# Copyright (C) 2019-2020 all contributors # License: AGPL-3.0+ # # used by PublicInbox::View # This adds CSS spans for diff highlighting. # It also generates links for ViewVCS + SolverGit to show # (or reconstruct) blobs. package PublicInbox::ViewDiff; use 5.010_001; use strict; use warnings; use base qw(Exporter); our @EXPORT_OK = qw(flush_diff); use URI::Escape qw(uri_escape_utf8); use PublicInbox::Hval qw(ascii_html to_attr); use PublicInbox::Git qw(git_unquote); sub UNSAFE () { "^A-Za-z0-9\-\._~/" } my $OID_NULL = '0{7,}'; my $OID_BLOB = '[a-f0-9]{7,}'; my $LF = qr!\n!; my $ANY = qr![^\n]!; my $FN = qr!(?:"?[^/\n]+/[^\n]+|/dev/null)!; # cf. git diff.c :: get_compact_summary my $DIFFSTAT_COMMENT = qr/(?: *\((?:new|gone|(?:(?:new|mode) [\+\-][lx]))\))? *\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 ($$$$) { my ($dst, $dctx, $ca, $cb) = @_; my ($oid_a, $oid_b, $spfx) = @$dctx{qw(oid_a oid_b spfx)}; if (defined($spfx) && defined($oid_a) && defined($oid_b)) { my ($n) = ($ca =~ /^-([0-9]+)/); $n = defined($n) ? "#n$n" : ''; $$dst .= qq(@@ {Q}$n">$ca); ($n) = ($cb =~ /^\+([0-9]+)/); $n = defined($n) ? "#n$n" : ''; $$dst .= qq( {Q}$n">$cb @@); } else { $$dst .= "@@ $ca $cb @@"; } } sub oid ($$$) { my ($dctx, $spfx, $oid) = @_; defined($spfx) ? qq({Q}">$oid) : $oid; } # returns true if diffstat anchor written, false otherwise sub anchor0 ($$$$) { my ($dst, $ctx, $fn, $rest) = @_; my $orig = $fn; # normal git diffstat output is impossible to parse reliably # without --numstat, and that isn't the default for format-patch. # So only do best-effort handling of renames for common cases; # which works well in practice. If projects put "=>", or trailing # spaces in filenames, oh well :P $fn =~ s/$DIFFSTAT_COMMENT//; $fn =~ s/{(?:.+) => (.+)}/$1/ or $fn =~ s/.* => (.+)/$1/; $fn = git_unquote($fn); # long filenames will require us to check in anchor1() push(@{$ctx->{-long_path}}, $fn) if $fn =~ s!\A\.\.\./?!!; if (my $attr = to_attr($ctx->{-apfx}.$fn)) { $ctx->{-anchors}->{$attr} = 1; my $spaces = ($orig =~ s/( +)\z//) ? $1 : ''; $$dst .= " " . ascii_html($orig) . '' . $spaces . $ctx->{-linkify}->to_html($rest); return 1; } undef; } # returns "diff --git" anchor destination, undef otherwise sub anchor1 ($$) { my ($ctx, $pb) = @_; my $attr = to_attr($ctx->{-apfx}.$pb) or return; my $ok = delete $ctx->{-anchors}->{$attr}; # unlikely, check the end of long path names we captured, # assume diffstat and diff output follow the same order, # and ignore different ordering (could be malicious input) unless ($ok) { my $fn = shift(@{$ctx->{-long_path}}) or return; $pb =~ /\Q$fn\E\z/s or return; $attr = to_attr($ctx->{-apfx}.$fn) or return; $ok = delete $ctx->{-anchors}->{$attr} or return; } $ok ? "diff --git" : undef } sub diff_header ($$$) { my ($x, $ctx, $top) = @_; my (undef, undef, $pa, $pb) = splice(@$top, 0, 4); # ignore oid_{a,b} my $spfx = $ctx->{-spfx}; my $dctx = { spfx => $spfx }; # get rid of leading "a/" or "b/" (or whatever --{src,dst}-prefix are) $pa = (split('/', git_unquote($pa), 2))[1] if $pa ne '/dev/null'; $pb = (split('/', git_unquote($pb), 2))[1] if $pb ne '/dev/null'; if ($pa eq $pb && $pb ne '/dev/null') { $dctx->{Q} = "?b=".uri_escape_utf8($pb, UNSAFE); } else { my @q; if ($pb ne '/dev/null') { push @q, 'b='.uri_escape_utf8($pb, UNSAFE); } if ($pa ne '/dev/null') { push @q, 'a='.uri_escape_utf8($pa, UNSAFE); } $dctx->{Q} = '?'.join('&', @q); } # linkify early and all at once, since we know the following # subst ops on $$x won't need further escaping: $$x = $ctx->{-linkify}->to_html($$x); # no need to capture oid_a and oid_b on add/delete, # we just linkify OIDs directly via s///e in conditional if (($$x =~ s/$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'!ems; my $dst = $ctx->{obuf}; $$dst .= qq(); $$dst .= $$x; $$dst .= ''; $dctx; } sub diff_before_or_after ($$) { my ($ctx, $x) = @_; my $linkify = $ctx->{-linkify}; my $dst = $ctx->{obuf}; my $anchors = exists($ctx->{-anchors}) ? 1 : 0; for my $y (split(/(^---\n)/sm, $$x)) { if ($y =~ /\A---\n\z/s) { $$dst .= "---\n"; # all HTML is "\r\n" => "\n" $anchors |= 2; } elsif ($anchors == 3 && $y =~ /^ [0-9]+ files? changed, /sm) { # ok, looks like a diffstat, go line-by-line: for my $l (split(/^/m, $y)) { if ($l =~ /^ (.+)( +\| .*\z)/s) { anchor0($dst, $ctx, $1, $2) and next; } $$dst .= $linkify->to_html($l); } } else { # commit message, notes, etc $$dst .= $linkify->to_html($y); } } } # callers must do CRLF => LF conversion before calling this sub flush_diff ($$) { my ($ctx, $cur) = @_; my @top = split($EXTRACT_DIFFS, $$cur); undef $$cur; # free memory my $linkify = $ctx->{-linkify}; my $dst = $ctx->{obuf}; my $dctx; # {}, keys: Q, oid_a, oid_b while (defined(my $x = shift @top)) { if (scalar(@top) >= 4 && $top[1] =~ $IS_OID && $top[0] =~ $IS_OID) { $dctx = diff_header(\$x, $ctx, \@top); } elsif ($dctx) { my $after = ''; # Quiet "Complex regular subexpression recursion limit" # warning. Perl will truncate matches upon hitting # that limit, giving us more (and shorter) scalars than # would be ideal, but otherwise it's harmless. # # We could replace the `+' metacharacter with `{1,100}' # to limit the matches ourselves to 100, but we can # let Perl do it for us, quietly. no warnings 'regexp'; for my $s (split(/((?:(?:^\+[^\n]*\n)+)| (?:(?:^-[^\n]*\n)+)| (?:^@@ [^\n]+\n))/xsm, $x)) { if (!defined($dctx)) { $after .= $s; } elsif ($s =~ s/\A@@ (\S+) (\S+) @@//) { $$dst .= qq(); diff_hunk($dst, $dctx, $1, $2); $$dst .= $linkify->to_html($s); $$dst .= ''; } elsif ($s =~ /\A\+/) { $$dst .= qq(); $$dst .= $linkify->to_html($s); $$dst .= ''; } elsif ($s =~ /\A-- $/sm) { # email sig starts $dctx = undef; $after .= $s; } elsif ($s =~ /\A-/) { $$dst .= qq(); $$dst .= $linkify->to_html($s); $$dst .= ''; } else { $$dst .= $linkify->to_html($s); } } diff_before_or_after($ctx, \$after) unless $dctx; } else { diff_before_or_after($ctx, \$x); } } } 1;