Introduced support for external services registration in the ServiceProtocol

sdk/lib/vmservice/vmservice.dart

Index: sdk/lib/vmservice/vmservice.dart
diff --git a/sdk/lib/vmservice/vmservice.dart b/sdk/lib/vmservice/vmservice.dart
index 5b60ad814c53ea14d677ce05a1ea7e7dde012713..0de475ee143d47893289aa2bf5cad0e627260e79 100644
--- a/sdk/lib/vmservice/vmservice.dart
+++ b/sdk/lib/vmservice/vmservice.dart
@@ -20,6 +20,7 @@ part 'running_isolate.dart';
 part 'running_isolates.dart';
 part 'message.dart';
 part 'message_router.dart';
+part 'named_lookup.dart';
 
 final RawReceivePort isolateControlPort = new RawReceivePort();
 final RawReceivePort scriptLoadPort = new RawReceivePort();
@@ -51,11 +52,27 @@ final Map<int, IsolateEmbedderData> isolateEmbedderData =
     new Map<int, IsolateEmbedderData>();
 
 // These must be kept in sync with the declarations in vm/json_stream.h.
+const kParseError = -32700;
+const kInvalidRequest = -32600;
+const kMethodNotFound = -32601;
 const kInvalidParams = -32602;
 const kInternalError = -32603;
+
+const kExtensionError = -32000;
+
 const kFeatureDisabled = 100;
+const kCannotAddBreakpoint = 102;
 const kStreamAlreadySubscribed = 103;
 const kStreamNotSubscribed = 104;
+const kIsolateMustBeRunnable = 105;
+const kIsolateMustBePaused = 106;
+const kCannotResume = 107;
+const kIsolateIsReloading = 108;
+const kIsolateReloadBarred = 109;
+const kServiceAlreadyRegistered = 110;
+const kServiceDisappeared = 111;
+
+// Experimental (used in private rpcs).
 const kFileSystemAlreadyExists = 1001;
 const kFileSystemDoesNotExist = 1002;
 const kFileDoesNotExist = 1003;
@@ -69,6 +86,8 @@ var _errorMessages = {
   kFileSystemAlreadyExists: 'File system already exists',
   kFileSystemDoesNotExist: 'File system does not exist',
   kFileDoesNotExist: 'File does not exist',
+  kServiceAlreadyRegistered: 'Service already registered',
+  kServiceDisappeared: 'Service has disappeared',
 };
 
 String encodeRpcError(Message message, int code, {String details}) {
@@ -141,6 +160,9 @@ typedef Future<List<int>> ReadFileCallback(Uri path);
 /// Called to list all files under some path.
 typedef Future<List<Map<String, String>>> ListFilesCallback(Uri path);
 
+/// Called when we need information about the server.
+typedef Future<Uri> ServerInformamessage_routertionCallback();
+
 /// Called when we need information about the server.
 typedef Future<Uri> ServerInformationCallback();
 
@@ -165,8 +187,12 @@ class VMServiceEmbedderHooks {
 class VMService extends MessageRouter {
   static VMService _instance;
 
+  static const serviceNamespace = 's';
+
   /// Collection of currently connected clients.
-  final Set<Client> clients = new Set<Client>();
+  final NamedLookup<Client> clients =
+      new NamedLookup<Client>(prologue: serviceNamespace);
+  final IdGenerator _serviceRequests = new IdGenerator(prologue: 'sr');
 
   /// Collection of currently running isolates.
   RunningIsolates runningIsolates = new RunningIsolates();
@@ -178,16 +204,41 @@ class VMService extends MessageRouter {
 
   void _addClient(Client client) {
     assert(client.streams.isEmpty);
+    assert(client.services.isEmpty);
     clients.add(client);
   }
 
   void _removeClient(Client client) {
+    final namespace = clients.keyOf(client);
     clients.remove(client);
     for (var streamId in client.streams) {
       if (!_isAnyClientSubscribed(streamId)) {
         _vmCancelStream(streamId);
       }
     }
+    for (var service in client.services.keys) {
+      _eventMessageHandler([
+        '_Service',
+        JSON.encode({
+          'jsonrpc': '2.0',
+          'method': 'streamNotify',
+          'params': {
+            'streamId': '_Service',
+            'event': {
+              "type": "Event",
+              "kind": "ServiceUnregistered",
+              'timestamp': new DateTime.now().millisecondsSinceEpoch,
+              'service': service,
+              'method': namespace + '.' + service,
+            }
+          }
+        })
+      ]);
+    }
+    // Complete all requestes as failed
+    for (var handle in client.serviceHandles.values) {
+      handle(null);
+    }
   }
 
   void _eventMessageHandler(List eventMessage) {
@@ -313,6 +364,9 @@ class VMService extends MessageRouter {
     return false;
   }
 
+  static const kServiceStream = '_Service';
+  static const serviceStreams = const [kServiceStream];
+
   Future<String> _streamListen(Message message) async {
     var client = message.client;
     var streamId = message.params['streamId'];
@@ -321,13 +375,26 @@ class VMService extends MessageRouter {
       return encodeRpcError(message, kStreamAlreadySubscribed);
     }
     if (!_isAnyClientSubscribed(streamId)) {
-      if (!_vmListenStream(streamId)) {
+      if (!serviceStreams.contains(streamId) && !_vmListenStream(streamId)) {
         return encodeRpcError(message, kInvalidParams,
             details: "streamListen: invalid 'streamId' parameter: ${streamId}");
       }
     }
-    client.streams.add(streamId);
 
+    // Some streams can generate events or side effects after registration
+    switch (streamId) {
+      case kServiceStream:
+        for (Client c in clients) {
+          if (c == client) continue;
+          for (String service in c.services.keys) {
+            _sendServiceRegisteredEvent(c, service, target: client);
+          }
+        }
+        ;
+        break;
+    }
+
+    client.streams.add(streamId);
     return encodeSuccess(message);
   }
 
@@ -339,13 +406,101 @@ class VMService extends MessageRouter {
       return encodeRpcError(message, kStreamNotSubscribed);
     }
     client.streams.remove(streamId);
-    if (!_isAnyClientSubscribed(streamId)) {
+    if (!serviceStreams.contains(streamId) &&
+        !_isAnyClientSubscribed(streamId)) {
       _vmCancelStream(streamId);
     }
 
     return encodeSuccess(message);
   }
 
+  static bool _hasNamespace(String method) =>
+      method.contains('.') &&
+      _getNamespace(method).startsWith(serviceNamespace);
+  static String _getNamespace(String method) => method.split('.').first;
+  static String _getMethod(String method) => method.split('.').last;
+
+  Future<String> _registerService(Message message) async {
+    final client = message.client;
+    final service = message.params['service'];
+    final alias = message.params['alias'];
+
+    if (service is! String || service == '') {
+      return encodeRpcError(message, kInvalidParams,
+          details: "registerService: invalid 'service' parameter: ${service}");
+    }
+    if (alias is! String || alias == '') {
+      return encodeRpcError(message, kInvalidParams,
+          details: "registerService: invalid 'alias' parameter: ${alias}");
+    }
+    if (client.services.containsKey(service)) {
+      return encodeRpcError(message, kServiceAlreadyRegistered);
+    }
+    client.services[service] = alias;
+
+    bool removed;
+    try {
+      // Do not send streaming events to the client which registers the service
+      removed = client.streams.remove(kServiceStream);
+      await _sendServiceRegisteredEvent(client, service);
+    } finally {
+      if (removed) client.streams.add(kServiceStream);
+    }
+
+    return encodeSuccess(message);
+  }
+
+  _sendServiceRegisteredEvent(Client client, String service,
+      {Client target}) async {
+    final namespace = clients.keyOf(client);
+    final alias = client.services[service];
+    final event = JSON.encode({
+      'jsonrpc': '2.0',
+      'method': 'streamNotify',
+      'params': {
+        'streamId': kServiceStream,
+        'event': {
+          "type": "Event",
+          "kind": "ServiceRegistered",
+          'timestamp': new DateTime.now().millisecondsSinceEpoch,
+          'service': service,
+          'method': namespace + '.' + service,
+          'alias': alias
+        }
+      }
+    });
+    if (target == null) {
+      _eventMessageHandler([kServiceStream, event]);
+    } else {
+      target.post(event);
+    }
+  }
+
+  Future<String> _handleService(Message message) async {
+    final namespace = _getNamespace(message.method);
+    final method = _getMethod(message.method);
+    final client = clients[namespace];
+    if (client != null) {
+      if (client.services.containsKey(method)) {
+        final id = _serviceRequests.newId();
+        final oldId = message.serial;
+        final completer = new Completer<String>();
+        client.serviceHandles[id] = (Message m) {
+          if (m != null) {
+            completer.complete(JSON.encode(m.forwardToJson({'id': oldId})));
+          } else {
+            completer.complete(encodeRpcError(message, kServiceDisappeared));
+          }
+        };
+        client.post(
+            JSON.encode(message.forwardToJson({'id': id, 'method': method})));
+        return completer.future;
+      }
+    }
+    return encodeRpcError(message, kMethodNotFound,
+        details: "Unknown service: ${message.method}");
+  }
+
   Future<String> _spawnUri(Message message) async {
     var token = message.params['token'];
     if (token == null) {
@@ -423,13 +578,13 @@ class VMService extends MessageRouter {
         var message = new Message.forIsolate(client, request, isolate);
         // Decode the JSON and and insert it into the map. The map key
         // is the request Uri.
-        var response = responseAsJson(await isolate.route(message));
+        var response = responseAsJson(await isolate.routeRequest(message));
         responses[message.toUri().toString()] = response['result'];
       }
       // Dump the object id ring requests.
       var message =
           new Message.forIsolate(client, Uri.parse('_dumpIdZone'), isolate);
-      var response = responseAsJson(await isolate.route(message));
+      var response = responseAsJson(await isolate.routeRequest(message));
       // Insert getObject requests into responses map.
       for (var object in response['result']['objects']) {
         final requestUri =
@@ -442,30 +597,49 @@ class VMService extends MessageRouter {
     return encodeResult(message, responses);
   }
 
-  Future<String> route(Message message) {
-    if (message.completed) {
+  Future routeRequest(Message message) async {
+    try {
+      if (message.completed) {
+        return await message.response;
+      }
+      // TODO(turnidge): Update to json rpc.  BEFORE SUBMIT.
+      if (message.method == '_getCrashDump') {
+        return await _getCrashDump(message);
+      }
+      if (message.method == 'streamListen') {
+        return await _streamListen(message);
+      }
+      if (message.method == 'streamCancel') {
+        return await _streamCancel(message);
+      }
+      if (message.method == '_registerService') {
+        return await _registerService(message);
+      }
+      if (message.method == '_spawnUri') {
+        return await _spawnUri(message);
+      }
+      if (devfs.shouldHandleMessage(message)) {
+        return await devfs.handleMessage(message);
+      }
+      if (_hasNamespace(message.method)) {
+        return await _handleService(message);
+      }
+      if (message.params['isolateId'] != null) {
+        return await runningIsolates.routeRequest(message);
+      }
+      return await message.sendToVM();
+    } catch (e, st) {
+      message.setErrorResponse(kInternalError, 'Unexpected exception:$e\n$st');
       return message.response;
     }
-    // TODO(turnidge): Update to json rpc.  BEFORE SUBMIT.
-    if (message.method == '_getCrashDump') {
-      return _getCrashDump(message);
-    }
-    if (message.method == 'streamListen') {
-      return _streamListen(message);
-    }
-    if (message.method == 'streamCancel') {
-      return _streamCancel(message);
-    }
-    if (message.method == '_spawnUri') {
-      return _spawnUri(message);
-    }
-    if (devfs.shouldHandleMessage(message)) {
-      return devfs.handleMessage(message);
-    }
-    if (message.params['isolateId'] != null) {
-      return runningIsolates.route(message);
+  }
+
+  void routeResponse(message) {
+    final client = message.client;
+    if (client.serviceHandles.containsKey(message.serial)) {
+      client.serviceHandles.remove(message.serial)(message);
+      _serviceRequests.release(message.serial);
     }
-    return message.sendToVM();
   }
 }