[GRASS] prepared off_t fix on windows

Author: blazek

src/providers/grass/qgsgrassprovider.cpp

@@ -71,6 +71,30 @@ extern "C"
 #undef __STDC__
 #endif
 
+// Vect_rewrite_line and Vect_delete_line use int in GRASS 6 and off_t in GRASS 7 for line id argument.
+// off_t size is not specified by C, POSIX specifies it as signed integer and its size depends on compiler.
+// In OSGeo4W 32bit the off_t size is 8 bytes in GRASS (compiled with MinGW), and 4 bytes QGIS (compiled with MSVC), which is causing crashes.
+// The problem with off_t size was also reported for custom build of QGIS on Xubuntu 14.04 LTS using GRASS 7.0.1-2~ubuntu14.04.1.
+// See: https://lists.osgeo.org/pipermail/grass-dev/2015-June/075539.html
+//      https://lists.osgeo.org/pipermail/grass-dev/2015-September/076338.html
+// TODO: get real off_t size from GRASS, probably contribute a patch which will save 'g.version -g' to a header file during compilation
+#if GRASS_VERSION_MAJOR < 7
+typedef int Vect_rewrite_line_function_type( struct Map_info *, int, int, struct line_pnts *, struct line_cats * );
+typedef int Vect_delete_line_function_type( struct Map_info *, int );
+#else
+#ifdef Q_OS_WIN
+// TODO: switch to qint64 and compile with msvc (expected comilation error or warning)
+typedef off_t grass_off_t;
+//typedef qint64 grass_off_t;
+#else
+typedef off_t grass_off_t;
+#endif
+typedef off_t Vect_rewrite_line_function_type( struct Map_info *, grass_off_t, int, const struct line_pnts *, const struct line_cats * );
+typedef int Vect_delete_line_function_type( struct Map_info *, grass_off_t );
+#endif
+Vect_rewrite_line_function_type *Vect_rewrite_line_function_pointer = Vect_rewrite_line;
+Vect_delete_line_function_type *Vect_delete_line_function_pointer = Vect_delete_line;
+
 static QString GRASS_KEY = "grass";
 
 QgsGrassProvider::QgsGrassProvider( QString uri )
@@ -748,7 +772,7 @@ int QgsGrassProvider::rewriteLine( int oldLid, int type, struct line_pnts *Point
   int newLid = -1;
   G_TRY
   {
-    newLid = Vect_rewrite_line( map(), oldLid, type, Points, Cats );
+    newLid = Vect_rewrite_line_function_pointer( map(), oldLid, type, Points, Cats );
 
     // oldLids are maping to the very first, original version (used by undo)
     int oldestLid = oldLid;
@@ -778,7 +802,7 @@ int QgsGrassProvider::deleteLine( int line )
   if ( !isEdited() )
     return -1;
 
-  return ( Vect_delete_line( map(), line ) );
+  return ( Vect_delete_line_function_pointer( map(), line ) );
 }
 
 int QgsGrassProvider::findLine( double x, double y, int type, double threshold )