Andrew's git / gitweb.git / git-cvsexportcommit.perl
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git-cvsexportcommit.perlon commit Refer to git-rev-parse:Specifying Revisions from git.txt (d47107d)
   1#!/usr/bin/perl -w
   2
   3# Known limitations:
   4# - cannot add or remove binary files
   5# - does not propagate permissions
   6# - tells "ready for commit" even when things could not be completed
   7#   (eg addition of a binary file)
   8
   9use strict;
  10use Getopt::Std;
  11use File::Temp qw(tempdir);
  12use Data::Dumper;
  13use File::Basename qw(basename dirname);
  14
  15unless ($ENV{GIT_DIR} && -r $ENV{GIT_DIR}){
  16    die "GIT_DIR is not defined or is unreadable";
  17}
  18
  19our ($opt_h, $opt_p, $opt_v, $opt_c, $opt_f, $opt_a, $opt_m );
  20
  21getopts('hpvcfam:');
  22
  23$opt_h && usage();
  24
  25die "Need at least one commit identifier!" unless @ARGV;
  26
  27# setup a tempdir
  28our ($tmpdir, $tmpdirname) = tempdir('git-cvsapplycommit-XXXXXX',
  29                                     TMPDIR => 1,
  30                                     CLEANUP => 1);
  31
  32# resolve target commit
  33my $commit;
  34$commit = pop @ARGV;
  35$commit = safe_pipe_capture('git-rev-parse', '--verify', "$commit^0");
  36chomp $commit;
  37if ($?) {
  38    die "The commit reference $commit did not resolve!";
  39}
  40
  41# resolve what parent we want
  42my $parent;
  43if (@ARGV) {
  44    $parent = pop @ARGV;
  45    $parent =  safe_pipe_capture('git-rev-parse', '--verify', "$parent^0");
  46    chomp $parent;
  47    if ($?) {
  48        die "The parent reference did not resolve!";
  49    }
  50}
  51
  52# find parents from the commit itself
  53my @commit  = safe_pipe_capture('git-cat-file', 'commit', $commit);
  54my @parents;
  55my $committer;
  56my $author;
  57my $stage = 'headers'; # headers, msg
  58my $title;
  59my $msg = '';
  60
  61foreach my $line (@commit) {
  62    chomp $line;
  63    if ($stage eq 'headers' && $line eq '') {
  64        $stage = 'msg';
  65        next;
  66    }
  67
  68    if ($stage eq 'headers') {
  69        if ($line =~ m/^parent (\w{40})$/) { # found a parent
  70            push @parents, $1;
  71        } elsif ($line =~ m/^author (.+) \d+ \+\d+$/) {
  72            $author = $1;
  73        } elsif ($line =~ m/^committer (.+) \d+ \+\d+$/) {
  74            $committer = $1;
  75        }
  76    } else {
  77        $msg .= $line . "\n";
  78        unless ($title) {
  79            $title = $line;
  80        }
  81    }
  82}
  83
  84if ($parent) {
  85    my $found;
  86    # double check that it's a valid parent
  87    foreach my $p (@parents) {
  88        if ($p eq $parent) {
  89            $found = 1;
  90            last;
  91        }; # found it
  92    }
  93    die "Did not find $parent in the parents for this commit!" if !$found;
  94} else { # we don't have a parent from the cmdline...
  95    if (@parents == 1) { # it's safe to get it from the commit
  96        $parent = $parents[0];
  97    } else { # or perhaps not!
  98        die "This commit has more than one parent -- please name the parent you want to use explicitly";
  99    }
 100}
 101
 102$opt_v && print "Applying to CVS commit $commit from parent $parent\n";
 103
 104# grab the commit message
 105open(MSG, ">.msg") or die "Cannot open .msg for writing";
 106if ($opt_m) {
 107    print MSG $opt_m;
 108}
 109print MSG $msg;
 110if ($opt_a) {
 111    print MSG "\n\nAuthor: $author\n";
 112    if ($author ne $committer) {
 113        print MSG "Committer: $committer\n";
 114    }
 115}
 116close MSG;
 117
 118my (@afiles, @dfiles, @mfiles, @dirs);
 119my @files = safe_pipe_capture('git-diff-tree', '-r', $parent, $commit);
 120#print @files;
 121$? && die "Error in git-diff-tree";
 122foreach my $f (@files) {
 123    chomp $f;
 124    my @fields = split(m!\s+!, $f);
 125    if ($fields[4] eq 'A') {
 126        my $path = $fields[5];
 127        push @afiles, $path;
 128        # add any needed parent directories
 129        $path = dirname $path;
 130        while (!-d $path and ! grep { $_ eq $path } @dirs) {
 131            unshift @dirs, $path;
 132            $path = dirname $path;
 133        }
 134    }
 135    if ($fields[4] eq 'M') {
 136        push @mfiles, $fields[5];
 137    }
 138    if ($fields[4] eq 'D') {
 139        push @dfiles, $fields[5];
 140    }
 141}
 142$opt_v && print "The commit affects:\n ";
 143$opt_v && print join ("\n ", @afiles,@mfiles,@dfiles) . "\n\n";
 144undef @files; # don't need it anymore
 145
 146# check that the files are clean and up to date according to cvs
 147my $dirty;
 148foreach my $d (@dirs) {
 149    if (-e $d) {
 150        $dirty = 1;
 151        warn "$d exists and is not a directory!\n";
 152    }
 153}
 154foreach my $f (@afiles) {
 155    # This should return only one value
 156    my @status = grep(m/^File/,  safe_pipe_capture('cvs', '-q', 'status' ,$f));
 157    if (@status > 1) { warn 'Strange! cvs status returned more than one line?'};
 158    if (-d dirname $f and $status[0] !~ m/Status: Unknown$/
 159        and $status[0] !~ m/^File: no file /) {
 160        $dirty = 1;
 161        warn "File $f is already known in your CVS checkout -- perhaps it has been added by another user. Or this may indicate that it exists on a different branch. If this is the case, use -f to force the merge.\n";
 162        warn "Status was: $status[0]\n";
 163    }
 164}
 165foreach my $f (@mfiles, @dfiles) {
 166    # TODO:we need to handle removed in cvs
 167    my @status = grep(m/^File/,  safe_pipe_capture('cvs', '-q', 'status' ,$f));
 168    if (@status > 1) { warn 'Strange! cvs status returned more than one line?'};
 169    unless ($status[0] =~ m/Status: Up-to-date$/) {
 170        $dirty = 1;
 171        warn "File $f not up to date in your CVS checkout!\n";
 172    }
 173}
 174if ($dirty) {
 175    if ($opt_f) {       warn "The tree is not clean -- forced merge\n";
 176        $dirty = 0;
 177    } else {
 178        die "Exiting: your CVS tree is not clean for this merge.";
 179    }
 180}
 181
 182###
 183### NOTE: if you are planning to die() past this point
 184###       you MUST call cleanupcvs(@files) before die()
 185###
 186
 187
 188print "Creating new directories\n";
 189foreach my $d (@dirs) {
 190    unless (mkdir $d) {
 191        warn "Could not mkdir $d: $!";
 192        $dirty = 1;
 193    }
 194    `cvs add $d`;
 195    if ($?) {
 196        $dirty = 1;
 197        warn "Failed to cvs add directory $d -- you may need to do it manually";
 198    }
 199}
 200
 201print "'Patching' binary files\n";
 202
 203my @bfiles = grep(m/^Binary/, safe_pipe_capture('git-diff-tree', '-p', $parent, $commit));
 204@bfiles = map { chomp } @bfiles;
 205foreach my $f (@bfiles) {
 206    # check that the file in cvs matches the "old" file
 207    # extract the file to $tmpdir and compare with cmp
 208    my $tree = safe_pipe_capture('git-rev-parse', "$parent^{tree}");
 209    chomp $tree;
 210    my $blob = `git-ls-tree $tree "$f" | cut -f 1 | cut -d ' ' -f 3`;
 211    chomp $blob;
 212    `git-cat-file blob $blob > $tmpdir/blob`;
 213    if (system('cmp', '-s', $f, "$tmpdir/blob")) {
 214        warn "Binary file $f in CVS does not match parent.\n";
 215        $dirty = 1;
 216        next;
 217    }
 218
 219    # replace with the new file
 220     `git-cat-file blob $blob > $f`;
 221
 222    # TODO: something smart with file modes
 223
 224}
 225if ($dirty) {
 226    cleanupcvs(@files);
 227    die "Exiting: Binary files in CVS do not match parent";
 228}
 229
 230## apply non-binary changes
 231my $fuzz = $opt_p ? 0 : 2;
 232
 233print "Patching non-binary files\n";
 234print `(git-diff-tree -p $parent -p $commit | patch -p1 -F $fuzz ) 2>&1`;
 235
 236my $dirtypatch = 0;
 237if (($? >> 8) == 2) {
 238    cleanupcvs(@files);
 239    die "Exiting: Patch reported serious trouble -- you will have to apply this patch manually";
 240} elsif (($? >> 8) == 1) { # some hunks failed to apply
 241    $dirtypatch = 1;
 242}
 243
 244foreach my $f (@afiles) {
 245    system('cvs', 'add', $f);
 246    if ($?) {
 247        $dirty = 1;
 248        warn "Failed to cvs add $f -- you may need to do it manually";
 249    }
 250}
 251
 252foreach my $f (@dfiles) {
 253    system('cvs', 'rm', '-f', $f);
 254    if ($?) {
 255        $dirty = 1;
 256        warn "Failed to cvs rm -f $f -- you may need to do it manually";
 257    }
 258}
 259
 260print "Commit to CVS\n";
 261print "Patch: $title\n";
 262my $commitfiles = join(' ', @afiles, @mfiles, @dfiles);
 263my $cmd = "cvs commit -F .msg $commitfiles";
 264
 265if ($dirtypatch) {
 266    print "NOTE: One or more hunks failed to apply cleanly.\n";
 267    print "Resolve the conflicts and then commit using:\n";
 268    print "\n    $cmd\n\n";
 269    exit(1);
 270}
 271
 272
 273if ($opt_c) {
 274    print "Autocommit\n  $cmd\n";
 275    print safe_pipe_capture('cvs', 'commit', '-F', '.msg', @afiles, @mfiles, @dfiles);
 276    if ($?) {
 277        cleanupcvs(@files);
 278        die "Exiting: The commit did not succeed";
 279    }
 280    print "Committed successfully to CVS\n";
 281} else {
 282    print "Ready for you to commit, just run:\n\n   $cmd\n";
 283}
 284sub usage {
 285        print STDERR <<END;
 286Usage: GIT_DIR=/path/to/.git ${\basename $0} [-h] [-p] [-v] [-c] [-f] [-m msgprefix] [ parent ] commit
 287END
 288        exit(1);
 289}
 290
 291# ensure cvs is clean before we die
 292sub cleanupcvs {
 293    my @files = @_;
 294    foreach my $f (@files) {
 295        system('cvs', '-q', 'update', '-C', $f);
 296        if ($?) {
 297            warn "Warning! Failed to cleanup state of $f\n";
 298        }
 299    }
 300}
 301
 302# An alternative to `command` that allows input to be passed as an array
 303# to work around shell problems with weird characters in arguments
 304# if the exec returns non-zero we die
 305sub safe_pipe_capture {
 306    my @output;
 307    if (my $pid = open my $child, '-|') {
 308        @output = (<$child>);
 309        close $child or die join(' ',@_).": $! $?";
 310    } else {
 311        exec(@_) or die "$! $?"; # exec() can fail the executable can't be found
 312    }
 313    return wantarray ? @output : join('',@output);
 314}