Rework standalone to use a synchronous loader that does not invoke Dart code

runtime/bin/main.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 <stdlib.h>
 #include <string.h>
 #include <stdio.h>
 
 #include "include/dart_api.h"
 #include "include/dart_tools_api.h"
 
 #include "bin/builtin.h"
 #include "bin/dartutils.h"
 #include "bin/directory.h"
 #include "bin/embedded_dart_io.h"
 #include "bin/eventhandler.h"
 #include "bin/extensions.h"
 #include "bin/file.h"
 #include "bin/isolate_data.h"
+#include "bin/loader.h"
 #include "bin/log.h"
 #include "bin/platform.h"
 #include "bin/process.h"
 #include "bin/thread.h"
 #include "bin/utils.h"
 #include "bin/vmservice_impl.h"
 #include "platform/globals.h"
 #include "platform/hashmap.h"
 #include "platform/text_buffer.h"
 #if !defined(DART_PRECOMPILER)
@@ skipping 689 matching lines @@
 
   Dart_EnterScope();
 
   if (isolate_snapshot_buffer != NULL) {
     // Setup the native resolver as the snapshot does not carry it.
     Builtin::SetNativeResolver(Builtin::kBuiltinLibrary);
     Builtin::SetNativeResolver(Builtin::kIOLibrary);
   }
 
   // Set up the library tag handler for this isolate.
-  Dart_Handle result = Dart_SetLibraryTagHandler(DartUtils::LibraryTagHandler);
+  Dart_Handle result = Dart_SetLibraryTagHandler(Loader::LibraryTagHandler);
   CHECK_RESULT(result);
 
   if (Dart_IsServiceIsolate(isolate)) {
     // If this is the service isolate, load embedder specific bits and return.
     bool skip_library_load = run_app_snapshot;
     if (!VmService::Setup(vm_service_server_ip,
                           vm_service_server_port,
                           skip_library_load)) {
       *error = strdup(VmService::GetErrorMessage());
       return NULL;
@@ skipping 25 matching lines @@
   CHECK_RESULT(result);
 
   result = Dart_SetEnvironmentCallback(EnvironmentCallback);
   CHECK_RESULT(result);
 
   if (run_app_snapshot) {
     result = DartUtils::SetupIOLibrary(script_uri);
     CHECK_RESULT(result);
   } else {
     // Load the specified application script into the newly created isolate.
-    result = DartUtils::LoadScript(script_uri);
-    CHECK_RESULT(result);
-
-    // Run event-loop and wait for script loading to complete.
-    result = Dart_RunLoop();
+    Dart_Handle uri =
+        DartUtils::ResolveScript(Dart_NewStringFromCString(script_uri));
+    CHECK_RESULT(uri);
+    result = Loader::LibraryTagHandler(Dart_kScriptTag,
+                                       Dart_Null(),
+                                       uri);
     CHECK_RESULT(result);
 
     Dart_TimelineEvent("LoadScript",
                        Dart_TimelineGetMicros(),
                        Dart_GetMainPortId(),
                        Dart_Timeline_Event_Async_End,
                        0, NULL, NULL);
 
     result = DartUtils::SetupIOLibrary(script_uri);
     CHECK_RESULT(result);
@@ skipping 941 matching lines @@
   Platform::Exit(Process::GlobalExitCode());
 }
 
 }  // namespace bin
 }  // namespace dart
 
 int main(int argc, char** argv) {
   dart::bin::main(argc, argv);
   UNREACHABLE();
 }