+ check if *.sqlite file exists and avoid creating a new one

plugins/input/sqlite/SConscript

@@ -36,7 +36,9 @@ if env['PLATFORM'] == 'Darwin':
     libraries.append('mapnik')
     libraries.append('icuuc')
     libraries.append('icudata')
-
+    libraries.append('boost_system%s' % env['BOOST_APPEND'])
+    libraries.append('boost_filesystem%s' % env['BOOST_APPEND'])
+    
 sqlite_inputdriver = env.SharedLibrary('sqlite', source=sqlite_src, SHLIBPREFIX='', SHLIBSUFFIX='.input', LIBS=libraries)
 
 env.Install(install_prefix + '/' + env['LIBDIR_SCHEMA'] + env['LIB_DIR_NAME'] + '/input', sqlite_inputdriver)

plugins/input/sqlite/sqlite_datasource.cpp

@@ -31,6 +31,7 @@
 #include <boost/algorithm/string.hpp>
 #include <boost/lexical_cast.hpp>
 #include <boost/tokenizer.hpp>
+#include <boost/filesystem/operations.hpp>
 
 using std::clog;
 using std::endl;
@@ -102,6 +103,8 @@ sqlite_datasource::sqlite_datasource(parameters const& params)
     multiple_geometries_ = *params_.get<mapnik::boolean>("multiple_geometries",false);
     use_spatial_index_ = *params_.get<mapnik::boolean>("use_spatial_index",true);
 
+    if (!boost::filesystem::exists(*file)) throw datasource_exception(*file + " don't exists");
+    
     dataset_ = new sqlite_connection (*file);
 
     boost::optional<std::string> ext  = params_.get<std::string>("extent");