hphp/hack/scripts/gen_build_id.ml

   1 (*
   2  * Copyright (c) 2013-present, Facebook, Inc.
   3  * All rights reserved.
   4  *
   5  * This source code is licensed under the MIT license found in the
   6  * LICENSE file in the "hack" directory of this source tree.
   7  *
   8  *)
   9
  10 #use "utils.ml"
  11
  12 (**
  13  * Computes some build identifiers based on the current commit. These IDs are
  14  * used to ensure that clients and servers are the same version, even between
  15  * releases. For example, if you build revision A and start a server, then check
  16  * out and build revision B, it's convenient for the server to restart itself
  17  * using revision B.
  18  *
  19  * This fails gracefully when neither hg nor git are installed, or when neither
  20  * .hg nor .git exist (e.g. when building from a tarball). This is fine because
  21  * you can't move between commits in such a snapshot.
  22  *)
  23 let () =
  24   let out_file = Sys.argv.(1) in
  25   let rev =
  26     try read_process_output "git" [|"git"; "rev-parse"; "HEAD"|]
  27     with Failure _ ->
  28       try read_process_output "hg" [|"hg"; "id"; "-i"|]
  29       with Failure _ -> ""
  30   in
  31   let time =
  32     try read_process_output "git" [|"git"; "log"; "-1"; "--pretty=tformat:%ct"|]
  33     with Failure _ ->
  34       try
  35         let raw = read_process_output "hg" [|"hg"; "log"; "-r"; "."; "-T"; "{date|hgdate}\\n"|] in
  36         String.sub raw 0 (String.index raw ' ')
  37       with
  38       | Failure _ -> "0"
  39       | Not_found -> "0"
  40   in
  41   let content = Printf.sprintf
  42     "const char* const BuildInfo_kRevision = %S;\nconst unsigned long BuildInfo_kRevisionCommitTimeUnix = %sul;\nconst char* const BuildInfo_kBuildMode = %S;\n"
  43     rev time "" (* not implemented *) in
  44   let do_dump =
  45     not (Sys.file_exists out_file) || string_of_file out_file <> content in
  46   if do_dump then
  47     with_out_channel out_file @@ fun oc ->
  48     output_string oc content