Introducing codec-protobuf, node-core, node-grpc modules (#88)

* Introducing codec-protobuf, node-core, node-grpc modules

* ⇒

protobuf/src/main/scala/fluence/codec/pb/ProtobufCodecs.scala

@@ -0,0 +1,39 @@
+/*
+ * Copyright (C) 2017  Fluence Labs Limited
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package fluence.codec.pb
+
+import cats.{ Applicative, MonadError }
+import com.google.protobuf.ByteString
+import fluence.codec.Codec
+import fluence.kad.protocol.Key
+import scodec.bits.ByteVector
+
+import scala.language.higherKinds
+
+object ProtobufCodecs {
+
+  implicit def byteVectorByteString[F[_] : Applicative]: Codec[F, ByteString, ByteVector] =
+    Codec.pure(
+      str ⇒ ByteVector(str.toByteArray),
+      vec ⇒ ByteString.copyFrom(vec.toArray)
+    )
+
+  // TODO: more precise error
+  implicit def keyByteString[F[_]](implicit F: MonadError[F, Throwable]): Codec[F, ByteString, Key] =
+    byteVectorByteString[F] andThen Key.vectorCodec.swap
+}