add session object and protocol with pinning

3 files changed, 31 insertions, 0 deletions

diff --git a/lib/kernel/Initialization.ml b/lib/kernel/Initialization.ml
index 25c2b3d..3c8addb 100644
--- a/lib/kernel/Initialization.ml
+++ b/lib/kernel/Initialization.ml
@@ -18,5 +18,6 @@ module Make (S : Abstract.Storage.STORAGE) = struct
         (Ok true) evaluators
     in
     let* _ = Registry.update registry "evaluator" None (Some evaluator_namespace) in
+    let* _ = Registry.update registry "session" None (Some (Namespace.make ())) in
     Ok root
 end
diff --git a/lib/kernel/Session.ml b/lib/kernel/Session.ml
new file mode 100644
index 0000000..75bf8c9
--- /dev/null
+++ b/lib/kernel/Session.ml
@@ -0,0 +1,27 @@
+module Make (S : Abstract.Storage.STORAGE) = struct
+  module SI = Storage.Make (S)
+  module B = Branch.Make (S)
+
+  class session storage state =
+    object (self)
+      inherit Lifecycle.null
+      inherit Identity.of_id
+      method to_string = "session"
+      val storage : S.connection = storage
+      val state : Protocols.Session.state Atomic.t = Atomic.make state
+      method state = Atomic.get state
+      method pin state' = Atomic.set state state'
+      method protocols = Protocols.[Directory.make self; Session.make self]
+      method list = Ok (BatFingerTree.singleton "branch")
+
+      method find =
+        function
+        | "branch" ->
+            SI.with_read storage (fun tx ->
+                B.load tx storage (Atomic.get state).Protocols.Session.snapshot )
+            |> Result.map Option.some
+        | _ -> Ok None
+    end
+
+  let make storage state = new session storage state |> Protocols.Handle.make
+end
diff --git a/lib/kernel/Session.mli b/lib/kernel/Session.mli
new file mode 100644
index 0000000..be4451b
--- /dev/null
+++ b/lib/kernel/Session.mli
@@ -0,0 +1,3 @@
+module Make (S : Abstract.Storage.STORAGE) : sig
+  val make : S.connection -> Protocols.Session.state -> Protocols.Handle.t
+end