Re: [PATCH 08/20] unlocked stdio extensions

[Yaakov Selkowitz <yselkowi at redhat dot com>]

Index: libc/stdio/fgetws.c
===================================================================
RCS file: /cvs/src/src/newlib/libc/stdio/fgetws.c,v
retrieving revision 1.8
diff -u -p -r1.8 fgetws.c
--- libc/stdio/fgetws.c	26 Nov 2013 17:20:59 -0000	1.8
+++ libc/stdio/fgetws.c	17 Dec 2014 18:26:57 -0000
@@ -26,22 +26,35 @@
 
 /*
 FUNCTION
-<<fgetws>>---get wide character string from a file or stream
+<<fgetws>>, <<fgetws_unlocked>>---get wide character string from a file or stream
 
 INDEX
 	fgetws
 INDEX
+	fgetws_unlocked
+INDEX
 	_fgetws_r
+INDEX
+	_fgetws_unlocked_r
 
 ANSI_SYNOPSIS
 	#include <wchar.h>
 	wchar_t *fgetws(wchar_t *__restrict <[ws]>, int <[n]>,
                         FILE *__restrict <[fp]>);
 
+	#define _GNU_SOURCE
+	#include <wchar.h>
+	wchar_t *fgetws_unlocked(wchar_t *__restrict <[ws]>, int <[n]>,
+                        FILE *__restrict <[fp]>);
+
 	#include <wchar.h>
 	wchar_t *_fgetws_r(struct _reent *<[ptr]>, wchar_t *<[ws]>,
                            int <[n]>, FILE *<[fp]>);
 
+	#include <wchar.h>
+	wchar_t *_fgetws_unlocked_r(struct _reent *<[ptr]>, wchar_t *<[ws]>,
+                           int <[n]>, FILE *<[fp]>);
+
 TRAD_SYNOPSIS
 	#include <wchar.h>
 	wchar_t *fgetws(<[ws]>,<[n]>,<[fp]>)
@@ -49,6 +62,13 @@ TRAD_SYNOPSIS
 	int <[n]>;
 	FILE *__restrict <[fp]>;
 
+	#define _GNU_SOURCE
+	#include <wchar.h>
+	wchar_t *fgetws_unlocked(<[ws]>,<[n]>,<[fp]>)
+	wchar_t *__restrict <[ws]>;
+	int <[n]>;
+	FILE *__restrict <[fp]>;
+
 	#include <wchar.h>
 	wchar_t *_fgetws_r(<[ptr]>, <[ws]>,<[n]>,<[fp]>)
 	struct _reent *<[ptr]>;
@@ -56,13 +76,29 @@ TRAD_SYNOPSIS
 	int <[n]>;
 	FILE *<[fp]>;
 
+	#include <wchar.h>
+	wchar_t *_fgetws_unlocked_r(<[ptr]>, <[ws]>,<[n]>,<[fp]>)
+	struct _reent *<[ptr]>;
+	wchar_t *<[ws]>;
+	int <[n]>;
+	FILE *<[fp]>;
+
 DESCRIPTION
 Reads at most <[n-1]> wide characters from <[fp]> until a newline
 is found. The wide characters including to the newline are stored
 in <[ws]>. The buffer is terminated with a 0.
 
-The <<_fgetws_r>> function is simply the reentrant version of
-<<fgetws>> and is passed an additional reentrancy structure
+<<fgetws_unlocked>> is a non-thread-safe version of <<fgetws>>.
+<<fgetws_unlocked>> may only safely be used within a scope
+protected by flockfile() (or ftrylockfile()) and funlockfile().  This
+function may safely be used in a multi-threaded program if and only
+if they are called while the invoking thread owns the (FILE *)
+object, as is the case after a successful call to the flockfile() or
+ftrylockfile() functions.  If threads are disabled, then
+<<fgetws_unlocked>> is equivalent to <<fgetws>>.
+
+The <<_fgetws_r>> and <<_fgetws_unlocked_r>> functions are simply reentrant
+version of the above and are passed an additional reentrancy structure
 pointer: <[ptr]>.
 
 RETURNS
@@ -72,7 +108,9 @@ accumulated, the data is returned with n
 no data are read, NULL is returned instead.
 
 PORTABILITY
-C99, POSIX.1-2001
+<<fgetws>> is required by C99 and POSIX.1-2001.
+
+<<fgetws_unlocked>> is a GNU extension.
 */
 
 #include <_ansi.h>
@@ -83,6 +121,17 @@ C99, POSIX.1-2001
 #include <wchar.h>
 #include "local.h"
 
+#ifdef FGETWS_UNLOCKED
+#undef _newlib_flockfile_start
+#undef _newlib_flockfile_exit
+#undef _newlib_flockfile_end
+#define _newlib_flockfile_start(x) {}
+#define _newlib_flockfile_exit(x) {}
+#define _newlib_flockfile_end(x) {}
+#define _fgetws_r _fgetws_unlocked_r
+#define fgetws fgetws_unlocked
+#endif
+
 wchar_t *
 _DEFUN(_fgetws_r, (ptr, ws, n, fp),
 	struct _reent *ptr _AND
Index: libc/stdio/fgetws_u.c
===================================================================
RCS file: libc/stdio/fgetws_u.c
diff -N libc/stdio/fgetws_u.c
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ libc/stdio/fgetws_u.c	17 Dec 2014 18:26:57 -0000
@@ -0,0 +1,28 @@
+/*
+ * Copyright (c) 2014 Red Hat, Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#define FGETWS_UNLOCKED
+#include "fgetws.c"