Merge the tonic layer from skydart branch back to master

sky/engine/tonic/dart_wrappable.h

+// Copyright 2015 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.
+
+#ifndef SKY_ENGINE_TONIC_DART_WRAPPABLE_H_
+#define SKY_ENGINE_TONIC_DART_WRAPPABLE_H_
+
+#include "base/logging.h"
+#include "base/template_util.h"
+#include "dart/runtime/include/dart_api.h"
+#include "sky/engine/tonic/dart_converter.h"
+#include "sky/engine/tonic/dart_error.h"
+#include "sky/engine/tonic/dart_state.h"
+#include "sky/engine/tonic/dart_wrapper_info.h"
+
+namespace blink {
+class DartGCVisitor;
+struct DartWrapperInfo;
+
+// DartWrappable is a base class that you can inherit from in order to be
+// exposed to Dart code as an interface.
+class DartWrappable {
+ public:
+  enum DartNativeFields {
+    kPeerIndex,  // Must be first to work with Dart_GetNativeReceiver.
+    kWrapperInfoIndex,
+    kNumberOfNativeFields,
+  };
+
+  DartWrappable() : dart_wrapper_(nullptr) {}
+
+  // Subclasses that wish to expose a new interface must override this function
+  // and provide information about their wrapper. There is no need to call your
+  // base class's implementation of this function.
+  virtual const DartWrapperInfo& GetDartWrapperInfo() const = 0;
+
+  // Subclasses that wish to integrate with the Dart garbage collector should
+  // override this function. Please call your base class's AcceptDartGCVisitor
+  // at the end of your override.
+  virtual void AcceptDartGCVisitor(DartGCVisitor& visitor) const;
+
+  Dart_Handle CreateDartWrapper(DartState* dart_state);
+  Dart_WeakPersistentHandle dart_wrapper() const { return dart_wrapper_; }
+
+ protected:
+  virtual ~DartWrappable();
+
+ private:
+  static void FinalizeDartWrapper(void* isolate_callback_data,
+                                  Dart_WeakPersistentHandle wrapper,
+                                  void* peer);
+
+  Dart_WeakPersistentHandle dart_wrapper_;
+
+  DISALLOW_COPY_AND_ASSIGN(DartWrappable);
+};
+
+#define DEFINE_WRAPPERTYPEINFO()                                               \
+ public:                                                                       \
+  const DartWrapperInfo& GetDartWrapperInfo() const override {                 \
+    return dart_wrapper_info_;                                                 \
+  }                                                                            \
+ private:                                                                      \
+  static const DartWrapperInfo& dart_wrapper_info_
+
+struct DartConverterWrappable {
+  static DartWrappable* FromDart(Dart_Handle handle);
+  static DartWrappable* FromArguments(Dart_NativeArguments args,
+                                      int index,
+                                      Dart_Handle& exception);
+  static DartWrappable* FromArgumentsWithNullCheck(Dart_NativeArguments args,
+                                                   int index,
+                                                   Dart_Handle& exception);
+};
+
+template<typename T>
+struct DartConverter<
+    T*,
+    typename base::enable_if<
+        base::is_convertible<T*, DartWrappable*>::value>::type> {
+  static Dart_Handle ToDart(DartWrappable* val) {
+    if (!val)
+      return Dart_Null();
+    if (Dart_WeakPersistentHandle wrapper = val->dart_wrapper())
+      return Dart_HandleFromWeakPersistent(wrapper);
+    return val->CreateDartWrapper(DartState::Current());
+  }
+
+  static void SetReturnValue(Dart_NativeArguments args,
+                             DartWrappable* val,
+                             bool auto_scope = true) {
+    if (!val)
+      Dart_SetReturnValue(args, Dart_Null());
+    else if (Dart_WeakPersistentHandle wrapper = val->dart_wrapper())
+      Dart_SetWeakHandleReturnValue(args, wrapper);
+    else
+      Dart_SetReturnValue(args, val->CreateDartWrapper(DartState::Current()));
+  }
+
+  static T* FromDart(Dart_Handle handle) {
+    // TODO(abarth): We're missing a type check.
+    return static_cast<T*>(DartConverterWrappable::FromDart(handle));
+  }
+
+  static T* FromArguments(Dart_NativeArguments args,
+                          int index,
+                          Dart_Handle& exception,
+                          bool auto_scope = true) {
+    // TODO(abarth): We're missing a type check.
+    return static_cast<T*>(DartConverterWrappable::FromArguments(
+        args, index, exception));
+  }
+
+  static T* FromArgumentsWithNullCheck(Dart_NativeArguments args,
+                                       int index,
+                                       Dart_Handle& exception,
+                                       bool auto_scope = true) {
+    // TODO(abarth): We're missing a type check.
+    return static_cast<T*>(DartConverterWrappable::FromArgumentsWithNullCheck(
+        args, index, exception));
+  }
+};
+
+template<typename T>
+struct DartConverter<RefPtr<T>> {
+  static Dart_Handle ToDart(RefPtr<T> val) {
+    return DartConverter<T*>::ToDart(val.get());
+  }
+};
+
+template<typename T>
+static T* GetReceiver(Dart_NativeArguments args) {
+  intptr_t receiver;
+  Dart_Handle result = Dart_GetNativeReceiver(args, &receiver);
+  DCHECK(!Dart_IsError(result));
+  return static_cast<T*>(reinterpret_cast<DartWrappable*>(receiver));
+}
+
+}  // namespace blink
+
+#endif  // SKY_ENGINE_TONIC_DART_WRAPPABLE_H_