Merge pull request #320 from talex5/head-to-id

Change "type head" to "type commit_id"

CHANGES.md

@@ -73,6 +73,13 @@
   `Repo.config` to be removed and allowing sharing of the back-end's
   internal state with the sync code. For example, the Git back-end
   no longer needs to create a new Git store object for sync.
+* Change `type head` to `type commit_id`. `head` was confusing because
+  it applied to all commits, not just branch heads. Putting `id` in the
+  name makes it clear that this is just data and (for example) holding
+  an ID will not prevent the corresponding commit from being GC'd (once
+  we have GC). `of_head` is now `of_commit_id`, `task_of_head` is now
+  `task_of_commit_id`, `Internals.commit_of_head` is now
+  `Internals.commit_of_id` and `BC.Head` is now `BC.Hash`.
 
 
 ### 0.9.10

bin/ir_cli.ml

@@ -349,7 +349,7 @@ let snapshot = {
       run begin
         store >>= fun t ->
         S.head_exn (t "Snapshot") >>= fun k ->
-        print "%s" (S.Head.to_hum k);
+        print "%s" (S.Hash.to_hum k);
         return_unit
       end
     in
@@ -368,7 +368,7 @@ let revert = {
     let revert (S ((module S), store)) snapshot =
       run begin
         store >>= fun t ->
-        let s = S.Head.of_hum snapshot in
+        let s = S.Hash.of_hum snapshot in
         S.update_head (t "Revert") s
       end
     in

lib/git/irmin_git.ml

@@ -650,7 +650,7 @@ module Make_ext
     module Sync = Git.Sync.Make(IO)(G)
 
     type t = G.t
-    type head = X.Commit.key
+    type commit_id = X.Commit.key
     type branch_id = XRef.key
 
     let head_of_git key = H.of_raw (X.GK.to_raw (Git.SHA.of_commit key))
@@ -723,8 +723,8 @@ module Make_ext
   include Irmin.Make_ext(P)
 
   module Internals = struct
-    let commit_of_head repo h =
-      let h = Head.to_raw h |> Cstruct.to_string |> Git.SHA.of_raw in
+    let commit_of_id repo h =
+      let h = Hash.to_raw h |> Cstruct.to_string |> Git.SHA.of_raw in
       Git_store.read repo.g h >|= function
       | Some Git.Value.Commit c -> Some c
       | _ -> None
@@ -804,13 +804,7 @@ module type S = sig
   include Irmin.S
 
   module Internals: sig
-
-    (** {1 Access to the Git objects} *)
-
-    val commit_of_head: Repo.t -> head -> Git.Commit.t option Lwt.t
-    (** [commit_of_head repo h] is the commit corresponding to [h] in the
-        repository [repo]. *)
-
+    val commit_of_id: Repo.t -> commit_id -> Git.Commit.t option Lwt.t
   end
 end
 
@@ -821,6 +815,6 @@ module type S_MAKER =
     S with type key = C.Path.t
        and type value = C.t
        and type branch_id = R.t
-       and type head = H.t
+       and type commit_id = H.t
 
 include Conf

lib/git/irmin_git.mli

@@ -86,8 +86,8 @@ module type S = sig
 
     (** {1 Access to the Git objects} *)
 
-    val commit_of_head: Repo.t -> head -> Git.Commit.t option Lwt.t
-    (** [commit_of_head repo h] is the commit corresponding to [h] in the
+    val commit_of_id: Repo.t -> commit_id -> Git.Commit.t option Lwt.t
+    (** [commit_of_id repo h] is the commit corresponding to [h] in the
         repository [repo]. *)
 
   end
@@ -100,7 +100,7 @@ module type S_MAKER =
     S with type key = C.Path.t
        and type value = C.t
        and type branch_id = R.t
-       and type head = H.t
+       and type commit_id = H.t
 
 module Memory (IO: Git.Sync.IO) (I: Git.Inflate.S):
   S_MAKER

lib/http/irmin_http.ml

@@ -446,7 +446,7 @@ struct
 
   end
 
-  module Head = H
+  module Hash = H
   module Val = C
 
   include Helper (Client)
@@ -464,7 +464,7 @@ struct
   (* The high-level bindings: every high-level operation is simply
      forwarded to the HTTP server. *much* more efficient than using
      [L]. *)
-  module L = Low(Client)(Val)(Ref)(Head)
+  module L = Low(Client)(Val)(Ref)(Hash)
   module LP = L.Private
   module S  = RW(Client)(Key)(Val)
 
@@ -475,7 +475,7 @@ struct
 
   let head_query name = function
     | [] -> []
-    | l  -> [name, List.map (Tc.write_string (module Head)) l]
+    | l  -> [name, List.map (Tc.write_string (module Hash)) l]
 
   module Repo = struct
     type t = {
@@ -508,7 +508,7 @@ struct
 
     let remove_branch t branch_id = delete t ["remove-tag"; Ref.to_hum branch_id] Tc.unit
 
-    let heads t = get t ["heads"] (module Tc.List(Head))
+    let heads t = get t ["heads"] (module Tc.List(Hash))
 
     let watch_branches t = L.Repo.watch_branches t.l
 
@@ -531,8 +531,8 @@ struct
     let import t slice =
       post_json t ["import"] ~body:(slice_tc, slice) ok_or_error
 
-    let task_of_head t head =
-      LP.Commit.read_exn (commit_t t) head >>= fun commit ->
+    let task_of_commit_id t commit_id =
+      LP.Commit.read_exn (commit_t t) commit_id >>= fun commit ->
       Lwt.return (LP.Commit.Val.task commit)
 
   end
@@ -542,13 +542,13 @@ struct
        - `$uri/tree/$tag` if head_ref = `Branch tag
        - `$uri/tree/$key if key = `Key key *)
   type t = {
-    head_ref: [`Branch of Ref.t | `Head of Head.t | `Empty] ref;
+    head_ref: [`Branch of Ref.t | `Head of Hash.t | `Empty] ref;
     l: L.t;
     repo: Repo.t;
     read_node: L.key -> LP.Node.key option Lwt.t;
     mem_node: L.key -> bool Lwt.t;
     update_node: L.key -> LP.Node.key -> unit Lwt.t;
-    merge_node: L.key -> (L.head * LP.Node.key) -> unit Irmin.Merge.result Lwt.t;
+    merge_node: L.key -> (L.commit_id * LP.Node.key) -> unit Irmin.Merge.result Lwt.t;
     remove_node: L.key -> unit Lwt.t;
     iter_node: LP.Node.key -> (L.key -> L.value Lwt.t -> unit Lwt.t) -> unit Lwt.t;
     lock: Lwt_mutex.t;
@@ -563,7 +563,7 @@ struct
       if Ref.equal name Ref.master then base
       else uri_append base ["tree"; Ref.to_hum name]
     | `Empty  -> uri_append base ["empty"]
-    | `Head h -> uri_append base ["tree"; Head.to_hum h]
+    | `Head h -> uri_append base ["tree"; Hash.to_hum h]
 
   let repo t = t.repo
   let task t = L.task t.l
@@ -575,11 +575,11 @@ struct
 
   type key = S.key
   type value = S.value
-  type head = L.head
+  type commit_id = L.commit_id
   type branch_id = L.branch_id
 
   let v: Val.t Tc.t = (module Val)
-  let head_tc: Head.t Tc.t = (module Head)
+  let head_tc: Hash.t Tc.t = (module Hash)
 
   let create_aux head_ref repo l =
     let fn a =
@@ -607,9 +607,9 @@ struct
     let head_ref = ref (`Branch branch_id) in
     create_aux head_ref repo l
 
-  let of_head task head repo =
-    L.of_head task head repo.Repo.l >>= fun l ->
-    let head_ref = ref (`Head head) in
+  let of_commit_id task commit_id repo =
+    L.of_commit_id task commit_id repo.Repo.l >>= fun l ->
+    let head_ref = ref (`Head commit_id) in
     create_aux head_ref repo l
 
   let empty task repo =
@@ -649,7 +649,7 @@ struct
     | `Branch  _ -> Lwt.return_unit
 
   let remove t key =
-    delete t ["remove"; Key.to_hum key] (module Head) >>= fun h ->
+    delete t ["remove"; Key.to_hum key] (module Hash) >>= fun h ->
     match head_ref t with
     | `Empty
     | `Head _ -> set_head t (Some h)
@@ -673,7 +673,7 @@ struct
   let head t = match head_ref t with
     | `Empty  -> Lwt.return_none
     | `Head h -> Lwt.return (Some h)
-    | `Branch _  -> get t ["head"] (module Tc.Option(Head))
+    | `Branch _  -> get t ["head"] (module Tc.Option(Hash))
 
   let head_exn t =
     head t >>= function
@@ -689,9 +689,9 @@ struct
   let update_head t head = match head_ref t with
     | `Empty
     | `Head _ -> set_head t (Some head)
-    | `Branch _  -> get t ["update-head"; Head.to_hum head] Tc.unit
+    | `Branch _  -> get t ["update-head"; Hash.to_hum head] Tc.unit
 
-  module CSH = Tc.Pair(Tc.Option(Head))(Tc.Option(Head))
+  module CSH = Tc.Pair(Tc.Option(Hash))(Tc.Option(Hash))
   let csh: CSH.t Tc.t = (module CSH)
 
   let compare_and_set_head_unsafe t ~test ~set =
@@ -709,7 +709,7 @@ struct
         compare_and_set_head_unsafe t ~test ~set
       )
 
-  module M = Tc.App1 (Irmin.Merge.Result) (Head)
+  module M = Tc.App1 (Irmin.Merge.Result) (Hash)
   let m: M.t Tc.t = (module M)
 
   let mk_query ?max_depth ?n () =
@@ -727,7 +727,7 @@ struct
 
   let fast_forward_head_unsafe t ?max_depth ?n head =
     let query = mk_query ?max_depth ?n () in
-    post t ?query ["fast-forward-head"; Head.to_hum head] Tc.bool >>= fun b ->
+    post t ?query ["fast-forward-head"; Hash.to_hum head] Tc.bool >>= fun b ->
     match head_ref t with
     | `Branch _  -> Lwt.return b
     | `Empty
@@ -741,7 +741,7 @@ struct
 
   let merge_head t ?max_depth ?n head =
     let query = mk_query ?max_depth ?n () in
-    post t ?query ["merge-head"; Head.to_hum head] m >>| fun h ->
+    post t ?query ["merge-head"; Hash.to_hum head] m >>| fun h ->
     match head_ref t with
     | `Empty
     | `Head _ -> set_head t (Some h) >>= ok
@@ -765,7 +765,7 @@ struct
         | Some v -> fn @@ `Added (x, v)
       end
     | `Updated (x, y) ->
-      assert (not (Head.equal x y));
+      assert (not (Hash.equal x y));
       value_of_head x >>= fun vx ->
       value_of_head y >>= fun vy ->
       match vx, vy with
@@ -783,7 +783,7 @@ struct
       | Some (h, _) -> Some h
     in
     let value_of_head h =
-      of_head (fun () -> task t) h t.repo >>= fun t ->
+      of_commit_id (fun () -> task t) h t.repo >>= fun t ->
       read (t ()) key
     in
     watch_head t ?init:init_head (lift value_of_head fn)
@@ -818,28 +818,28 @@ struct
   let merge_exn a ?max_depth ?n t ~into =
     merge a ?max_depth ?n t ~into >>= Irmin.Merge.exn
 
-  let lca = lca (module Head)
+  let lca = lca (module Hash)
 
   let lcas_branch t ?max_depth ?n other =
     let query = mk_query ?max_depth ?n () in
     get t ?query ["lcas-tag"; Ref.to_hum other] lca
 
   let lcas_head t ?max_depth ?n head =
     let query = mk_query ?max_depth ?n () in
-    get t ?query ["lcas-head"; Head.to_hum head] lca
+    get t ?query ["lcas-head"; Hash.to_hum head] lca
 
   let lcas a ?max_depth ?n t1 t2 =
     match head_ref (t2 a) with
     | `Branch name   -> lcas_branch  (t1 a) ?max_depth ?n name
     | `Head head -> lcas_head (t1 a) ?max_depth ?n head
     | `Empty     -> Lwt.return (`Ok [])
 
-  module E = Tc.Pair (Tc.List(Head)) (Tc.Option(Tc.List(Head)))
+  module E = Tc.Pair (Tc.List(Hash)) (Tc.Option(Tc.List(Hash)))
 
   module I = Tc.List(Ref)
 
   let remove_rec t dir =
-    delete t ["remove-rec"; Key.to_hum dir] (module Head) >>= fun h ->
+    delete t ["remove-rec"; Key.to_hum dir] (module Hash) >>= fun h ->
     match head_ref t with
       | `Empty
       | `Head _ -> set_head t (Some h)
@@ -848,8 +848,8 @@ struct
   let list t dir =
     get t ["list"; Key.to_hum dir] (module Tc.List(Key))
 
-  module History = Graph.Persistent.Digraph.ConcreteBidirectional(Head)
-  module G = Tc.Pair (Tc.List (Head))(Tc.List (Tc.Pair(Head)(Head)))
+  module History = Graph.Persistent.Digraph.ConcreteBidirectional(Hash)
+  module G = Tc.Pair (Tc.List (Hash))(Tc.List (Tc.Pair(Hash)(Hash)))
   module Conv = struct
     type t = History.t
     let to_t (vertices, edges) =
@@ -862,7 +862,7 @@ struct
       vertices, edges
   end
   module HTC = Tc.Biject (G)(Conv)
-  module EO = Tc.Pair (Tc.Option(Tc.List(Head))) (Tc.Option(Tc.List(Head)))
+  module EO = Tc.Pair (Tc.Option(Tc.List(Hash))) (Tc.Option(Tc.List(Hash)))
 
   let history ?depth ?(min=[]) ?(max=[]) t =
     let query =