Allow passing file name to parse_config_file(), Fixes #3264

[SVN r58248]

Author: Sascha Ochsenknecht

include/boost/program_options/errors.hpp

@@ -206,6 +206,13 @@ namespace boost { namespace program_options {
         {}
     };
 
+    /** Class thrown if config file can not be read */
+    class BOOST_PROGRAM_OPTIONS_DECL reading_file : public error {
+    public:
+        reading_file(const char* filename)
+         : error(std::string("can not read file ").append(filename))
+        {}
+    };
 }}
 
 

include/boost/program_options/parsers.hpp

@@ -147,6 +147,8 @@ namespace boost { namespace program_options {
                        = ext_parser());
 
     /** Parse a config file. 
+    
+        Read from given stream.
     */
     template<class charT>
 #if ! BOOST_WORKAROUND(__ICL, BOOST_TESTED_AT(700))
@@ -156,6 +158,19 @@ namespace boost { namespace program_options {
     parse_config_file(std::basic_istream<charT>&, const options_description&,
                       bool allow_unregistered = false);
 
+    /** Parse a config file. 
+    
+        Read from file with the given name. The character type is
+        passed to the file stream. 
+    */
+    template<class charT>
+#if ! BOOST_WORKAROUND(__ICL, BOOST_TESTED_AT(700))
+    BOOST_PROGRAM_OPTIONS_DECL
+#endif
+    basic_parsed_options<charT>
+    parse_config_file(const char* filename, const options_description&,
+                      bool allow_unregistered = false);
+
     /** Controls if the 'collect_unregistered' function should
         include positional options, or not. */
     enum collect_unrecognized_mode 

src/parsers.cpp

@@ -20,6 +20,7 @@
 #include <boost/throw_exception.hpp>
 
 #include <cctype>
+#include <fstream>
 
 #if !defined(__GNUC__) || __GNUC__ < 3
 #include <iostream>
@@ -134,6 +135,36 @@ namespace boost { namespace program_options {
                       const options_description& desc,
                       bool allow_unregistered);
 #endif
+
+    template<class charT>
+    basic_parsed_options<charT>
+    parse_config_file(const char* filename, 
+                      const options_description& desc,
+                      bool allow_unregistered)
+    { 
+        // Parser return char strings
+        std::basic_ifstream< charT > strm(filename);
+        if (!strm) 
+        {
+            boost::throw_exception(reading_file(filename));
+        }
+        return parse_config_file(strm, desc, allow_unregistered);
+    }
+
+    template
+    BOOST_PROGRAM_OPTIONS_DECL basic_parsed_options<char>
+    parse_config_file(const char* filename, 
+                      const options_description& desc,
+                      bool allow_unregistered);
+
+#ifndef BOOST_NO_STD_WSTRING
+    template
+    BOOST_PROGRAM_OPTIONS_DECL basic_parsed_options<wchar_t>
+    parse_config_file(const char* filename, 
+                      const options_description& desc,
+                      bool allow_unregistered);
+#endif
+
 
 // This versio, which accepts any options without validation, is disabled,
 // in the hope that nobody will need it and we cant drop it altogether.

test/config_test.cfg

@@ -0,0 +1,9 @@
+gv1 = 0#asd
+empty_value = 
+plug3 = 7
+b = true
+
+[m1]
+v1 = 1
+
+v2 = 2

test/parsers_test.cpp

@@ -229,7 +229,16 @@ void test_config_file()
     check_value(a1[3], "b", "true");
     check_value(a1[4], "m1.v1", "1");
     check_value(a1[5], "m1.v2", "2");
-
+    
+    // same test, but now options come from file 
+    vector<option> a2 = parse_config_file<char>("config_test.cfg", desc).options;
+    BOOST_REQUIRE(a2.size() == 6);
+    check_value(a2[0], "gv1", "0");
+    check_value(a2[1], "empty_value", "");
+    check_value(a2[2], "plug3", "7");
+    check_value(a2[3], "b", "true");
+    check_value(a2[4], "m1.v1", "1");
+    check_value(a2[5], "m1.v2", "2");
 }
 
 void test_environment()