diff options
Diffstat (limited to '')
| -rw-r--r-- | lib/protocols/Cursor.ml | 12 |
1 files changed, 0 insertions, 12 deletions
diff --git a/lib/protocols/Cursor.ml b/lib/protocols/Cursor.ml index 7c976b9..36db97d 100644 --- a/lib/protocols/Cursor.ml +++ b/lib/protocols/Cursor.ml @@ -19,17 +19,8 @@ let from handle = Handle.into handle (function Cursor impl -> Some impl | _ -> N let require handle = from handle |> Option.to_result ~none:(Error.not_a_cursor ()) let fetch i limit = Handle.invoke i (fun o -> o#fetch limit) -(* A scalar loop over a batching protocol. The buffer is per-call rather than per-cursor state, so - [next] stays a derived convenience and an implementation still writes exactly one method: the - cost is that a caller alternating [next] and [fetch] on one cursor sees the buffered tuples - dropped. Callers pick one or the other. *) let rec next i = let open Utilities.Result in - (* TODO: fetch 1 and hand back its head. Because an empty non-exhausted batch means "ask again", - this loops until it either has a tuple or sees [exhausted]. That loop is unbounded by - construction, which is precisely the bounded-work property [fetch] has and [next] gives up -- - which is why [next] is documented for small results and scalar loops, not for scans a host - needs to be able to cancel. *) let* batch = fetch i 1 in match BatFingerTree.front batch.tuples with | Some (_, tuple) -> Ok (Some tuple) @@ -37,9 +28,6 @@ let rec next i = let drain i ?(limit = 256) () = let open Utilities.Result in - (* TODO: fetch [limit] at a time, appending each batch, until [exhausted]. Appending is - [BatFingerTree.append], which is logarithmic, so accumulating a large result does not degrade - the way repeated list concatenation would. *) let rec loop tuples = let* batch = fetch i limit in let tuples = BatFingerTree.append tuples batch.tuples in |