viewdiff: favor `qr' to precompile regexps

We can also avoid `o' regexp modifier, since it isn't
recommended by Perl upstream, anymore (although we don't
have any bugs or unintended behavior because of it).

diff --git a/lib/PublicInbox/ViewDiff.pm b/lib/PublicInbox/ViewDiff.pm
index 57a1b5d66dd9dda27de87c3106da22fb3f385355..d22c80b97b4871a00dba47f3e8b055bd1659ab06 100644 (file)
--- a/lib/PublicInbox/ViewDiff.pm
+++ b/lib/PublicInbox/ViewDiff.pm
@@ -25,7 +25,23 @@ my $ANY = qr![^\n]!;
 my $FN = qr!(?:"?[^/\n]+/[^\n]+|/dev/null)!;
 
 # cf. git diff.c :: get_compact_summary
-my $DIFFSTAT_COMMENT = qr/\((?:new|gone|(?:(?:new|mode) [\+\-][lx]))\)/;
+my $DIFFSTAT_COMMENT =
+       qr/(?: *\((?:new|gone|(?:(?:new|mode) [\+\-][lx]))\))? *\z/s;
+my $NULL_TO_BLOB = qr/^(index $OID_NULL\.\.)($OID_BLOB)\b/ms;
+my $BLOB_TO_NULL = qr/^index ($OID_BLOB)(\.\.$OID_NULL)\b/ms;
+my $BLOB_TO_BLOB = qr/^index ($OID_BLOB)\.\.($OID_BLOB)/ms;
+my $EXTRACT_DIFFS = qr/(
+               (?:     # begin header stuff, don't capture filenames, here,
+                       # but instead wait for the --- and +++ lines.
+                       (?:^diff\x20--git\x20$FN\x20$FN$LF)
+
+                       # old mode || new mode || copy|rename|deleted|...
+                       (?:^[a-z]$ANY+$LF)*
+               )? # end of optional stuff, everything below is required
+               ^index\x20($OID_BLOB)\.\.($OID_BLOB)$ANY*$LF
+               ^---\x20($FN)$LF
+               ^\+{3}\x20($FN)$LF)/msx;
+my $IS_OID = qr/\A$OID_BLOB\z/s;
 
 # link to line numbers in blobs
 sub diff_hunk ($$$$) {
@@ -62,7 +78,7 @@ sub anchor0 ($$$$) {
        # So only do best-effort handling of renames for common cases;
        # which works well in practice. If projects put "=>", or trailing
        # spaces in filenames, oh well :P
-       $fn =~ s/(?: *$DIFFSTAT_COMMENT)? *\z//so;
+       $fn =~ s/$DIFFSTAT_COMMENT//;
        $fn =~ s/{(?:.+) => (.+)}/$1/ or $fn =~ s/.* => (.+)/$1/;
        $fn = git_unquote($fn);
 
@@ -132,18 +148,17 @@ sub diff_header ($$$$) {
 
        # no need to capture oid_a and oid_b on add/delete,
        # we just linkify OIDs directly via s///e in conditional
-       if (($$x =~ s/^(index $OID_NULL\.\.)($OID_BLOB)\b/
-                       $1 . oid($dctx, $spfx, $2)/emos) ||
-               ($$x =~ s/^index ($OID_BLOB)(\.\.$OID_NULL)\b/
-                       'index ' . oid($dctx, $spfx, $1) . $2/emos)) {
-       } elsif ($$x =~ /^index ($OID_BLOB)\.\.($OID_BLOB)/mos) {
+       if (($$x =~ s/$NULL_TO_BLOB/$1 . oid($dctx, $spfx, $2)/e) ||
+               ($$x =~ s/$BLOB_TO_NULL/
+                       'index ' . oid($dctx, $spfx, $1) . $2/e)) {
+       } elsif ($$x =~ $BLOB_TO_BLOB) {
                # modification-only, not add/delete:
                # linkify hunk headers later using oid_a and oid_b
                @$dctx{qw(oid_a oid_b)} = ($1, $2);
        } else {
                warn "BUG? <$$x> had no ^index line";
        }
-       $$x =~ s!^diff --git!anchor1($ctx, $pb) // 'diff --git'!emos;
+       $$x =~ s!^diff --git!anchor1($ctx, $pb) // 'diff --git'!ems;
        $$dst .= qq(<span\nclass="head">);
        $$dst .= $$x;
        $$dst .= '</span>';
@@ -174,17 +189,7 @@ sub diff_before_or_after ($$$) {
 sub flush_diff ($$$) {
        my ($dst, $ctx, $cur) = @_;
 
-       my @top = split(/(
-               (?:     # begin header stuff, don't capture filenames, here,
-                       # but instead wait for the --- and +++ lines.
-                       (?:^diff\x20--git\x20$FN\x20$FN$LF)
-
-                       # old mode || new mode || copy|rename|deleted|...
-                       (?:^[a-z]$ANY+$LF)*
-               )? # end of optional stuff, everything below is required
-               ^index\x20($OID_BLOB)\.\.($OID_BLOB)$ANY*$LF
-               ^---\x20($FN)$LF
-               ^\+{3}\x20($FN)$LF)/smxo, $$cur);
+       my @top = split($EXTRACT_DIFFS, $$cur);
        $$cur = undef;
 
        my $linkify = $ctx->{-linkify};
@@ -192,8 +197,8 @@ sub flush_diff ($$$) {
 
        while (defined(my $x = shift @top)) {
                if (scalar(@top) >= 4 &&
-                               $top[1] =~ /\A$OID_BLOB\z/os &&
-                               $top[0] =~ /\A$OID_BLOB\z/os) {
+                               $top[1] =~ $IS_OID &&
+                               $top[0] =~ $IS_OID) {
                        $dctx = diff_header($dst, \$x, $ctx, \@top);
                } elsif ($dctx) {
                        my $after = '';