add paths to plugin files in copyright

[ikiwiki.git] / IkiWiki / Plugin / git.pm

#!/usr/bin/perl
package IkiWiki::Plugin::git;

use warnings;
use strict;
use IkiWiki;
use Encode;
use open qw{:utf8 :std};

my $sha1_pattern     = qr/[0-9a-fA-F]{40}/; # pattern to validate Git sha1sums
my $dummy_commit_msg = 'dummy commit';      # message to skip in recent changes
my $git_dir=undef;

sub import {
        hook(type => "checkconfig", id => "git", call => \&checkconfig);
        hook(type => "getsetup", id => "git", call => \&getsetup);
        hook(type => "genwrapper", id => "git", call => \&genwrapper);
        hook(type => "rcs", id => "rcs_update", call => \&rcs_update);
        hook(type => "rcs", id => "rcs_prepedit", call => \&rcs_prepedit);
        hook(type => "rcs", id => "rcs_commit", call => \&rcs_commit);
        hook(type => "rcs", id => "rcs_commit_staged", call => \&rcs_commit_staged);
        hook(type => "rcs", id => "rcs_add", call => \&rcs_add);
        hook(type => "rcs", id => "rcs_remove", call => \&rcs_remove);
        hook(type => "rcs", id => "rcs_rename", call => \&rcs_rename);
        hook(type => "rcs", id => "rcs_recentchanges", call => \&rcs_recentchanges);
        hook(type => "rcs", id => "rcs_diff", call => \&rcs_diff);
        hook(type => "rcs", id => "rcs_getctime", call => \&rcs_getctime);
        hook(type => "rcs", id => "rcs_getmtime", call => \&rcs_getmtime);
        hook(type => "rcs", id => "rcs_receive", call => \&rcs_receive);
        hook(type => "rcs", id => "rcs_preprevert", call => \&rcs_preprevert);
        hook(type => "rcs", id => "rcs_revert", call => \&rcs_revert);
}

sub checkconfig () {
        if (! defined $config{gitorigin_branch}) {
                $config{gitorigin_branch}="origin";
        }
        if (! defined $config{gitmaster_branch}) {
                $config{gitmaster_branch}="master";
        }
        if (defined $config{git_wrapper} &&
            length $config{git_wrapper}) {
                push @{$config{wrappers}}, {
                        wrapper => $config{git_wrapper},
                        wrappermode => (defined $config{git_wrappermode} ? $config{git_wrappermode} : "06755"),
                        wrapper_background_command => $config{git_wrapper_background_command},
                };
        }

        if (defined $config{git_test_receive_wrapper} &&
            length $config{git_test_receive_wrapper} &&
            defined $config{untrusted_committers} &&
            @{$config{untrusted_committers}}) {
                push @{$config{wrappers}}, {
                        test_receive => 1,
                        wrapper => $config{git_test_receive_wrapper},
                        wrappermode => (defined $config{git_wrappermode} ? $config{git_wrappermode} : "06755"),
                };
        }

        # Avoid notes, parser does not handle and they only slow things down.
        $ENV{GIT_NOTES_REF}="";
        
        # Run receive test only if being called by the wrapper, and not
        # when generating same.
        if ($config{test_receive} && ! exists $config{wrapper}) {
                require IkiWiki::Receive;
                IkiWiki::Receive::test();
        }
}

sub getsetup () {
        return
                plugin => {
                        safe => 0, # rcs plugin
                        rebuild => undef,
                        section => "rcs",
                },
                git_wrapper => {
                        type => "string",
                        example => "/git/wiki.git/hooks/post-update",
                        description => "git hook to generate",
                        safe => 0, # file
                        rebuild => 0,
                },
                git_wrapper_background_command => {
                        type => "string",
                        example => "git push github",
                        description => "shell command for git_wrapper to run, in the background",
                        safe => 0, # command
                        rebuild => 0,
                },
                git_wrappermode => {
                        type => "string",
                        example => '06755',
                        description => "mode for git_wrapper (can safely be made suid)",
                        safe => 0,
                        rebuild => 0,
                },
                git_test_receive_wrapper => {
                        type => "string",
                        example => "/git/wiki.git/hooks/pre-receive",
                        description => "git pre-receive hook to generate",
                        safe => 0, # file
                        rebuild => 0,
                },
                untrusted_committers => {
                        type => "string",
                        example => [],
                        description => "unix users whose commits should be checked by the pre-receive hook",
                        safe => 0,
                        rebuild => 0,
                },
                historyurl => {
                        type => "string",
                        example => "http://git.example.com/gitweb.cgi?p=wiki.git;a=history;f=[[file]];hb=HEAD",
                        description => "gitweb url to show file history ([[file]] substituted)",
                        safe => 1,
                        rebuild => 1,
                },
                diffurl => {
                        type => "string",
                        example => "http://git.example.com/gitweb.cgi?p=wiki.git;a=blobdiff;f=[[file]];h=[[sha1_to]];hp=[[sha1_from]];hb=[[sha1_commit]];hpb=[[sha1_parent]]",
                        description => "gitweb url to show a diff ([[file]], [[sha1_to]], [[sha1_from]], [[sha1_commit]], and [[sha1_parent]] substituted)",
                        safe => 1,
                        rebuild => 1,
                },
                gitorigin_branch => {
                        type => "string",
                        example => "origin",
                        description => "where to pull and push changes (set to empty string to disable)",
                        safe => 0, # paranoia
                        rebuild => 0,
                },
                gitmaster_branch => {
                        type => "string",
                        example => "master",
                        description => "branch that the wiki is stored in",
                        safe => 0, # paranoia
                        rebuild => 0,
                },
}

sub genwrapper {
        if ($config{test_receive}) {
                require IkiWiki::Receive;
                return IkiWiki::Receive::genwrapper();
        }
        else {
                return "";
        }
}

sub safe_git (&@) {
        # Start a child process safely without resorting to /bin/sh.
        # Returns command output (in list content) or success state
        # (in scalar context), or runs the specified data handler.

        my ($error_handler, $data_handler, @cmdline) = @_;

        my $pid = open my $OUT, "-|";

        error("Cannot fork: $!") if !defined $pid;

        if (!$pid) {
                # In child.
                # Git commands want to be in wc.
                if (! defined $git_dir) {
                        chdir $config{srcdir}
                            or error("cannot chdir to $config{srcdir}: $!");
                }
                else {
                        chdir $git_dir
                            or error("cannot chdir to $git_dir: $!");
                }
                exec @cmdline or error("Cannot exec '@cmdline': $!");
        }
        # In parent.

        # git output is probably utf-8 encoded, but may contain
        # other encodings or invalidly encoded stuff. So do not rely
        # on the normal utf-8 IO layer, decode it by hand.
        binmode($OUT);

        my @lines;
        while (<$OUT>) {
                $_=decode_utf8($_, 0);

                chomp;

                if (! defined $data_handler) {
                        push @lines, $_;
                }
                else {
                        last unless $data_handler->($_);
                }
        }

        close $OUT;

        $error_handler->("'@cmdline' failed: $!") if $? && $error_handler;

        return wantarray ? @lines : ($? == 0);
}
# Convenient wrappers.
sub run_or_die ($@) { safe_git(\&error, undef, @_) }
sub run_or_cry ($@) { safe_git(sub { warn @_ }, undef, @_) }
sub run_or_non ($@) { safe_git(undef, undef, @_) }


sub merge_past ($$$) {
        # Unlike with Subversion, Git cannot make a 'svn merge -rN:M file'.
        # Git merge commands work with the committed changes, except in the
        # implicit case of '-m' of git checkout(1).  So we should invent a
        # kludge here.  In principle, we need to create a throw-away branch
        # in preparing for the merge itself.  Since branches are cheap (and
        # branching is fast), this shouldn't cost high.
        #
        # The main problem is the presence of _uncommitted_ local changes.  One
        # possible approach to get rid of this situation could be that we first
        # make a temporary commit in the master branch and later restore the
        # initial state (this is possible since Git has the ability to undo a
        # commit, i.e. 'git reset --soft HEAD^').  The method can be summarized
        # as follows:
        #
        #       - create a diff of HEAD:current-sha1
        #       - dummy commit
        #       - create a dummy branch and switch to it
        #       - rewind to past (reset --hard to the current-sha1)
        #       - apply the diff and commit
        #       - switch to master and do the merge with the dummy branch
        #       - make a soft reset (undo the last commit of master)
        #
        # The above method has some drawbacks: (1) it needs a redundant commit
        # just to get rid of local changes, (2) somewhat slow because of the
        # required system forks.  Until someone points a more straight method
        # (which I would be grateful) I have implemented an alternative method.
        # In this approach, we hide all the modified files from Git by renaming
        # them (using the 'rename' builtin) and later restore those files in
        # the throw-away branch (that is, we put the files themselves instead
        # of applying a patch).

        my ($sha1, $file, $message) = @_;

        my @undo;      # undo stack for cleanup in case of an error
        my $conflict;  # file content with conflict markers

        eval {
                # Hide local changes from Git by renaming the modified file.
                # Relative paths must be converted to absolute for renaming.
                my ($target, $hidden) = (
                    "$config{srcdir}/${file}", "$config{srcdir}/${file}.${sha1}"
                );
                rename($target, $hidden)
                    or error("rename '$target' to '$hidden' failed: $!");
                # Ensure to restore the renamed file on error.
                push @undo, sub {
                        return if ! -e "$hidden"; # already renamed
                        rename($hidden, $target)
                            or warn "rename '$hidden' to '$target' failed: $!";
                };

                my $branch = "throw_away_${sha1}"; # supposed to be unique

                # Create a throw-away branch and rewind backward.
                push @undo, sub { run_or_cry('git', 'branch', '-D', $branch) };
                run_or_die('git', 'branch', $branch, $sha1);

                # Switch to throw-away branch for the merge operation.
                push @undo, sub {
                        if (!run_or_cry('git', 'checkout', $config{gitmaster_branch})) {
                                run_or_cry('git', 'checkout','-f',$config{gitmaster_branch});
                        }
                };
                run_or_die('git', 'checkout', $branch);

                # Put the modified file in _this_ branch.
                rename($hidden, $target)
                    or error("rename '$hidden' to '$target' failed: $!");

                # _Silently_ commit all modifications in the current branch.
                run_or_non('git', 'commit', '-m', $message, '-a');
                # ... and re-switch to master.
                run_or_die('git', 'checkout', $config{gitmaster_branch});

                # Attempt to merge without complaining.
                if (!run_or_non('git', 'pull', '--no-commit', '.', $branch)) {
                        $conflict = readfile($target);
                        run_or_die('git', 'reset', '--hard');
                }
        };
        my $failure = $@;

        # Process undo stack (in reverse order).  By policy cleanup
        # actions should normally print a warning on failure.
        while (my $handle = pop @undo) {
                $handle->();
        }

        error("Git merge failed!\n$failure\n") if $failure;

        return $conflict;
}

{
my $prefix;
sub decode_git_file ($) {
        my $file=shift;

        # git does not output utf-8 filenames, but instead
        # double-quotes them with the utf-8 characters
        # escaped as \nnn\nnn.
        if ($file =~ m/^"(.*)"$/) {
                ($file=$1) =~ s/\\([0-7]{1,3})/chr(oct($1))/eg;
        }

        # strip prefix if in a subdir
        if (! defined $prefix) {
                ($prefix) = run_or_die('git', 'rev-parse', '--show-prefix');
                if (! defined $prefix) {
                        $prefix="";
                }
        }
        $file =~ s/^\Q$prefix\E//;

        return decode("utf8", $file);
}
}

sub parse_diff_tree ($) {
        # Parse the raw diff tree chunk and return the info hash.
        # See git-diff-tree(1) for the syntax.
        my $dt_ref = shift;

        # End of stream?
        return if !defined @{ $dt_ref } ||
                  !defined @{ $dt_ref }[0] || !length @{ $dt_ref }[0];

        my %ci;
        # Header line.
        while (my $line = shift @{ $dt_ref }) {
                return if $line !~ m/^(.+) ($sha1_pattern)/;

                my $sha1 = $2;
                $ci{'sha1'} = $sha1;
                last;
        }

        # Identification lines for the commit.
        while (my $line = shift @{ $dt_ref }) {
                # Regexps are semi-stolen from gitweb.cgi.
                if ($line =~ m/^tree ([0-9a-fA-F]{40})$/) {
                        $ci{'tree'} = $1;
                }
                elsif ($line =~ m/^parent ([0-9a-fA-F]{40})$/) {
                        # XXX: collecting in reverse order
                        push @{ $ci{'parents'} }, $1;
                }
                elsif ($line =~ m/^(author|committer) (.*) ([0-9]+) (.*)$/) {
                        my ($who, $name, $epoch, $tz) =
                           ($1,   $2,    $3,     $4 );

                        $ci{  $who          } = $name;
                        $ci{ "${who}_epoch" } = $epoch;
                        $ci{ "${who}_tz"    } = $tz;

                        if ($name =~ m/^([^<]+)\s+<([^@>]+)/) {
                                $ci{"${who}_name"} = $1;
                                $ci{"${who}_username"} = $2;
                        }
                        elsif ($name =~ m/^([^<]+)\s+<>$/) {
                                $ci{"${who}_username"} = $1;
                        }
                        else {
                                $ci{"${who}_username"} = $name;
                        }
                }
                elsif ($line =~ m/^$/) {
                        # Trailing empty line signals next section.
                        last;
                }
        }

        debug("No 'tree' seen in diff-tree output") if !defined $ci{'tree'};
        
        if (defined $ci{'parents'}) {
                $ci{'parent'} = @{ $ci{'parents'} }[0];
        }
        else {
                $ci{'parent'} = 0 x 40;
        }

        # Commit message (optional).
        while ($dt_ref->[0] =~ /^    /) {
                my $line = shift @{ $dt_ref };
                $line =~ s/^    //;
                push @{ $ci{'comment'} }, $line;
        }
        shift @{ $dt_ref } if $dt_ref->[0] =~ /^$/;

        # Modified files.
        while (my $line = shift @{ $dt_ref }) {
                if ($line =~ m{^
                        (:+)       # number of parents
                        ([^\t]+)\t # modes, sha1, status
                        (.*)       # file names
                $}xo) {
                        my $num_parents = length $1;
                        my @tmp = split(" ", $2);
                        my ($file, $file_to) = split("\t", $3);
                        my @mode_from = splice(@tmp, 0, $num_parents);
                        my $mode_to = shift(@tmp);
                        my @sha1_from = splice(@tmp, 0, $num_parents);
                        my $sha1_to = shift(@tmp);
                        my $status = shift(@tmp);

                        if (length $file) {
                                push @{ $ci{'details'} }, {
                                        'file'      => decode_git_file($file),
                                        'sha1_from' => $sha1_from[0],
                                        'sha1_to'   => $sha1_to,
                                        'mode_from' => $mode_from[0],
                                        'mode_to'   => $mode_to,
                                        'status'    => $status,
                                };
                        }
                        next;
                };
                last;
        }

        return \%ci;
}

sub git_commit_info ($;$) {
        # Return an array of commit info hashes of num commits
        # starting from the given sha1sum.
        my ($sha1, $num) = @_;

        my @opts;
        push @opts, "--max-count=$num" if defined $num;

        my @raw_lines = run_or_die('git', 'log', @opts,
                '--pretty=raw', '--raw', '--abbrev=40', '--always', '-c',
                '-r', $sha1, '--', '.');

        my @ci;
        while (my $parsed = parse_diff_tree(\@raw_lines)) {
                push @ci, $parsed;
        }

        warn "Cannot parse commit info for '$sha1' commit" if !@ci;

        return wantarray ? @ci : $ci[0];
}

sub git_sha1 (;$) {
        # Return head sha1sum (of given file).
        my $file = shift || q{--};

        # Ignore error since a non-existing file might be given.
        my ($sha1) = run_or_non('git', 'rev-list', '--max-count=1', 'HEAD',
                '--', $file);
        if ($sha1) {
                ($sha1) = $sha1 =~ m/($sha1_pattern)/; # sha1 is untainted now
        }
        else {
                debug("Empty sha1sum for '$file'.");
        }
        return defined $sha1 ? $sha1 : q{};
}

sub rcs_update () {
        # Update working directory.

        if (length $config{gitorigin_branch}) {
                run_or_cry('git', 'pull', '--prune', $config{gitorigin_branch});
        }
}

sub rcs_prepedit ($) {
        # Return the commit sha1sum of the file when editing begins.
        # This will be later used in rcs_commit if a merge is required.
        my ($file) = @_;

        return git_sha1($file);
}

sub rcs_commit (@) {
        # Try to commit the page; returns undef on _success_ and
        # a version of the page with the rcs's conflict markers on
        # failure.
        my %params=@_;

        # Check to see if the page has been changed by someone else since
        # rcs_prepedit was called.
        my $cur    = git_sha1($params{file});
        my ($prev) = $params{token} =~ /^($sha1_pattern)$/; # untaint

        if (defined $cur && defined $prev && $cur ne $prev) {
                my $conflict = merge_past($prev, $params{file}, $dummy_commit_msg);
                return $conflict if defined $conflict;
        }

        return rcs_commit_helper(@_);
}

sub rcs_commit_staged (@) {
        # Commits all staged changes. Changes can be staged using rcs_add,
        # rcs_remove, and rcs_rename.
        return rcs_commit_helper(@_);
}

sub rcs_commit_helper (@) {
        my %params=@_;
        
        my %env=%ENV;

        if (defined $params{session}) {
                # Set the commit author and email based on web session info.
                my $u;
                if (defined $params{session}->param("name")) {
                        $u=$params{session}->param("name");
                }
                elsif (defined $params{session}->remote_addr()) {
                        $u=$params{session}->remote_addr();
                }
                if (defined $u) {
                        $u=encode_utf8($u);
                        $ENV{GIT_AUTHOR_NAME}=$u;
                }
                if (defined $params{session}->param("nickname")) {
                        $u=encode_utf8($params{session}->param("nickname"));
                        $u=~s/\s+/_/g;
                        $u=~s/[^-_0-9[:alnum:]]+//g;
                }
                if (defined $u) {
                        $ENV{GIT_AUTHOR_EMAIL}="$u\@web";
                }
        }

        $params{message} = IkiWiki::possibly_foolish_untaint($params{message});
        my @opts;
        if ($params{message} !~ /\S/) {
                # Force git to allow empty commit messages.
                # (If this version of git supports it.)
                my ($version)=`git --version` =~ /git version (.*)/;
                if ($version ge "1.5.4") {
                        push @opts, '--cleanup=verbatim';
                }
                else {
                        $params{message}.=".";
                }
        }
        if (exists $params{file}) {
                push @opts, '--', $params{file};
        }
        # git commit returns non-zero if nothing really changed.
        # So we should ignore its exit status (hence run_or_non).
        if (run_or_non('git', 'commit', '-m', $params{message}, '-q', @opts)) {
                if (length $config{gitorigin_branch}) {
                        run_or_cry('git', 'push', $config{gitorigin_branch});
                }
        }
        
        %ENV=%env;
        return undef; # success
}

sub rcs_add ($) {
        # Add file to archive.

        my ($file) = @_;

        run_or_cry('git', 'add', $file);
}

sub rcs_remove ($) {
        # Remove file from archive.

        my ($file) = @_;

        run_or_cry('git', 'rm', '-f', $file);
}

sub rcs_rename ($$) {
        my ($src, $dest) = @_;

        run_or_cry('git', 'mv', '-f', $src, $dest);
}

sub rcs_recentchanges ($) {
        # List of recent changes.

        my ($num) = @_;

        eval q{use Date::Parse};
        error($@) if $@;

        my @rets;
        foreach my $ci (git_commit_info('HEAD', $num || 1)) {
                # Skip redundant commits.
                next if ($ci->{'comment'} && @{$ci->{'comment'}}[0] eq $dummy_commit_msg);

                my ($sha1, $when) = (
                        $ci->{'sha1'},
                        $ci->{'author_epoch'}
                );

                my @pages;
                foreach my $detail (@{ $ci->{'details'} }) {
                        my $file = $detail->{'file'};

                        my $diffurl = defined $config{'diffurl'} ? $config{'diffurl'} : "";
                        $diffurl =~ s/\[\[file\]\]/$file/go;
                        $diffurl =~ s/\[\[sha1_parent\]\]/$ci->{'parent'}/go;
                        $diffurl =~ s/\[\[sha1_from\]\]/$detail->{'sha1_from'}/go;
                        $diffurl =~ s/\[\[sha1_to\]\]/$detail->{'sha1_to'}/go;
                        $diffurl =~ s/\[\[sha1_commit\]\]/$sha1/go;

                        push @pages, {
                                page => pagename($file),
                                diffurl => $diffurl,
                        };
                }

                my @messages;
                my $pastblank=0;
                foreach my $line (@{$ci->{'comment'}}) {
                        $pastblank=1 if $line eq '';
                        next if $pastblank && $line=~m/^ *(signed[ \-]off[ \-]by[ :]|acked[ \-]by[ :]|cc[ :])/i;
                        push @messages, { line => $line };
                }

                my $user=$ci->{'author_username'};
                my $web_commit = ($ci->{'author'} =~ /\@web>/);
                my $nickname;

                # Set nickname only if a non-url author_username is available,
                # and author_name is an url.
                if ($user !~ /:\/\// && defined $ci->{'author_name'} &&
                    $ci->{'author_name'} =~ /:\/\//) {
                        $nickname=$user;
                        $user=$ci->{'author_name'};
                }

                # compatability code for old web commit messages
                if (! $web_commit &&
                      defined $messages[0] &&
                      $messages[0]->{line} =~ m/$config{web_commit_regexp}/) {
                        $user = defined $2 ? "$2" : "$3";
                        $messages[0]->{line} = $4;
                        $web_commit=1;
                }

                push @rets, {
                        rev        => $sha1,
                        user       => $user,
                        nickname   => $nickname,
                        committype => $web_commit ? "web" : "git",
                        when       => $when,
                        message    => [@messages],
                        pages      => [@pages],
                } if @pages;

                last if @rets >= $num;
        }

        return @rets;
}

sub rcs_diff ($;$) {
        my $rev=shift;
        my $maxlines=shift;
        my ($sha1) = $rev =~ /^($sha1_pattern)$/; # untaint
        my @lines;
        my $addlines=sub {
                my $line=shift;
                return if defined $maxlines && @lines == $maxlines;
                push @lines, $line."\n"
                        if (@lines || $line=~/^diff --git/);
                return 1;
        };
        safe_git(undef, $addlines, "git", "show", $sha1);
        if (wantarray) {
                return @lines;
        }
        else {
                return join("", @lines);
        }
}

{
my %time_cache;

sub findtimes ($$) {
        my $file=shift;
        my $id=shift; # 0 = mtime ; 1 = ctime

        if (! keys %time_cache) {
                my $date;
                foreach my $line (run_or_die('git', 'log',
                                '--pretty=format:%at',
                                '--name-only', '--relative')) {
                        if (! defined $date && $line =~ /^(\d+)$/) {
                                $date=$line;
                        }
                        elsif (! length $line) {
                                $date=undef;
                        }
                        else {
                                my $f=decode_git_file($line);

                                if (! $time_cache{$f}) {
                                        $time_cache{$f}[0]=$date; # mtime
                                }
                                $time_cache{$f}[1]=$date; # ctime
                        }
                }
        }

        return exists $time_cache{$file} ? $time_cache{$file}[$id] : 0;
}

}

sub rcs_getctime ($) {
        my $file=shift;

        return findtimes($file, 1);
}

sub rcs_getmtime ($) {
        my $file=shift;

        return findtimes($file, 0);
}

{
my $ret;
sub git_find_root {
        # The wiki may not be the only thing in the git repo.
        # Determine if it is in a subdirectory by examining the srcdir,
        # and its parents, looking for the .git directory.

        return @$ret if defined $ret;
        
        my $subdir="";
        my $dir=$config{srcdir};
        while (! -d "$dir/.git") {
                $subdir=IkiWiki::basename($dir)."/".$subdir;
                $dir=IkiWiki::dirname($dir);
                if (! length $dir) {
                        error("cannot determine root of git repo");
                }
        }

        $ret=[$subdir, $dir];
        return @$ret;
}

}

sub git_parse_changes {
        my @changes = @_;

        my ($subdir, $rootdir) = git_find_root();
        my @rets;
        foreach my $ci (@changes) {
                foreach my $detail (@{ $ci->{'details'} }) {
                        my $file = $detail->{'file'};

                        # check that all changed files are in the subdir
                        if (length $subdir &&
                            ! ($file =~ s/^\Q$subdir\E//)) {
                                error sprintf(gettext("you are not allowed to change %s"), $file);
                        }

                        my ($action, $mode, $path);
                        if ($detail->{'status'} =~ /^[M]+\d*$/) {
                                $action="change";
                                $mode=$detail->{'mode_to'};
                        }
                        elsif ($detail->{'status'} =~ /^[AM]+\d*$/) {
                                $action="add";
                                $mode=$detail->{'mode_to'};
                        }
                        elsif ($detail->{'status'} =~ /^[DAM]+\d*/) {
                                $action="remove";
                                $mode=$detail->{'mode_from'};
                        }
                        else {
                                error "unknown status ".$detail->{'status'};
                        }

                        # test that the file mode is ok
                        if ($mode !~ /^100[64][64][64]$/) {
                                error sprintf(gettext("you cannot act on a file with mode %s"), $mode);
                        }
                        if ($action eq "change") {
                                if ($detail->{'mode_from'} ne $detail->{'mode_to'}) {
                                        error gettext("you are not allowed to change file modes");
                                }
                        }

                        # extract attachment to temp file
                        if (($action eq 'add' || $action eq 'change') &&
                            ! pagetype($file)) {
                                eval q{use File::Temp};
                                die $@ if $@;
                                my $fh;
                                ($fh, $path)=File::Temp::tempfile(undef, UNLINK => 1);
                                my $cmd = "cd $git_dir && ".
                                          "git show $detail->{sha1_to} > '$path'";
                                if (system($cmd) != 0) {
                                        error("failed writing temp file '$path'.");
                                }
                        }

                        push @rets, {
                                file => $file,
                                action => $action,
                                path => $path,
                        };
                }
        }

        return @rets;
}

sub rcs_receive () {
        my @rets;
        while (<>) {
                chomp;
                my ($oldrev, $newrev, $refname) = split(' ', $_, 3);

                # only allow changes to gitmaster_branch
                if ($refname !~ /^refs\/heads\/\Q$config{gitmaster_branch}\E$/) {
                        error sprintf(gettext("you are not allowed to change %s"), $refname);
                }

                # Avoid chdir when running git here, because the changes
                # are in the master git repo, not the srcdir repo.
                # (Also, if a subdir is involved, we don't want to chdir to
                # it and only see changes in it.)
                # The pre-receive hook already puts us in the right place.
                $git_dir=".";
                push @rets, git_parse_changes(git_commit_info($oldrev."..".$newrev));
                $git_dir=undef;
        }

        return reverse @rets;
}

sub rcs_preprevert ($) {
        my $rev=shift;
        my ($sha1) = $rev =~ /^($sha1_pattern)$/; # untaint

        # Examine changes from root of git repo, not from any subdir,
        # in order to see all changes.
        my ($subdir, $rootdir) = git_find_root();
        $git_dir=$rootdir;

        my @commits=git_commit_info($sha1, 1);
        if (! @commits) {
                error "unknown commit"; # just in case
        }

        # git revert will fail on merge commits. Add a nice message.
        if (exists $commits[0]->{parents} &&
            @{$commits[0]->{parents}} > 1) {
                error gettext("you are not allowed to revert a merge");
        }

        my @ret=git_parse_changes(@commits);

        $git_dir=undef;
        return @ret;
}

sub rcs_revert ($) {
        # Try to revert the given rev; returns undef on _success_.
        my $rev = shift;
        my ($sha1) = $rev =~ /^($sha1_pattern)$/; # untaint

        if (run_or_non('git', 'revert', '--no-commit', $sha1)) {
                return undef;
        }
        else {
                run_or_die('git', 'reset', '--hard');
                return sprintf(gettext("Failed to revert commit %s"), $sha1);
        }
}

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