Fix for issue 5223 : Import 'dart:core' implicitly only if it has not been

runtime/vm/object.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 "vm/object.h"
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "vm/assembler.h"
 #include "vm/bigint_operations.h"
@@ skipping 6469 matching lines @@
       const LibraryPrefix& lib_prefix = LibraryPrefix::Cast(obj);
       if (lib_prefix.ContainsLibrary(imported)) {
         return lib_prefix.raw();
       }
     }
   }
   return LibraryPrefix::null();
 }
 
 
+bool Library::ImportsCorelib() const {
+  Isolate* isolate = Isolate::Current();
+  Library& imported = Library::Handle(isolate);
+  intptr_t count = num_imports();
+  for (int i = 0; i < count; i++) {
+    imported = ImportAt(i);
+    if (imported.IsCoreLibrary()) {
+      return true;
+    }
+  }
+  LibraryPrefix& prefix = LibraryPrefix::Handle(isolate);
+  LibraryPrefixIterator it(*this);
+  while (it.HasNext()) {
+    prefix = it.GetNext();
+    count = prefix.num_libs();
+    for (int i = 0; i < count; i++) {
+      imported = prefix.GetLibrary(i);
+      if (imported.IsCoreLibrary()) {
+        return true;
+      }
+    }
+  }
+  return false;
+}
+
+
 void Library::AddImport(const Library& library) const {
   Array& imports = Array::Handle(this->imports());
   intptr_t capacity = imports.Length();
   if (num_imports() == capacity) {
     capacity = capacity + kImportsCapacityIncrement;
     imports = Array::Grow(imports, capacity);
     StorePointer(&raw_ptr()->imports_, imports.raw());
   }
   intptr_t index = num_imports();
   imports.SetAt(index, library);
@@ skipping 51 matching lines @@
   if (import_core_lib) {
     Library& core_lib = Library::Handle(Library::CoreLibrary());
     ASSERT(!core_lib.IsNull());
     result.AddImport(core_lib);
   }
   return result.raw();
 }
 
 
 RawLibrary* Library::New(const String& url) {
-  return NewLibraryHelper(url, true);
+  return NewLibraryHelper(url, false);
 }
 
 
 void Library::InitCoreLibrary(Isolate* isolate) {
   const String& core_lib_url = String::Handle(Symbols::New("dart:core"));
   const Library& core_lib =
       Library::Handle(Library::NewLibraryHelper(core_lib_url, false));
   core_lib.Register();
   isolate->object_store()->set_core_library(core_lib);
   const String& core_impl_lib_url =
@@ skipping 13 matching lines @@
   // Hook up predefined classes without setting their library pointers. These
   // classes are coming from the VM isolate, and are shared between multiple
   // isolates so setting their library pointers would be wrong.
   const Class& cls = Class::Handle(Object::dynamic_class());
   core_lib.AddObject(cls, String::Handle(cls.Name()));
 }
 
 
 void Library::InitMathLibrary(Isolate* isolate) {
   const String& url = String::Handle(Symbols::New("dart:math"));
-  const Library& lib = Library::Handle(Library::New(url));
+  const Library& lib = Library::Handle(Library::NewLibraryHelper(url, true));
   lib.Register();
   const Library& core_impl_lib = Library::Handle(Library::CoreImplLibrary());
   lib.AddImport(core_impl_lib);
   isolate->object_store()->set_math_library(lib);
 }
 
 
 void Library::InitIsolateLibrary(Isolate* isolate) {
   const String& url = String::Handle(Symbols::New("dart:isolate"));
-  const Library& lib = Library::Handle(Library::New(url));
+  const Library& lib = Library::Handle(Library::NewLibraryHelper(url, true));
   lib.Register();
   isolate->object_store()->set_isolate_library(lib);
 }
 
 
 void Library::InitMirrorsLibrary(Isolate* isolate) {
   const String& url = String::Handle(Symbols::New("dart:mirrors"));
-  const Library& lib = Library::Handle(Library::New(url));
+  const Library& lib = Library::Handle(Library::NewLibraryHelper(url, true));
   lib.Register();
   const Library& isolate_lib = Library::Handle(Library::IsolateLibrary());
   lib.AddImport(isolate_lib);
   const Library& wrappers_lib =
       Library::Handle(Library::NativeWrappersLibrary());
   lib.AddImport(wrappers_lib);
   isolate->object_store()->set_mirrors_library(lib);
 }
 
 
 void Library::InitScalarlistLibrary(Isolate* isolate) {
   const String& url = String::Handle(Symbols::New("dart:scalarlist"));
-  const Library& lib = Library::Handle(Library::New(url));
+  const Library& lib = Library::Handle(Library::NewLibraryHelper(url, true));
   lib.Register();
   const Library& core_impl_lib = Library::Handle(Library::CoreImplLibrary());
   lib.AddImport(core_impl_lib);
   isolate->object_store()->set_scalarlist_library(lib);
 }
 
 
 void Library::InitNativeWrappersLibrary(Isolate* isolate) {
   static const int kNumNativeWrappersClasses = 4;
   ASSERT(kNumNativeWrappersClasses > 0 && kNumNativeWrappersClasses < 10);
@@ skipping 5171 matching lines @@
   }
   return result.raw();
 }
 
 
 const char* WeakProperty::ToCString() const {
   return "_WeakProperty";
 }
 
 }  // namespace dart