ikiwiki/IkiWiki/Rcs/git.pm

492 lines
14 KiB
Perl

#!/usr/bin/perl
# Git backend for IkiWiki.
# Copyright 2006 Recai Oktaş <roktas@debian.org>
#
# Licensed under the same terms as IkiWiki.
use warnings;
use strict;
use IkiWiki;
package IkiWiki;
my $origin_branch = 'origin'; # Git ref for main repository
my $master_branch = 'master'; # working branch
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 $web_commit_msg = qr/^web commit by (\w+):?(.*)/; # pattern for web commits
sub _safe_git (&@) { #{{{
# Start a child process safely without resorting /bin/sh.
# Return command output or success state (in scalar context).
my ($error_handler, @cmdline) = @_;
my $pid = open my $OUT, "-|";
error("Cannot fork: $!") if !defined $pid;
if (!$pid) {
# In child.
open STDERR, ">&STDOUT"
or error("Cannot dup STDOUT: $!");
# Git commands want to be in wc.
chdir $config{srcdir}
or error("Cannot chdir to $config{srcdir}: $!");
exec @cmdline or error("Cannot exec '@cmdline': $!");
}
# In parent.
my @lines;
while (<$OUT>) {
chomp;
push @lines, $_;
}
close $OUT;
($error_handler || sub { })->("'@cmdline' failed: $!") if $?;
return wantarray ? @lines : ($? == 0);
}
# Convenient wrappers.
sub run_or_die ($@) { _safe_git(\&IkiWiki::error, @_) }
sub run_or_cry ($@) { _safe_git(sub { warn @_ }, @_) }
sub run_or_non ($@) { _safe_git(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', $master_branch)) {
run_or_cry('git-checkout','-f',$master_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', $master_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;
} #}}}
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) = @_;
# End of stream?
return if !defined @{ $dt_ref } || !length @{ $dt_ref }[0];
my %ci;
# Header line.
HEADER: while (my $line = shift @{ $dt_ref }) {
return if $line !~ m/^diff-tree ($sha1_pattern)/;
my $sha1 = $1;
$ci{'sha1'} = $sha1;
last HEADER;
}
# Identification lines for the commit.
IDENT: 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/^([^<]+) <([^@]+)/) {
my ($fullname, $username) = ($1, $2);
$ci{"${who}_fullname"} = $fullname;
$ci{"${who}_username"} = $username;
} else {
$ci{"${who}_fullname"} =
$ci{"${who}_username"} = $name;
}
} elsif ($line =~ m/^$/) {
# Trailing empty line signals next section.
last IDENT;
}
}
error("No 'tree' or 'parents' seen in diff-tree output")
if !defined $ci{'tree'} || !defined $ci{'parents'};
$ci{'parent'} = @{ $ci{'parents'} }[0];
# Commit message.
COMMENT: while (my $line = shift @{ $dt_ref }) {
if ($line =~ m/^$/) {
# Trailing empty line signals next section.
last COMMENT;
};
$line =~ s/^ //;
push @{ $ci{'comment'} }, $line;
}
# Modified files.
FILE: while (my $line = shift @{ $dt_ref }) {
if ($line =~ m{^:
([0-7]{6})[ ] # from mode
([0-7]{6})[ ] # to mode
($sha1_pattern)[ ] # from sha1
($sha1_pattern)[ ] # to sha1
(.) # status
([0-9]{0,3})\t # similarity
(.*) # file
$}xo) {
my ($sha1_from, $sha1_to, $file) =
($3, $4, $7 );
if ($file =~ m/^"(.*)"$/) {
($file=$1) =~ s/\\([0-7]{1,3})/chr(oct($1))/eg;
}
if (length $file) {
push @{ $ci{'details'} }, {
'file' => $file,
'sha1_from' => $sha1_from,
'sha1_to' => $sha1_to,
};
}
next FILE;
};
last FILE;
}
warn "No detail in diff-tree output" if !defined $ci{'details'};
return \%ci;
} #}}}
sub git_commit_info (;$$) { #{{{
# Return an array of commit info hashes of num commits (default: 1)
# starting from the given sha1sum (default: HEAD).
my ($sha1, $num) = @_;
$num ||= 1;
my @raw_lines =
run_or_die(qq{git-rev-list --max-count=$num $sha1 |
git-diff-tree --stdin --pretty=raw -M -r});
my @ci;
while (my $parsed = _parse_diff_tree(\@raw_lines)) {
push @ci, $parsed;
}
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.
run_or_cry('git-pull', $origin_branch);
} #}}}
sub rcs_prepedit ($) { #{{{
# 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 ($file, $message, $rcstoken) = @_;
# XXX: Wiki directory is in the unlocked state when starting this
# action. But it takes time for a Git process to finish its job
# (especially if a merge required), so we must re-lock to prevent
# race conditions. Only when the time of the real commit action
# (i.e. git-push(1)) comes, we'll unlock the directory.
lockwiki();
# Check to see if the page has been changed by someone else since
# rcs_prepedit was called.
my $cur = git_sha1($file);
my ($prev) = $rcstoken =~ /^($sha1_pattern)$/; # untaint
if (defined $cur && defined $prev && $cur ne $prev) {
my $conflict = _merge_past($prev, $file, $dummy_commit_msg);
return $conflict if defined $conflict;
}
# git-commit(1) returns non-zero if file has not been really changed.
# so we should ignore its exit status (hence run_or_non).
$message = possibly_foolish_untaint($message);
if (run_or_non('git-commit', '-m', $message, '-i', $file)) {
unlockwiki();
run_or_cry('git-push', $origin_branch);
}
return undef; # success
} #}}}
sub rcs_add ($) { # {{{
# Add file to archive.
my ($file) = @_;
run_or_cry('git-add', $file);
} #}}}
sub rcs_recentchanges ($) { #{{{
# List of recent changes.
my ($num) = @_;
eval q{use CGI 'escapeHTML'};
eval q{use Date::Parse};
eval q{use Time::Duration};
my ($sha1, $type, $when, $diffurl, $user, @pages, @message, @rets);
INFO: foreach my $ci (git_commit_info('HEAD', $num)) {
my $title = @{ $ci->{'comment'} }[0];
# Skip redundant commits.
next INFO if ($title eq $dummy_commit_msg);
$sha1 = $ci->{'sha1'};
$type = "web";
$when = concise(ago(time - $ci->{'author_epoch'}));
foreach my $bit (@{ $ci->{'details'} }) {
my $diffurl = $config{'diffurl'};
my $file = $bit->{'file'};
$diffurl =~ s/\[\[file\]\]/$file/go;
$diffurl =~ s/\[\[sha1_parent\]\]/$ci->{'parent'}/go;
$diffurl =~ s/\[\[sha1_from\]\]/$bit->{'sha1_from'}/go;
$diffurl =~ s/\[\[sha1_to\]\]/$bit->{'sha1_to'}/go;
push @pages, {
link => htmllink("", "", pagename($file), 1),
diffurl => $diffurl,
},
}
push @message, { line => escapeHTML($title) };
if (defined $message[0] &&
$message[0]->{line} =~ m/$web_commit_msg/) {
$user = "$1";
$message[0]->{line} = $2;
} else {
$type ="git";
$user = $ci->{'author_username'};
}
push @rets, {
rev => $sha1,
user => htmllink("", "", $user, 1),
committype => $type,
when => $when,
message => [@message],
pages => [@pages],
} if @pages;
$sha1 = $type = $when = $diffurl = $user = undef;
@pages = @message = ();
}
return @rets;
} #}}}
sub rcs_notify () { #{{{
# Send notification mail to subscribed users.
#
# In usual Git usage, hooks/update script is presumed to send
# notification mails (see git-receive-pack(1)). But we prefer
# hooks/post-update to support IkiWiki commits coming from a
# cloned repository (through command line) because post-update
# is called _after_ each ref in repository is updated (update
# hook is called _before_ the repository is updated). Since
# post-update hook does not accept command line arguments, we
# don't have an $ENV variable in this function.
#
# Here, we rely on a simple fact: we can extract all parts of the
# notification content by parsing the "HEAD" commit (which also
# triggers a refresh of IkiWiki pages) and we can obtain the diff
# by comparing HEAD and HEAD^ (the previous commit).
my $sha1 = 'HEAD'; # the commit which triggers this action
my $ci = git_commit_info($sha1);
if (!defined $ci) {
warn "Cannot parse info for '$sha1' commit";
return;
}
my @changed_pages = map { $_->{'file'} } @{ $ci->{'details'} };
my ($user, $message);
if (@{ $ci->{'comment'} }[0] =~ m/$web_commit_msg/) {
$user = "$1";
$message = $2;
} else {
$user = $ci->{'author_username'};
$message = join "\n", @{ $ci->{'comment'} };
}
require IkiWiki::UserInfo;
my @email_recipients = commit_notify_list($user, @changed_pages);
return if !@email_recipients;
# TODO: if a commit spans multiple pages, this will send
# subscribers a diff that might contain pages they did not
# sign up for. Should separate the diff per page and
# reassemble into one mail with just the pages subscribed to.
my $diff = join "\n", run_or_die('git-diff', "${sha1}^", $sha1);
my $subject = "$config{wikiname} update of ";
if (@changed_pages > 2) {
$subject .= "$changed_pages[0] $changed_pages[1] etc";
} else {
$subject .= join " ", @changed_pages;
}
$subject .= " by $user";
my $template = HTML::Template->new(
filename => "$config{templatedir}/notifymail.tmpl"
);
$template->param(
wikiname => $config{wikiname},
diff => $diff,
user => $user,
message => $message,
);
eval q{use Mail::Sendmail};
foreach my $email (@email_recipients) {
sendmail(
To => $email,
From => "$config{wikiname} <$config{adminemail}>",
Subject => $subject,
Message => $template->output,
) or error("Failed to send update notification mail: $!");
}
} #}}}
sub rcs_getctime ($) { #{{{
# Get the ctime of file.
my ($file) = @_;
my $sha1 = git_sha1($file);
my $ci = git_commit_info($sha1);
my $ctime = $ci->{'author_epoch'};
debug("ctime for '$file': ". localtime($ctime) . "\n");
return $ctime;
} #}}}
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