-# Copyright (C) 2019 all contributors <meta@public-inbox.org>
+# Copyright (C) 2019-2021 all contributors <meta@public-inbox.org>
# License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
#
# 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 strict;
-use warnings;
-use base qw(Exporter);
+use v5.10.1;
+use parent qw(Exporter);
our @EXPORT_OK = qw(flush_diff);
-
-use PublicInbox::Hval qw(ascii_html);
+use URI::Escape qw(uri_escape_utf8);
+use PublicInbox::Hval qw(ascii_html to_attr);
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 } # /^\-/
-
-my $OID_NULL = '0{7,40}';
-my $OID_BLOB = '[a-f0-9]{7,40}';
-my $PATH_A = '"?a/.+|/dev/null';
-my $PATH_B = '"?b/.+|/dev/null';
-
-sub to_html ($$) {
- $_[0]->linkify_1($_[1]);
- $_[0]->linkify_2(ascii_html($_[1]));
-}
+my $UNSAFE = "^A-Za-z0-9\-\._~/"; # '/' + $URI::Escape::Unsafe{RFC3986}
+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;
+our $EXTRACT_DIFFS = qr/(
+ (?: # begin header stuff, don't capture filenames, here,
+ # but instead wait for the --- and +++ lines.
+ (?:^diff\x20--git\x20$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;
+our $IS_OID = qr/\A$OID_BLOB\z/s;
# link to line numbers in blobs
sub diff_hunk ($$$$) {
- my ($dctx, $spfx, $ca, $cb) = @_;
- my $oid_a = $dctx->{oid_a};
- my $oid_b = $dctx->{oid_b};
+ my ($dst, $dctx, $ca, $cb) = @_;
+ my ($oid_a, $oid_b, $spfx) = @$dctx{qw(oid_a oid_b spfx)};
+
+ if (defined($spfx) && defined($oid_a) && defined($oid_b)) {
+ my ($n) = ($ca =~ /^-([0-9]+)/);
+ $n = defined($n) ? "#n$n" : '';
+
+ $$dst .= qq(@@ <a\nhref="$spfx$oid_a/s/$dctx->{Q}$n">$ca</a>);
+
+ ($n) = ($cb =~ /^\+([0-9]+)/);
+ $n = defined($n) ? "#n$n" : '';
+ $$dst .= qq( <a\nhref="$spfx$oid_b/s/$dctx->{Q}$n">$cb</a> @@);
+ } else {
+ $$dst .= "@@ $ca $cb @@";
+ }
+}
+
+sub oid ($$$) {
+ my ($dctx, $spfx, $oid) = @_;
+ defined($spfx) ? qq(<a\nhref="$spfx$oid/s/$dctx->{Q}">$oid</a>) : $oid;
+}
- (defined($oid_a) && defined($oid_b)) or return "@@ $ca $cb @@";
+# returns true if diffstat anchor written, false otherwise
+sub anchor0 ($$$$) {
+ my ($dst, $ctx, $fn, $rest) = @_;
- my ($n) = ($ca =~ /^-(\d+)/);
- $n = defined($n) ? do { ++$n; "#n$n" } : '';
+ my $orig = $fn;
- my $rv = qq(@@ <a\nhref=$spfx$oid_a/s$n>$ca</a>);
+ # normal git diffstat output is impossible to parse reliably
+ # without --numstat, and that isn't the default for format-patch.
+ # So only do best-effort handling of renames for common cases;
+ # which works well in practice. If projects put "=>", or trailing
+ # spaces in filenames, oh well :P
+ $fn =~ s/$DIFFSTAT_COMMENT//;
+ $fn =~ s/\{(?:.+) => (.+)\}/$1/ or $fn =~ s/.* => (.+)/$1/;
+ $fn = git_unquote($fn);
- ($n) = ($cb =~ /^\+(\d+)/);
- $n = defined($n) ? do { ++$n; "#n$n" } : '';
+ # long filenames will require us to check in anchor1()
+ push(@{$ctx->{-long_path}}, $fn) if $fn =~ s!\A\.\.\./?!!;
- $rv .= qq( <a\nhref=$spfx$oid_b/s$n>$cb</a> @@);
+ if (defined(my $attr = to_attr($ctx->{-apfx}.$fn))) {
+ $ctx->{-anchors}->{$attr} = 1;
+ my $spaces = ($orig =~ s/( +)\z//) ? $1 : '';
+ $$dst .= " <a\nid=i$attr\nhref=#$attr>" .
+ ascii_html($orig) . '</a>' . $spaces .
+ $ctx->{-linkify}->to_html($rest);
+ return 1;
+ }
+ undef;
}
-sub flush_diff ($$$$) {
- my ($dst, $spfx, $linkify, $diff) = @_;
- my $state = DSTATE_INIT;
- my $dctx; # {}, keys: oid_a, oid_b, path_a, path_b
-
- foreach my $s (@$diff) {
- if ($s =~ /^ /) {
- if ($state == DSTATE_HUNK || $state == DSTATE_ADD ||
- $state == DSTATE_DEL || $state == DSTATE_HEAD) {
- $$dst .= "</span><span\nclass=ctx>";
- $state = DSTATE_CTX;
- }
- $$dst .= to_html($linkify, $s);
- } elsif ($s =~ /^-- $/) { # email signature begins
- if ($state != DSTATE_INIT) {
- $state = DSTATE_INIT;
- $$dst .= '</span>';
- }
- $$dst .= $s;
- } elsif ($s =~ m!^diff --git ($PATH_A) ($PATH_B)$!x) {
- if ($state != DSTATE_HEAD) {
- my ($pa, $pb) = ($1, $2);
- $$dst .= '</span>' if $state != DSTATE_INIT;
- $$dst .= "<span\nclass=head>";
- $state = DSTATE_HEAD;
- $pa = (split('/', git_unquote($pa), 2))[1];
- $pb = (split('/', git_unquote($pb), 2))[1];
- $dctx = { path_a => $pa, path_b => $pb };
- }
- $$dst .= to_html($linkify, $s);
- } elsif ($s =~ s/^(index $OID_NULL\.\.)($OID_BLOB)\b//o) {
- $$dst .= qq($1<a\nhref=$spfx$2/s>$2</a>);
- $$dst .= to_html($linkify, $s) ;
- } elsif ($s =~ s/^index ($OID_NULL)(\.\.$OID_BLOB)\b//o) {
- $$dst .= 'index ';
- $$dst .= qq(<a\nhref=$spfx$1/s>$1</a>$2);
- $$dst .= to_html($linkify, $s);
- } elsif ($s =~ /^index ($OID_BLOB)\.\.($OID_BLOB)/o) {
- $dctx->{oid_a} = $1;
- $dctx->{oid_b} = $2;
- $$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 .= 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;
- $$dst .= "<span\nclass=head>";
- }
- $$dst .= to_html($linkify, $s);
- } elsif ($s =~ /^\+/) {
- if ($state != DSTATE_ADD && $state != DSTATE_INIT) {
- $$dst .= "</span><span\nclass=add>";
- $state = DSTATE_ADD;
+# returns "diff --git" anchor destination, undef otherwise
+sub anchor1 ($$) {
+ my ($ctx, $pb) = @_;
+ my $attr = to_attr($ctx->{-apfx}.$pb) // 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}}) // return;
+ $pb =~ /\Q$fn\E\z/s or return;
+ $attr = to_attr($ctx->{-apfx}.$fn) // return;
+ $ok = delete $ctx->{-anchors}->{$attr} // return;
+ }
+ $ok ? "<a\nhref=#i$attr\nid=$attr>diff</a> --git" : undef
+}
+
+sub diff_header ($$$) {
+ my ($x, $ctx, $top) = @_;
+ my (undef, undef, $pa, $pb) = splice(@$top, 0, 4); # ignore oid_{a,b}
+ my $spfx = $ctx->{-spfx};
+ my $dctx = { spfx => $spfx };
+
+ # get rid of leading "a/" or "b/" (or whatever --{src,dst}-prefix are)
+ $pa = (split(m'/', git_unquote($pa), 2))[1] if $pa ne '/dev/null';
+ $pb = (split(m'/', git_unquote($pb), 2))[1] if $pb ne '/dev/null';
+ if ($pa eq $pb && $pb ne '/dev/null') {
+ $dctx->{Q} = "?b=".uri_escape_utf8($pb, $UNSAFE);
+ } else {
+ my @q;
+ if ($pb ne '/dev/null') {
+ push @q, 'b='.uri_escape_utf8($pb, $UNSAFE);
+ }
+ if ($pa ne '/dev/null') {
+ push @q, 'a='.uri_escape_utf8($pa, $UNSAFE);
+ }
+ $dctx->{Q} = '?'.join('&', @q);
+ }
+
+ # linkify early and all at once, since we know the following
+ # subst ops on $$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(<span\nclass="head">);
+ $$dst .= $$x;
+ $$dst .= '</span>';
+ $dctx;
+}
+
+sub diff_before_or_after ($$) {
+ 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;
+ }
+ $$dst .= $linkify->to_html($l);
}
- $$dst .= to_html($linkify, $s);
- } elsif ($s =~ /^-/) {
- if ($state != DSTATE_DEL && $state != DSTATE_INIT) {
- $$dst .= "</span><span\nclass=del>";
- $state = DSTATE_DEL;
+ } else { # commit message, notes, etc
+ $$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(<span\nclass="hunk">);
+ diff_hunk($dst, $dctx, $1, $2);
+ $$dst .= $linkify->to_html($s);
+ $$dst .= '</span>';
+ } elsif ($s =~ /\A\+/) {
+ $$dst .= qq(<span\nclass="add">);
+ $$dst .= $linkify->to_html($s);
+ $$dst .= '</span>';
+ } elsif ($s =~ /\A-- $/sm) { # email sig starts
+ $dctx = undef;
+ $after .= $s;
+ } elsif ($s =~ /\A-/) {
+ $$dst .= qq(<span\nclass="del">);
+ $$dst .= $linkify->to_html($s);
+ $$dst .= '</span>';
+ } else {
+ $$dst .= $linkify->to_html($s);
+ }
}
- $$dst .= to_html($linkify, $s);
- # ignore the following lines in headers:
- } elsif ($s =~ /^(?:dis)similarity index/ ||
- $s =~ /^(?:old|new) mode/ ||
- $s =~ /^(?:deleted|new) file mode/ ||
- $s =~ /^(?:copy|rename) (?:from|to) / ||
- $s =~ /^(?:dis)?similarity index /) {
- $$dst .= to_html($linkify, $s);
+ diff_before_or_after($ctx, \$after) unless $dctx;
} else {
- if ($state != DSTATE_INIT) {
- $$dst .= '</span>';
- $state = DSTATE_INIT;
- }
- $$dst .= to_html($linkify, $s);
+ diff_before_or_after($ctx, \$x);
}
}
- @$diff = ();
- $$dst .= '</span>' if $state != DSTATE_INIT;
- undef;
}
1;