Re: [bug-gnulib] gnulib-tool plays nice with make

[Derek Price]

Paul Eggert wrote:

> The basic idea looks fine, but isn't there a lot of repeated code there?
> It could be factored into a shell function.

Is this what you had in mind?

2005-03-04  Derek R. Price  <address@hidden>

   * gnulib-tool: Only replace files via --import when they have
actually changed.


Regards,

Derek

Index: gnulib-tool
===================================================================
RCS file: /cvsroot/gnulib/gnulib/gnulib-tool,v
retrieving revision 1.38
diff -u -p -r1.38 gnulib-tool
--- gnulib-tool 5 Jan 2005 02:50:04 -0000       1.38
+++ gnulib-tool 4 Mar 2005 15:39:47 -0000
@@ -117,6 +117,33 @@ func_fatal_error ()
   exit 1
 }

+# cp, but avoid munging timestamps if the file hasn't changed.
+cp_if_changed ()
+{
+  if test $# -ne 2; then
+    echo "usage: cp_if_changed SRC DEST" >&2
+  fi
+  test -n "$dry_run" && dry=echo
+  if cmp "$1" "$2" >/dev/null 2>&1; then :; else
+    $dry cp -p "$1" "$2"
+  fi
+}
+
+# mv, but avoid munging timestamps if the file hasn't changed.
+# Remove the source file if it is not renamed.
+mv_if_changed ()
+{
+  if test $# -ne 2; then
+    echo "usage: mv_if_changed SRC DEST" >&2
+  fi
+  test -n "$dry_run" && dry=echo
+  if cmp "$1" "$2" >/dev/null 2>&1; then
+    $dry rm "$1"
+  else
+    $dry mv "$1" "$2"
+  fi
+}
+
 # Command-line option processing.
 # Removes the OPTIONS from the arguments. Sets the variables:
 # - mode            list or import or create-testdir or create-megatestdir
@@ -523,8 +550,7 @@ func_import ()
       m4/*) g=`echo "$f" | sed -e "s,^m4/,$m4base/,"` ;;
       *) g="$f" ;;
     esac
-    test -n "$dry_run" && dry=echo
-    $dry cp -p "$gnulib_dir/$f" "$destdir/$g"
+    cp_if_changed "$gnulib_dir/$f" "$destdir/$g"
     # Update license.
     if test -z "$dry_run" && test -n "$lgpl" && test -n "$source"; then
       perl -pi -e 's/GNU General/GNU Lesser General/g;' \
@@ -546,18 +572,20 @@ func_import ()
   actioncmd="gnulib-tool --import --dir=$destdir --lib=$libname 
--source-base=$sourcebase --m4-base=$m4base $opt_libtool $opt_lgpl `echo 
$modules`"

   # Create lib/Makefile.am.
-  echo "Creating $destdir/$sourcebase/Makefile.am..."
+  echo "Creating $destdir/$sourcebase/Makefile.am.new..."
   if test -z "$dry_run"; then
-    func_emit_lib_Makefile_am > $destdir/$sourcebase/Makefile.am
+    func_emit_lib_Makefile_am > $destdir/$sourcebase/Makefile.am.new
   else
     func_emit_lib_Makefile_am
   fi
+  mv_if_changed $destdir/$sourcebase/Makefile.am.new \
+                $destdir/$sourcebase/Makefile.am

   # Create gnulib.m4.
-  echo "Creating $destdir/$m4base/gnulib.m4..."
+  echo "Creating $destdir/$m4base/gnulib.m4.new..."
   (
     if test -z "$dry_run"; then
-      exec > $destdir/$m4base/gnulib.m4
+      exec > $destdir/$m4base/gnulib.m4.new
     else
       echo "# $destdir/$m4base/gnulib.m4"
     fi
@@ -616,6 +644,7 @@ func_import ()
     echo
     echo "# gnulib.m4 ends here"
   )
+  mv_if_changed $destdir/$m4base/gnulib.m4.new $destdir/$m4base/gnulib.m4
   echo "Finished."
   echo
   echo "You may need to add #include directives for the following .h files."

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