Recompute cache size at application start

src/cache.ml

@@ -1236,3 +1236,21 @@ let clean_up_cache cache =
       (Sys.readdir cache.cache_dir)
   end
 
+let compute_cache_size cache =
+  if Sys.file_exists cache.cache_dir &&
+     Sys.is_directory cache.cache_dir then begin
+    Array.fold_left
+      (fun size file ->
+         try
+           let path = Filename.concat cache.cache_dir file in
+           if Sys.file_exists path && path <> cache.db_path then begin
+             let stats = Unix.LargeFile.stat path in
+             let file_size = stats.Unix.LargeFile.st_size in
+             Int64.add size file_size
+           end else size
+         with e -> Utils.log_exception e; size
+      )
+      0L
+      (Sys.readdir cache.cache_dir)
+  end else 0L
+

src/drive.ml

@@ -728,13 +728,28 @@ let get_metadata () =
     SessionM.return updated_metadata
   in
 
+  let resync_cache_size db_metadata =
+    let old_cache_size = db_metadata.Cache.Metadata.cache_size in
+    Utils.log_with_header
+      "BEGIN: Recalculating cache size (old value=%Ld)\n%!"
+      old_cache_size;
+    let cache_size = Cache.compute_cache_size context.Context.cache in
+    Utils.log_with_header
+      "END: Recalculating cache size (new value=%Ld)\n%!"
+      cache_size;
+    db_metadata |> Cache.Metadata.cache_size ^= cache_size
+  in
+
   with_metadata_lock
     (fun () ->
        let metadata =
+         let context = Context.get_ctx () in
          if Option.is_none context.Context.metadata then begin
            Utils.log_with_header "BEGIN: Loading metadata from db\n%!";
            let db_metadata =
              Cache.Metadata.select_metadata context.Context.cache in
+           let db_metadata =
+             Option.map resync_cache_size db_metadata in
            Context.update_ctx (Context.metadata ^= db_metadata);
            db_metadata
          end else begin