From: Karel Zak <kzak@redhat.com>
Date: Mon, 13 Nov 2023 13:16:03 +0000 (+0100)
Subject: autotools: use stamp file to build filter parser, improve portability
X-Git-Tag: v2.40-rc1~151^2~11
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=55a460055204047a196efdc2826b3493ee0b6194;p=thirdparty%2Futil-linux.git

autotools: use stamp file to build filter parser, improve portability

* use .stamp files to generate .c and .h by only one flex and bison call

* use bison --defines=HEADER rather than --header=, the --header is
  supported also by old bison version (like common bison 3.0.4)

* make sure there is defined dependence between the scanner and parser
  .c and .h files (scanner need header from parser and vice-versa)

* distribute .stamp files to avoid flex and bison for people who use
  sources from tarball (we distribute generated source files)

Signed-off-by: Karel Zak <kzak@redhat.com>
---

diff --git a/libsmartcols/src/Makemodule.am b/libsmartcols/src/Makemodule.am
index c0f0dfaef9..377888e81e 100644
--- a/libsmartcols/src/Makemodule.am
+++ b/libsmartcols/src/Makemodule.am
@@ -39,11 +39,49 @@ BUILT_SOURCES += libsmartcols/src/filter-parser.c \
 EXTRA_DIST += libsmartcols/src/filter-parser.y \
 	      libsmartcols/src/filter-scanner.l
 
-libsmartcols/src/filter-parser.h libsmartcols/src/filter-parser.c: libsmartcols/src/filter-parser.y libsmartcols/src/filter-scanner.h
-	$(AM_V_YACC) $(BISON) $< --output=${basename $@}.c --header=${basename $@}.h
+## Generate filter parser (YACC) and tokenizer (LEX) .c and .h files.
+#
+# Note that we need advanced bison and flex features and configuration
+# directives to generated thread safe parser (usable in stared library), so
+# it's probably a bad idea to use "-y" (posix compatible) as default in
+# autotools. We also need to generate .c and .h files in the same time to avoid
+# duplicate stuff.
+#
+SCOLS_YACC_BASENAME = libsmartcols/src/filter-parser
+SCOLS_YACC_STEMP = $(SCOLS_YACC_BASENAME).stamp
+
+SCOLS_LEX_BASENAME = libsmartcols/src/filter-scanner
+SCOLS_LEX_STEMP = $(SCOLS_LEX_BASENAME).stamp
+
+
+$(SCOLS_YACC_STEMP): $(SCOLS_YACC_BASENAME).y
+	@rm -f $(SCOLS_YACC_STEMP).tmp
+	@touch -f $(SCOLS_YACC_STEMP).tmp
+	$(AM_V_YACC) $(BISON) $< --output=${basename $@}.c --defines=${basename $@}.h
+	@mv -f $(SCOLS_YACC_STEMP).tmp $@
+
+$(SCOLS_YACC_BASENAME).c $(SCOLS_YACC_BASENAME).h: $(SCOLS_YACC_STEMP)
+	@test -f $@ || rm -f $(SCOLS_YACC_STEMP)
+	@test -f $@ || $(MAKE) $(AM_MAKEFLAGS) $(SCOLS_YACC_STEMP)
+
+
+$(SCOLS_LEX_STEMP): $(SCOLS_LEX_BASENAME).l
+	@rm -f $(SCOLS_LEX_STEMP).tmp
+	@touch -f $(SCOLS_LEX_STEMP).tmp
+	$(AM_V_GEN) $(FLEX) --header-file=${basename $@}.h --outfile=${basename $@}.c $<
+	@mv -f $(SCOLS_LEX_STEMP).tmp $@
+
+$(SCOLS_LEX_BASENAME).c $(SCOLS_LEX_BASENAME).h: $(SCOLS_LEX_STEMP)
+	@test -f $@ || rm -f $(SCOLS_LEX_STEMP)
+	@test -f $@ || $(MAKE) $(AM_MAKEFLAGS) $(SCOLS_LEX_STEMP)
+
+# Each part of the parser depends on the header files
+$(SCOLS_LEX_BASENAME).c: $(SCOLS_YACC_BASENAME).h
+$(SCOLS_YACC_BASENAME).c: $(SCOLS_LEX_BASENAME).h
+
+# Don't re-generate parser when use sources from tarball
+EXTRA_DIST += $(SCOLS_YACC_STEMP) $(SCOLS_LEX_STEMP)
 
-libsmartcols/src/filter-scanner.h libsmartcols/src/filter-scanner.c: libsmartcols/src/filter-scanner.l
-	$(AM_V_LEX) $(FLEX) --header-file=${basename $@}.h --outfile=${basename $@}.c $<
 
 libsmartcols_la_LIBADD = $(LDADD) libcommon.la