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lix/corepkgs/buildenv.pl

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use strict;
use Cwd;
use IO::Handle;
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use utf8;
STDOUT->autoflush(1);
my $out = $ENV{"out"};
mkdir "$out", 0755 || die "error creating $out";
my $symlinks = 0;
my %priorities;
# For each activated package, create symlinks.
sub createLinks {
my $srcDir = shift;
my $dstDir = shift;
my $priority = shift;
my @srcFiles = glob("$srcDir/*");
foreach my $srcFile (@srcFiles) {
my $baseName = $srcFile;
$baseName =~ s/^.*\///g; # strip directory
my $dstFile = "$dstDir/$baseName";
# The files below are special-cased so that they don't show up
# in user profiles, either because they are useless, or
# because they would cause pointless collisions (e.g., each
# Python package brings its own
# `$out/lib/pythonX.Y/site-packages/easy-install.pth'.)
# Urgh, hacky...
if ($srcFile =~ /\/propagated-build-inputs$/ ||
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$srcFile =~ /\/nix-support$/ ||
$srcFile =~ /\/perllocal.pod$/ ||
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$srcFile =~ /\/info\/dir$/ ||
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$srcFile =~ /\/log$/)
{
# Do nothing.
}
elsif (-d $srcFile) {
lstat $dstFile;
if (-d _) {
createLinks($srcFile, $dstFile, $priority);
}
elsif (-l _) {
my $target = readlink $dstFile or die;
if (!-d $target) {
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die "collision between directory $srcFile and non-directory $target";
}
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unlink $dstFile or die "error unlinking $dstFile: $!";
mkdir $dstFile, 0755 ||
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die "error creating directory $dstFile: $!";
createLinks($target, $dstFile, $priorities{$dstFile});
createLinks($srcFile, $dstFile, $priority);
}
else {
symlink($srcFile, $dstFile) ||
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die "error creating link $dstFile: $!";
$priorities{$dstFile} = $priority;
$symlinks++;
}
}
else {
if (-l $dstFile) {
my $target = readlink $dstFile;
my $prevPriority = $priorities{$dstFile};
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die("collision between $srcFile and $target; " .
"use nix-env --set-flag priority NUMBER PKGNAME " .
"to change the priority of one of the conflicting packages\n")
if $prevPriority == $priority;
next if $prevPriority < $priority;
unlink $dstFile or die;
}
symlink($srcFile, $dstFile) ||
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die "error creating link $dstFile: $!";
$priorities{$dstFile} = $priority;
$symlinks++;
}
}
}
my %done;
my %postponed;
sub addPkg;
sub addPkg {
my $pkgDir = shift;
my $priority = shift;
return if (defined $done{$pkgDir});
$done{$pkgDir} = 1;
# print "symlinking $pkgDir\n";
createLinks("$pkgDir", "$out", $priority);
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};
}
}
}
# Convert the stuff we get from the environment back into a coherent
# data type.
my @pkgs;
my @derivations = split ' ', $ENV{"derivations"};
while (scalar @derivations) {
my $active = shift @derivations;
my $priority = shift @derivations;
my $outputs = shift @derivations;
for (my $n = 0; $n < $outputs; $n++) {
my $path = shift @derivations;
push @pkgs,
{ path => $path
, active => $active ne "false"
, priority => int($priority) };
}
}
# Symlink to the packages that have been installed explicitly by the
# user. Process in priority order to reduce unnecessary
# symlink/unlink steps.
@pkgs = sort { $a->{priority} <=> $b->{priority} || $a->{path} cmp $b->{path} } @pkgs;
foreach my $pkg (@pkgs) {
#print $pkg, " ", $pkgs{$pkg}->{priority}, "\n";
addPkg($pkg->{path}, $pkg->{priority}) if $pkg->{active};
}
# Symlink to the packages that have been "propagated" by packages
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# installed by the user (i.e., package X declares that it wants Y
# installed as well). We do these later because they have a lower
# priority in case of collisions.
my $priorityCounter = 1000; # don't care about collisions
while (scalar(keys %postponed) > 0) {
my @pkgDirs = keys %postponed;
%postponed = ();
foreach my $pkgDir (sort @pkgDirs) {
addPkg($pkgDir, $priorityCounter++);
}
}
print STDERR "created $symlinks symlinks in user environment\n";
symlink($ENV{"manifest"}, "$out/manifest.nix") or die "cannot create manifest";