Jim Meyering wrote:
Technically, we could fix it by adding more ifdefs, but I think it
would not be worthwhile to accommodate this use case.
I looked into this and discovered that fixing this can actually simplify the
source code by removing the need for the "We can't get here" glitch in
pcresearch.c. Although the fix does add complexity elsewhere so that the total
number of ifdefs and ifs remains the same, overall grep gets a bit simpler and
cleaner with the fix so I took the liberty of installing it (attached).
>From f417ea8186c0ef0271ee5cf6943923bd60d06223 Mon Sep 17 00:00:00 2001
From: Paul Eggert <egg...@cs.ucla.edu>
Date: Sun, 20 Jan 2019 09:52:09 -0800
Subject: [PATCH] grep: simplify pcresearch.c ifdefs
This fixes a warning if PCRE is not used (Bug#34054).
* configure.ac (USE_PCRE): New conditional.
* src/Makefile.am (grep_SOURCES) [!USE_PCRE]: Omit pcresearch.c.
* src/grep.c (matchers) [!HAVE_LIBPCRE]: Omit perl matcher.
(setmatcher) [!HAVE_LIBPCRE]: If helpful, mention
--disable-perl-regexp in diagnostic.
* src/pcresearch.c: Simplify by assuming HAVE_LIBPCRE.
---
configure.ac | 1 +
src/Makefile.am | 4 +++-
src/grep.c | 7 +++++++
src/pcresearch.c | 54 ++++++++++++++++++------------------------------
4 files changed, 31 insertions(+), 35 deletions(-)
diff --git a/configure.ac b/configure.ac
index 4ce7216..1bbfc4f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -206,6 +206,7 @@ if test "$ac_use_included_regex" = no; then
fi
gl_FUNC_PCRE
+AM_CONDITIONAL([USE_PCRE], [test $use_pcre = yes])
case $host_os in
mingw*) suffix=w32 ;;
diff --git a/src/Makefile.am b/src/Makefile.am
index 40e9a96..1cfca3f 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -29,8 +29,10 @@ grep_SOURCES = \
grep.c \
kwsearch.c \
kwset.c \
- pcresearch.c \
searchutils.c
+if USE_PCRE
+grep_SOURCES += pcresearch.c
+endif
noinst_HEADERS = grep.h kwset.h search.h system.h
diff --git a/src/grep.c b/src/grep.c
index 95fa809..e53b8cd 100644
--- a/src/grep.c
+++ b/src/grep.c
@@ -2016,7 +2016,9 @@ static struct
{ "awk", RE_SYNTAX_AWK, GEAcompile, EGexecute },
{ "gawk", RE_SYNTAX_GNU_AWK, GEAcompile, EGexecute },
{ "posixawk", RE_SYNTAX_POSIX_AWK, GEAcompile, EGexecute },
+#if HAVE_LIBPCRE
{ "perl", 0, Pcompile, Pexecute, },
+#endif
};
/* Keep these in sync with the 'matchers' table. */
enum { E_MATCHER_INDEX = 1, F_MATCHER_INDEX = 2, G_MATCHER_INDEX = 0 };
@@ -2035,6 +2037,11 @@ setmatcher (char const *m, int matcher)
return i;
}
+#if !HAVE_LIBPCRE
+ if (STREQ (m, "perl"))
+ die (EXIT_TROUBLE, 0,
+ _("Perl matching not supported in a --disable-perl-regexp build"));
+#endif
die (EXIT_TROUBLE, 0, _("invalid matcher %s"), m);
}
diff --git a/src/pcresearch.c b/src/pcresearch.c
index 64e189c..3e45c00 100644
--- a/src/pcresearch.c
+++ b/src/pcresearch.c
@@ -22,22 +22,21 @@
#include "search.h"
#include "die.h"
-#if HAVE_LIBPCRE
-# include <pcre.h>
+#include <pcre.h>
/* This must be at least 2; everything after that is for performance
in pcre_exec. */
enum { NSUB = 300 };
-# ifndef PCRE_EXTRA_MATCH_LIMIT_RECURSION
-# define PCRE_EXTRA_MATCH_LIMIT_RECURSION 0
-# endif
-# ifndef PCRE_STUDY_JIT_COMPILE
-# define PCRE_STUDY_JIT_COMPILE 0
-# endif
-# ifndef PCRE_STUDY_EXTRA_NEEDED
-# define PCRE_STUDY_EXTRA_NEEDED 0
-# endif
+#ifndef PCRE_EXTRA_MATCH_LIMIT_RECURSION
+# define PCRE_EXTRA_MATCH_LIMIT_RECURSION 0
+#endif
+#ifndef PCRE_STUDY_JIT_COMPILE
+# define PCRE_STUDY_JIT_COMPILE 0
+#endif
+#ifndef PCRE_STUDY_EXTRA_NEEDED
+# define PCRE_STUDY_EXTRA_NEEDED 0
+#endif
struct pcre_comp
{
@@ -47,11 +46,11 @@ struct pcre_comp
/* Additional information about the pattern. */
pcre_extra *extra;
-# if PCRE_STUDY_JIT_COMPILE
+#if PCRE_STUDY_JIT_COMPILE
/* The JIT stack and its maximum size. */
pcre_jit_stack *jit_stack;
int jit_stack_size;
-# endif
+#endif
/* Table, indexed by ! (flag & PCRE_NOTBOL), of whether the empty
string matches when that flag is used. */
@@ -72,7 +71,7 @@ jit_exec (struct pcre_comp *pc, char const *subject, int search_bytes,
int e = pcre_exec (pc->cre, pc->extra, subject, search_bytes,
search_offset, options, sub, NSUB);
-# if PCRE_STUDY_JIT_COMPILE
+#if PCRE_STUDY_JIT_COMPILE
if (e == PCRE_ERROR_JIT_STACKLIMIT
&& 0 < pc->jit_stack_size && pc->jit_stack_size <= INT_MAX / 2)
{
@@ -87,9 +86,9 @@ jit_exec (struct pcre_comp *pc, char const *subject, int search_bytes,
pcre_assign_jit_stack (pc->extra, NULL, pc->jit_stack);
continue;
}
-# endif
+#endif
-# if PCRE_EXTRA_MATCH_LIMIT_RECURSION
+#if PCRE_EXTRA_MATCH_LIMIT_RECURSION
if (e == PCRE_ERROR_RECURSIONLIMIT
&& (PCRE_STUDY_EXTRA_NEEDED || pc->extra)
&& pc->extra->match_limit_recursion <= ULONG_MAX / 2)
@@ -102,22 +101,15 @@ jit_exec (struct pcre_comp *pc, char const *subject, int search_bytes,
}
continue;
}
-# endif
+#endif
return e;
}
}
-#endif
-
void *
Pcompile (char *pattern, size_t size, reg_syntax_t ignored)
{
-#if !HAVE_LIBPCRE
- die (EXIT_TROUBLE, 0,
- _("support for the -P option is not compiled into "
- "this --disable-perl-regexp binary"));
-#else
int e;
char const *ep;
static char const wprefix[] = "(?<!\\w)(?:";
@@ -184,14 +176,14 @@ Pcompile (char *pattern, size_t size, reg_syntax_t ignored)
if (ep)
die (EXIT_TROUBLE, 0, "%s", ep);
-# if PCRE_STUDY_JIT_COMPILE
+#if PCRE_STUDY_JIT_COMPILE
if (pcre_fullinfo (pc->cre, pc->extra, PCRE_INFO_JIT, &e))
die (EXIT_TROUBLE, 0, _("internal error (should never happen)"));
/* The PCRE documentation says that a 32 KiB stack is the default. */
if (e)
pc->jit_stack_size = 32 << 10;
-# endif
+#endif
free (re);
@@ -202,17 +194,12 @@ Pcompile (char *pattern, size_t size, reg_syntax_t ignored)
NSUB);
return pc;
-#endif /* HAVE_LIBPCRE */
}
size_t
Pexecute (void *vcp, char const *buf, size_t size, size_t *match_size,
char const *start_ptr)
{
-#if !HAVE_LIBPCRE
- /* We can't get here, because Pcompile would have been called earlier. */
- die (EXIT_TROUBLE, 0, _("internal error"));
-#else
int sub[NSUB];
char const *p = start_ptr ? start_ptr : buf;
bool bol = p[-1] == eolbyte;
@@ -312,10 +299,10 @@ Pexecute (void *vcp, char const *buf, size_t size, size_t *match_size,
case PCRE_ERROR_NOMEMORY:
die (EXIT_TROUBLE, 0, _("memory exhausted"));
-# if PCRE_STUDY_JIT_COMPILE
+#if PCRE_STUDY_JIT_COMPILE
case PCRE_ERROR_JIT_STACKLIMIT:
die (EXIT_TROUBLE, 0, _("exhausted PCRE JIT stack"));
-# endif
+#endif
case PCRE_ERROR_MATCHLIMIT:
die (EXIT_TROUBLE, 0, _("exceeded PCRE's backtracking limit"));
@@ -349,5 +336,4 @@ Pexecute (void *vcp, char const *buf, size_t size, size_t *match_size,
*match_size = end - beg;
return beg - buf;
}
-#endif
}
--
2.17.1
