Create isolates in a separate thread.

runtime/lib/isolate.cc

 // 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.
 
+#include "include/dart_native_api.h"
 #include "platform/assert.h"
 #include "vm/bootstrap_natives.h"
 #include "vm/class_finalizer.h"
 #include "vm/dart.h"
 #include "vm/dart_api_impl.h"
 #include "vm/dart_entry.h"
 #include "vm/exceptions.h"
 #include "vm/lockers.h"
 #include "vm/longjump.h"
 #include "vm/message_handler.h"
@@ skipping 73 matching lines @@
   writer.WriteMessage(obj);
 
   // TODO(turnidge): Throw an exception when the return value is false?
   PortMap::PostMessage(new Message(port.Id(),
                                    data, writer.BytesWritten(),
                                    Message::kNormalPriority));
   return Object::null();
 }
 
 
-static void ThrowIsolateSpawnException(const String& message) {
-  const Array& args = Array::Handle(Array::New(1));
-  args.SetAt(0, message);
-  Exceptions::ThrowByType(Exceptions::kIsolateSpawn, args);
-}
-
-
 static bool CanonicalizeUri(Isolate* isolate,
                             const Library& library,
                             const String& uri,
                             char** canonical_uri,
                             char** error) {
   Zone* zone = isolate->current_zone();
   bool retval = false;
   Dart_LibraryTagHandler handler = isolate->library_tag_handler();
   if (handler != NULL) {
     Dart_EnterScope();
@@ skipping 17 matching lines @@
     Dart_ExitScope();
   } else {
     *error = zone->PrintToString(
         "Unable to canonicalize uri '%s': no library tag handler found.",
         uri.ToCString());
   }
   return retval;
 }
 
 
-static bool CreateIsolate(Isolate* parent_isolate,
-                          IsolateSpawnState* state,
-                          char** error) {
-  Dart_IsolateCreateCallback callback = Isolate::CreateCallback();
-  if (callback == NULL) {
-    *error = strdup("Null callback specified for isolate creation\n");
-    Isolate::SetCurrent(parent_isolate);
-    return false;
+class SpawnIsolateTask : public ThreadPool::Task {
+ public:
+  explicit SpawnIsolateTask(IsolateSpawnState* state)
+      : state_(state) {
   }
 
-  void* init_data = parent_isolate->init_callback_data();
-  Isolate* child_isolate = reinterpret_cast<Isolate*>(
-      (callback)(state->script_url(),
-                 state->function_name(),
-                 init_data,
-                 error));
-  if (child_isolate == NULL) {
-    Isolate::SetCurrent(parent_isolate);
-    return false;
-  }
-  state->set_isolate(reinterpret_cast<Isolate*>(child_isolate));
+  virtual void Run() {
+    // Create a new isolate.
+    char* error = NULL;
+    Dart_IsolateCreateCallback callback = Isolate::CreateCallback();
+    if (callback == NULL) {
+      ReportError("Isolate spawn is not supported in this Dart embedding.\n");

[Cutch, 2014/08/27 18:18:42]

What about: "Isolate spawn is not supported by this Dart embedder."?

[turnidge, 2014/08/27 19:28:59]

Changed to "by this Dart implemation"

+      delete state_;
+      return;
+    }
 
-  Isolate::SetCurrent(parent_isolate);
-  return true;
-}
+    Isolate* isolate = reinterpret_cast<Isolate*>(
+        (callback)(state_->script_url(),
+                   state_->function_name(),
+                   state_->init_data(),
+                   &error));
+    if (isolate == NULL) {
+      // We were unable to create the child isolate.  Report the error
+      // back to the parent isolate.
+      ReportError(error);
+      delete state_;
+      return;
+    }
 
-
-static RawObject* Spawn(Isolate* parent_isolate,
-                        IsolateSpawnState* state) {
-  // Create a new isolate.
-  char* error = NULL;
-  if (!CreateIsolate(parent_isolate, state, &error)) {
-    delete state;
-    const String& msg = String::Handle(String::New(error));
-    free(error);
-    ThrowIsolateSpawnException(msg);
+    MutexLocker ml(isolate->mutex());
+    state_->set_isolate(reinterpret_cast<Isolate*>(isolate));
+    isolate->set_spawn_state(state_);
+    if (isolate->is_runnable()) {
+      // Start the new isolate if it has been marked as runnable.
+      isolate->Run();
+    }
   }
 
-  // Create a SendPort for the new isolate.
-  Isolate* spawned_isolate = state->isolate();
-  const SendPort& port = SendPort::Handle(
-      SendPort::New(spawned_isolate->main_port()));
-
-  // Start the new isolate if it is already marked as runnable.
-  MutexLocker ml(spawned_isolate->mutex());
-  spawned_isolate->set_spawn_state(state);
-  if (spawned_isolate->is_runnable()) {
-    spawned_isolate->Run();
+ private:
+  void ReportError(const char* error) {
+    Dart_CObject error_cobj;
+    error_cobj.type = Dart_CObject_kString;
+    error_cobj.value.as_string = const_cast<char*>(error);
+    if (!Dart_PostCObject(state_->parent_port(), &error_cobj)) {
+      // Perhaps the parent isolate died or closed the port before we
+      // could report the error.  Ignore.
+    }
   }
 
-  return port.raw();
-}
+  IsolateSpawnState* state_;
+
+  DISALLOW_COPY_AND_ASSIGN(SpawnIsolateTask);
+};
 
 
 DEFINE_NATIVE_ENTRY(Isolate_spawnFunction, 3) {
   GET_NON_NULL_NATIVE_ARGUMENT(SendPort, port, arguments->NativeArgAt(0));
   GET_NON_NULL_NATIVE_ARGUMENT(Instance, closure, arguments->NativeArgAt(1));
   GET_NON_NULL_NATIVE_ARGUMENT(Instance, message, arguments->NativeArgAt(2));
   if (closure.IsClosure()) {
     Function& func = Function::Handle();
     func = Closure::function(closure);
     if (func.IsImplicitClosureFunction() && func.is_static()) {
 #if defined(DEBUG)
       Context& ctx = Context::Handle();
       ctx = Closure::context(closure);
       ASSERT(ctx.num_variables() == 0);
 #endif
-      return Spawn(isolate, new IsolateSpawnState(port.Id(), func, message));
+      Dart::thread_pool()->Run(new SpawnIsolateTask(
+          new IsolateSpawnState(port.Id(),
+                                isolate->init_callback_data(),
+                                func, message)));
+      return Object::null();
     }
   }
   const String& msg = String::Handle(String::New(
       "Isolate.spawn expects to be passed a static or top-level function"));
   Exceptions::ThrowArgumentError(msg);
   return Object::null();
 }
 
 
 DEFINE_NATIVE_ENTRY(Isolate_spawnUri, 4) {
   GET_NON_NULL_NATIVE_ARGUMENT(SendPort, port, arguments->NativeArgAt(0));
   GET_NON_NULL_NATIVE_ARGUMENT(String, uri, arguments->NativeArgAt(1));
   GET_NON_NULL_NATIVE_ARGUMENT(Instance, args, arguments->NativeArgAt(2));
   GET_NON_NULL_NATIVE_ARGUMENT(Instance, message, arguments->NativeArgAt(3));
 
   // Canonicalize the uri with respect to the current isolate.
   char* error = NULL;
   char* canonical_uri = NULL;
   const Library& root_lib =
       Library::Handle(arguments->isolate()->object_store()->root_library());
   if (!CanonicalizeUri(arguments->isolate(), root_lib, uri,
                        &canonical_uri, &error)) {
-    const String& msg = String::Handle(String::New(error));
-    ThrowIsolateSpawnException(msg);
+    const String& message = String::Handle(String::New(error));
+    const Array& args = Array::Handle(Array::New(1));
+    args.SetAt(0, message);
+    Exceptions::ThrowByType(Exceptions::kIsolateSpawn, args);
   }
 
-  return Spawn(isolate, new IsolateSpawnState(port.Id(), canonical_uri,
-                                              args, message));
+  Dart::thread_pool()->Run(new SpawnIsolateTask(
+      new IsolateSpawnState(port.Id(),
+                            isolate->init_callback_data(),
+                            canonical_uri,
+                            args, message)));
+  return Object::null();
 }
 
 
 DEFINE_NATIVE_ENTRY(Isolate_sendOOB, 2) {
   GET_NON_NULL_NATIVE_ARGUMENT(SendPort, port, arguments->NativeArgAt(0));
   GET_NON_NULL_NATIVE_ARGUMENT(Array, msg, arguments->NativeArgAt(1));
 
   // Make sure to route this request to the isolate library OOB mesage handler.
   msg.SetAt(0, Smi::Handle(Smi::New(Message::kIsolateLibOOBMsg)));
 
   uint8_t* data = NULL;
   MessageWriter writer(&data, &allocator);
   writer.WriteMessage(msg);
 
   PortMap::PostMessage(new Message(port.Id(),
                                    data, writer.BytesWritten(),
                                    Message::kOOBPriority));
   return Object::null();
 }
 
 }  // namespace dart