builder-web/lib/dream_tar.ml
dinosaure 071183ff6c Add GZip support when we generate a tar archive (#119)
Fixes #116.

Co-authored-by: Romain Calascibetta <romain.calascibetta@gmail.com>
Co-authored-by: Reynir Björnsson <reynir@reynir.dk>
Reviewed-on: https://git.robur.io/robur/builder-web/pulls/119
Co-authored-by: dinosaure <romain.calascibetta@gmail.com>
Co-committed-by: dinosaure <romain.calascibetta@gmail.com>
2022-06-21 15:17:50 +00:00

88 lines
3.2 KiB
OCaml

open Lwt.Infix
module Writer = struct
type out_channel =
{ mutable gz : Gz.Def.encoder
; ic : Cstruct.t
; oc : Cstruct.t
; stream : Dream.stream }
type 'a t = 'a Lwt.t
let really_write ({ oc; stream; _ } as state) cs =
let rec until_await gz =
match Gz.Def.encode gz with
| `Await gz -> state.gz <- gz ; Lwt.return_unit
| `Flush gz ->
let max = Cstruct.length oc - Gz.Def.dst_rem gz in
let str = Cstruct.copy oc 0 max in
Dream.write stream str >>= fun () ->
let { Cstruct.buffer; off= cs_off; len= cs_len; } = oc in
until_await (Gz.Def.dst gz buffer cs_off cs_len)
| `End _gz -> assert false in
if Cstruct.length cs = 0
then Lwt.return_unit
else ( let { Cstruct.buffer; off; len; } = cs in
let gz = Gz.Def.src state.gz buffer off len in
until_await gz )
end
module HW = Tar.HeaderWriter(Lwt)(Writer)
let write_block (header : Tar.Header.t) lpath ({ Writer.ic= buf; _ } as state) =
HW.write ~level:Tar.Header.Ustar header state >>= fun () ->
Lwt_io.open_file ~mode:Lwt_io.Input (Fpath.to_string lpath) >>= fun ic ->
let rec loop () =
let { Cstruct.buffer; off; len; } = buf in
Lwt_io.read_into_bigstring ic buffer off len >>= function
| 0 -> Lwt.return ()
| len' ->
Writer.really_write state (Cstruct.sub buf 0 len') >>= fun () ->
loop ()
in
loop () >>= fun () ->
Writer.really_write state (Tar.Header.zero_padding header)
let header_of_file mod_time (file : Builder_db.file) =
let file_mode = if Fpath.is_prefix Fpath.(v "bin/") file.filepath then
0o755
else
0o644
in
Tar.Header.make ~file_mode ~mod_time (Fpath.to_string file.filepath) (Int64.of_int file.size)
let targz_response datadir finish (files : Builder_db.file list) (stream : Dream.stream) =
let state =
let ic = Cstruct.create (4 * 4 * 1024) in
let oc = Cstruct.create 4096 in
let gz =
let w = De.Lz77.make_window ~bits:15 in
let q = De.Queue.create 0x1000 in
let mtime = Int32.of_float (Unix.gettimeofday ()) in
let gz = Gz.Def.encoder `Manual `Manual ~mtime Gz.Unix ~q ~w ~level:4 in
let { Cstruct.buffer; off; len; } = oc in
Gz.Def.dst gz buffer off len
in
{ Writer.gz; ic; oc; stream; }
in
Lwt_list.iter_s (fun file ->
let hdr = header_of_file finish file in
write_block hdr Fpath.(datadir // file.localpath) state)
files >>= fun () ->
Writer.really_write state Tar.Header.zero_block >>= fun () ->
Writer.really_write state Tar.Header.zero_block >>= fun () ->
(* assert (Gz.Def.encode gz = `Await) *)
let rec until_end gz = match Gz.Def.encode gz with
| `Await _gz -> assert false
| `Flush gz | `End gz as flush_or_end ->
let max = Cstruct.length state.oc - Gz.Def.dst_rem gz in
let str = Cstruct.copy state.oc 0 max in
Dream.write stream str >>= fun () -> match flush_or_end with
| `Flush gz ->
let { Cstruct.buffer; off= cs_off; len= cs_len; } = state.oc in
until_end (Gz.Def.dst gz buffer cs_off cs_len)
| `End _ -> Lwt.return_unit
in
until_end (Gz.Def.src state.gz De.bigstring_empty 0 0) >>= fun () ->
Dream.flush stream >>= fun () ->
Dream.close stream