Added IsolateNameServer functionality (flutter#5410)

* Added IsolateNameServer functionality, which allows for the association
of string names with isolate SendPort ids that can be used to establish
inter-isolate communications.

lib/ui/BUILD.gn

@@ -14,6 +14,10 @@ source_set("ui") {
     "dart_runtime_hooks.h",
     "dart_ui.cc",
     "dart_ui.h",
+    "isolate_name_server/isolate_name_server.cc",
+    "isolate_name_server/isolate_name_server.h",
+    "isolate_name_server/isolate_name_server_natives.cc",
+    "isolate_name_server/isolate_name_server_natives.h",
     "painting/canvas.cc",
     "painting/canvas.h",
     "painting/codec.cc",

lib/ui/dart_ui.cc

@@ -7,6 +7,7 @@
 #include "flutter/lib/ui/compositing/scene.h"
 #include "flutter/lib/ui/compositing/scene_builder.h"
 #include "flutter/lib/ui/dart_runtime_hooks.h"
+#include "flutter/lib/ui/isolate_name_server/isolate_name_server_natives.h"
 #include "flutter/lib/ui/painting/canvas.h"
 #include "flutter/lib/ui/painting/codec.h"
 #include "flutter/lib/ui/painting/frame_info.h"
@@ -60,6 +61,7 @@ void DartUI::InitForGlobal() {
     FrameInfo::RegisterNatives(g_natives);
     ImageFilter::RegisterNatives(g_natives);
     ImageShader::RegisterNatives(g_natives);
+    IsolateNameServerNatives::RegisterNatives(g_natives);
     Paragraph::RegisterNatives(g_natives);
     ParagraphBuilder::RegisterNatives(g_natives);
     Picture::RegisterNatives(g_natives);

lib/ui/dart_ui.gni

@@ -7,6 +7,7 @@ dart_ui_files = [
   "$flutter_root/lib/ui/geometry.dart",
   "$flutter_root/lib/ui/hash_codes.dart",
   "$flutter_root/lib/ui/hooks.dart",
+  "$flutter_root/lib/ui/isolate_name_server.dart",
   "$flutter_root/lib/ui/lerp.dart",
   "$flutter_root/lib/ui/natives.dart",
   "$flutter_root/lib/ui/painting.dart",

lib/ui/isolate_name_server.dart

@@ -0,0 +1,44 @@
+// Copyright 2018 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+part of dart.ui;
+
+abstract class IsolateNameServer {
+  // Looks up the [SendPort] associated with a given name. Returns null
+  // if the name does not exist.
+  static SendPort lookupPortByName(String name) {
+    if (name == null) {
+      throw new ArgumentError("'name' cannot be null.");
+    }
+    return _lookupPortByName(name);
+  }
+
+  // Registers a SendPort with a given name. Returns true if registration is
+  // successful, false if the name entry already exists.
+  static bool registerPortWithName(SendPort port, String name) {
+    if (name == null) {
+      throw new ArgumentError("'name' cannot be null.");
+    }
+    if (port == null) {
+      throw new ArgumentError("'port' cannot be null.");
+    }
+    return _registerPortWithName(port, name);
+  }
+
+  // Removes a name to SendPort mapping given a name. Returns true if the
+  // mapping was successfully removed, false if the mapping does not exist.
+  static bool removePortNameMapping(String name) {
+    if (name == null) {
+      throw new ArgumentError("'name' cannot be null.");
+    }
+    return _removePortNameMapping(name);
+  }
+
+  static SendPort _lookupPortByName(String name)
+      native 'IsolateNameServerNatives_LookupPortByName';
+  static bool _registerPortWithName(SendPort port, String name)
+      native 'IsolateNameServerNatives_RegisterPortWithName';
+  static bool _removePortNameMapping(String name)
+      native 'IsolateNameServerNatives_RemovePortNameMapping';
+}

lib/ui/isolate_name_server/isolate_name_server.cc

@@ -0,0 +1,44 @@
+// Copyright 2018 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "flutter/lib/ui/isolate_name_server/isolate_name_server.h"
+
+namespace blink {
+
+Dart_Port IsolateNameServer::LookupIsolatePortByName(const std::string& name) {
+  std::unique_lock<std::mutex> lock(mutex_);
+  return LookupIsolatePortByNameUnprotected(name);
+}
+
+Dart_Port IsolateNameServer::LookupIsolatePortByNameUnprotected(
+    const std::string& name) {
+  auto port_iterator = port_mapping_.find(name);
+  if (port_iterator != port_mapping_.end()) {
+    return port_iterator->second;
+  }
+  return ILLEGAL_PORT;
+}
+
+bool IsolateNameServer::RegisterIsolatePortWithName(Dart_Port port,
+                                                    const std::string& name) {
+  std::unique_lock<std::mutex> lock(mutex_);
+  if (LookupIsolatePortByNameUnprotected(name) != ILLEGAL_PORT) {
+    // Name is already registered.
+    return false;
+  }
+  port_mapping_[name] = port;
+  return true;
+}
+
+bool IsolateNameServer::RemoveIsolateNameMapping(const std::string& name) {
+  std::unique_lock<std::mutex> lock(mutex_);
+  auto port_iterator = port_mapping_.find(name);
+  if (port_iterator == port_mapping_.end()) {
+    return false;
+  }
+  port_mapping_.erase(port_iterator);
+  return true;
+}
+
+}  // namespace blink

lib/ui/isolate_name_server/isolate_name_server.h

@@ -0,0 +1,50 @@
+// Copyright 2018 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef FLUTTER_LIB_UI_ISOLATE_NAME_SERVER_H_
+#define FLUTTER_LIB_UI_ISOLATE_NAME_SERVER_H_
+
+#include <map>
+#include <mutex>
+#include <string>
+
+#include "flutter/fml/synchronization/thread_annotations.h"
+#include "lib/fxl/macros.h"
+#include "third_party/dart/runtime/include/dart_api.h"
+
+#define LOCK_UNLOCK(m) FML_ACQUIRE(m) FML_RELEASE(m)
+
+namespace blink {
+
+class IsolateNameServer {
+ public:
+  IsolateNameServer() {}
+
+  // Looks up the Dart_Port associated with a given name. Returns ILLEGAL_PORT
+  // if the name does not exist.
+  Dart_Port LookupIsolatePortByName(const std::string& name)
+      LOCK_UNLOCK(mutex_);
+
+  // Registers a Dart_Port with a given name. Returns true if registration is
+  // successful, false if the name entry already exists.
+  bool RegisterIsolatePortWithName(Dart_Port port, const std::string& name)
+      LOCK_UNLOCK(mutex_);
+
+  // Removes a name to Dart_Port mapping given a name. Returns true if the
+  // mapping was successfully removed, false if the mapping does not exist.
+  bool RemoveIsolateNameMapping(const std::string& name) LOCK_UNLOCK(mutex_);
+
+ private:
+  Dart_Port LookupIsolatePortByNameUnprotected(const std::string& name)
+      FML_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
+
+  mutable std::mutex mutex_;
+  std::map<std::string, Dart_Port> port_mapping_ FML_GUARDED_BY(mutex_);
+
+  FXL_DISALLOW_COPY_AND_ASSIGN(IsolateNameServer);
+};
+
+}  // namespace blink
+
+#endif  // FLUTTER_LIB_UI_ISOLATE_NAME_SERVER_H_

lib/ui/isolate_name_server/isolate_name_server_natives.cc

@@ -0,0 +1,64 @@
+// Copyright 2018 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <string>
+
+#include "flutter/lib/ui/isolate_name_server/isolate_name_server.h"
+#include "flutter/lib/ui/isolate_name_server/isolate_name_server_natives.h"
+#include "flutter/lib/ui/ui_dart_state.h"
+#include "lib/tonic/dart_binding_macros.h"
+#include "lib/tonic/dart_library_natives.h"
+
+namespace blink {
+
+Dart_Handle IsolateNameServerNatives::LookupPortByName(
+    const std::string& name) {
+  IsolateNameServer* name_server =
+      UIDartState::Current()->GetIsolateNameServer();
+  Dart_Port port = name_server->LookupIsolatePortByName(name);
+  if (port == ILLEGAL_PORT) {
+    return Dart_Null();
+  }
+  return Dart_NewSendPort(port);
+}
+
+Dart_Handle IsolateNameServerNatives::RegisterPortWithName(
+    Dart_Handle port_handle,
+    const std::string& name) {
+  IsolateNameServer* name_server =
+      UIDartState::Current()->GetIsolateNameServer();
+  Dart_Port port = ILLEGAL_PORT;
+  Dart_SendPortGetId(port_handle, &port);
+  if (!name_server->RegisterIsolatePortWithName(port, name)) {
+    return Dart_False();
+  }
+  return Dart_True();
+}
+
+Dart_Handle IsolateNameServerNatives::RemovePortNameMapping(
+    const std::string& name) {
+  IsolateNameServer* name_server =
+      UIDartState::Current()->GetIsolateNameServer();
+  if (!name_server->RemoveIsolateNameMapping(name)) {
+    return Dart_False();
+  }
+  return Dart_True();
+}
+
+#define FOR_EACH_BINDING(V)                         \
+  V(IsolateNameServerNatives, LookupPortByName)     \
+  V(IsolateNameServerNatives, RegisterPortWithName) \
+  V(IsolateNameServerNatives, RemovePortNameMapping)
+
+FOR_EACH_BINDING(DART_NATIVE_CALLBACK_STATIC)
+
+#define DART_REGISTER_NATIVE_STATIC_(CLASS, METHOD) \
+  DART_REGISTER_NATIVE_STATIC(CLASS, METHOD),
+
+void IsolateNameServerNatives::RegisterNatives(
+    tonic::DartLibraryNatives* natives) {
+  natives->Register({FOR_EACH_BINDING(DART_REGISTER_NATIVE_STATIC_)});
+}
+
+}  // namespace blink

lib/ui/isolate_name_server/isolate_name_server_natives.h

@@ -0,0 +1,27 @@
+// Copyright 2018 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef FLUTTER_LIB_UI_ISOLATE_NAME_SERVER_NATIVES_H_
+#define FLUTTER_LIB_UI_ISOLATE_NAME_SERVER_NATIVES_H_
+
+#include "third_party/dart/runtime/include/dart_api.h"
+
+namespace tonic {
+class DartLibraryNatives;
+}  // namespace tonic
+
+namespace blink {
+
+class IsolateNameServerNatives {
+ public:
+  static Dart_Handle LookupPortByName(const std::string& name);
+  static Dart_Handle RegisterPortWithName(Dart_Handle port_handle,
+                                          const std::string& name);
+  static Dart_Handle RemovePortNameMapping(const std::string& name);
+  static void RegisterNatives(tonic::DartLibraryNatives* natives);
+};
+
+}  // namespace blink
+
+#endif  // FLUTTER_LIB_UI_ISOLATE_NAME_SERVER_NATIVES_H_

lib/ui/ui.dart

@@ -17,6 +17,7 @@ import 'dart:collection' as collection;
 import 'dart:convert';
 import 'dart:developer' as developer;
 import 'dart:io';
+import 'dart:isolate' show SendPort;
 import 'dart:math' as math;
 import 'dart:nativewrappers';
 import 'dart:typed_data';
@@ -25,6 +26,7 @@ part 'compositing.dart';
 part 'geometry.dart';
 part 'hash_codes.dart';
 part 'hooks.dart';
+part 'isolate_name_server.dart';
 part 'lerp.dart';
 part 'natives.dart';
 part 'painting.dart';

lib/ui/ui_dart_state.cc

@@ -19,15 +19,17 @@ UIDartState::UIDartState(TaskRunners task_runners,
                          fxl::RefPtr<flow::SkiaUnrefQueue> skia_unref_queue,
                          std::string advisory_script_uri,
                          std::string advisory_script_entrypoint,
-                         std::string logger_prefix)
+                         std::string logger_prefix,
+                         IsolateNameServer* isolate_name_server)
     : task_runners_(std::move(task_runners)),
       add_callback_(std::move(add_callback)),
       remove_callback_(std::move(remove_callback)),
       resource_context_(std::move(resource_context)),
       advisory_script_uri_(std::move(advisory_script_uri)),
       advisory_script_entrypoint_(std::move(advisory_script_entrypoint)),
       logger_prefix_(std::move(logger_prefix)),
-      skia_unref_queue_(std::move(skia_unref_queue)) {
+      skia_unref_queue_(std::move(skia_unref_queue)),
+      isolate_name_server_(isolate_name_server) {
   AddOrRemoveTaskObserver(true /* add */);
 }
 
@@ -100,4 +102,8 @@ fml::WeakPtr<GrContext> UIDartState::GetResourceContext() const {
   return resource_context_;
 }
 
+IsolateNameServer* UIDartState::GetIsolateNameServer() {
+  return isolate_name_server_;
+}
+
 }  // namespace blink

lib/ui/ui_dart_state.h

@@ -13,6 +13,7 @@
 #include "flutter/common/task_runners.h"
 #include "flutter/flow/skia_gpu_object.h"
 #include "flutter/fml/memory/weak_ptr.h"
+#include "flutter/lib/ui/isolate_name_server/isolate_name_server.h"
 #include "lib/fxl/build_config.h"
 #include "lib/tonic/dart_microtask_queue.h"
 #include "lib/tonic/dart_persistent_value.h"
@@ -46,6 +47,8 @@ class UIDartState : public tonic::DartState {
 
   fml::WeakPtr<GrContext> GetResourceContext() const;
 
+  IsolateNameServer* GetIsolateNameServer();
+
   template <class T>
   static flow::SkiaGPUObject<T> CreateGPUObject(sk_sp<T> object) {
     if (!object) {
@@ -65,7 +68,8 @@ class UIDartState : public tonic::DartState {
               fxl::RefPtr<flow::SkiaUnrefQueue> skia_unref_queue,
               std::string advisory_script_uri,
               std::string advisory_script_entrypoint,
-              std::string logger_prefix);
+              std::string logger_prefix,
+              IsolateNameServer* isolate_name_server);
 
   ~UIDartState() override;
 
@@ -90,6 +94,7 @@ class UIDartState : public tonic::DartState {
   std::unique_ptr<Window> window_;
   fxl::RefPtr<flow::SkiaUnrefQueue> skia_unref_queue_;
   tonic::DartMicrotaskQueue microtask_queue_;
+  IsolateNameServer* isolate_name_server_;
 
   void AddOrRemoveTaskObserver(bool add);
 };

runtime/dart_isolate.cc

@@ -33,7 +33,7 @@
 namespace blink {
 
 fml::WeakPtr<DartIsolate> DartIsolate::CreateRootIsolate(
-    const DartVM* vm,
+    DartVM* vm,
     fxl::RefPtr<DartSnapshot> isolate_snapshot,
     fxl::RefPtr<DartSnapshot> shared_snapshot,
     TaskRunners task_runners,
@@ -94,7 +94,7 @@ fml::WeakPtr<DartIsolate> DartIsolate::CreateRootIsolate(
   return embedder_isolate;
 }
 
-DartIsolate::DartIsolate(const DartVM* vm,
+DartIsolate::DartIsolate(DartVM* vm,
                          fxl::RefPtr<DartSnapshot> isolate_snapshot,
                          fxl::RefPtr<DartSnapshot> shared_snapshot,
                          TaskRunners task_runners,
@@ -110,7 +110,8 @@ DartIsolate::DartIsolate(const DartVM* vm,
                   std::move(unref_queue),
                   advisory_script_uri,
                   advisory_script_entrypoint,
-                  vm->GetSettings().log_tag),
+                  vm->GetSettings().log_tag,
+                  vm->GetIsolateNameServer()),
       vm_(vm),
       isolate_snapshot_(std::move(isolate_snapshot)),
       shared_snapshot_(std::move(shared_snapshot)),
@@ -131,7 +132,7 @@ DartIsolate::Phase DartIsolate::GetPhase() const {
   return phase_;
 }
 
-const DartVM* DartIsolate::GetDartVM() const {
+DartVM* DartIsolate::GetDartVM() const {
   return vm_;
 }
 
@@ -651,7 +652,7 @@ DartIsolate::CreateDartVMAndEmbedderObjectPair(
     return {nullptr, {}};
   }
 
-  const DartVM* vm = embedder_isolate->GetDartVM();
+  DartVM* const vm = embedder_isolate->GetDartVM();
 
   if (!is_root_isolate) {
     auto raw_embedder_isolate = embedder_isolate.release();