#!/usr/bin/env perl # Copyright 2005, Ryan Anderson <ryan@michonline.com> # Distribution permitted under the GPL v2, as distributed # by the Free Software Foundation. # Later versions of the GPL at the discretion of Linus Torvalds # # Scan two git object-trees, and hardlink any common objects between them. use 5.008; use strict; use warnings; use Getopt::Long; sub get_canonical_form($); sub do_scan_directory($$$); sub compare_two_files($$); sub usage(); sub link_two_files($$); # stats my $total_linked = 0; my $total_already = 0; my ($linked,$already); my $fail_on_different_sizes = 0; my $help = 0; GetOptions("safe" => \$fail_on_different_sizes, "help" => \$help); usage() if $help; my (@dirs) = @ARGV; usage() if (!defined $dirs[0] || !defined $dirs[1]); $_ = get_canonical_form($_) foreach (@dirs); my $master_dir = pop @dirs; opendir(D,$master_dir . "objects/") or die "Failed to open $master_dir/objects/ : $!"; my @hashdirs = grep { ($_ eq 'pack') || /^[0-9a-f]{2}$/ } readdir(D); foreach my $repo (@dirs) { $linked = 0; $already = 0; printf("Searching '%s' and '%s' for common objects and hardlinking them...\n", $master_dir,$repo); foreach my $hashdir (@hashdirs) { do_scan_directory($master_dir, $hashdir, $repo); } printf("Linked %d files, %d were already linked.\n",$linked, $already); $total_linked += $linked; $total_already += $already; } printf("Totals: Linked %d files, %d were already linked.\n", $total_linked, $total_already); sub do_scan_directory($$$) { my ($srcdir, $subdir, $dstdir) = @_; my $sfulldir = sprintf("%sobjects/%s/",$srcdir,$subdir); my $dfulldir = sprintf("%sobjects/%s/",$dstdir,$subdir); opendir(S,$sfulldir) or die "Failed to opendir $sfulldir: $!"; foreach my $file (grep(!/\.{1,2}$/, readdir(S))) { my $sfilename = $sfulldir . $file; my $dfilename = $dfulldir . $file; compare_two_files($sfilename,$dfilename); } closedir(S); } sub compare_two_files($$) { my ($sfilename, $dfilename) = @_; # Perl's stat returns relevant information as follows: # 0 = dev number # 1 = inode number # 7 = size my @sstatinfo = stat($sfilename); my @dstatinfo = stat($dfilename); if (@sstatinfo == 0 && @dstatinfo == 0) { die sprintf("Stat of both %s and %s failed: %s\n",$sfilename, $dfilename, $!); } elsif (@dstatinfo == 0) { return; } if ( ($sstatinfo[0] == $dstatinfo[0]) && ($sstatinfo[1] != $dstatinfo[1])) { if ($sstatinfo[7] == $dstatinfo[7]) { link_two_files($sfilename, $dfilename); } else { my $err = sprintf("ERROR: File sizes are not the same, cannot relink %s to %s.\n", $sfilename, $dfilename); if ($fail_on_different_sizes) { die $err; } else { warn $err; } } } elsif ( ($sstatinfo[0] == $dstatinfo[0]) && ($sstatinfo[1] == $dstatinfo[1])) { $already++; } } sub get_canonical_form($) { my $dir = shift; my $original = $dir; die "$dir is not a directory." unless -d $dir; $dir .= "/" unless $dir =~ m#/$#; $dir .= ".git/" unless $dir =~ m#\.git/$#; die "$original does not have a .git/ subdirectory.\n" unless -d $dir; return $dir; } sub link_two_files($$) { my ($sfilename, $dfilename) = @_; my $tmpdname = sprintf("%s.old",$dfilename); rename($dfilename,$tmpdname) or die sprintf("Failure renaming %s to %s: %s", $dfilename, $tmpdname, $!); if (! link($sfilename,$dfilename)) { my $failtxt = ""; unless (rename($tmpdname,$dfilename)) { $failtxt = sprintf( "Git Repository containing %s is probably corrupted, " . "please copy '%s' to '%s' to fix.\n", $tmpdname, $dfilename); } die sprintf("Failed to link %s to %s: %s\n%s" . $sfilename, $dfilename, $!, $dfilename, $failtxt); } unlink($tmpdname) or die sprintf("Unlink of %s failed: %s\n", $dfilename, $!); $linked++; } sub usage() { print("Usage: git relink [--safe] <dir>... <master_dir> \n"); print("All directories should contain a .git/objects/ subdirectory.\n"); print("Options\n"); print("\t--safe\t" . "Stops if two objects with the same hash exist but " . "have different sizes. Default is to warn and continue.\n"); exit(1); }