tvl-depot/corepkgs/buildenv/builder.pl.in
Eelco Dolstra 3d05166086 * Allow conflicting packages to be kept in a user environment, and
allow switching between them (NIX-80).

  Example: two versions of Pan:

    $ nix-env -q pan
    pan-0.128
    pan-0.14.2.91

    $ readlink $(which pan)
    /nix/store/l38jrbilw269drpjkx7kinhrxj6fjh59-pan-0.14.2.91/bin/pan

  At most one of them can be active any given time.  Assuming than
  0.14.2.91 is active, you can active 0.128 as follows:

    $ nix-env --set-flag active false pan-0.14.2.91
    $ nix-env --set-flag active true pan-0.128

    $ readlink $(which pan)
    /nix/store/nziqwnlzy7xl385kglxhg75pfl5i936n-pan-0.128/bin/pan

  More flags to follow.
2007-04-27 22:40:59 +00:00

139 lines
3.5 KiB
Perl
Executable file

#! @perl@ -w
use strict;
use Cwd;
use IO::Handle;
STDOUT->autoflush(1);
my $out = $ENV{"out"};
mkdir "$out", 0755 || die "error creating $out";
my $symlinks = 0;
# For each activated package, create symlinks.
sub createLinks {
my $srcDir = shift;
my $dstDir = shift;
my $ignoreCollisions = shift;
my @srcFiles = glob("$srcDir/*");
foreach my $srcFile (@srcFiles) {
my $baseName = $srcFile;
$baseName =~ s/^.*\///g; # strip directory
my $dstFile = "$dstDir/$baseName";
# Urgh, hacky...
if ($srcFile =~ /\/propagated-build-inputs$/ ||
$srcFile =~ /\/nix-support$/ ||
$srcFile =~ /\/perllocal.pod$/ ||
$srcFile =~ /\/info\/dir$/ ||
$srcFile =~ /\/log$/)
{
# Do nothing.
}
elsif (-d $srcFile) {
lstat $dstFile;
if (-d _) {
createLinks($srcFile, $dstFile, $ignoreCollisions);
}
elsif (-l _) {
my $target = readlink $dstFile or die;
if (!-d $target) {
die "collission between directory `$srcFile' and non-directory `$target'";
}
unlink $dstFile or die "error unlinking `$dstFile': $!";
mkdir $dstFile, 0755 ||
die "error creating directory `$dstFile': $!";
createLinks($target, $dstFile, $ignoreCollisions);
createLinks($srcFile, $dstFile, $ignoreCollisions);
}
else {
symlink($srcFile, $dstFile) ||
die "error creating link `$dstFile': $!";
$symlinks++;
}
}
elsif (-l $dstFile) {
if (!$ignoreCollisions) {
my $target = readlink $dstFile;
die "collission between `$srcFile' and `$target'";
}
}
else {
symlink($srcFile, $dstFile) ||
die "error creating link `$dstFile': $!";
$symlinks++;
}
}
}
my %done;
my %postponed;
sub addPkg;
sub addPkg {
my $pkgDir = shift;
my $ignoreCollisions = shift;
return if (defined $done{$pkgDir});
$done{$pkgDir} = 1;
# print "symlinking $pkgDir\n";
createLinks("$pkgDir", "$out", $ignoreCollisions);
my $propagatedFN = "$pkgDir/nix-support/propagated-user-env-packages";
if (-e $propagatedFN) {
open PROP, "<$propagatedFN" or die;
my $propagated = <PROP>;
close PROP;
my @propagated = split ' ', $propagated;
foreach my $p (@propagated) {
$postponed{$p} = 1 unless defined $done{$p};
}
}
}
# Symlink to the packages that have been installed explicitly by the user.
my @paths = split ' ', $ENV{"derivations"};
my @active = split ' ', $ENV{"active"};
die if scalar @paths != scalar @active;
for (my $n = 0; $n < scalar @paths; $n++) {
my $pkgDir = $paths[$n];
my $isActive = $active[$n];
addPkg($pkgDir, 0) if $isActive ne "false";
}
# Symlink to the packages that have been "propagated" by packages
# installed by the user (i.e., package X declares that it want Y
# installed as well). We do these later because they have a lower
# priority in case of collisions.
while (scalar(keys %postponed) > 0) {
my @pkgDirs = keys %postponed;
%postponed = ();
foreach my $pkgDir (sort @pkgDirs) {
addPkg($pkgDir, 1);
}
}
print STDERR "created $symlinks symlinks in user environment\n";
symlink($ENV{"manifest"}, "$out/manifest") or die "cannot create manifest";