From 5cad324e693396ad7ee646102b51dd610addefae Mon Sep 17 00:00:00 2001
From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Sat, 25 Jul 2020 19:00:24 +0100
Subject: [PATCH] Provide --just-linkfarm option

Closes #10

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
---
 README.md     |  4 ++++
 nailing-cargo | 17 +++++++++++++++--
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index b1946b0..0a6b478 100644
--- a/README.md
+++ b/README.md
@@ -363,6 +363,10 @@ Options
     * `!locked`: cargo would reject `--locked`, so don't pass it.  Hazardous.
     * `!offline`: the build command would reject `--offline`, so never pass it.  *Not* overridden by configuration or command line.
 
+  * `--just-linkfarm`: Make the out-of-tree linkfarm as if for
+    `--cargo-lock-update`, but do not actually run any command, nor
+    try to copy back a a generated `Cargo.lock`.
+
   * `-h` | `--help`: Print usage summary.
 
   * `--man` | `--manual`: Format this manual into html using `pandoc`
diff --git a/nailing-cargo b/nailing-cargo
index 370fa05..cfcb97b 100755
--- a/nailing-cargo
+++ b/nailing-cargo
@@ -26,6 +26,7 @@ options:
   -T<arch>  --target=<arch>       Specify target architecture
   -h --help                       Print this message
   --man --manual                  Display complete manual (in w3m)
+  --just-linkfarm                 Make the linkfarm as for -u, then stop
 
   -s<subcommand>                  Treat command as `cargo <subcommand>`
   --subcommand-props=<prop>,...   Override command props (see docs)
@@ -85,6 +86,7 @@ our $alt_cargo_lock;
 our $cargo_lock_update;
 our $pass_options;
 our $online;
+our $just_linkfarm;
 
 #
 our %subcmd_props = (
@@ -518,6 +520,13 @@ sub calculate () {
 }
 
 sub addargs () {
+  if ($just_linkfarm) {
+    die "$self: --just-linkfarm but not doing out-of-tree builds!\n"
+      unless defined $oot_dir;
+    @ARGV = ();
+    return;
+  }
+
   if (!defined $online) {
     $_ = cfg_uc qw(misc online);
     if (!defined $_) {
@@ -794,7 +803,7 @@ sub invoke () {
 }
 
 sub cargo_lock_update_after () {
-  if ($cargo_lock_update) {
+  if ($cargo_lock_update && !$just_linkfarm) {
     # avoids importing File::Copy and the error handling is about as good
     $!=0; $?=0;
     my $r= system qw(cp --), "$build_absdir/Cargo.lock", "Cargo.lock";
@@ -846,7 +855,8 @@ sub parse_args () {
 
  OPTS: for (;;) {
     if (!@ARGV) {
-      die "$self: need cargo subcommand\n" unless $noact;
+      die "$self: need cargo subcommand\n"
+	unless $noact || $just_linkfarm;;
       push @ARGV, "CARGO-SUBCOMMAND"; # dummy, user may see it
     }
 
@@ -915,6 +925,9 @@ sub parse_args () {
       $target = $_;
     } elsif (m{^--(on|off)line$}) {
       $online = $1 eq 'on';
+    } elsif (m{^--just-linkfarm$}) {
+      $just_linkfarm = 1;
+      $cargo_lock_update= 1;
     } elsif (s{^--subcommand-props=}{}) {
       my @props = split /\,/, $_;
       our %subcmd_prop_ok;
-- 
2.30.2