doc: Create a script to filter xmlto output

This reduces the build log spam while still preserving the xmlto
status to catch build failures correctly.

Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>

2 files changed, 22 insertions, 1 deletions

diff --git a/doc/Makefile.am b/doc/Makefile.am
index e6974fef1..b305f4db7 100644
--- a/doc/Makefile.am
+++ b/doc/Makefile.am
@@ -12,4 +12,4 @@ include $(top_srcdir)/devbook.am
 endif HAVE_XMLTO
 endif ENABLE_DEVEL_DOCS
 
-EXTRA_DIST = smartsched
+EXTRA_DIST = smartsched filter-xmlto.sh
diff --git a/doc/filter-xmlto.sh b/doc/filter-xmlto.sh
new file mode 100755
index 000000000..3596ed13a
--- /dev/null
+++ b/doc/filter-xmlto.sh
@@ -0,0 +1,21 @@
+#!/bin/sh
+#
+# Run the xmlto command, filtering its output to
+# reduce the amount of useless warnings in the build log.
+#
+# Exit with the status of the xmlto process, not the status of the
+# output filtering commands
+#
+# This is a bit twisty, but avoids any temp files by using pipes for
+# everything. It routes the command output through file
+# descriptor 4 while sending the (numeric) exit status through
+# standard output.
+#
+(((("$@" 2>&1; echo $? >&3) |
+       grep -v overflows |
+       grep -v 'Making' |
+       grep -v 'hyphenation' |
+       grep -v 'Font.*not found' |
+       grep -v '/tmp/xml' |
+       grep -v Rendered >&4) 3>&1) |
+     (read status; exit $status)) 4>&1