bae75ca5a1
path can be created by copying it from another location in the file system. This is useful in the NixOS installation.
304 lines
8.8 KiB
Perl
304 lines
8.8 KiB
Perl
#! @perl@ -w -I@libexecdir@/nix
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use strict;
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use readmanifest;
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use POSIX qw(strftime);
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use File::Temp qw(tempdir);
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my $manifestDir = "@localstatedir@/nix/manifests";
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my $logFile = "@localstatedir@/log/nix/downloads";
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open LOGFILE, ">>$logFile" or die "cannot open log file $logFile";
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# Create a temporary directory.
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my $tmpDir = tempdir("nix-download.XXXXXX", CLEANUP => 1, TMPDIR => 1)
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or die "cannot create a temporary directory";
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chdir $tmpDir or die "cannot change to `$tmpDir': $!";
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my $tmpNar = "$tmpDir/nar";
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my $tmpNar2 = "$tmpDir/nar2";
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END { unlink $tmpNar; unlink $tmpNar2; rmdir $tmpDir; }
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# Check the arguments.
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die unless scalar @ARGV == 1;
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my $targetPath = $ARGV[0];
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my $date = strftime ("%F %H:%M:%S UTC", gmtime (time));
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print LOGFILE "$$ get $targetPath $date\n";
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print "\n*** Trying to download/patch `$targetPath'\n";
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# Load all manifests.
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my %narFiles;
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my %localPaths;
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my %patches;
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for my $manifest (glob "$manifestDir/*.nixmanifest") {
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# print STDERR "reading $manifest\n";
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if (readManifest($manifest, \%narFiles, \%localPaths, \%patches) < 3) {
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print STDERR "you have an old-style manifest `$manifest'; please delete it\n";
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exit 1;
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}
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}
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# If we can copy from a local path, do that.
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my $localPathList = $localPaths{$targetPath};
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foreach my $localPath (@{$localPathList}) {
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my $sourcePath = $localPath->{copyFrom};
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if (-e $sourcePath) {
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print "\n*** Step 1/1: copying from $sourcePath\n";
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system("@bindir@/nix-store --dump $sourcePath | @bindir@/nix-store --restore $targetPath") == 0
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or die "cannot copy `$sourcePath' to `$targetPath'";
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exit 0;
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}
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}
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# Build a graph of all store paths that might contribute to the
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# construction of $targetPath, and the special node "start". The
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# edges are either patch operations, or downloads of full NAR files.
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# The latter edges only occur between "start" and a store path.
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my %graph;
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$graph{"start"} = {d => 0, pred => undef, edges => []};
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my @queue = ();
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my $queueFront = 0;
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my %done;
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sub addToQueue {
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my $v = shift;
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return if defined $done{$v};
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$done{$v} = 1;
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push @queue, $v;
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}
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sub addNode {
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my $u = shift;
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$graph{$u} = {d => 999999999999, pred => undef, edges => []}
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unless defined $graph{$u};
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}
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sub addEdge {
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my $u = shift;
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my $v = shift;
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my $w = shift;
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my $type = shift;
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my $info = shift;
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addNode $u;
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push @{$graph{$u}->{edges}},
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{weight => $w, start => $u, end => $v, type => $type, info => $info};
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my $n = scalar @{$graph{$u}->{edges}};
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}
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addToQueue $targetPath;
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sub isValidPath {
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my $p = shift;
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return system("@bindir@/nix-store --check-validity '$p' 2> /dev/null") == 0;
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}
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sub parseHash {
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my $hash = shift;
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if ($hash =~ /^(.+):(.+)$/) {
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return ($1, $2);
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} else {
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return ("md5", $hash);
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}
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}
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while ($queueFront < scalar @queue) {
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my $u = $queue[$queueFront++];
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# print "$u\n";
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addNode $u;
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# If the path already exists, it has distance 0 from the "start"
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# node.
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if (isValidPath($u)) {
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addEdge "start", $u, 0, "present", undef;
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}
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else {
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# Add patch edges.
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my $patchList = $patches{$u};
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foreach my $patch (@{$patchList}) {
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if (isValidPath($patch->{basePath})) {
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# !!! this should be cached
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my ($baseHashAlgo, $baseHash) = parseHash $patch->{baseHash};
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my $format = "--base32";
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$format = "" if $baseHashAlgo eq "md5";
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my $hash = `@bindir@/nix-hash --type '$baseHashAlgo' $format "$patch->{basePath}"`;
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chomp $hash;
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# print " MY HASH is $hash\n";
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if ($hash ne $baseHash) {
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print LOGFILE "$$ rejecting $patch->{basePath}\n";
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next;
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}
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}
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# print " PATCH from $patch->{basePath}\n";
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addToQueue $patch->{basePath};
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addEdge $patch->{basePath}, $u, $patch->{size}, "patch", $patch;
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}
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# Add NAR file edges to the start node.
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my $narFileList = $narFiles{$u};
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foreach my $narFile (@{$narFileList}) {
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# print " NAR from $narFile->{url}\n";
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addEdge "start", $u, $narFile->{size}, "narfile", $narFile;
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if ($u eq $targetPath) {
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print LOGFILE "$$ full-download-would-be $narFile->{size}\n";
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}
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}
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}
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}
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# Run Dijkstra's shortest path algorithm to determine the shortest
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# sequence of download and/or patch actions that will produce
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# $targetPath.
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sub byDistance { # sort by distance, reversed
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return -($graph{$a}->{d} <=> $graph{$b}->{d});
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}
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my @todo = keys %graph;
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while (scalar @todo > 0) {
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# Remove the closest element from the todo list.
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@todo = sort byDistance @todo;
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my $u = pop @todo;
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my $u_ = $graph{$u};
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# print "IN $u $u_->{d}\n";
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foreach my $edge (@{$u_->{edges}}) {
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my $v_ = $graph{$edge->{end}};
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if ($v_->{d} > $u_->{d} + $edge->{weight}) {
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$v_->{d} = $u_->{d} + $edge->{weight};
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# Store the edge; to edge->start is actually the
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# predecessor.
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$v_->{pred} = $edge;
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# print " RELAX $edge->{end} $v_->{d}\n";
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}
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}
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}
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# Retrieve the shortest path from "start" to $targetPath.
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my @path = ();
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my $cur = $targetPath;
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die "don't know how to produce $targetPath\n"
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unless defined $graph{$targetPath}->{pred};
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while ($cur ne "start") {
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push @path, $graph{$cur}->{pred};
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$cur = $graph{$cur}->{pred}->{start};
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}
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# Traverse the shortest path, perform the actions described by the
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# edges.
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my $curStep = 1;
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my $maxStep = scalar @path;
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sub downloadFile {
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my $url = shift;
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my ($hashAlgo, $hash) = parseHash(shift);
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$ENV{"PRINT_PATH"} = 1;
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$ENV{"QUIET"} = 1;
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$ENV{"NIX_HASH_ALGO"} = $hashAlgo;
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my ($hash2, $path) = `@bindir@/nix-prefetch-url '$url' '$hash'`;
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die "download of `$url' failed" unless $? == 0;
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chomp $hash2;
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chomp $path;
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die "hash mismatch, expected $hash, got $hash2" if $hash ne $hash2;
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return $path;
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}
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while (scalar @path > 0) {
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my $edge = pop @path;
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my $u = $edge->{start};
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my $v = $edge->{end};
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print "\n*** Step $curStep/$maxStep: ";
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if ($edge->{type} eq "present") {
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print "using already present path `$v'\n";
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print LOGFILE "$$ present $v\n";
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if ($curStep < $maxStep) {
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# Since this is not the last step, the path will be used
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# as a base to one or more patches. So turn the base path
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# into a NAR archive, to which we can apply the patch.
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print " packing base path...\n";
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system("@bindir@/nix-store --dump $v > $tmpNar") == 0
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or die "cannot dump `$v'";
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}
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}
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elsif ($edge->{type} eq "patch") {
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my $patch = $edge->{info};
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print "applying patch `$patch->{url}' to `$u' to create `$v'\n";
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print LOGFILE "$$ patch $patch->{url} $patch->{size} $patch->{baseHash} $u $v\n";
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# Download the patch.
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print " downloading patch...\n";
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my $patchPath = downloadFile "$patch->{url}", "$patch->{hash}";
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# Apply the patch to the NAR archive produced in step 1 (for
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# the already present path) or a later step (for patch sequences).
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print " applying patch...\n";
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system("@libexecdir@/bspatch $tmpNar $tmpNar2 $patchPath") == 0
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or die "cannot apply patch `$patchPath' to $tmpNar";
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if ($curStep < $maxStep) {
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# The archive will be used as the base of the next patch.
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rename "$tmpNar2", "$tmpNar" or die "cannot rename NAR archive: $!";
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} else {
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# This was the last patch. Unpack the final NAR archive
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# into the target path.
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print " unpacking patched archive...\n";
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system("@bindir@/nix-store --restore $v < $tmpNar2") == 0
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or die "cannot unpack $tmpNar2 into `$v'";
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}
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}
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elsif ($edge->{type} eq "narfile") {
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my $narFile = $edge->{info};
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print "downloading `$narFile->{url}' into `$v'\n";
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print LOGFILE "$$ narfile $narFile->{url} $narFile->{size} $v\n";
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# Download the archive.
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print " downloading archive...\n";
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my $narFilePath = downloadFile "$narFile->{url}", "$narFile->{hash}";
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if ($curStep < $maxStep) {
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# The archive will be used a base to a patch.
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system("@bunzip2@ < '$narFilePath' > $tmpNar") == 0
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or die "cannot unpack `$narFilePath' into `$v'";
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} else {
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# Unpack the archive into the target path.
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print " unpacking archive...\n";
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system("@bunzip2@ < '$narFilePath' | @bindir@/nix-store --restore '$v'") == 0
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or die "cannot unpack `$narFilePath' into `$v'";
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}
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}
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$curStep++;
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}
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print LOGFILE "$$ success\n";
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close LOGFILE;
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