2 files changed, 109 insertions, 0 deletions
diff --git a/lib/concepts/Object.ml b/lib/concepts/Object.ml
new file mode 100644
index 0000000..22fb14a
--- /dev/null
+++ b/lib/concepts/Object.ml
@@ -0,0 +1,64 @@
+type bencode = Codec.Bencode.t
+
+module Bencode = Codec.Bencode
+
+module type S = sig
+  type t
+
+  val equal : t -> t -> bool
+
+  val to_bencode : t -> bencode
+  val of_bencode : bencode -> (t, Condition.condition) result
+
+  val to_blob : t -> Representation.blob
+  val of_blob : Representation.blob -> (t, Condition.condition) result
+
+  val to_bytes : t -> bytes
+  val of_bytes : bytes -> (t, Condition.condition) result
+end
+
+module type OBJECT = S
+
+module Field = struct
+  let string value = Bencode.String value
+  let address address = Bencode.String (Hash.to_raw_string address)
+
+  let require_string key data =
+    Codec.Bencode.field key data |> Utilities.Result.fmap Codec.Bencode.as_string
+
+  let require_address ~malformed key data =
+    let open Utilities.Result in
+    let* raw = require_string key data in
+    if String.length raw = Hash.size then Ok (Hash.of_raw_string raw)
+    else Error (malformed (String.length raw))
+end
+
+module Codec = struct
+  module type BODY = sig
+    type t
+
+    val tag : char
+    val malformed : unit -> Condition.condition
+    val equal : t -> t -> bool
+    val fields : t -> (string * bencode) list
+    val of_fields : bencode -> (t, Condition.condition) result
+  end
+
+  module Make (B : BODY) = struct
+    type t = B.t
+
+    let equal = B.equal
+    let to_bencode object_ = Bencode.Tagged (B.tag, Bencode.Dict (B.fields object_))
+
+    let of_bencode = function
+      | Bencode.Tagged (tag, (Bencode.Dict _ as data)) when Char.equal tag B.tag ->
+          B.of_fields data
+      | _ -> Error (B.malformed ())
+
+    let to_blob object_ = to_bencode object_ |> Bencode.to_blob
+    let of_blob blob = Bencode.of_blob blob |> Utilities.Result.fmap of_bencode
+
+    let to_bytes object_ = to_blob object_ |> Representation.bytes_of_blob
+    let of_bytes bytes = Bencode.of_bytes bytes |> Utilities.Result.fmap of_bencode
+  end
+end
diff --git a/lib/concepts/Object.mli b/lib/concepts/Object.mli
new file mode 100644
index 0000000..e132673
--- /dev/null
+++ b/lib/concepts/Object.mli
@@ -0,0 +1,45 @@
+type bencode = Codec.Bencode.t
+
+module type S = sig
+  type t
+
+  val equal : t -> t -> bool
+
+  val to_bencode : t -> bencode
+  val of_bencode : bencode -> (t, Condition.condition) result
+
+  val to_blob : t -> Representation.blob
+  val of_blob : Representation.blob -> (t, Condition.condition) result
+
+  val to_bytes : t -> bytes
+  val of_bytes : bytes -> (t, Condition.condition) result
+end
+
+module type OBJECT = S
+
+module Field : sig
+  val string : string -> bencode
+  val address : Hash.hash -> bencode
+
+  val require_string : string -> bencode -> (string, Condition.condition) result
+
+  val require_address :
+    malformed:(int -> Condition.condition) ->
+    string ->
+    bencode ->
+    (Hash.hash, Condition.condition) result
+end
+
+module Codec : sig
+  module type BODY = sig
+    type t
+
+    val tag : char
+    val malformed : unit -> Condition.condition
+    val equal : t -> t -> bool
+    val fields : t -> (string * bencode) list
+    val of_fields : bencode -> (t, Condition.condition) result
+  end
+
+  module Make (B : BODY) : S with type t = B.t
+end