From 2ef62f3307e43bc7c12d02a4f1527e02d501f1cf Mon Sep 17 00:00:00 2001
From: Romain Calascibetta <romain.calascibetta@gmail.com>
Date: Wed, 21 Sep 2022 12:01:51 +0200
Subject: [PATCH 1/3] Implement exists function

---
 src/git_kv.ml | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/src/git_kv.ml b/src/git_kv.ml
index e7c4cb9..e41abed 100644
--- a/src/git_kv.ml
+++ b/src/git_kv.ml
@@ -109,10 +109,18 @@ let of_octets ctx ~remote data =
   let edn, branch = split_url remote in
   { ctx ; edn ; branch ; store ; head = Some head }
 
-let exists _t _key =
-  (*  Search.find t.store t.head (`Path (Mirage_kv.Key.segments key)) >>= function *)
-  (* ([`Value | `Dictionary] option, error) result Lwt.t *)
-  assert false
+let exists t key =
+  let open Lwt.Infix in
+  match t.head with
+  | None -> Lwt.return (Ok None)
+  | Some head ->
+    Search.mem t.store head (`Path (Mirage_kv.Key.segments key)) >>= function
+    | false -> Lwt.return (Ok None)
+    | true ->
+      Search.find t.store head (`Path (Mirage_kv.Key.segments key))
+      >|= Option.get >>= Store.read_exn t.store >>= function
+      | Blob _ -> Lwt.return (Ok (Some `Value))
+      | Tree _ | Commit _ | Tag _ -> Lwt.return (Ok (Some `Dictionary))
 
 let get t key =
   let open Lwt.Infix in

From ad09080ee61ad8de5fe9ca09da6764c10c2ba951 Mon Sep 17 00:00:00 2001
From: Romain Calascibetta <romain.calascibetta@gmail.com>
Date: Wed, 21 Sep 2022 12:02:19 +0200
Subject: [PATCH 2/3] Remove an assert false and return an error instead of

---
 src/git_kv.ml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/git_kv.ml b/src/git_kv.ml
index e41abed..97375be 100644
--- a/src/git_kv.ml
+++ b/src/git_kv.ml
@@ -132,7 +132,7 @@ let get t key =
     | Some blob ->
       Store.read_exn t.store blob >|= function
       | Blob b -> Ok (Git.Blob.to_string b)
-      | _ -> assert false
+      | _ -> Error (`Value_expected key)
 
 let get_partial t key ~offset ~length =
   let open Lwt_result.Infix in

From 503bf47ccb68ddd6dbcec6d73f1595e88bde105d Mon Sep 17 00:00:00 2001
From: Romain Calascibetta <romain.calascibetta@gmail.com>
Date: Wed, 21 Sep 2022 12:02:34 +0200
Subject: [PATCH 3/3] Implement list function

---
 src/git_kv.ml | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/src/git_kv.ml b/src/git_kv.ml
index 97375be..8f4c7b5 100644
--- a/src/git_kv.ml
+++ b/src/git_kv.ml
@@ -143,9 +143,22 @@ let get_partial t key ~offset ~length =
     let l = min length (String.length data - offset) in
     String.sub data offset l
 
-let list _t _key =
-  (* ((string * [`Value | `Dictionary]) list, error) result Lwt.t *)
-  assert false
+let list t key =
+  let open Lwt.Infix in
+  match t.head with
+  | None -> Lwt.return (Error (`Not_found key))
+  | Some head ->
+    Search.find t.store head (`Path (Mirage_kv.Key.segments key)) >>= function
+    | None -> Lwt.return (Error (`Not_found key))
+    | Some tree ->
+      Store.read_exn t.store tree >>= function
+      | Tree t ->
+        Lwt_list.map_p (fun { Git.Tree.perm; name; _ } -> match perm with
+          | `Commit | `Dir -> Lwt.return (name, `Dictionary)
+          | `Everybody | `Exec | `Normal -> Lwt.return (name, `Value)
+          | `Link -> failwith "Unimplemented link follow")
+        (Store.Value.Tree.to_list t) >|= Result.ok
+      | _ -> Lwt.return (Error (`Dictionary_expected key))
 
 let last_modified t key =
   let open Lwt.Infix in