Allow invocation of constructors using Dart_Invoke.

runtime/vm/dart_api_impl.cc

 // Copyright (c) 2013, 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_api.h"
 #include "include/dart_mirrors_api.h"
 #include "include/dart_native_api.h"
 
 #include "platform/assert.h"
 #include "vm/bigint_operations.h"
@@ skipping 2956 matching lines @@
   if (type_obj.IsNull()) {
     RETURN_TYPE_ERROR(isolate, type, Type);
   }
   const Class& cls = Class::Handle(isolate, type_obj.type_class());
 
   // Allocate an object for the given class.
   return Api::NewHandle(isolate, Instance::New(cls));
 }
 
 
+static Dart_Handle SetupArguments(Isolate* isolate,
+                                  int num_args,
+                                  Dart_Handle* arguments,
+                                  int extra_args,
+                                  Array* args) {
+  // Check for malformed arguments in the arguments list.
+  *args = Array::New(num_args + extra_args);
+  Object& arg = Object::Handle(isolate);
+  for (int i = 0; i < num_args; i++) {
+    arg = Api::UnwrapHandle(arguments[i]);
+    if (!arg.IsNull() && !arg.IsInstance()) {
+      *args = Array::null();
+      if (arg.IsError()) {
+        return Api::NewHandle(isolate, arg.raw());
+      } else {
+        return Api::NewError(
+            "%s expects arguments[%d] to be an Instance handle.",
+            "Dart_Invoke", i);
+      }
+    }
+    args->SetAt((i + extra_args), arg);
+  }
+  return Api::Success();
+}
+
+
 DART_EXPORT Dart_Handle Dart_Invoke(Dart_Handle target,
                                     Dart_Handle name,
                                     int number_of_arguments,
                                     Dart_Handle* arguments) {
   Isolate* isolate = Isolate::Current();
   DARTSCOPE(isolate);
   CHECK_CALLBACK_STATE(isolate);
 
   const String& function_name = Api::UnwrapStringHandle(isolate, name);
   if (function_name.IsNull()) {
     RETURN_TYPE_ERROR(isolate, name, String);
   }
   if (number_of_arguments < 0) {
     return Api::NewError(
         "%s expects argument 'number_of_arguments' to be non-negative.",
         CURRENT_FUNC);
   }
   const Object& obj = Object::Handle(isolate, Api::UnwrapHandle(target));
   if (obj.IsError()) {
     return target;
   }
+  Dart_Handle result;
 
   // Check for malformed arguments in the arguments list.
-  intptr_t num_receiver =
-      (obj.IsNull() || (obj.IsInstance() && !obj.IsType())) ? 1 : 0;
-  const Array& args =
-      Array::Handle(isolate, Array::New(number_of_arguments + num_receiver));
-  Object& arg = Object::Handle(isolate);
-  for (int i = 0; i < number_of_arguments; i++) {
-    arg = Api::UnwrapHandle(arguments[i]);
-    if (!arg.IsNull() && !arg.IsInstance()) {
-      if (arg.IsError()) {
-        return Api::NewHandle(isolate, arg.raw());
-      } else {
-        return Api::NewError(
-            "%s expects arguments[%d] to be an Instance handle.",
-            CURRENT_FUNC, i);
-      }
-    }
-    args.SetAt((i + num_receiver), arg);
-  }
-
+  Array& args = Array::Handle(isolate);
   if (obj.IsType()) {
     // Finalize all classes.
     Dart_Handle state = Api::CheckIsolateState(isolate);
     if (::Dart_IsError(state)) {
       return state;
     }
 
     const Class& cls = Class::Handle(isolate, Type::Cast(obj).type_class());

[regis, 2013/10/04 00:03:09]

So, target is a type and we use its type class to resolve the function name, but
we ignore its type arguments (which only make sense if we call a constructor or
a factory). Should we return an error if they are not null?

[siva, 2013/10/04 18:32:57]

We don't expect to call constructors using this method.

On 2013/10/04 00:03:09, regis wrote:

     const Function& function = Function::Handle(
         isolate,
         Resolver::ResolveStatic(cls,
                                 function_name,
                                 number_of_arguments,
                                 Object::empty_array(),
                                 Resolver::kIsQualified));
     if (function.IsNull()) {
       const String& cls_name = String::Handle(isolate, cls.Name());
       return Api::NewError("%s: did not find static method '%s.%s'.",
                            CURRENT_FUNC,
                            cls_name.ToCString(),
                            function_name.ToCString());
     }
-    return Api::NewHandle(isolate, DartEntry::InvokeFunction(function, args));
-
+    result = SetupArguments(isolate, number_of_arguments, arguments, 0, &args);
+    if (!::Dart_IsError(result)) {
+      result = Api::NewHandle(isolate,
+                              DartEntry::InvokeFunction(function, args));
+    }
+    return result;
   } else if (obj.IsNull() || obj.IsInstance()) {
+    // Since we have allocated an object it would mean that all classes
+    // are finalized and hence it is not necessary to call
+    // Api::CheckIsolateState.
     Instance& instance = Instance::Handle(isolate);
     instance ^= obj.raw();
     ArgumentsDescriptor args_desc(
         Array::Handle(ArgumentsDescriptor::New(number_of_arguments + 1)));
     const Function& function = Function::Handle(
         isolate,
         Resolver::ResolveDynamic(instance, function_name, args_desc));
-    args.SetAt(0, instance);
     if (function.IsNull()) {
-      const Array& args_descriptor =
-          Array::Handle(ArgumentsDescriptor::New(args.Length()));
-      return Api::NewHandle(isolate,
-                            DartEntry::InvokeNoSuchMethod(instance,
-                                                          function_name,
-                                                          args,
-                                                          args_descriptor));
+      // See if we are trying to invoke a constructor here.

[regis, 2013/10/04 00:03:09]

Wouldn't target be a type to call a constructor?
Or is target an already allocated instance of the correct type, but not a
constructed one? If so, this will not work for a factory call.

[siva, 2013/10/04 18:32:57]

Target is an already allocated instance.

On 2013/10/04 00:03:09, regis wrote:

+      if (!instance.IsNull()) {
+        // Constuct name of the constructor to invoke.

[regis, 2013/10/04 00:03:09]

construct

[siva, 2013/10/04 18:32:57]

Done.

+        const Type& type_obj = Type::Handle(isolate, instance.GetType());
+        const Class& cls = Class::Handle(isolate, type_obj.type_class());
+        const String& class_name = String::Handle(isolate, cls.Name());
+        const Array& strings = Array::Handle(Array::New(3));
+        strings.SetAt(0, class_name);
+        strings.SetAt(1, Symbols::Dot());
+        strings.SetAt(2, function_name);
+        const String& dot_name = String::Handle(isolate,
+                                                String::ConcatAll(strings));
+        const AbstractTypeArguments& type_arguments =
+            AbstractTypeArguments::Handle(isolate, type_obj.arguments());
+        const Function& constructor =
+            Function::Handle(isolate, cls.LookupFunctionAllowPrivate(dot_name));
+        const int extra_args = 2;
+        if (!constructor.IsNull() &&
+            constructor.IsConstructor() &&
+            constructor.AreValidArgumentCounts(number_of_arguments + extra_args,
+                                               0,
+                                               NULL)) {
+          // Create the argument list.
+          // Constructors get the uninitialized object and a constructor phase.
+          if (!type_arguments.IsNull()) {
+            // The type arguments will be null if the class has no type
+            // parameters, in which case the following call would fail
+            // because there is no slot reserved in the object for the
+            // type vector.
+            instance.SetTypeArguments(type_arguments);
+          }
+          result = SetupArguments(isolate,
+                                  number_of_arguments,
+                                  arguments,
+                                  extra_args,
+                                  &args);
+          if (!::Dart_IsError(result)) {
+            args.SetAt(0, instance);
+            args.SetAt(1, Smi::Handle(isolate,
+                                      Smi::New(Function::kCtorPhaseAll)));
+            result = Api::NewHandle(
+                isolate, DartEntry::InvokeFunction(constructor, args));
+          }
+          return result;
+        }
+      }
+      result = SetupArguments(isolate,
+                              number_of_arguments,
+                              arguments,
+                              1,
+                              &args);
+      if (!::Dart_IsError(result)) {
+        args.SetAt(0, instance);
+        const Array& args_descriptor =
+            Array::Handle(ArgumentsDescriptor::New(args.Length()));
+        result = Api::NewHandle(isolate,
+                                DartEntry::InvokeNoSuchMethod(instance,
+                                                              function_name,
+                                                              args,
+                                                              args_descriptor));
+      }
+      return result;
     }
-    return Api::NewHandle(isolate, DartEntry::InvokeFunction(function, args));
-
+    result = SetupArguments(isolate, number_of_arguments, arguments, 1, &args);
+    if (!::Dart_IsError(result)) {
+      args.SetAt(0, instance);
+      result = Api::NewHandle(isolate,
+                              DartEntry::InvokeFunction(function, args));
+    }
+    return result;
   } else if (obj.IsLibrary()) {
     // Check whether class finalization is needed.
     const Library& lib = Library::Cast(obj);
 
     // Finalize all classes if needed.
     Dart_Handle state = Api::CheckIsolateState(isolate);
     if (::Dart_IsError(state)) {
       return state;
     }
 
     const Function& function =
         Function::Handle(isolate,
                          lib.LookupFunctionAllowPrivate(function_name));
     if (function.IsNull()) {
       return Api::NewError("%s: did not find top-level function '%s'.",
                            CURRENT_FUNC,
                            function_name.ToCString());
     }
     // LookupFunctionAllowPrivate does not check argument arity, so we
     // do it here.
     String& error_message = String::Handle();
     if (!function.AreValidArgumentCounts(number_of_arguments,
                                          0,
                                          &error_message)) {
       return Api::NewError("%s: wrong argument count for function '%s': %s.",
                            CURRENT_FUNC,
                            function_name.ToCString(),
                            error_message.ToCString());
     }
-    return Api::NewHandle(isolate, DartEntry::InvokeFunction(function, args));
-
+    result = SetupArguments(isolate, number_of_arguments, arguments, 0, &args);
+    if (!::Dart_IsError(result)) {
+      result = Api::NewHandle(isolate,
+                              DartEntry::InvokeFunction(function, args));
+    }
+    return result;
   } else {
     return Api::NewError(
         "%s expects argument 'target' to be an object, type, or library.",
         CURRENT_FUNC);
   }
 }
 
 
 DART_EXPORT Dart_Handle Dart_InvokeClosure(Dart_Handle closure,
                                            int number_of_arguments,
@@ skipping 1197 matching lines @@
   }
   {
     NoGCScope no_gc;
     RawObject* raw_obj = obj.raw();
     isolate->heap()->SetPeer(raw_obj, peer);
   }
   return Api::Success();
 }
 
 }  // namespace dart