viewvcs: start improving display of git commits

For non-merge git commits, we already have ViewDiff for
displaying patch emails, we can reuse it to display non-merge
git commits.

AFAIK, this is the first web-based git repository viewer
to display the output of "git-patch-id --stable".
It currently fills in the search form box with "patchid:",
but maybe it'll do more than that.

More work will be done to support bidirectional mapping
of commits to emails in the future.

2 files changed, 107 insertions, 1 deletions

diff --git a/lib/PublicInbox/ViewVCS.pm b/lib/PublicInbox/ViewVCS.pm
index 94656ad3..96883f6c 100644
--- a/lib/PublicInbox/ViewVCS.pm
+++ b/lib/PublicInbox/ViewVCS.pm
@@ -2,7 +2,6 @@
 # License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
 
 # show any VCS object, similar to "git show"
-# FIXME: we only show blobs for now
 #
 # This can use a "solver" to reconstruct blobs based on git
 # patches (with abbreviated OIDs in the header).  However, the
@@ -16,10 +15,12 @@
 package PublicInbox::ViewVCS;
 use strict;
 use v5.10.1;
+use File::Temp 0.19 (); # newdir
 use PublicInbox::SolverGit;
 use PublicInbox::WwwStream qw(html_oneshot);
 use PublicInbox::Linkify;
 use PublicInbox::Tmpfile;
+use PublicInbox::ViewDiff qw(flush_diff);
 use PublicInbox::Hval qw(ascii_html to_filename);
 my $hl = eval {
         require PublicInbox::HlMod;
@@ -29,6 +30,8 @@ my $hl = eval {
 my %QP_MAP = ( A => 'oid_a', a => 'path_a', b => 'path_b' );
 our $MAX_SIZE = 1024 * 1024; # TODO: configurable
 my $BIN_DETECT = 8000; # same as git
+my $SHOW_FMT = '--pretty=format:'.join('%n', '%H', '%T', '%P', '%s',
+        '%an <%ae>%x09%ai', '%cn <%ce>%x09%ci', '%b%x00');
 
 sub html_page ($$$) {
         my ($ctx, $code, $strref) = @_;
@@ -88,6 +91,99 @@ sub show_other_result ($$) {
         html_page($ctx, 200, $bref);
 }
 
+sub show_commit_result ($$) {
+        my ($bref, $ctx) = @_;
+        my ($qsp_err, $logref, $tmp) = @$ctx{qw(-qsp_err -logref -tmp)};
+        if ($qsp_err) {
+                $$logref .= "git show/patch-id error:$qsp_err";
+                return html_page($ctx, 500, $logref);
+        }
+        my $upfx = $ctx->{-upfx} = '../../'; # from "/$INBOX/$OID/s/"
+        my $patchid = (split(/ /, $$bref))[0]; # ignore commit
+        if (defined $patchid) {
+                $ctx->{-q_value_html} = "patchid:$patchid";
+                $patchid = "\n  patchid $patchid";
+        } else {
+                $patchid = '';
+        }
+        my $l = $ctx->{-linkify} = PublicInbox::Linkify->new;
+        open my $fh, '<:utf8', "$tmp/h" or die "open $tmp/h: $!";
+        chop(my $buf = do { local $/ = "\0"; <$fh> });
+        my ($H, $T, $P, $s, $au, $co, $bdy) = split(/\n/, $buf, 7);
+        chomp $bdy;
+        # try to keep author and committer dates lined up
+        my $x = length($au) - length($co);
+        if ($x > 0) {
+                $x = ' ' x $x;
+                $co =~ s/\t/$x\t/;
+        } elsif ($x < 0) {
+                $x = ' ' x (-$x);
+                $au =~ s/\t/$x\t/;
+        }
+        $_ = ascii_html($_) for ($au, $co);
+        $_ = $l->to_html($_) for ($s, $bdy);
+        $ctx->{-title_html} = $s;
+        my @p = split(/ /, $P);
+        if (@p == 1) {
+                $P = qq(\n   parent <a href="$upfx$P/s/">$P</a>);
+        } elsif (@p > 1) {
+                $P = qq(\n  parents <a href="$upfx$p[0]/s/">$p[0]</a>\n);
+                shift @p;
+                $P .= qq(          <a href="$upfx$_/s/">$_</a>\n) for @p;
+                chop $P;
+        } else { # root commit
+                $P = ' (root commit)';
+        }
+        PublicInbox::WwwStream::html_init($ctx);
+        $ctx->zmore(<<EOM);
+<pre>   commit $H$P
+     tree <a href="$upfx$T/s/">$T</a>
+   author $au
+committer $co$patchid
+
+<b>$s</b>\n
+EOM
+        $ctx->zmore($bdy);
+        open $fh, '<', "$tmp/p" or die "open $tmp/p: $!";
+        if (-s $fh > $MAX_SIZE) {
+                $ctx->zmore("---\n patch is too large to show\n");
+        } else { # prepare flush_diff:
+                $buf = '';
+                $ctx->{obuf} = \$buf;
+                $ctx->{-apfx} = $ctx->{-spfx} = $upfx;
+                $ctx->{-anchors} = {};
+                $bdy = '';
+                read($fh, $bdy, -s _);
+                $bdy =~ s/\r?\n/\n/gs;
+                flush_diff($ctx, \$bdy);
+                $ctx->zmore($buf);
+        }
+        $x = $ctx->zflush($ctx->_html_end);
+        my $res_hdr = delete $ctx->{-res_hdr};
+        push @$res_hdr, 'Content-Length', length($x);
+        delete($ctx->{env}->{'qspawn.wcb'})->([200, $res_hdr, [$x]]);
+}
+
+sub show_commit ($$$$) {
+        my ($ctx, $res, $logref, $fn) = @_;
+        my ($git, $oid) = @$res;
+        # patch-id needs two passes, and we use the initial show to ensure
+        # a patch embedded inside the commit message body doesn't get fed
+        # to patch-id:
+        my $cmd = [ '/bin/sh', '-c',
+                "git show '$SHOW_FMT' -z --no-notes --no-patch $oid >h && ".
+                "git show --pretty=format:%n -M --stat -p $oid >p && ".
+                "git patch-id --stable <p" ];
+        my $xenv = { GIT_DIR => $git->{git_dir} };
+        my $tmp = File::Temp->newdir("show-$oid-XXXX", TMPDIR => 1);
+        my $qsp = PublicInbox::Qspawn->new($cmd, $xenv, { -C => "$tmp" });
+        $qsp->{qsp_err} = \($ctx->{-qsp_err} = '');
+        $ctx->{-logref} = $logref;
+        $ctx->{-tmp} = $tmp;
+        $ctx->{env}->{'qspawn.wcb'} = delete $ctx->{-wcb};
+        $qsp->psgi_qx($ctx->{env}, undef, \&show_commit_result, $ctx);
+}
+
 sub show_other ($$$$) {
         my ($ctx, $res, $logref, $fn) = @_;
         my ($git, $oid, $type, $size) = @$res;
@@ -122,6 +218,7 @@ sub solve_result {
         ref($res) eq 'ARRAY' or return html_page($ctx, 500, \$log);
 
         my ($git, $oid, $type, $size, $di) = @$res;
+        return show_commit($ctx, $res, \$log, $fn) if $type eq 'commit';
         return show_other($ctx, $res, \$log, $fn) if $type ne 'blob';
         my $path = to_filename($di->{path_b} // $hints->{path_b} // 'blob');
         my $raw_link = "(<a\nhref=$path>raw</a>)";
diff --git a/lib/PublicInbox/WwwStream.pm b/lib/PublicInbox/WwwStream.pm
index 0416db0b..ab006c40 100644
--- a/lib/PublicInbox/WwwStream.pm
+++ b/lib/PublicInbox/WwwStream.pm
@@ -201,4 +201,13 @@ sub aresponse {
         $ctx->psgi_response($code, $res_hdr);
 }
 
+sub html_init {
+        my ($ctx) = @_;
+        $ctx->{base_url} = base_url($ctx);
+        my $h = $ctx->{-res_hdr} = ['Content-Type', 'text/html; charset=UTF-8'];
+        $ctx->{gz} = PublicInbox::GzipFilter::gz_or_noop($h, $ctx->{env});
+        bless $ctx, __PACKAGE__;
+        $ctx->zmore(html_top($ctx));
+}
+
 1;