Added new 'fsync' option.

ChangeLog

+2017-11-15  Mark Lindner  <markl@avalon>
+
+  * lib/wincompat.c, lib/wincompat.h - added fsync() implementation for Windows
+  * lib/libconfig.c, lib/libconfig.h - added CONFIG_OPTION_FSYNC
+  * lib/libconfigcpp.c++, lib/libconfig.h++ - added Config::OptionFsync
+  * doc/libconfig.texi - Documentation updates
+
   ----- version 1.7 ------
 
 2017-10-24  Mark Lindner  <markl@avalon>

configure.ac

 dnl Process this file with autoconf to produce a configure script.
 
-AC_INIT(libconfig, 1.7, hyperrealm@gmail.com, libconfig,
+AC_INIT(libconfig, 1.7.1, hyperrealm@gmail.com, libconfig,
 	[https://hyperrealm.github.io/libconfig/])
 AC_CONFIG_AUX_DIR([aux-build])
 AC_CONFIG_MACRO_DIR([m4])

doc/libconfig.texi

@@ -6,8 +6,8 @@
 @setfilename libconfig.info
 @settitle libconfig
 
-@set edition 1.7
-@set update-date 31 Oct 2017
+@set edition 1.7.1
+@set update-date ?? Nov 2017
 @set subtitle-text A Library For Processing Structured Configuration Files
 @set author-text Mark A.@: Lindner
 
@@ -945,6 +945,11 @@ when writing floating point values (corresponding to @code{printf()}
 @samp{%g} format) or should never be used (corresponding to @code{printf()}
 @samp{%f} format). By default this option is turned off.
 
+@item CONFIG_OPTION_FSYNC
+(@b{Since @i{v1.7.1}})
+This option controls whether the @code{config_write_file()} function performs
+an @i{fsync} operation after writing the configuration and before closing the
+file. By default this option is turned off.
 @end table
 
 @end deftypefun
@@ -1580,6 +1585,12 @@ when writing floating point values (corresponding to @code{printf()}
 @samp{%g} format) or should never be used (corresponding to @code{printf()}
 @samp{%f} format). By default this option is turned off.
 
+@item Config::OptionFsync
+(@b{Since @i{v1.7.1}})
+This option controls whether the @code{writeFile()} method performs an @i{fsync}
+operation after writing the configuration and before closing the file. By
+default this option is turned off.
+
 @end table
 
 @end deftypemethod

examples/c++/example2.cpp

@@ -38,6 +38,11 @@ int main(int argc, char **argv)
 
   Config cfg;
 
+  cfg.setOptions(Config::OptionFsync
+                 | Config::OptionSemicolonSeparators
+                 | Config::OptionColonAssignmentForGroups
+                 | Config::OptionOpenBraceOnSeparateLine);
+
   // Read the file. If there is an error, report it and exit.
   try
   {

examples/c/example2.c

@@ -36,6 +36,11 @@ int main(int argc, char **argv)
   config_setting_t *root, *setting, *movie;
 
   config_init(&cfg);
+  config_set_options(&cfg,
+                     (CONFIG_OPTION_FSYNC
+                      | CONFIG_OPTION_SEMICOLON_SEPARATORS
+                      | CONFIG_OPTION_COLON_ASSIGNMENT_FOR_GROUPS
+                      | CONFIG_OPTION_OPEN_BRACE_ON_SEPARATE_LINE));
 
   /* Read the file. If there is an error, report it and exit. */
   if(! config_read_file(&cfg, "example.cfg"))
@@ -74,8 +79,6 @@ int main(int argc, char **argv)
   setting = config_setting_add(movie, "qty", CONFIG_TYPE_INT);
   config_setting_set_float(setting, 20);
 
-  config_set_options(&cfg, 0);
-
   /* Write out the updated configuration. */
   if(! config_write_file(&cfg, output_file))
   {

lib/Makefile.am

@@ -18,7 +18,7 @@
 #
 # For more info see section 6.3 of the GNU Libtool Manual.
 
-VERINFO = -version-info 11:0:0
+VERINFO = -version-info 11:1:0
 
 ## Flex
 PARSER_PREFIX = libconfig_yy
@@ -28,8 +28,8 @@ AM_LFLAGS = --header-file=scanner.h --prefix=$(PARSER_PREFIX)
 AM_YFLAGS = -d -p $(PARSER_PREFIX)
 
 
-libsrc = libconfig.c scanner.l grammar.y parsectx.h wincompat.h \
-  scanctx.c scanctx.h strbuf.c strbuf.h strvec.c strvec.h util.c util.h
+libsrc = grammar.y libconfig.c parsectx.h scanctx.c scanctx.h scanner.l \
+    strbuf.c strbuf.h strvec.c strvec.h util.c util.h wincompat.c wincompat.h
 libinc = libconfig.h
 
 libsrc_cpp =  $(libsrc) libconfigcpp.c++

lib/libconfig++.vcproj

@@ -198,6 +198,10 @@
 				RelativePath=".\util.c"
 				>
 			</File>
+			<File
+				RelativePath=".\wincompat.c"
+				>
+			</File>
 		</Filter>
 		<Filter
 			Name="Header Files"

lib/libconfig++.vcxproj

@@ -92,6 +92,7 @@
     <ClCompile Include="strbuf.c" />
     <ClCompile Include="strvec.c" />
     <ClCompile Include="util.c" />
+    <ClCompile Include="wincompat.c" />
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="..\ac_config.h" />
@@ -112,4 +113,4 @@
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
   <ImportGroup Label="ExtensionTargets">
   </ImportGroup>
-</Project>
\ No newline at end of file
+</Project>

lib/libconfig.c

@@ -691,6 +691,23 @@ int config_write_file(config_t *config, const char *filename)
   }
 
   config_write(config, stream);
+
+  if(config_get_option(config, CONFIG_OPTION_FSYNC))
+  {
+    int fd = fileno(stream);
+
+    if(fd >= 0)
+    {
+      if(fsync(fd) != 0)
+      {
+        fclose(stream);
+        config->error_text = __io_error;
+        config->error_type = CONFIG_ERR_FILE_IO;
+        return(CONFIG_FALSE);
+      }
+    }
+  }
+
   fclose(stream);
   config->error_type = CONFIG_ERR_NONE;
   return(CONFIG_TRUE);

lib/libconfig.h

@@ -64,6 +64,7 @@ extern "C" {
 #define CONFIG_OPTION_COLON_ASSIGNMENT_FOR_NON_GROUPS 0x08
 #define CONFIG_OPTION_OPEN_BRACE_ON_SEPARATE_LINE     0x10
 #define CONFIG_OPTION_ALLOW_SCIENTIFIC_NOTATION       0x20
+#define CONFIG_OPTION_FSYNC                           0x40
 
 #define CONFIG_TRUE  (1)
 #define CONFIG_FALSE (0)

lib/libconfig.h++

@@ -448,7 +448,8 @@ class LIBCONFIGXX_API Config
     OptionColonAssignmentForGroups = 0x04,
     OptionColonAssignmentForNonGroups = 0x08,
     OptionOpenBraceOnSeparateLine = 0x10,
-    OptionAllowScientificNotation = 0x20
+    OptionAllowScientificNotation = 0x20,
+    OptionFsync = 0x40
   };
 
   Config();

lib/libconfig.vcproj

@@ -185,6 +185,10 @@
 				RelativePath=".\util.c"
 				>
 			</File>
+			<File
+				RelativePath=".\wincompat.c"
+				>
+			</File>
 		</Filter>
 		<Filter
 			Name="Header Files"

lib/libconfig.vcxproj

@@ -81,6 +81,7 @@
     <ClCompile Include="strbuf.c" />
     <ClCompile Include="strvec.c" />
     <ClCompile Include="util.c" />
+    <ClCompile Include="wincompat.c" />
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="..\ac_config.h" />
@@ -99,4 +100,4 @@
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
   <ImportGroup Label="ExtensionTargets">
   </ImportGroup>
-</Project>
\ No newline at end of file
+</Project>

lib/wincompat.c

+/* ----------------------------------------------------------------------------
+   libconfig - A library for processing structured configuration files
+   Copyright (C) 2005-2018  Mark A Lindner
+
+   This file is part of libconfig.
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public License
+   as published by the Free Software Foundation; either version 2.1 of
+   the License, or (at your option) any later version.
+
+   This library is distributed in the hope that it will be useful, but
+   WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Library General Public
+   License along with this library; if not, see
+   <http://www.gnu.org/licenses/>.
+   ----------------------------------------------------------------------------
+*/
+
+#include "wincompat.h"
+
+#if defined(WIN32) || defined(_WIN32) || defined(__WIN32__) \
+  || defined(WIN64) || defined(_WIN64) || defined(__WIN64__)
+
+#include <errno.h>
+#include <io.h>
+
+int fsync(int fd)
+{
+  HANDLE h = (HANDLE)_get_osfhandle(fd);
+  if(h == INVALID_HANDLE_VALUE)
+  {
+    errno = EBADF;
+    return(-1);
+  }
+
+  if(!FlushFileBuffers(h))
+  {
+    DWORD err = GetLastError();
+    switch(err)
+    {
+      case ERROR_ACCESS_DENIED:
+        return(0);
+
+      case ERROR_INVALID_HANDLE:
+        errno = EINVAL;
+        break;
+
+      default:
+        errno = EIO;
+    }
+    return(-1);
+  }
+
+  return(0);
+}
+
+#endif // WIN32 || WIN64

lib/wincompat.h

@@ -101,6 +101,8 @@
 #define IS_RELATIVE_PATH(P) \
   (PathIsRelativeA(P))
 
+extern int fsync(int fd);
+
 #else /* defined(WIN32/WIN64) && ! defined(__MINGW32__) */
 
 #define INT64_CONST(I)  (I ## LL)
@@ -109,6 +111,8 @@
 #define IS_RELATIVE_PATH(P) \
   ((P)[0] != '/')
 
+#include <unistd.h> /* for fsync() */
+
 #endif /* defined(WIN32/WIN64) && ! defined(__MINGW32__) */
 
 #endif /* __wincompat_h */