lib/PublicInbox/ViewDiff.pm - pub/scm/infra/public-inbox - Git at Google

 # Copyright (C) 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 v5.12;
 use parent qw(Exporter);
 our @EXPORT_OK = qw(flush_diff uri_escape_path);
 use URI::Escape qw(uri_escape_utf8);
 use PublicInbox::Hval qw(ascii_html to_attr utf8_maybe);
 use PublicInbox::Git qw(git_unquote);

 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;

 sub uri_escape_path {
 	# '/' + $URI::Escape::Unsafe{RFC3986}
 	uri_escape_utf8($_[0], "^A-Za-z0-9\-\._~/");
 }

 # link to line numbers in blobs
 sub diff_hunk ($$$) {
 	my ($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$1" : '';
 		my $x = qq(@@ <a\nhref="$spfx$oid_a/s/$dctx->{Q}$n">$ca</a>);

 		$n = ($cb =~ /^\+([0-9]+)/) ? "#n$1" : '';
 		$x .= qq( <a\nhref="$spfx$oid_b/s/$dctx->{Q}$n">$cb</a> @@);
 	} else {
 		"@@ $ca $cb @@";
 	}
 }

 sub oid ($$$) {
 	my ($dctx, $spfx, $oid) = @_;
 	defined($spfx) ? qq(<a\nhref="$spfx$oid/s/$dctx->{Q}">$oid</a>) : $oid;
 }

 # returns true if diffstat anchor written, false otherwise
 sub anchor0 ($$$) {
 	my ($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\.\.\./?!!;

 	my $attr = to_attr($ctx->{-apfx}.$fn) // return;
 	$ctx->{-anchors}->{$attr} = 1;
 	my $spaces = ($orig =~ s/( +)\z//) ? $1 : '';
 	print { $ctx->{zfh} } " <a\nid=i$attr\nhref=#$attr>",
 			ascii_html($orig), '</a>', $spaces,
 			$ctx->{-linkify}->to_html($rest);
 }

 # 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') {
 		$dctx->{Q} = '?b='.uri_escape_path($pb);
 	} else {
 		my @q;
 		push @q, 'b='.uri_escape_path($pb) if $pb ne '/dev/null';
 		push @q, 'a='.uri_escape_path($pa) if $pa ne '/dev/null';
 		$dctx->{Q} = '?'.join('&amp;', @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 ($$x =~ s/$NULL_TO_BLOB/$1 . oid($dctx, $spfx, $2)/e) {
 		push @{$ctx->{-qry_dfblob}}, $2;
 	} elsif ($$x =~ s/$BLOB_TO_NULL/'index '.oid($dctx, $spfx, $1).$2/e) {
 		push @{$ctx->{-qry_dfblob}}, $1;
 	} elsif ($$x =~ $BLOB_TO_BLOB) {
 		# modification-only, not add/delete:
 		# linkify hunk headers later using oid_a and oid_b
 		@$dctx{qw(oid_a oid_b)} = ($1, $2);
 		push @{$ctx->{-qry_dfblob}}, $1, $2;
 	} else {
 		warn "BUG? <$$x> had no ^index line";
 	}
 	$$x =~ s!^diff --git!anchor1($ctx, $pb) // 'diff --git'!ems;
 	print { $ctx->{zfh} } qq(<span\nclass="head">), $$x, '</span>';
 	$dctx;
 }

 sub diff_before_or_after ($$) {
 	my ($ctx, $x) = @_;
 	if (exists $ctx->{-anchors} && $$x =~ # diffstat lines:
 			/((?:^\x20(?:[^\n]+?)(?:\x20+\|\x20[^\n]*\n))+)
 			(\x20[0-9]+\x20files?\x20)changed,/msx) {
 		my $pre = substr($$x, 0, $-[0]); # (likely) short prefix
 		substr($$x, 0, $+[0], ''); # sv_chop on $$x ($$x may be long)
 		my @x = ($2, $1);
 		my $lnk = $ctx->{-linkify};
 		my $zfh = $ctx->{zfh};
 		# uninteresting prefix
 		print $zfh $lnk->to_html($pre);
 		for my $l (split(/^/m, pop(@x))) { # $2 per-file stat lines
 			$l =~ /^ (.+)( +\| .*\z)/s and
 				anchor0($ctx, $1, $2) and next;
 			 print $zfh $lnk->to_html($l);
 		}
 		my $ch = $ctx->{changed_href} // '#related';
 		print $zfh pop(@x), # $3 /^ \d+ files? /
 			qq(<a href="$ch">changed</a>,),
 			# insertions/deletions, notes, commit message, etc:
 			$lnk->to_html($$x);
 	} else {
 		print { $ctx->{zfh} } $ctx->{-linkify}->to_html($$x);
 	}
 }

 # callers must do CRLF => LF conversion before calling this
 sub flush_diff ($$) {
 	my ($ctx, $cur) = @_;

 	my ($subj) = ($$cur =~ /^Subject:\s*\[[^\]]+\]\s*(.+?)$/sm);
 	my @top = split(/$EXTRACT_DIFFS/o, $$cur);
 	undef $$cur; # free memory
 	$ctx->{-qry_subj} = $subj if $subj;
 	my $lnk = $ctx->{-linkify};
 	my $dctx; # {}, keys: Q, oid_a, oid_b
 	my $zfh = $ctx->zfh;

 	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) {
 			open(my $afh, '>>:utf8', \(my $after='')) or
 				die "open: $!";

 			# 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)) {
 				undef $x;
 				if (!defined($dctx)) {
 					print $afh $s;
 				} elsif ($s =~ s/\A@@ (\S+) (\S+) @@//) {
 					print $zfh qq(<span\nclass="hunk">),
 						diff_hunk($dctx, $1, $2),
 						$lnk->to_html($s),
 						'</span>';
 				} elsif ($s =~ /\A\+/) { # $s may be huge
 					print $zfh qq(<span\nclass="add">),
 							$lnk->to_html($s),
 							'</span>';
 				} elsif ($s =~ /\A-- $/sm) { # email sig starts
 					$dctx = undef;
 					print $afh $s;
 				} elsif ($s =~ /\A-/) { # $s may be huge
 					print $zfh qq(<span\nclass="del">),
 							$lnk->to_html($s),
 							'</span>';
 				} else { # $s may be huge
 					print $zfh $lnk->to_html($s);
 				}
 			}
 			if (!$dctx) {
 				utf8_maybe($after);
 				diff_before_or_after($ctx, \$after);
 			}
 		} else {
 			diff_before_or_after($ctx, \$x);
 		}
 	}
 }

 1;
	# Copyright (C) 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 v5.12;
	use parent qw(Exporter);
	our @EXPORT_OK = qw(flush_diff uri_escape_path);
	use URI::Escape qw(uri_escape_utf8);
	use PublicInbox::Hval qw(ascii_html to_attr utf8_maybe);
	use PublicInbox::Git qw(git_unquote);

	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;

	sub uri_escape_path {
	# '/' + $URI::Escape::Unsafe{RFC3986}
	uri_escape_utf8($_[0], "^A-Za-z0-9\-\._~/");
	}

	# link to line numbers in blobs
	sub diff_hunk ($$$) {
	my ($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$1" : '';
	my $x = qq(@@ <a\nhref="$spfx$oid_a/s/$dctx->{Q}$n">$ca</a>);

	$n = ($cb =~ /^\+([0-9]+)/) ? "#n$1" : '';
	$x .= qq( <a\nhref="$spfx$oid_b/s/$dctx->{Q}$n">$cb</a> @@);
	} else {
	"@@ $ca $cb @@";
	}
	}

	sub oid ($$$) {
	my ($dctx, $spfx, $oid) = @_;
	defined($spfx) ? qq(<a\nhref="$spfx$oid/s/$dctx->{Q}">$oid</a>) : $oid;
	}

	# returns true if diffstat anchor written, false otherwise
	sub anchor0 ($$$) {
	my ($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\.\.\./?!!;

	my $attr = to_attr($ctx->{-apfx}.$fn) // return;
	$ctx->{-anchors}->{$attr} = 1;
	my $spaces = ($orig =~ s/( +)\z//) ? $1 : '';
	print { $ctx->{zfh} } " <a\nid=i$attr\nhref=#$attr>",
	ascii_html($orig), '</a>', $spaces,
	$ctx->{-linkify}->to_html($rest);
	}

	# 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') {
	$dctx->{Q} = '?b='.uri_escape_path($pb);
	} else {
	my @q;
	push @q, 'b='.uri_escape_path($pb) if $pb ne '/dev/null';
	push @q, 'a='.uri_escape_path($pa) if $pa ne '/dev/null';
	$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 ($$x =~ s/$NULL_TO_BLOB/$1 . oid($dctx, $spfx, $2)/e) {
	push @{$ctx->{-qry_dfblob}}, $2;
	} elsif ($$x =~ s/$BLOB_TO_NULL/'index '.oid($dctx, $spfx, $1).$2/e) {
	push @{$ctx->{-qry_dfblob}}, $1;
	} elsif ($$x =~ $BLOB_TO_BLOB) {
	# modification-only, not add/delete:
	# linkify hunk headers later using oid_a and oid_b
	@$dctx{qw(oid_a oid_b)} = ($1, $2);
	push @{$ctx->{-qry_dfblob}}, $1, $2;
	} else {
	warn "BUG? <$$x> had no ^index line";
	}
	$$x =~ s!^diff --git!anchor1($ctx, $pb) // 'diff --git'!ems;
	print { $ctx->{zfh} } qq(<span\nclass="head">), $$x, '</span>';
	$dctx;
	}

	sub diff_before_or_after ($$) {
	my ($ctx, $x) = @_;
	if (exists $ctx->{-anchors} && $$x =~ # diffstat lines:
	/((?:^\x20(?:[^\n]+?)(?:\x20+\\|\x20[^\n]*\n))+)
	(\x20[0-9]+\x20files?\x20)changed,/msx) {
	my $pre = substr($$x, 0, $-[0]); # (likely) short prefix
	substr($$x, 0, $+[0], ''); # sv_chop on $$x ($$x may be long)
	my @x = ($2, $1);
	my $lnk = $ctx->{-linkify};
	my $zfh = $ctx->{zfh};
	# uninteresting prefix
	print $zfh $lnk->to_html($pre);
	for my $l (split(/^/m, pop(@x))) { # $2 per-file stat lines
	$l =~ /^ (.+)( +\\| .*\z)/s and
	anchor0($ctx, $1, $2) and next;
	print $zfh $lnk->to_html($l);
	}
	my $ch = $ctx->{changed_href} // '#related';
	print $zfh pop(@x), # $3 /^ \d+ files? /
	qq(<a href="$ch">changed</a>,),
	# insertions/deletions, notes, commit message, etc:
	$lnk->to_html($$x);
	} else {
	print { $ctx->{zfh} } $ctx->{-linkify}->to_html($$x);
	}
	}

	# callers must do CRLF => LF conversion before calling this
	sub flush_diff ($$) {
	my ($ctx, $cur) = @_;

	my ($subj) = ($$cur =~ /^Subject:\s\[[^\]]+\]\s(.+?)$/sm);
	my @top = split(/$EXTRACT_DIFFS/o, $$cur);
	undef $$cur; # free memory
	$ctx->{-qry_subj} = $subj if $subj;
	my $lnk = $ctx->{-linkify};
	my $dctx; # {}, keys: Q, oid_a, oid_b
	my $zfh = $ctx->zfh;

	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) {
	open(my $afh, '>>:utf8', \(my $after='')) or
	die "open: $!";

	# 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)) {
	undef $x;
	if (!defined($dctx)) {
	print $afh $s;
	} elsif ($s =~ s/\A@@ (\S+) (\S+) @@//) {
	print $zfh qq(<span\nclass="hunk">),
	diff_hunk($dctx, $1, $2),
	$lnk->to_html($s),
	'</span>';
	} elsif ($s =~ /\A\+/) { # $s may be huge
	print $zfh qq(<span\nclass="add">),
	$lnk->to_html($s),
	'</span>';
	} elsif ($s =~ /\A-- $/sm) { # email sig starts
	$dctx = undef;
	print $afh $s;
	} elsif ($s =~ /\A-/) { # $s may be huge
	print $zfh qq(<span\nclass="del">),
	$lnk->to_html($s),
	'</span>';
	} else { # $s may be huge
	print $zfh $lnk->to_html($s);
	}
	}
	if (!$dctx) {
	utf8_maybe($after);
	diff_before_or_after($ctx, \$after);
	}
	} else {
	diff_before_or_after($ctx, \$x);
	}
	}
	}

	1;