egrep, fgrep: go back to shell scripts

Although egrep's and fgrep's switch from shell scripts to
executables may have made sense in 2005, it complicated
maintenance and recently has caused subtle performance bugs.
Go back to the old way of doing things, as it's simpler and more
easily separated from the mainstream implementation.  This should
be good enough nowadays, as POSIX has withdrawn egrep/fgrep and
portable applications should be using -E/-F anyway.
* po/POTFILES.in: Remove src/egrep.c, src/fgrep.c, src/main.c.
* src/Makefile.am (bin_PROGRAMS): Remove egrep, fgrep.
(bin_SCRIPTS): New macro.
(grep_SOURCES): Move searchutils.c, dfa.c, dfasearch.c, kwset.c,
kwsearch.c, pcresearch.c here from libgrep_a_SOURCES.
(egrep_SOURCES, fgrep_SOURCES, noinst_LIBRARIES, libgrep_a_SOURCES):
Remove.
(LDADD): Remove libgrep.a.
(egrep, fgrep): New rules.
(CLEANFILES): New macro.
* src/grep.c: Rename from src/main.c.
(usage, setmatcher, main):
Simplify, since there's now just one executable.
(Gcompile, Ecompile, Acompile, GAcompile, PAcompile, matchers):
Move here from the (removed) src/grep.c.
(compile_fp_t, execute_fp_t, struct matcher, matchers):
Move here from src/grep.h, as they no longer need to be public.
(struct matcher.name): Avoid one level of indirection/relocation.
(do_execute, main): Fix a performance bug when it was compiled
as 'fgrep', due to confusion about which matcher was which.
(main): Fix a performance bug with -P, likewise.
* src/grep.h (before_options, after_options): Remove.
* src/egrep.c, src/fgrep.c, src/grep.c: Remove.

1 files changed, 22 insertions, 9 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
index 9283d1a3..2b5a365c 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -21,23 +21,20 @@ AM_CFLAGS = $(WARN_CFLAGS) $(WERROR_CFLAGS)
 # Tell the linker to omit references to unused shared libraries.
 AM_LDFLAGS = $(IGNORE_UNUSED_LIBRARIES_CFLAGS)
 
-bin_PROGRAMS = grep egrep fgrep
-grep_SOURCES  = grep.c
-egrep_SOURCES = egrep.c
-fgrep_SOURCES = fgrep.c
+bin_PROGRAMS = grep
+bin_SCRIPTS = egrep fgrep
+grep_SOURCES = grep.c searchutils.c \
+          dfa.c dfasearch.c \
+          kwset.c kwsearch.c \
+          pcresearch.c
 noinst_HEADERS = grep.h dfa.h kwset.h search.h system.h mbsupport.h
 
-noinst_LIBRARIES = libgrep.a
-libgrep_a_SOURCES = kwset.c dfa.c searchutils.c dfasearch.c kwsearch.c \
-	pcresearch.c main.c
-
 # Sometimes, the expansion of $(LIBINTL) includes -lc which may
 # include modules defining variables like 'optind', so libgreputils.a
 # must precede $(LIBINTL) in order to ensure we use GNU getopt.
 # But libgreputils.a must also follow $(LIBINTL), since libintl uses
 # replacement functions defined in libgreputils.a.
 LDADD = \
-  libgrep.a \
   ../lib/libgreputils.a $(LIBINTL) ../lib/libgreputils.a $(LIBICONV) \
   $(LIBTHREAD)
 
@@ -46,3 +43,19 @@ localedir = $(datadir)/locale
 AM_CPPFLAGS = -I$(top_builddir)/lib -I$(top_srcdir)/lib
 
 EXTRA_DIST = dosbuf.c
+
+egrep fgrep:
+	$(AM_V_GEN)grep=`echo grep | sed -e '$(transform)'`	&& \
+	case $@ in egrep) option=-E;; fgrep) option=-F;; esac	&& \
+	(echo '#!$(SHELL)'					&& \
+	 echo 'grep=grep'					&& \
+	 echo 'case $$0 in */*)'				&& \
+	 echo '  g=$${0%/*}/'"'$$grep'"				&& \
+	 echo '  test -x "$$g" && grep=$$g'			&& \
+	 echo 'esac'						&& \
+	 echo 'exec "$$grep" '"$$option"' "$$@"'	\
+	) >$@-t
+	$(AM_V_at)chmod +x $@-t
+	$(AM_V_at)mv $@-t $@
+
+CLEANFILES = egrep fgrep *-t