Faster strip whitespace cleaning script

From: Trent Piepho <xyzzy@speakeasy.org>

Faster script that doesn't use any temporary files.  The old one
would also miss cleaning four spaces in a row in places where
it would clean one to eight spaces.  Has two options:
        fast
Only clean whitespace in files Hg thinks are modified or added.  Used by
make whitespace and much (about 100x) faster.
        manifest
Clean all files controlled by Hg, using "hg manifest"
The default with no options is the old behaviour, clean all files under
the linux directory, except CVS files.

Signed-off-by: Trent Piepho <xyzzy@speakeasy.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

2 files changed, 24 insertions, 34 deletions

diff --git a/Makefile b/Makefile
index 1f11bcb3f..42c22f72a 100644
--- a/Makefile
+++ b/Makefile
@@ -43,5 +43,5 @@ push::
 
 whitespace:
 	@echo "Cleaning bad whitespaces"
-	@v4l/scripts/strip-trailing-whitespaces.sh | patch -p0
+	@v4l/scripts/strip-trailing-whitespaces.sh fast | patch -p0
 
diff --git a/v4l/scripts/strip-trailing-whitespaces.sh b/v4l/scripts/strip-trailing-whitespaces.sh
index 1a23e436d..5bd7784e4 100755
--- a/v4l/scripts/strip-trailing-whitespaces.sh
+++ b/v4l/scripts/strip-trailing-whitespaces.sh
@@ -1,37 +1,27 @@
 #!/bin/sh
+# Strips trailing whitespace.  Leading spaces and spaces after tabs are
+# converted to the equivalent sequence of tabs only.
 
-# tmp dir for my files
-WORK="${TMPDIR-/tmp}/${0##*/}-$$"
-mkdir "$WORK" || exit 1
-trap 'rm -rf "$WORK"' EXIT
+# Use the option "fast" to only check files Hg thinks are new or modified.
+# The option "manifest" will use Hg's manifest command to check all files
+# under Hg revision control.
+# Otherwise, all files under the linux tree are checked, except files in CVS
+# directories and .cvsignore files. This is the historical behavior.
 
-for file in `find linux -type d | grep -v CVS | grep -v .cvsignore` ; do
-    mkdir -p "$WORK/${file}"
-done
-for file in `find linux -type f | grep -v CVS | grep -v .cvsignore` ; do
-	tmpfile="$WORK/${file}.$$"
-	perl -ne 's/[ \t]+$//;
-        s/^\ \ \ \ \ \ \ \ /\t/; 
-        s/^\ \ \ \ \ \ \ \t/\t/; 
-        s/^\ \ \ \ \ \ \t/\t/; 
-        s/^\ \ \ \ \ \t/\t/; 
-        s/^\ \ \ \t/\t/; 
-        s/^\ \ \t/\t/; 
-        s/^\ \t/\t/;
-	$m=1;
-	while ($m>0) {
-		$m=0;
-	        $m=   s/\t\ \ \ \ \ \ \ \ /\t\t/g; 
-	        $m=$m+s/\t\ \ \ \ \ \ \ \t/\t\t/g; 
-	        $m=$m+s/\t\ \ \ \ \ \ \t/\t\t/g; 
-	        $m=$m+s/\t\ \ \ \ \ \t/\t\t/g; 
-	        $m=$m+s/\t\ \ \ \t/\t\t/g; 
-		$m=$m+s/\t\ \ \t/\t\t/g; 
-	        $m=$m+s/\t\ \t/\t\t/g;
-	}
-	print' < "${file}" > "${tmpfile}"
-	diff -u "${file}" "${tmpfile}" | sed 		\
-		-e "s|^--- ${file}|--- ${file}.orig|"	\
-		-e "s|^+++ ${tmpfile}|+++ ${file}|"
-	rm -f "$tmpfile"
+
+if [ "x$1" = "xfast" ]; then
+	files="hg status -man"
+elif [ "x$1" = "xmanifest" ]; then
+	files="hg manifest | cut '-d ' -f3"
+else
+	files="find linux -name CVS -prune -o -type f -not -name .cvsignore -print"
+fi
+
+for file in `eval $files`; do
+	perl -ne '
+	s/[ \t]+$//;
+	s<^ {8}> <\t>;
+	s<^ {1,7}\t> <\t>;
+	while( s<\t {8}> <\t\t>g || s<\t {1,7}\t> <\t\t>g ) {};
+	print' < "${file}" | diff -u "${file}" -
 done