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* First figure out what symlinks need to be created, then create
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  them.  This prevents unnecessary unlink operations to resolve
  collisions between directories.

svn path=/nixpkgs/trunk/; revision=22526
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@edolstra
edolstra committed Jul 8, 2010
1 parent eb2cb9a commit a6fcf45
Showing 1 changed file with 67 additions and 91 deletions.
158 changes: 67 additions & 91 deletions pkgs/build-support/buildenv/builder.pl
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Original file line number Diff line number Diff line change
Expand Up @@ -9,10 +9,6 @@
STDOUT->autoflush(1);

my $out = $ENV{"out"};
mkdir "$out", 0755 || die "error creating $out";


my $symlinks = 0;


my @pathsToLink = split ' ', $ENV{"pathsToLink"};
Expand All @@ -27,95 +23,58 @@ sub isInPathsToLink {
}


sub symLinkMkdir {
my $src = shift;
my $dst = shift;
my $dir = dirname $dst;
mkpath $dir;
symlink($src, $dst) ||
die "error creating link `$dst': $!";
$symlinks++;
}
# For each activated package, determine what symlinks to create.

my %symlinks;
$symlinks{""} = ""; # create root directory

# For each activated package, create symlinks.
sub findFiles;

sub createLinks {
my $relName = shift;
my $srcDir = shift;
my $dstDir = shift;
my $ignoreCollisions = shift;
sub findFilesInDir {
my ($relName, $target, $ignoreCollisions) = @_;

my @srcFiles = glob("$srcDir/*");

foreach my $srcFile (@srcFiles) {
my $baseName = $srcFile;
$baseName =~ s/^.*\///g; # strip directory
my $dstFile = "$dstDir/$baseName";
my $relName2 = "$relName/$baseName";

# Urgh, hacky...
if ($srcFile =~ /\/propagated-build-inputs$/ ||
$srcFile =~ /\/nix-support$/ ||
$srcFile =~ /\/perllocal.pod$/ ||
$srcFile =~ /\/info\/dir$/ ||
( $relName2 =~ /^\/share\/mime\// && !( $relName2 =~ /^\/share\/mime\/packages/ ) ) ||
$srcFile =~ /\/log$/)
{
# Do nothing.
}

elsif (-d $srcFile) {

if (!isInPathsToLink($relName2)) {
# This path is not in the list of paths to link, but
# some of its children may be.
createLinks($relName2, $srcFile, $dstFile, $ignoreCollisions);
next;
}

lstat $dstFile;

if (-d _) {
createLinks($relName2, $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': $!";
mkpath $dstFile;
createLinks($relName2, $target, $dstFile, $ignoreCollisions);
createLinks($relName2, $srcFile, $dstFile, $ignoreCollisions);
}

else {
symLinkMkdir $srcFile, $dstFile;
}
}

elsif (-l $dstFile) {
my $oldTarget = readlink $dstFile;
my $oldTargetReal = abs_path $oldTarget;
my $newTarget = $srcFile;
my $newTargetReal = abs_path $newTarget;
unless ($newTargetReal eq $oldTargetReal) {
if ($ignoreCollisions) {
warn "collision between `$newTarget' and `$oldTarget'\n";
}
else {
die "collision between `$newTarget' and `$oldTarget'";
}
}
}
opendir DIR, "$target" or die "cannot open `$target': $!";
my @names = readdir DIR or die;
closedir DIR;

foreach my $name (@names) {
next if $name eq "." || $name eq "..";
findFiles("$relName/$name", "$target/$name", $name, $ignoreCollisions);
}
}

sub findFiles {
my ($relName, $target, $baseName, $ignoreCollisions) = @_;

# Urgh, hacky...
return if
$relName eq "/propagated-build-inputs" ||
$relName eq "/nix-support" ||
$relName =~ /info\/dir/ ||
( $relName =~ /^\/share\/mime\// && !( $relName =~ /^\/share\/mime\/packages/ ) ) ||
$baseName eq "perllocal.pod" ||
$baseName eq "log";

my $oldTarget = $symlinks{$relName};

if (!defined $oldTarget) {
$symlinks{$relName} = $target;
return;
}

else {
next unless isInPathsToLink($relName2);
symLinkMkdir $srcFile, $dstFile;
unless (-d $target && ($oldTarget eq "" || -d $oldTarget)) {
if ($ignoreCollisions) {
warn "collision between `$target' and `$oldTarget'";
return;
} else {
die "collision between `$target' and `$oldTarget'";
}
}

findFilesInDir($relName, $oldTarget, $ignoreCollisions) unless $oldTarget eq "";
findFilesInDir($relName, $target, $ignoreCollisions);

$symlinks{$relName} = ""; # denotes directory
}


Expand All @@ -130,8 +89,7 @@ ($;$)
return if (defined $done{$pkgDir});
$done{$pkgDir} = 1;

# print "symlinking $pkgDir\n";
createLinks("", "$pkgDir", "$out", $ignoreCollisions);
findFiles("", "$pkgDir", "", $ignoreCollisions);

my $propagatedFN = "$pkgDir/nix-support/propagated-user-env-packages";
if (-e $propagatedFN) {
Expand All @@ -140,7 +98,6 @@ ($;$)
close PROP;
my @propagated = split ' ', $propagated;
foreach my $p (@propagated) {
print "$pkgDir propagates $p\n";
$postponed{$p} = 1 unless defined $done{$p};
}
}
Expand All @@ -167,17 +124,36 @@ ($;$)
}
}


# Create the symlinks.
my $nrLinks = 0;
foreach my $relName (sort keys %symlinks) {
my $target = $symlinks{$relName};
my $abs = "$out/$relName";
next unless isInPathsToLink $relName;
if ($target eq "") {
#print "creating directory $relName\n";
mkpath $abs or die "cannot create directory `$abs': $!";
} else {
#print "creating symlink $relName to $target\n";
symlink $target, $abs ||
die "error creating link `$abs': $!";
$nrLinks++;
}
}


if (-x "$out/bin/update-mime-database" && -d "$out/share/mime/packages") {
system("$out/bin/update-mime-database -V $out/share/mime") == 0
or die "Can't update mime-database";
}


print STDERR "created $symlinks symlinks in user environment\n";
print STDERR "created $nrLinks symlinks in user environment\n";


my $manifest = $ENV{"manifest"};
if ($manifest ne "") {
if ($manifest) {
symlink($manifest, "$out/manifest") or die "cannot create manifest";
}

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1 comment on commit a6fcf45

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This commit has been mentioned on NixOS Discourse. There might be relevant details there:

https://discourse.nixos.org/t/cant-call-a-program-log/49868/12

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