2 files changed, 37 insertions, 34 deletions

diff --git a/lib/kernel/BranchManager.ml b/lib/kernel/BranchManager.ml
index 03a2765..a698a87 100644
--- a/lib/kernel/BranchManager.ml
+++ b/lib/kernel/BranchManager.ml
@@ -9,8 +9,8 @@ module Error = struct
     condition "no-such-branch" "A branch with the specified name was not found"
       ("branch"    |=| Concepts.Value.String branch_name)
 
-  let comparison_failed branch_name reference head =
-    condition "comparison-failed" "The HEAD of the branch did not match what was expected"
+  let branch_head_mismatch branch_name reference head =
+    condition "branch-head-mismatch" "The HEAD of the branch did not match what was expected"
       ("branch"    |=| Concepts.Value.String branch_name &
        "reference" |=| Concepts.Value.String (Concepts.Hash.to_hum_string reference) &
        "head"      |=| Concepts.Value.String (Concepts.Hash.to_hum_string head))
@@ -20,17 +20,45 @@ module Make (S : Abstract.Storage.STORAGE) = struct
   module M = Merkle.Make (S) (Merkle.StringKey)
   module SI = Storage.Make (S)
 
-  type manager = { storage: S.connection;
-                   label : string;
-                   head: M.node Atomic.t }
-
   let root_for tx label =
     let open Utilities.Result in
     let* label = S.get tx (S.Label label) in
     let label = Option.map Concepts.Hash.hash_of_blob label in
     Ok label
 
-  let initialize storage label =
+  class manager storage label head = object (self)
+    inherit Lifecycle.null
+
+    val storage : S.connection = storage
+    val label : string = label
+    val head : M.node Atomic.t = Atomic.make head
+
+    method fetch branch_name =
+      SI.with_transaction storage (fun tx ->
+          let head = Atomic.get head in
+          M.lookup tx branch_name head)
+
+    method update branch_name reference new_branch =
+      let open Utilities.Result in
+      SI.with_transaction storage (fun tx ->
+          Utilities.Atomic.mswap head (fun head ->
+              let* branch = M.lookup tx branch_name head
+                            |> fmap (Option.to_result ~none:(Error.no_such_branch branch_name)) in
+              if branch = reference then
+                let* new_head = M.insert tx label new_branch head in
+                Ok new_head
+              else
+                Error (Error.branch_head_mismatch branch_name reference branch)))
+      |> Result.map ignore
+
+    method protocols = Protocols.[Directory.make self]
+
+    method list = SI.with_transaction storage (fun tx -> Atomic.get head |> M.keys tx)
+
+    method find _ = failwith "TODO"
+  end
+
+  let make storage label =
     let open Utilities.Result in
     SI.with_transaction storage (fun tx ->
         let* addr = root_for tx label in
@@ -39,25 +67,6 @@ module Make (S : Abstract.Storage.STORAGE) = struct
         | Some addr ->
            let* head = M.find tx addr in
            let* head = Option.to_result ~none:(Error.invalid_root addr) head in
-           Ok { storage; label; head = Atomic.make head })
-
-  let fetch { storage; head; _ } branch_name =
-    SI.with_transaction storage (fun tx ->
-        let head = Atomic.get head in
-        M.lookup tx branch_name head)
-
-  let update { storage; head; label } branch_name reference new_branch =
-    let open Utilities.Result in
-    let* _ = SI.with_transaction storage (fun tx ->
-                 Utilities.Atomic.mswap head (fun head ->
-                     let* branch = M.lookup tx branch_name head
-                                   |> Result.map (Option.to_result ~none:(Error.no_such_branch branch_name))
-                                   |> Result.join in
-                     if branch = reference then
-                       let* new_head = M.insert tx label new_branch head in
-                       Ok new_head
-                     else
-                       Error (Error.comparison_failed branch_name reference branch))) in
-    Ok ()
+           Ok (new manager storage label head |> Protocols.Handle.make))
 
 end
diff --git a/lib/kernel/BranchManager.mli b/lib/kernel/BranchManager.mli
index 052f9a1..a75875f 100644
--- a/lib/kernel/BranchManager.mli
+++ b/lib/kernel/BranchManager.mli
@@ -1,9 +1,3 @@
 module Make (S : Abstract.Storage.STORAGE) : sig
-  type manager
-
-  val initialize : S.connection -> string -> (manager, Concepts.Condition.condition) result
-  val fetch : manager -> string -> (Concepts.Hash.hash option, Concepts.Condition.condition) result
-  val update : manager -> string -> Concepts.Hash.hash -> Concepts.Hash.hash -> (unit, Concepts.Condition.condition) result
-
-  (* TODO: fork, join *)
+  val make : S.connection -> string -> (Protocols.Handle.t, Concepts.Condition.condition) result
 end