1 files changed, 229 insertions, 0 deletions
diff --git a/ocaml/lib/eventlog_lmdb.ml b/ocaml/lib/eventlog_lmdb.ml
new file mode 100644
index 0000000..256a662
--- /dev/null
+++ b/ocaml/lib/eventlog_lmdb.ml
@@ -0,0 +1,229 @@
+[@@@ocaml.warning "-69"]
+
+open Noun
+
+(* Event log using LMDB backend to match Vere's implementation *)
+
+type event_num = int64
+
+external murmur3_hash32 : string ->  int32 = "caml_murmur3_hash32"
+
+let debug_enabled () =
+  match Sys.getenv_opt "NEOVERE_EVENTLOG_DEBUG" with
+  | None -> false
+  | Some value ->
+      let v = String.lowercase_ascii value in
+      not (v = "0" || v = "false" || v = "off")
+
+let debug fmt =
+  if debug_enabled () then
+    Printf.ksprintf (fun msg -> Printf.printf "[eventlog_lmdb] %s\n%!" msg) fmt
+  else
+    Printf.ksprintf (fun _ -> ()) fmt
+
+(* LMDB environment and databases *)
+type t = {
+  env: Lmdb.Env.t;
+  events_map: (int64, string, [`Uni]) Lmdb.Map.t;  (* event_num -> serialized bytes *)
+  meta_map: (string, string, [`Uni]) Lmdb.Map.t;   (* metadata key-value *)
+  mutable last_event: event_num;
+  mutable enabled: bool;
+}
+
+(* Serialize event: 4-byte mug + jammed noun (matches Vere) *)
+let serialize_event ?(verbose=false) (noun : noun) : string =
+  let jam_bytes = Serial.jam ~verbose noun in
+  (* Compute mug from jammed bytes instead of traversing the noun tree
+     This is much faster for large nouns (3M+ nodes) and avoids stack overflow *)
+  let mug = murmur3_hash32 (Bytes.to_string jam_bytes) in
+  let jam_len = Bytes.length jam_bytes in
+  let total_len = 4 + jam_len in
+  let result = Bytes.create total_len in
+  Bytes.set_int32_le result 0 mug;
+  Bytes.blit jam_bytes 0 result 4 jam_len;
+  Bytes.to_string result
+
+(* Deserialize event: extract mug and cue the noun *)
+let deserialize_event ?(verbose=false) (data : string) : noun =
+  if String.length data < 4 then
+    failwith "Event data too short (< 4 bytes)";
+  let _mug = String.get_int32_le data 0 in
+  let jam_data = String.sub data 4 (String.length data - 4) in
+  Serial.cue ~verbose (Bytes.of_string jam_data)
+
+(* Create or open event log *)
+let create ?(enabled=true) (pier_path : string) : t =
+  debug "opening LMDB event log at: %s" pier_path;
+
+  (* Create .urb/log directory if it doesn't exist *)
+  let urb_dir = Filename.concat pier_path ".urb" in
+  let log_dir = Filename.concat urb_dir "log" in
+
+  if not (Sys.file_exists urb_dir) then
+    Unix.mkdir urb_dir 0o755;
+  if not (Sys.file_exists log_dir) then
+    Unix.mkdir log_dir 0o755;
+
+  (* Open LMDB environment - match Vere's default of 1TB (0x10000000000) *)
+  let env = Lmdb.Env.create Lmdb.Rw
+    ~max_maps:2
+    ~map_size:0x10000000000  (* 1TB - matches Vere's default *)
+    ~flags:Lmdb.Env.Flags.no_subdir
+    (Filename.concat log_dir "data.mdb")
+  in
+
+  (* Open or create the two databases *)
+  let events_map =
+    try
+      Lmdb.Map.open_existing Lmdb.Map.Nodup
+        ~name:"EVENTS"
+        ~key:Lmdb.Conv.int64_le
+        ~value:Lmdb.Conv.string
+        env
+    with Not_found ->
+      Lmdb.Map.create Lmdb.Map.Nodup
+        ~name:"EVENTS"
+        ~key:Lmdb.Conv.int64_le
+        ~value:Lmdb.Conv.string
+        env
+  in
+
+  let meta_map =
+    try
+      Lmdb.Map.open_existing Lmdb.Map.Nodup
+        ~name:"META"
+        ~key:Lmdb.Conv.string
+        ~value:Lmdb.Conv.string
+        env
+    with Not_found ->
+      Lmdb.Map.create Lmdb.Map.Nodup
+        ~name:"META"
+        ~key:Lmdb.Conv.string
+        ~value:Lmdb.Conv.string
+        env
+  in
+
+  (* Read last event number from metadata or find highest event *)
+  let last_event =
+    try
+      let last_str = Lmdb.Map.get meta_map "last_event" in
+      Int64.of_string last_str
+    with Not_found ->
+      (* Find highest event number by iterating backwards *)
+      try
+        match Lmdb.Txn.go Lmdb.Ro env (fun txn ->
+          Lmdb.Cursor.go Lmdb.Ro ~txn events_map (fun cursor ->
+            let (event_num, _) = Lmdb.Cursor.last cursor in
+            debug "found last event: %Ld" event_num;
+            event_num
+          )
+        ) with
+        | Some event_num -> event_num
+        | None -> 0L
+      with Not_found ->
+        0L
+  in
+
+  debug "last event number: %Ld" last_event;
+
+  { env; events_map; meta_map; last_event; enabled }
+
+(* Close the event log *)
+let close (log : t) : unit =
+  debug "closing event log";
+  Lmdb.Env.sync log.env;
+  Lmdb.Env.close log.env
+
+(* Append a new event to the log *)
+let append ?(verbose=false) (log : t) (noun : noun) : event_num =
+  if not log.enabled then begin
+    log.last_event <- Int64.succ log.last_event;
+    log.last_event
+  end else begin
+    let event_num = Int64.succ log.last_event in
+    debug "appending event %Ld" event_num;
+
+    debug "serializing event %Ld..." event_num;
+    let serialized = serialize_event ~verbose noun in
+    debug "serialized event %Ld: %d bytes" event_num (String.length serialized);
+
+    (* Write event in a transaction *)
+    debug "starting LMDB transaction for event %Ld" event_num;
+    Lmdb.Txn.go Lmdb.Rw log.env (fun txn ->
+      debug "writing event %Ld to EVENTS map" event_num;
+      Lmdb.Map.set log.events_map ~txn event_num serialized;
+      debug "writing metadata for event %Ld" event_num;
+      Lmdb.Map.set log.meta_map ~txn "last_event" (Int64.to_string event_num);
+      debug "transaction complete for event %Ld" event_num;
+      Some ()
+    ) |> ignore;
+
+    log.last_event <- event_num;
+    debug "wrote event %Ld (%d bytes)" event_num (String.length serialized);
+    event_num
+  end
+
+(* Read a specific event from the log *)
+let read_event ?(verbose=false) (log : t) (event_num : event_num) : noun =
+  debug "reading event %Ld" event_num;
+
+  try
+    let serialized = Lmdb.Map.get log.events_map event_num in
+    debug "read event %Ld (%d bytes)" event_num (String.length serialized);
+    deserialize_event ~verbose serialized
+  with Not_found ->
+    failwith (Printf.sprintf "Event %Ld not found" event_num)
+
+(* Get the range of events in the log (first, last) *)
+let gulf (log : t) : (event_num * event_num) option =
+  try
+    Lmdb.Txn.go Lmdb.Ro log.env (fun txn ->
+      Lmdb.Cursor.go Lmdb.Ro ~txn log.events_map (fun cursor ->
+        let (first_num, _) = Lmdb.Cursor.first cursor in
+        let (last_num, _) = Lmdb.Cursor.last cursor in
+        (first_num, last_num)
+      )
+    )
+  with Not_found ->
+    None
+
+(* Replay all events in the log *)
+let replay ?(verbose=false) (log : t) (callback : event_num -> noun -> unit) : unit =
+  debug "starting replay";
+
+  match gulf log with
+  | None ->
+      debug "no events to replay";
+      ()
+  | Some (first, last) ->
+      debug "replaying events %Ld to %Ld" first last;
+
+      Lmdb.Txn.go Lmdb.Ro log.env (fun txn ->
+        Lmdb.Cursor.go Lmdb.Ro ~txn log.events_map (fun cursor ->
+          let rec replay_loop () =
+            try
+              let (event_num, serialized) = Lmdb.Cursor.current cursor in
+              debug "replaying event %Ld" event_num;
+              let noun = deserialize_event ~verbose serialized in
+              callback event_num noun;
+              ignore (Lmdb.Cursor.next cursor);
+              replay_loop ()
+            with Not_found ->
+              ()  (* End of cursor *)
+          in
+          (* Start from first event *)
+          ignore (Lmdb.Cursor.first cursor);
+          replay_loop ();
+          Some ()
+        )
+      ) |> ignore;
+
+      debug "replay complete"
+
+(* Get last event number *)
+let last_event (log : t) : event_num =
+  log.last_event
+
+(* Sync to disk *)
+let sync (log : t) : unit =
+  Lmdb.Env.sync log.env