[PATCH 3/4] maint.mk: speed up require_config_h_first

[Ján Tomko]

Instead of spawning three processes per file, rewrite the check
in perl and run it once for all the files.
---
Alternatively, grep --max-count 1 could help with getting rid of
the per-file commands and extra sed, but I don't know if it's
portable enough.

 ChangeLog    |  7 +++++++
 top/maint.mk | 25 ++++++++++++++++++-------
 2 files changed, 25 insertions(+), 7 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index b698a6c..64e2026 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,12 @@
 2016-07-26  Ján Tomko  <address@hidden>
 
+       maint.mk: speed up require_config_h_first
+
+       Instead of spawning three processes per file, rewrite the check
+       in perl and run it once for all the files.
+
+2016-07-26  Ján Tomko  <address@hidden>
+
        maint.mk: expand the prohibit_doubled_word regex
 
        This check has a static list of words that are checked for
diff --git a/top/maint.mk b/top/maint.mk
index b074609..3cd79bc 100644
--- a/top/maint.mk
+++ b/top/maint.mk
@@ -437,17 +437,28 @@ sc_require_config_h:
        halt='the above files do not include <config.h>'                \
          $(_sc_search_regexp)
 
+# Print all filenames where the first include does not match
+# $(config_h_header)
+#
+# Like grep -m 1, this only looks at the first match.
+perl_config_h_first_ =                                                 \
+    -e 'BEGIN {$$ret = 0}'                                             \
+    -e 'if (/^\# *include\b/) {'                                       \
+    -e '  if (not m{^\# *include $(config_h_header)}) {'               \
+    -e '    print "$$ARGV\n";'                                         \
+    -e '    $$ret = 1;'                                                        
\
+    -e '  }'                                                           \
+    -e '  \# Move on to next file after first include'                 \
+    -e '  close ARGV;'                                                 \
+    -e '}'                                                             \
+    -e 'END {exit $$ret}'
+
 # You must include <config.h> before including any other header file.
 # This can possibly be via a package-specific header, if given by cfg.mk.
 sc_require_config_h_first:
        @if $(VC_LIST_EXCEPT) | grep '\.c$$' > /dev/null; then          \
-         fail=0;                                                       \
-         for i in $$($(VC_LIST_EXCEPT) | grep '\.c$$'); do             \
-           grep '^# *include\>' $$i | $(SED) 1q                        \
-               | grep -E '^# *include $(config_h_header)' > /dev/null  \
-             || { echo $$i; fail=1; };                                 \
-         done;                                                         \
-         test $$fail = 1 &&                                            \
+         files=$$($(VC_LIST_EXCEPT) | grep '\.c$$') &&                 \
+         perl -n $(perl_config_h_first_) $$files ||                    \
            { echo '$(ME): the above files include some other header'   \
                'before <config.h>' 1>&2; exit 1; } || :;               \
        else :;                                                         \
-- 
2.7.3