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|
#! /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;
|
