
+    // Read a file outside of the fs.
     caughtException = false;
     try {
-      result = await vm.invokeRpcNoUpgrade('_readDevFSFile', {
-          'fsName': fsId,
-          'path': filePath.substring(1)  // Strip the leading '/'.
+      await vm.invokeRpcNoUpgrade('_readDevFSFile', {
+        'fsName': fsId,
+        'path': '../foo',
       });
+      expect(false, isTrue, reason:'Unreachable');
     } on ServerRpcException catch(e) {
       caughtException = true;
       expect(e.code, equals(ServerRpcException.kInvalidParams));
-      expect(e.message,
-             "_readDevFSFile: file system path \'foobar.dat\' "
-             "must begin with a /");
+      expect(e.message, "_readDevFSFile: invalid 'path' parameter: ../foo");
     }
     expect(caughtException, isTrue);
 
-    expect(result['type'], equals('FSFile'));
-    expect(result['fileContents'], equals(fileContents));
-
     // Write a set of files.
     result = await vm.invokeRpcNoUpgrade('_writeDevFSFiles', {
         'fsName': fsId,
         'files': [
           ['/a', BASE64.encode(UTF8.encode('a_contents'))],
           ['/b', BASE64.encode(UTF8.encode('b_contents'))]
         ]
     });
     expect(result['type'], equals('Success'));
 
     // Read one of the files back.
     result = await vm.invokeRpcNoUpgrade('_readDevFSFile', {
         'fsName': fsId,
         'path': '/b',
     });
     expect(result['type'], equals('FSFile'));
     expect(result['fileContents'],
            equals(BASE64.encode(UTF8.encode('b_contents'))));
 
     // List all the files in the file system.
     result = await vm.invokeRpcNoUpgrade('_listDevFSFiles', {
         'fsName': fsId,
     });
-    expect(result['type'], equals('FSFilesList'));
+    expect(result['type'], equals('FSFileList'));
     expect(result['files'].length, equals(3));
 
     // Delete DevFS.
     result = await vm.invokeRpcNoUpgrade('_deleteDevFS', {
         'fsName': fsId,
     });
     expect(result['type'], equals('Success'));
   },
 ];
 
 main(args) async => runVMTests(args, tests);