1 files changed, 54 insertions, 0 deletions
diff --git a/widget/android/jni/GeckoResultUtils.h b/widget/android/jni/GeckoResultUtils.h
new file mode 100644
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+++ b/widget/android/jni/GeckoResultUtils.h
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_jni_GeckoResultUtils_h
+#define mozilla_jni_GeckoResultUtils_h
+
+#include "mozilla/java/GeckoResultNatives.h"
+#include "mozilla/jni/Conversions.h"
+
+namespace mozilla {
+namespace jni {
+
+// C++-side object bound to Java's GeckoResult.GeckoCallback.
+//
+// Note that we can't template this class because that breaks JNI dispatch
+// (surprisingly: it compiles, but selects the wrong method specialization
+// during dispatch). So instead we use a templated factory function, which
+// bundles the per-ArgType conversion logic into the callback.
+class GeckoResultCallback final
+    : public java::GeckoResult::GeckoCallback::Natives<GeckoResultCallback> {
+ public:
+  typedef java::GeckoResult::GeckoCallback::Natives<GeckoResultCallback> Base;
+  typedef std::function<void(mozilla::jni::Object::Param)> OuterCallback;
+
+  void Call(mozilla::jni::Object::Param aArg) { mCallback(aArg); }
+
+  template <typename ArgType>
+  static java::GeckoResult::GeckoCallback::LocalRef CreateAndAttach(
+      std::function<void(ArgType)>&& aInnerCallback) {
+    auto java = java::GeckoResult::GeckoCallback::New();
+    OuterCallback outerCallback =
+        [inner{std::move(aInnerCallback)}](mozilla::jni::Object::Param aParam) {
+          ArgType converted = Java2Native<ArgType>(aParam);
+          inner(converted);
+        };
+    auto native = MakeUnique<GeckoResultCallback>(std::move(outerCallback));
+    Base::AttachNative(java, std::move(native));
+    return java;
+  }
+
+  explicit GeckoResultCallback(OuterCallback&& aCallback)
+      : mCallback(std::move(aCallback)) {}
+
+ private:
+  OuterCallback mCallback;
+};
+
+}  // namespace jni
+}  // namespace mozilla
+
+#endif  // mozilla_jni_GeckoResultUtils_h