tvl-depot/scripts/nix-pull.in
Eelco Dolstra e877c69d78 * Substitutes now should produce a path with the same id as they are
substituting for (obvious, really).

* For greater efficiency, nix-pull/unnar will place the output in a
  path that is probably the same as what is actually needed, thus
  preventing a path copy.

* Even if a output id is given in a Fix package expression, ensure
  that the resulting Nix derive expression has a different id.  This
  is because Nix expressions that are semantically equivalent (i.e.,
  build the same result) might be different w.r.t. efficiency or
  divergence.  It is absolutely vital for the substitute mechanism
  that such expressions are not used interchangeably.
2003-07-22 15:15:15 +00:00

91 lines
2.5 KiB
Perl

#! /usr/bin/perl -w
my $tmpfile = "@localstatedir@/nix/pull.tmp";
my $conffile = "@sysconfdir@/nix/prebuilts.conf";
my @subs;
my @sucs;
open CONFFILE, "<$conffile";
while (<CONFFILE>) {
chomp;
if (/^\s*(\S+)\s*(\#.*)?$/) {
my $url = $1;
print "obtaining list of Nix archives at $url...\n";
system "wget '$url' -O '$tmpfile' 2> /dev/null"; # !!! escape
if ($?) { die "`wget' failed"; }
open INDEX, "<$tmpfile";
while (<INDEX>) {
# Get all links to prebuilts, that is, file names of the
# form foo-HASH-HASH.tar.bz2.
next unless (/HREF=\"([^\"]*)\"/);
my $fn = $1;
next if $fn =~ /\.\./;
next if $fn =~ /\//;
next unless $fn =~ /^([0-9a-z]{32})-([0-9a-z]{32})(.*)\.nar\.bz2$/;
my $hash = $1;
my $id = $2;
my $outname = $3;
my $fsid;
if ($outname =~ /^-/) {
next unless $outname =~ /^-((s-([0-9a-z]{32}))?.*)$/;
$outname = $1;
$fsid = $3;
} else {
$outname = "";
}
print "registering $id -> $url/$fn\n";
# Construct a Fix expression that fetches and unpacks a
# Nix archive from the network.
my $fetch =
"App(IncludeFix(\"fetchurl/fetchurl.fix\"), " .
"[(\"url\", \"$url/$fn\"), (\"md5\", \"$hash\")])";
my $fixexpr =
"App(IncludeFix(\"nar/unnar.fix\"), " .
"[ (\"nar\", $fetch)" .
", (\"name\", \"$outname\")" .
", (\"id\", \"$id\")" .
"])";
my $fixfile = "/tmp/nix-pull-tmp.fix";
open FIX, ">$fixfile";
print FIX $fixexpr;
close FIX;
# Instantiate a Nix expression from the Fix expression.
my $nid = `fix $fixfile`;
$? and die "instantiating Nix archive expression";
chomp $nid;
die unless $nid =~ /^([0-9a-z]{32})$/;
push @subs, $id;
push @subs, $nid;
# Does the name encode a successor relation?
if (defined $fsid) {
print "NORMAL $fsid -> $id\n";
push @sucs, $fsid;
push @sucs, $id;
}
}
close INDEX;
unlink $tmpfile;
}
}
system "nix --substitute @subs";
if ($?) { die "`nix --substitute' failed"; }
system "nix --successor @sucs";
if ($?) { die "`nix --successor' failed"; }