bug #801199 Infinite recursion in Gcalc_function::count_internal with ST_BUFFER over MULTIPOINT

        Collections were treated mistakenly, so the counter for the final UNION operation
        received the wrong value.
        As a fix we implement Item_func_buffer::Transporter::start_collection() method,
        where we set the proper operation and the operand counter.
        start_poly() and start_line() were also modified to function correctly for the 
        polygon as a part of a collection.

per-file comments:
  mysql-test/r/gis-precise.result
bug #801199 Infinite recursion in Gcalc_function::count_internal with ST_BUFFER over MULTIPOINT
        test result updated.

  mysql-test/t/gis-precise.test
bug #801199 Infinite recursion in Gcalc_function::count_internal with ST_BUFFER over MULTIPOINT
        test case added.

  sql/item_geofunc.cc
bug #801199 Infinite recursion in Gcalc_function::count_internal with ST_BUFFER over MULTIPOINT
        start_collection() implemented.

  sql/item_geofunc.h
bug #801199 Infinite recursion in Gcalc_function::count_internal with ST_BUFFER over MULTIPOINT
        Item_func_buffer::Transporter::start_collection() defined.

1 files changed, 13 insertions, 2 deletions

diff --git a/sql/item_geofunc.h b/sql/item_geofunc.h
index 1838a3783e8..d5ed2c1f764 100644
--- a/sql/item_geofunc.h
+++ b/sql/item_geofunc.h
@@ -26,6 +26,7 @@
 #endif
 
 #include "gcalc_slicescan.h"
+#include "gcalc_tools.h"
 
 class Item_geometry_func: public Item_str_func
 {
@@ -298,18 +299,28 @@ protected:
     int add_last_edge_buffer();
     int add_point_buffer(double x, double y);
     int complete();
-  public:
     int m_nshapes;
+    Gcalc_function::op_type buffer_op;
+    int last_shape_pos;
+    bool skip_line;
+
+  public:
     Transporter(Gcalc_function *fn, Gcalc_heap *heap, double d) :
-      Gcalc_operation_transporter(fn, heap), m_npoints(0), m_d(d), m_nshapes(0)
+      Gcalc_operation_transporter(fn, heap), m_npoints(0), m_d(d),
+      m_nshapes(0), buffer_op((d > 0.0) ? Gcalc_function::op_union :
+                                          Gcalc_function::op_difference),
+      skip_line(FALSE)
     {}
     int single_point(double x, double y);
     int start_line();
     int complete_line();
     int start_poly();
+    int complete_poly();
     int start_ring();
     int complete_ring();
     int add_point(double x, double y);
+
+    int start_collection(int n_objects);
   };
   Gcalc_heap collector;
   Gcalc_function func;