+sub cmt_title { # git->cat_async callback
+ my ($bref, $oid, $type, $size, $ctx) = @_;
+ utf8::decode($$bref);
+ my $title = $$bref =~ /\r?\n\r?\n([^\r\n]+)\r?\n?/ ? $1 : '';
+ push(@{$ctx->{-cmt_pt}} , ascii_html($title)) == @{$ctx->{-cmt_P}} and
+ cmt_finalize($ctx);
+}
+
+sub show_commit_start { # ->psgi_qx callback
+ my ($bref, $ctx) = @_;
+ if (my $qsp_err = delete $ctx->{-qsp_err}) {
+ return html_page($ctx, 500, dbg_log($ctx) .
+ "git show/patch-id error:$qsp_err");
+ }
+ my $patchid = (split(/ /, $$bref))[0]; # ignore commit
+ $ctx->{-q_value_html} = "patchid:$patchid" if defined $patchid;
+ open my $fh, '<:utf8', "$ctx->{-tmp}/h" or
+ die "open $ctx->{-tmp}/h: $!";
+ chop(my $buf = do { local $/ = "\0"; <$fh> });
+ chomp $buf;
+ my ($P, $p);
+ ($P, $p, @{$ctx->{cmt_info}}) = split(/\n/, $buf, 9);
+ return cmt_finalize($ctx) if !$P;
+ @{$ctx->{-cmt_P}} = split(/ /, $P);
+ @{$ctx->{-cmt_p}} = split(/ /, $p); # abbreviated
+ if ($ctx->{env}->{'pi-httpd.async'}) {
+ for (@{$ctx->{-cmt_P}}) {
+ ibx_async_cat($ctx, $_, \&cmt_title, $ctx);
+ }
+ } else { # synchronous
+ for (@{$ctx->{-cmt_P}}) {
+ $ctx->{git}->cat_async($_, \&cmt_title, $ctx);
+ }
+ $ctx->{git}->cat_async_wait;
+ }
+}
+
+sub cmt_finalize {
+ my ($ctx) = @_;
+ $ctx->{-linkify} //= PublicInbox::Linkify->new;
+ my $upfx = $ctx->{-upfx} = '../../'; # from "/$INBOX/$OID/s/"
+ my ($H, $T, $s, $f, $au, $co, $bdy) = @{delete $ctx->{cmt_info}};
+ # try to keep author and committer dates lined up
+ my $x = length($au) - length($co);
+ if ($x > 0) {
+ $x = ' ' x $x;
+ $co =~ s/>/>$x/;
+ } elsif ($x < 0) {
+ $x = ' ' x (-$x);
+ $au =~ s/>/>$x/;
+ }
+ $_ = ascii_html($_) for ($au, $co);
+ $au =~ s!(> +)([0-9]{4,}-\S+ \S+)!
+ my ($gt, $t) = ($1, $2);
+ $t =~ tr/ :-//d;
+ qq($gt<a
+href="$upfx?t=$t"
+title="list contemporary emails">$2</a>)
+ !e;
+ $ctx->{-title_html} = $s = $ctx->{-linkify}->to_html($s);
+ my ($P, $p, $pt) = delete @$ctx{qw(-cmt_P -cmt_p -cmt_pt)};
+ $_ = qq(<a href="$upfx$_/s/">).shift(@$p).'</a> '.shift(@$pt) for @$P;
+ if (@$P == 1) {
+ $x = qq{ (<a
+href="$f.patch">patch</a>)\n <a href=#parent>parent</a> $P->[0]};
+ } elsif (@$P > 1) {
+ $x = qq(\n <a href=#parents>parents</a> $P->[0]\n);
+ shift @$P;
+ $x .= qq( $_\n) for @$P;
+ chop $x;
+ } else {
+ $x = ' (<a href=#root_commit>root commit</a>)';
+ }
+ PublicInbox::WwwStream::html_init($ctx);
+ $ctx->zmore(<<EOM);
+<pre> <a href=#commit>commit</a> $H$x
+ <a href=#tree>tree</a> <a href="$upfx$T/s/">$T</a>
+ author $au
+committer $co
+
+<b>$s</b>
+EOM
+ $ctx->zmore("\n", $ctx->{-linkify}->to_html($bdy)) if length($bdy);
+ $bdy = '';
+ open my $fh, '<:utf8', "$ctx->{-tmp}/p" or
+ die "open $ctx->{-tmp}/p: $!";
+ if (-s $fh > $MAX_SIZE) {
+ $ctx->zmore("---\n patch is too large to show\n");
+ } else { # prepare flush_diff:
+ read($fh, $x, -s _);
+ $ctx->{obuf} = \$bdy;
+ $ctx->{-apfx} = $ctx->{-spfx} = $upfx;
+ $x =~ s/\r?\n/\n/gs;
+ $ctx->{-anchors} = {} if $x =~ /^diff --git /sm;
+ flush_diff($ctx, \$x); # undefs $x
+ $ctx->zmore($bdy);
+ undef $bdy;
+ # TODO: should there be another textarea which attempts to
+ # search for the exact email which was applied to make this
+ # commit?
+ if (my $qry = delete $ctx->{-qry}) {
+ my $q = '';
+ for (@{$qry->{dfpost}}, @{$qry->{dfpre}}) {
+ # keep blobs as short as reasonable, emails
+ # are going to be older than what's in git
+ substr($_, 7, 64, '');
+ $q .= "dfblob:$_ ";
+ }
+ chop $q; # no trailing SP
+ local $Text::Wrap::columns = PublicInbox::View::COLS;
+ local $Text::Wrap::huge = 'overflow';
+ $q = wrap('', '', $q);
+ my $rows = ($q =~ tr/\n/\n/) + 1;
+ $q = ascii_html($q);
+ $ctx->zmore(<<EOM);
+<hr><form action=$upfx
+id=related><pre>find related emails, including ancestors/descendants/conflicts
+<textarea name=q cols=${\PublicInbox::View::COLS} rows=$rows>$q</textarea>
+<input type=submit value=search
+/>\t(<a href=${upfx}_/text/help/>help</a>)</pre></form>
+EOM
+ }
+ }
+ chop($x = <<EOM);
+<hr><pre>glossary
+--------
+<dfn
+id=commit>Commit</dfn> objects reference one tree, and zero or more parents.
+
+Single <dfn
+id=parent>parent</dfn> commits can typically generate a patch in
+unified diff format via `git format-patch'.
+
+Multiple <dfn id=parents>parents</dfn> means the commit is a merge.
+
+<dfn id=root_commit>Root commits</dfn> have no ancestor. Note that it is
+possible to have multiple root commits when merging independent histories.
+
+Every commit references one top-level <dfn id=tree>tree</dfn> object.</pre>
+EOM
+ $x = $ctx->zflush($x, $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 stream_patch_parse_hdr { # {parse_hdr} for Qspawn
+ my ($r, $bref, $ctx) = @_;
+ if (!defined $r) { # sysread error
+ html_page($ctx, 500, dbg_log($ctx));
+ } elsif (index($$bref, "\n\n") >= 0) {
+ my $eml = bless { hdr => $bref }, 'PublicInbox::Eml';
+ my $fn = to_filename($eml->header('Subject') // '');
+ $fn = substr($fn // 'PATCH-no-subject', 6); # drop "PATCH-"
+ return [ 200, [ 'Content-Type', 'text/plain; charset=UTF-8',
+ 'Content-Disposition',
+ qq(inline; filename=$fn.patch) ] ];
+ } elsif ($r == 0) {
+ my $log = dbg_log($ctx);
+ warn "premature EOF on $ctx->{patch_oid} $log";
+ return html_page($ctx, 500, $log);
+ } else {
+ undef; # bref keeps growing until "\n\n"