repobrowse: simplify git log parsing implementation

Based on what was done for the Atom feed, this will allow us to
simplify state management through metaprogramming and avoid
placeholder characters ('D' for decoration) for empty fields.

1 files changed, 61 insertions, 89 deletions

diff --git a/lib/PublicInbox/RepobrowseGitLog.pm b/lib/PublicInbox/RepobrowseGitLog.pm
index e62486ba..21c23fd3 100644
--- a/lib/PublicInbox/RepobrowseGitLog.pm
+++ b/lib/PublicInbox/RepobrowseGitLog.pm
@@ -10,8 +10,9 @@ use base qw(PublicInbox::RepobrowseBase);
 use PublicInbox::RepobrowseGit qw(git_dec_links git_commit_title);
 use PublicInbox::Qspawn;
 # cannot rely on --date=format-local:... yet, it is too new (September 2015)
-my $LOG_FMT = '--pretty=tformat:'.
-                join('%x00', qw(%h %p %s D%D %ai a%an b%b), '', '');
+use constant STATES => qw(h p D ai an s b);
+use constant STATE_BODY => (scalar(STATES) - 1);
+my $LOG_FMT = '--pretty=tformat:'.  join('%n', map { "%$_" } STATES).'%x00';
 
 sub parent_links {
         if (@_ == 1) { # typical, single-parent commit
@@ -24,11 +25,33 @@ sub parent_links {
         }
 }
 
+sub flush_log_hdr ($$$) {
+        my ($req, $dst, $hdr) = @_;
+        my $rel = $req->{relcmd};
+        my $seen = $req->{seen};
+        $$dst .= '<hr /><pre>' if scalar keys %$seen;
+        my $id = $hdr->{h};
+        $seen->{$id} = 1;
+        $$dst .= qq(<a\nid=p$id\n);
+        $$dst .= qq(href="${rel}commit?id=$id"><b>);
+        $$dst .= utf8_html($hdr->{'s'}); # FIXME may still OOM
+        $$dst .= '</b></a>';
+        my $D = $hdr->{D}; # FIXME: thousands of decorations may OOM us
+        if ($D ne '') {
+                $$dst .= ' (' . join(', ', git_dec_links($rel, $D)) . ')';
+        }
+        my @p = split(/ /, $hdr->{p});
+        push @{$req->{parents}}, @p;
+        my $plinks = parent_links(@p);
+        $$dst .= "\n- ";
+        $$dst .= utf8_html($hdr->{an});
+        $$dst .= " @ $hdr->{ai}\n  commit $id$plinks\n";
+        undef
+}
+
 sub git_log_sed_end ($$) {
-        my $req = $_[0];
-        my $dst = delete $req->{lhtml} || '';
-        $dst .= utf8_html($_[1]); # existing buffer
-        $dst .= '</pre><hr /><pre>';
+        my ($req, $dst) = @_;
+        $$dst .= '<hr /><pre>';
         my $m = '';
         my $np = 0;
         my $seen = $req->{seen};
@@ -43,106 +66,55 @@ sub git_log_sed_end ($$) {
                 $m .= qq(<a\nhref="${rel}commit?id=$p">$s</a>);
         }
         if ($np == 0) {
-                $dst .= "No commits follow";
+                $$dst .= "No commits follow";
         } elsif ($np > 1) {
-                $dst .= "Unseen parent commits to follow (multiple choice):\n";
+                $$dst .= "Unseen parent commits to follow (multiple choice):\n";
         } else {
-                $dst .= "Next parent to follow:\n";
+                $$dst .= "Next parent to follow:\n";
         }
-        $dst .= $m;
-        $dst .= '</pre></body></html>';
+        $$dst .= $m;
+        $$dst .= '</pre></body></html>';
 }
 
 sub git_log_sed ($$) {
         my ($self, $req) = @_;
         my $buf = '';
-        my $state = 'h';
-        my %acache;
-        my $rel = $req->{relcmd};
-        my $seen = $req->{seen} = {};
-        my $parents = $req->{parents} = [];
-        my ($plinks, $id, $ai);
+        my $state = 0;
+        $req->{seen} = {};
+        $req->{parents} = [];
+        my $hdr = {};
         sub {
                 my $dst;
                 # $_[0] == scalar buffer, undef means EOF from "git log"
-                return git_log_sed_end($req, $buf) unless defined $_[0];
                 $dst = delete $req->{lhtml} || '';
                 my @tmp;
-                $buf .= $_[0];
-                @tmp = split(/\0/, $buf, -1);
-                $buf = @tmp ? pop(@tmp) : '';
+                if (defined $_[0]) {
+                        $buf .= $_[0];
+                        @tmp = split(/\n/, $buf, -1);
+                        $buf = @tmp ? pop(@tmp) : '';
+                } else {
+                        @tmp = split(/\n/, $buf, -1);
+                        $buf = undef;
+                }
 
-                while (@tmp) {
-                        if ($state eq 'b') {
-                                my $bb = shift @tmp;
-                                $state = 'B' if $bb =~ s/\Ab/\n/;
-                                my @lines = split(/\n/, $bb);
-                                $bb = utf8_html(pop @lines);
-                                $dst .= utf8_html($_)."\n" for @lines;
-                                $dst .= $bb;
-                        } elsif ($state eq 'B') {
-                                my $bb = shift @tmp;
-                                if ($bb eq '') {
-                                        $state = 'BB';
-                                } else {
-                                        my @lines = split(/\n/, $bb);
-                                        $bb = undef;
-                                        my $last = utf8_html(pop @lines);
-                                        $dst .= utf8_html($_)."\n" for @lines;
-                                        $dst .= $last;
-                                }
-                        } elsif ($state eq 'BB') {
-                                if ($tmp[0] =~ s/\A\n//s) {
-                                        $state = 'h';
-                                } else {
-                                        @tmp = ();
-                                        warn 'Bad state BB in log parser: ',
-                                                $req->{-debug};
-                                }
-                        } elsif ($state eq 'h') {
-                                if (scalar keys %$seen) {
-                                        $dst .= '</pre><hr /><pre>';
+                foreach my $l (@tmp) {
+                        if ($state != STATE_BODY) {
+                                $hdr->{((STATES)[$state])} = $l;
+                                if (++$state == STATE_BODY) {
+                                        flush_log_hdr($req, \$dst, $hdr);
+                                        $hdr = {};
                                 }
-                                $id = shift @tmp;
-                                $seen->{$id} = 1;
-                                $state = 'p'
-                        } elsif ($state eq 'p') {
-                                my @p = split(/ /, shift @tmp);
-                                push @$parents, @p;
-                                $plinks = parent_links(@p);
-                                $state = 's'
-                        } elsif ($state eq 's') {
-                                # FIXME: excessively long subjects OOM us
-                                my $s = shift @tmp;
-                                $dst .= qq(<a\nid=p$id\n);
-                                $dst .= qq(href="${rel}commit?id=$id"><b>);
-                                $dst .= utf8_html($s);
-                                $dst .= '</b></a>';
-                                $state = 'D'
-                        } elsif ($state eq 'D') {
-                                # FIXME: thousands of decorations may OOM us
-                                my $D = shift @tmp;
-                                if ($D =~ /\AD(.+)/) {
-                                        $dst .= ' (';
-                                        $dst .= join(', ',
-                                                git_dec_links($rel, $1));
-                                        $dst .= ')';
-                                }
-                                $state = 'ai';
-                        } elsif ($state eq 'ai') {
-                                $ai = shift @tmp;
-                                $state = 'an';
-                        } elsif ($state eq 'an') {
-                                my $an = shift @tmp;
-                                $an =~ s/\Aa// or
-                                        die "missing 'a' from author: $an";
-                                my $ah = $acache{$an} ||= utf8_html($an);
-                                $dst .= "\n- $ah @ $ai\n  commit $id$plinks\n";
-                                $id = $plinks = $ai = '';
-                                $state = 'b';
+                                next;
+                        }
+                        if ($l eq "\0") {
+                                $dst .= qq(</pre>);
+                                $state = 0;
+                        } else {
+                                $dst .= "\n";
+                                $dst .= utf8_html($l);
                         }
                 }
-
+                git_log_sed_end($req, \$dst) unless defined $buf;
                 $dst;
         };
 }