diff options
Diffstat (limited to 'scripts/generate-patches.pl')
| -rwxr-xr-x | scripts/generate-patches.pl | 216 |
1 files changed, 216 insertions, 0 deletions
diff --git a/scripts/generate-patches.pl b/scripts/generate-patches.pl new file mode 100755 index 000000000..e084b994d --- /dev/null +++ b/scripts/generate-patches.pl @@ -0,0 +1,216 @@ +#! /usr/bin/perl -w -I. + +use strict; +use POSIX qw(tmpnam); +use readmanifest; + +die unless scalar @ARGV == 5; + +my $cacheDir = $ARGV[0]; +my $patchesDir = $ARGV[1]; +my $patchesURL = $ARGV[2]; +my $srcDir = $ARGV[3]; +my $dstDir = $ARGV[4]; + +my $tmpdir; +do { $tmpdir = tmpnam(); } +until mkdir $tmpdir, 0777; + +print "TEMP = $tmpdir\n"; + +#END { rmdir $tmpdir; } + +my %srcNarFiles; +my %srcPatches; +my %srcSuccessors; + +my %dstNarFiles; +my %dstPatches; +my %dstSuccessors; + +readManifest "$srcDir/MANIFEST", + \%srcNarFiles, \%srcPatches, \%srcSuccessors; + +readManifest "$dstDir/MANIFEST", + \%dstNarFiles, \%dstPatches, \%dstSuccessors; + + +sub findOutputPaths { + my $narFiles = shift; + my $successors = shift; + + my %outPaths; + + foreach my $p (keys %{$narFiles}) { + + # Ignore store expressions. + next if ($p =~ /\.store$/); + + # Ignore builders (too much ambiguity -- they're all called + # `builder.sh'). + next if ($p =~ /\.sh$/); + next if ($p =~ /\.patch$/); + + # Don't bother including tar files etc. + next if ($p =~ /\.tar\.(gz|bz2)$/ || $p =~ /\.zip$/ || $p =~ /\.bin$/); + + $outPaths{$p} = 1; + } + + return %outPaths; +} + +print "finding src output paths...\n"; +my %srcOutPaths = findOutputPaths \%srcNarFiles, \%srcSuccessors; + +print "finding dst output paths...\n"; +my %dstOutPaths = findOutputPaths \%dstNarFiles, \%dstSuccessors; + + +sub getNameVersion { + my $p = shift; + $p =~ /\/[0-9a-f]+((?:-[a-zA-Z][^\/-]*)+)([^\/]*)$/; + my $name = $1; + my $version = $2; + $name =~ s/^-//; + $version =~ s/^-//; + return ($name, $version); +} + + +# A quick hack to get a measure of the `distance' between two +# versions: it's just the position of the first character that differs +# (or 999 if they are the same). +sub versionDiff { + my $s = shift; + my $t = shift; + my $i; + return 999 if $s eq $t; + for ($i = 0; $i < length $s; $i++) { + return $i if $i >= length $t or + substr($s, $i, 1) ne substr($t, $i, 1); + } + return $i; +} + + +sub getNarBz2 { + my $narFiles = shift; + my $storePath = shift; + + my $narFileList = $$narFiles{$storePath}; + die "missing store expression $storePath" unless defined $narFileList; + + my $narFile = @{$narFileList}[0]; + die unless defined $narFile; + + $narFile->{url} =~ /\/([^\/]+)$/; + die unless defined $1; + return "$cacheDir/$1"; +} + + +# For each output path in the destination, see if we need to / can +# create a patch. + +print "creating patches...\n"; + +foreach my $p (keys %dstOutPaths) { + + # If exactly the same path already exists in the source, skip it. + next if defined $srcOutPaths{$p}; + +# print " $p\n"; + + # If not, then we should find the path in the source that is + # `most' likely to be present on a system that wants to install + # this path. + + (my $name, my $version) = getNameVersion $p; + + my @closest = (); + my $closestVersion; + my $minDist = -1; # actually, larger means closer + + # Find all source paths with the same name. + + foreach my $q (keys %srcOutPaths) { + (my $name2, my $version2) = getNameVersion $q; + if ($name eq $name2) { + my $dist = versionDiff $version, $version2; + if ($dist > $minDist) { + $minDist = $dist; + @closest = ($q); + $closestVersion = $version2; + } elsif ($dist == $minDist) { + push @closest, $q; + } + } + } + + if (scalar(@closest) == 0) { + print " NO BASE: $p\n"; + next; + } + + foreach my $closest (@closest) { + + # Generate a patch between $closest and $p. + print " $p <- $closest\n"; + + # If the patch already exists, skip it. + my $patchList = $dstPatches{$p}; + if (defined $patchList) { + my $found = 0; + foreach my $patch (@{$patchList}) { + if ($patch->{basePath} eq $closest) { + # !!! baseHash might differ + print " skipping, already exists\n"; + $found = 1; + last; + } + } + next if $found; + } + + my $srcNarBz2 = getNarBz2 \%srcNarFiles, $closest; + my $dstNarBz2 = getNarBz2 \%dstNarFiles, $p; + + system("bunzip2 < $srcNarBz2 > $tmpdir/A") == 0 + or die "cannot unpack $srcNarBz2"; + + system("bunzip2 < $dstNarBz2 > $tmpdir/B") == 0 + or die "cannot unpack $dstNarBz2"; + + system("bsdiff $tmpdir/A $tmpdir/B $tmpdir/DIFF") == 0 + or die "cannot compute binary diff"; + + my $baseHash = `nix-hash --flat $tmpdir/A` or die; + chomp $baseHash; + + my $narHash = `nix-hash --flat $tmpdir/B` or die; + chomp $narHash; + + my $narBz2Hash = `nix-hash --flat $tmpdir/DIFF` or die; + chomp $narBz2Hash; + + my $narBz2Size = (stat "$tmpdir/DIFF")[7]; + + my $finalName = + "$narBz2Hash-$name-$closestVersion-to-$version.nar-diff"; + + system("cp '$tmpdir/DIFF' '$patchesDir/$finalName'") == 0 + or die "cannot copy diff"; + + # Add the patch to the manifest. + addPatch \%dstPatches, $p, + { url => "$patchesURL/$finalName", hash => $narBz2Hash + , size => $narBz2Size + , basePath => $closest, baseHash => $baseHash + , narHash => $narHash, patchType => "nar-bsdiff" + }; + } +} + +writeManifest "$dstDir/MANIFEST", + \%dstNarFiles, \%dstPatches, \%dstSuccessors; |