Make.Wo
val open_wo :
mapping_size:int ->
mapping:string ->
data:string ->
(t, [> open_error ]) Stdlib.result
open_wo ~mapping_size ~mapping ~data
returns a write-only instance of the sparse file.
Note: This is unsafe and is only used by the GC to mark the parent commits as dangling. One must ensure that no read-only instance is opened at the same time, as otherwise the writes would be observable by it.
val write_exn : t -> off:Optint.Int63.t -> len:int -> string -> unit
write_exn t ~off ~len str
writes the first len
bytes of str
to t
at the virtual offset off
.
val fsync : t -> (unit, [> Io.write_error ]) Stdlib.result
fsync t
persists to the file system the effects of previous writes.
val close : t -> (unit, [> Io.close_error ]) Stdlib.result
Close the underlying files.
val create_from_data :
mapping:string ->
dead_header_size:int ->
size:Optint.Int63.t ->
data:string ->
(Optint.Int63.t, [> Io.create_error | Io.write_error | Io.close_error ])
Stdlib.result
create_from_data ~mapping ~dead_header_size ~size ~data
initializes a new sparse file on disk from the existing file data
, by creating the corresponding mapping
file. The first dead_header_size
bytes are ignored and the remaining size
bytes of data
are made available.
On success, returns the size of the mapping
file to be stored in the control file for consistency checking on open.