Revert: makediff: cleanup using begingroup/endgroup

This reverts commit
	commit ef519a86f046d1be22f82f32d845653a850c21dd
	Author: mstsirkin <mstsirkin@0c8fb4dd-22a2-4bb5-bc14-6c75a5f43652>
	Date:   Thu Jun 26 16:50:13 2014 +0000

	makediff: cleanup using begingroup/endgroup

This seemed like a good idea originally: replace perl hacks with
tex hacks. However adding \begingroup and \endgroup within macros
used by latex-diff breaks its assumption that these are low level
tex and can be used in arbitrary situations, e.g.  cross the
boundaries of environments, use mis-matching begin and end
instructions (DIFaddbegin with DIFaddendFL), etc.

Let's go back to the original work-around:

commit b665b3165b454b98c782617e37a128b53b56c89c
Author: mstsirkin <mstsirkin@0c8fb4dd-22a2-4bb5-bc14-6c75a5f43652>
Date:   Thu Jun 26 12:34:38 2014 +0000

    work around xetex bug

    Too many \color directives produce corrupted output
    and this warning:
    WARNING ** Color stack overflow. Just ignore.

    Use script to reduce # of these directives.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

git-svn-id: https://tools.oasis-open.org/version-control/svn/virtio/branches/v1.0@545 0c8fb4dd-22a2-4bb5-bc14-6c75a5f43652

2 files changed, 24 insertions, 61 deletions

diff --git a/diffpreamble.tex b/diffpreamble.tex
index 9b5b7e5..f7b5cec 100644
--- a/diffpreamble.tex
+++ b/diffpreamble.tex
@@ -8,10 +8,13 @@
 
 %DIF COLOR PREAMBLE
 \RequirePackage{color}
-\providecommand{\DIFaddbegin}{\begingroup\color{green}\hypersetup{linkcolor=green,urlcolor=green}}
-\providecommand{\DIFaddend}{\hypersetup{linkcolor=blue,urlcolor=blue}\endgroup}
-\providecommand{\DIFdelbegin}{\begingroup\color{red}\hypersetup{linkcolor=red,urlcolor=red}}
-\providecommand{\DIFdelend}{\hypersetup{linkcolor=blue,urlcolor=blue}\endgroup}
+\providecommand{\DIFaddbegin}{\protect\color{green}\hypersetup{linkcolor=green,urlcolor=green}}
+\providecommand{\DIFaddend}{\protect\color{black}\hypersetup{linkcolor=blue,urlcolor=blue}}
+\providecommand{\DIFdelbegin}{\protect\color{red}\hypersetup{linkcolor=red,urlcolor=red}}
+\providecommand{\DIFdelend}{\protect\color{black}\hypersetup{linkcolor=blue,urlcolor=blue}}
+\providecommand{\DIFaddtext}[1]{\textcolor{blue}{\sf #1}}
+\providecommand{\DIFdeltext}[1]{\textcolor{red}{\footnotesize \sout{#1}}}
+
 %DIF END COLOR PREAMBLE
 \providecommand{\DIFaddtext}[1]{\textcolor{green}{\sf #1}}
 \providecommand{\DIFdeltext}[1]{\textcolor{red}{\footnotesize \sout{#1}}}
diff --git a/fixupdiff.pl b/fixupdiff.pl
index e557e2b..5c82526 100644
--- a/fixupdiff.pl
+++ b/fixupdiff.pl
@@ -1,6 +1,7 @@
-my $bufferdiff="";
-my $diff="";
-my $buffer="";
+use strict;
+
+my $lstlisting=0;
+
 while (<>) {
 	my $line = $_;
 	if (m/%DIFDELCMD\s+<\s+\\begin{lstlisting}/) {
@@ -15,60 +16,19 @@ while (<>) {
 		}
 		#print "%FIXED BY RULE 1\n";
 	}
-	#In section headings, replace begin/end with begin/endFL,
-	#but be careful in case some tag spills over to the next
-	#line
-	if (m/\\(section|subsection|subsubsection|paragraph)/ and m/DIF/) {
-		my @list = split(/(\\DIF(?:add|del)(?:begin|end)(?:FL)?)/, $line, -1);
-		#if there's only one tag, don't touch it:
-		#matching one is on the other line
-		if ($#list >= 5) {
-			#if first tag is end, don't touch it - matching
-			#begin is on the previous line
-			if ($list[1] =~ m/begin$/) {
-				$list[1] .= "FL";
-			}
-			#if last tag is begin, don't touch it - matching
-			#end is on the next line
-			if ($list[$#list - 1] =~ m/end$/) {
-				$list[$#list - 1] .= "FL";
-			}
-		}
-		for (my $i = 3; $i <= $#list - 3; $i += 2) {
-			if (not $list[$i] =~ m/FL$/) {
-				$list[$i] .= "FL";
-			}
-		}
-		$line = join("", @list);
-		#print "%FIXED BY RULE 2\n";
-	}
-	#detect where we have DIFbegin/end cross
-	#enumerate/itemize environments and fix up
-	if (m/\\DIF(?:add|del)(?:begin|end)/) {
-		my @list = split(/(\\DIF(?:add|del)(?:begin|end)(?:FL)?)/, $line, -1);
-		$diff = $list[$#list - 1];
-		if ($diff =~ m/begin/) {
-			$diff =~ s/begin/end/;
-		} else {
-			$diff = "";
-		}
-	}
-	if ($diff ne "" and m/\\(?:begin|end){(?:enumerate|itemize)}$/ and not m/\\DIF/) {
-		$buffer = $line;
-		$bufferdiff = $diff;
-		$line = "";
-		#print "%BUFFERED BY RULE 3: $bufferdiff\n";
-	}
-	if ($buffer ne "" and $line ne "") {
-		if (m/^(\\DIF(?:add|del)end(?:FL)?)/ and $bufferdiff ne $1) {
-			$line =~ s/^(\\DIF(?:add|del)end(?:FL)?)//;
-			$buffer =~ s/(\\(?:begin|end){(?:enumerate|itemize)})$/$bufferdiff$1/;
-			#print "%FIXED BY RULE 3: $bufferdiff\n";
-		}
-		print $buffer;
-		$buffer = "";
-		$bufferdiff = "";
-	}
+
+	# Too many \color directives (generated by DIFdel/addbegin/end)
+	# confuse xetex, producing errors:
+	# WARNING ** Color stack overflow. Just ignore.
+	# and resulting in corrupted color in output.
+	# As a work-around, detect cases where it's safe, and replace \color with
+	# \textcolor.
+	# As a result, number of \color directives goes does sufficiently
+	# enough to avoid the overflow error.
+
+	s/\\DIFdelbegin \\DIFdel{([^}]*)}\\DIFdelend/\\DIFdeltext{$1}/;
+	s/\\DIFaddbegin \\DIFadd{([^}]*)}\\DIFaddend/\\DIFaddtext{$1}/;
+
 	print $line;
 	if (m/%DIFDELCMD\s+<\s+\\end{lstlisting}/) {
 		print "}\n";