viewdiff: cleanup state transitions a bit

This makes things less error-prone and allows us to only
highlight the "@@ -\S+ \+\S+ @@" part of the hunk header
line, without highlighting the function context.

This more closely matches the coloring behavior of git-diff(1)

diff --git a/lib/PublicInbox/ViewDiff.pm b/lib/PublicInbox/ViewDiff.pm
index 0d1aefb78bdea037425867bc9f3366a7ed7b1fc5..1fa18459425533893f3b725ed64c8a0b7f3d89e4 100644 (file)
--- a/lib/PublicInbox/ViewDiff.pm
+++ b/lib/PublicInbox/ViewDiff.pm
@@ -18,10 +18,18 @@ use PublicInbox::Git qw(git_unquote);
 sub DSTATE_INIT () { 0 }
 sub DSTATE_STAT () { 1 } # TODO
 sub DSTATE_HEAD () { 2 } # /^diff --git /, /^index /, /^--- /, /^\+\+\+ /
-sub DSTATE_HUNK () { 3 } # /^@@ /
-sub DSTATE_CTX () { 4 } # /^ /
-sub DSTATE_ADD () { 5 } # /^\+/
-sub DSTATE_DEL () { 6 } # /^\-/
+sub DSTATE_CTX () { 3 } # /^ /
+sub DSTATE_ADD () { 4 } # /^\+/
+sub DSTATE_DEL () { 5 } # /^\-/
+my @state2class = (
+       '', # init
+       '', # stat
+       'head',
+       '', # ctx
+       'add',
+       'del'
+);
+
 sub UNSAFE () { "^A-Za-z0-9\-\._~/" }
 
 my $OID_NULL = '0{7,40}';
@@ -59,6 +67,14 @@ sub oid ($$$) {
        defined($spfx) ? qq(<a\nhref=$spfx$oid/s/$dctx->{Q}>$oid</a>) : $oid;
 }
 
+sub to_state ($$$) {
+       my ($dst, $state, $new_state) = @_;
+       $$dst .= '</span>' if $state2class[$state];
+       $_[1] = $new_state;
+       my $class = $state2class[$new_state] or return;
+       $$dst .= "<span\nclass=$class>";
+}
+
 sub flush_diff ($$$$) {
        my ($dst, $spfx, $linkify, $diff) = @_;
        my $state = DSTATE_INIT;
@@ -66,24 +82,18 @@ sub flush_diff ($$$$) {
 
        foreach my $s (@$diff) {
                if ($s =~ /^ /) {
-                       if ($state == DSTATE_HUNK || $state == DSTATE_ADD ||
-                           $state == DSTATE_DEL || $state == DSTATE_HEAD) {
-                               $$dst .= "</span><span\nclass=ctx>";
-                               $state = DSTATE_CTX;
+                       if ($state2class[$state]) {
+                               to_state($dst, $state, DSTATE_CTX);
                        }
                        $$dst .= to_html($linkify, $s);
                } elsif ($s =~ /^-- $/) { # email signature begins
-                       if ($state != DSTATE_INIT) {
-                               $state = DSTATE_INIT;
-                               $$dst .= '</span>';
-                       }
+                       $state == DSTATE_INIT or
+                               to_state($dst, $state, DSTATE_INIT);
                        $$dst .= $s;
                } elsif ($s =~ m!^diff --git ($PATH_A) ($PATH_B)$!) {
                        if ($state != DSTATE_HEAD) {
                                my ($pa, $pb) = ($1, $2);
-                               $$dst .= '</span>' if $state != DSTATE_INIT;
-                               $$dst .= "<span\nclass=head>";
-                               $state = DSTATE_HEAD;
+                               to_state($dst, $state, DSTATE_HEAD);
                                $pa = (split('/', git_unquote($pa), 2))[1];
                                $pb = (split('/', git_unquote($pb), 2))[1];
                                $dctx = {
@@ -106,38 +116,26 @@ sub flush_diff ($$$$) {
                        $dctx->{oid_b} = $2;
                        $$dst .= to_html($linkify, $s);
                } elsif ($s =~ s/^@@ (\S+) (\S+) @@//) {
-                       my ($ca, $cb) = ($1, $2);
-                       if ($state == DSTATE_HEAD || $state == DSTATE_CTX ||
-                           $state == DSTATE_ADD || $state == DSTATE_DEL) {
-                               $$dst .= "</span><span\nclass=hunk>";
-                               $state = DSTATE_HUNK;
-                               $$dst .= diff_hunk($dctx, $spfx, $ca, $cb);
-                       } else {
-                               $$dst .= to_html($linkify, "@@ $ca $cb @@");
-                       }
+                       $$dst .= '</span>' if $state2class[$state];
+                       $$dst .= "<span\nclass=hunk>";
+                       $$dst .= diff_hunk($dctx, $spfx, $1, $2);
+                       $$dst .= '</span>';
+                       $state = DSTATE_CTX;
                        $$dst .= to_html($linkify, $s);
-               } elsif ($s =~ m!^--- $PATH_A!) {
-                       if ($state == DSTATE_INIT) { # color only (no oid link)
-                               $state = DSTATE_HEAD;
-                               $$dst .= "<span\nclass=head>";
-                       }
-                       $$dst .= to_html($linkify, $s);
-               } elsif ($s =~ m!^\+{3} $PATH_B!)  {
-                       if ($state == DSTATE_INIT) { # color only (no oid link)
-                               $state = DSTATE_HEAD;
-                               $$dst .= "<span\nclass=head>";
-                       }
+               } elsif ($s =~ m!^--- $PATH_A! ||
+                        $s =~ m!^\+{3} $PATH_B!)  {
+                       # color only (no oid link)
+                       $state == DSTATE_INIT and
+                               to_state($dst, $state, DSTATE_HEAD);
                        $$dst .= to_html($linkify, $s);
                } elsif ($s =~ /^\+/) {
                        if ($state != DSTATE_ADD && $state != DSTATE_INIT) {
-                               $$dst .= "</span><span\nclass=add>";
-                               $state = DSTATE_ADD;
+                               to_state($dst, $state, DSTATE_ADD);
                        }
                        $$dst .= to_html($linkify, $s);
                } elsif ($s =~ /^-/) {
                        if ($state != DSTATE_DEL && $state != DSTATE_INIT) {
-                               $$dst .= "</span><span\nclass=del>";
-                               $state = DSTATE_DEL;
+                               to_state($dst, $state, DSTATE_DEL);
                        }
                        $$dst .= to_html($linkify, $s);
                # ignore the following lines in headers:
@@ -148,15 +146,13 @@ sub flush_diff ($$$$) {
                         $s =~ /^(?:dis)?similarity index /) {
                        $$dst .= to_html($linkify, $s);
                } else {
-                       if ($state != DSTATE_INIT) {
-                               $$dst .= '</span>';
-                               $state = DSTATE_INIT;
-                       }
+                       $state == DSTATE_INIT or
+                               to_state($dst, $state, DSTATE_INIT);
                        $$dst .= to_html($linkify, $s);
                }
        }
        @$diff = ();
-       $$dst .= '</span>' if $state != DSTATE_INIT;
+       $$dst .= '</span>' if $state2class[$state];
        undef;
 }