MDEV-34276: Implements the function ST_IsValid

The GIS function ST_IsValid takes ad input a geometry and returns 1
if the argument is geometrically valid, 0 if the argument is not
geometrically valid.

Author: StefanoPetrilli <stefanop_1999@hotmail.it>
Co-authored-by: Ahmed Ibrahim <ahmed.ibr.hashim@gmail.com>
Co-authored-by: Jon Olav Hauglid <jon.hauglid@oracle.com>
Co-authored-by: Erlend Dahl <erlend.dahl@oracle.com>
Co-authored-by: Norvald H. Ryeng <norvald.ryeng@oracle.com>
Co-authored-by: Menelaos Karavelas <menelaos.karavelas@oracle.com>
Co-authored-by: David.Zhao <david.zhao@oracle.com>
Co-authored-by: Pavan <pavan.naik@oracle.com>

mysql-test/main/gis.result

@@ -4582,6 +4582,12 @@ SELECT ST_ISSIMPLE(1);
 ERROR HY000: Illegal parameter data type int for operation 'st_issimple'
 SELECT ST_ISSIMPLE('test');
 ERROR HY000: Illegal parameter data type varchar for operation 'st_issimple'
+SELECT ST_ISVALID(ROW(1,1));
+ERROR HY000: Illegal parameter data type row for operation 'st_isvalid'
+SELECT ST_ISVALID(1);
+ERROR HY000: Illegal parameter data type int for operation 'st_isvalid'
+SELECT ST_ISVALID('test');
+ERROR HY000: Illegal parameter data type varchar for operation 'st_isvalid'
 SELECT ST_ISRING(ROW(1,1));
 ERROR HY000: Illegal parameter data type row for operation 'st_isring'
 SELECT ST_ISRING(1);
@@ -5501,3 +5507,48 @@ ERROR HY000: Cannot cast 'point' as 'int' in assignment of `test`.`t1`.`b`
 #
 # End of 11.5 tests
 #
+#
+# Start of 11.6 tests
+#
+#
+# MDEV-34276 Tests for ST_isValid
+#
+# Some tests for Point, multipoint, linestring
+SET @g = ST_GEOMFROMTEXT('POINT(0 0)');
+SELECT ST_ISVALID(@g);
+ST_ISVALID(@g)
+1
+SELECT ISVALID(@g);
+ISVALID(@g)
+1
+SET @g = ST_GEOMFROMTEXT('POINT(15 0)');
+SELECT ST_ISVALID(@g);
+ST_ISVALID(@g)
+1
+SET @g = ST_GEOMFROMTEXT('MULTIPOINT(15 0, 10 0, 0 0, 11 11)');
+SELECT ST_ISVALID(@g);
+ST_ISVALID(@g)
+1
+SET @g = ST_GEOMFROMTEXT('LINESTRING(0 0, 1 1, 2 2, 2 3)');
+SELECT ST_ISVALID(@g);
+ST_ISVALID(@g)
+1
+# Some tests for Polygons
+SELECT ST_ISVALID(ST_GEOMFROMTEXT('POLYGON((40 40, 20 45, 45 30, 40 40)), ((20 35, 10 30, 10 10, 30 5, 45 20, 20 35), (30 20, 20 15, 20 25, 30 20))'));
+ST_ISVALID(ST_GEOMFROMTEXT('POLYGON((40 40, 20 45, 45 30, 40 40)), ((20 35, 10 30, 10 10, 30 5, 45 20, 20 35), (30 20, 20 15, 20 25, 30 20))'))
+1
+SELECT ST_ISVALID(ST_GEOMFROMTEXT('POLYGON((30 10, 40 40, 20 40, 10 20, 30 10))'));
+ST_ISVALID(ST_GEOMFROMTEXT('POLYGON((30 10, 40 40, 20 40, 10 20, 30 10))'))
+1
+SELECT ST_ISVALID(ST_GEOMFROMTEXT('POLYGON((0 0, 0 2, 2 2, 1 1, 2 0, 0 0))'));
+ST_ISVALID(ST_GEOMFROMTEXT('POLYGON((0 0, 0 2, 2 2, 1 1, 2 0, 0 0))'))
+1
+SELECT ST_ISVALID(ST_GEOMFROMTEXT('MULTIPOLYGON(((0 0, 0 2, 2 2, 2 0, 0 0)),((4 4, 4 5, 5 5, 5 4, 4 4)))')) AS a;
+a
+1
+SELECT ST_ISVALID(ST_GEOMFROMTEXT('POLYGON((0 0, 10 0, 10 10, 0 10, 0 0), (15 15, 15 20, 20 20, 20 15, 15 15))')) as t;
+t
+0
+#
+# End of 11.6 tests
+#

mysql-test/main/gis.test

@@ -2625,6 +2625,13 @@ SELECT ST_ISSIMPLE(1);
 --error ER_ILLEGAL_PARAMETER_DATA_TYPE_FOR_OPERATION
 SELECT ST_ISSIMPLE('test');
 
+--error ER_ILLEGAL_PARAMETER_DATA_TYPE_FOR_OPERATION
+SELECT ST_ISVALID(ROW(1,1));
+--error ER_ILLEGAL_PARAMETER_DATA_TYPE_FOR_OPERATION
+SELECT ST_ISVALID(1);
+--error ER_ILLEGAL_PARAMETER_DATA_TYPE_FOR_OPERATION
+SELECT ST_ISVALID('test');
+
 --error ER_ILLEGAL_PARAMETER_DATA_TYPE_FOR_OPERATION
 SELECT ST_ISRING(ROW(1,1));
 --error ER_ILLEGAL_PARAMETER_DATA_TYPE_FOR_OPERATION
@@ -3503,3 +3510,42 @@ CREATE TABLE t1 (a POINT, b INT GENERATED ALWAYS AS (a));
 --echo #
 --echo # End of 11.5 tests
 --echo #
+
+--echo #
+--echo # Start of 11.6 tests
+--echo #
+
+--echo #
+--echo # MDEV-34276 Tests for ST_isValid
+--echo #
+
+--echo # Some tests for Point, multipoint, linestring
+
+SET @g = ST_GEOMFROMTEXT('POINT(0 0)');
+SELECT ST_ISVALID(@g);
+SELECT ISVALID(@g);
+
+SET @g = ST_GEOMFROMTEXT('POINT(15 0)');
+SELECT ST_ISVALID(@g);
+
+SET @g = ST_GEOMFROMTEXT('MULTIPOINT(15 0, 10 0, 0 0, 11 11)');
+SELECT ST_ISVALID(@g);
+
+SET @g = ST_GEOMFROMTEXT('LINESTRING(0 0, 1 1, 2 2, 2 3)');
+SELECT ST_ISVALID(@g);
+
+--echo # Some tests for Polygons
+
+SELECT ST_ISVALID(ST_GEOMFROMTEXT('POLYGON((40 40, 20 45, 45 30, 40 40)), ((20 35, 10 30, 10 10, 30 5, 45 20, 20 35), (30 20, 20 15, 20 25, 30 20))'));
+
+SELECT ST_ISVALID(ST_GEOMFROMTEXT('POLYGON((30 10, 40 40, 20 40, 10 20, 30 10))'));
+
+SELECT ST_ISVALID(ST_GEOMFROMTEXT('POLYGON((0 0, 0 2, 2 2, 1 1, 2 0, 0 0))'));
+
+SELECT ST_ISVALID(ST_GEOMFROMTEXT('MULTIPOLYGON(((0 0, 0 2, 2 2, 2 0, 0 0)),((4 4, 4 5, 5 5, 5 4, 4 4)))')) AS a;
+
+SELECT ST_ISVALID(ST_GEOMFROMTEXT('POLYGON((0 0, 10 0, 10 10, 0 10, 0 0), (15 15, 15 20, 20 20, 20 15, 15 15))')) as t;
+
+--echo #
+--echo # End of 11.6 tests
+--echo #

sql/item_geofunc.cc

@@ -2073,6 +2073,29 @@ String *Item_func_buffer::val_str(String *str_value)
   DBUG_RETURN(str_result);
 }
 
+longlong Item_func_isvalid::val_int()
+{
+  String *wkb= args[0]->val_str(&tmp);
+  Geometry_buffer buffer;
+  Geometry *geometry;
+
+  int valid;
+  if ((args[0]->null_value ||
+      !(geometry= Geometry::construct(&buffer, wkb->ptr(), wkb->length()))))
+  {
+    my_error(ER_GIS_INVALID_DATA, MYF(0), func_name());
+    null_value= 1;
+    return 1;
+  }
+
+  if (geometry->is_valid(&valid))
+  {
+    null_value= 1;
+    return 1;
+  }
+
+  return (longlong) valid;
+}
 
 longlong Item_func_isempty::val_int()
 {
@@ -2080,7 +2103,7 @@ longlong Item_func_isempty::val_int()
   String tmp;
   String *swkb= args[0]->val_str(&tmp);
   Geometry_buffer buffer;
-  
+
   null_value= args[0]->null_value ||
               !(Geometry::construct(&buffer, swkb->ptr(), swkb->length()));
   return null_value ? 1 : 0;
@@ -2091,71 +2114,29 @@ longlong Item_func_issimple::val_int()
 {
   String *swkb= args[0]->val_str(&tmp);
   Geometry_buffer buffer;
-  Gcalc_operation_transporter trn(&func, &collector);
-  Geometry *g;
-  int result= 1;
-  MBR mbr;
-  const char *c_end;
+  Geometry *geometry;
 
   DBUG_ENTER("Item_func_issimple::val_int");
   DBUG_ASSERT(fixed());
-  
+
   null_value= 0;
   if ((args[0]->null_value ||
-       !(g= Geometry::construct(&buffer, swkb->ptr(), swkb->length())) ||
-       g->get_mbr(&mbr, &c_end)))
+       !(geometry= Geometry::construct(&buffer, swkb->ptr(), swkb->length()))))
   {
     /* We got NULL as an argument. Have to return -1 */
     DBUG_RETURN(-1);
   }
 
-  collector.set_extent(mbr.xmin, mbr.xmax, mbr.ymin, mbr.ymax);
-
-  if (g->get_class_info()->m_type_id == Geometry::wkb_point)
+  if (geometry->get_class_info()->m_type_id == Geometry::wkb_point)
     DBUG_RETURN(1);
 
-  if (g->store_shapes(&trn))
-    goto mem_error;
-
-  collector.prepare_operation();
-  scan_it.init(&collector);
-
-  while (scan_it.more_points())
-  {
-    const Gcalc_scan_iterator::event_point *ev, *next_ev;
-
-    if (scan_it.step())
-      goto mem_error;
-
-    ev= scan_it.get_events();
-    if (ev->simple_event())
-      continue;
-
-    next_ev= ev->get_next();
-    if ((ev->event & (scev_thread | scev_single_point)) && !next_ev)
-      continue;
-
-    if ((ev->event == scev_two_threads) && !next_ev->get_next())
-      continue;
-
-    /* If the first and last points of a curve coincide - that is     */
-    /* an exception to the rule and the line is considered as simple. */
-    if ((next_ev && !next_ev->get_next()) &&
-        (ev->event & (scev_thread | scev_end)) &&
-        (next_ev->event & (scev_thread | scev_end)))
-      continue;
-
-    result= 0;
-    break;
+  int simple;
+  if (geometry->is_simple(&simple)) {
+    null_value= 1;
+    DBUG_RETURN(0);
   }
 
-  collector.reset();
-  func.reset();
-  scan_it.reset();
-  DBUG_RETURN(result);
-mem_error:
-  null_value= 1;
-  DBUG_RETURN(0);
+  DBUG_RETURN(simple);
 }
 
 
@@ -4230,6 +4211,22 @@ class Create_func_isempty : public Create_func_arg1
 };
 
 
+class Create_func_isvalid : public Create_func_arg1
+{
+public:
+  Item *create_1_arg(THD *thd, Item *arg1) override
+  {
+    return new (thd->mem_root) Item_func_isvalid(thd, arg1);
+  }
+
+  static Create_func_isvalid s_singleton;
+
+protected:
+  Create_func_isvalid() = default;
+  virtual ~Create_func_isvalid() = default;
+};
+
+
 class Create_func_issimple : public Create_func_arg1
 {
 public:
@@ -4246,7 +4243,6 @@ class Create_func_issimple : public Create_func_arg1
 };
 
 
-
 class Create_func_numgeometries : public Create_func_arg1
 {
 public:
@@ -4516,6 +4512,7 @@ Create_func_intersection Create_func_intersection::s_singleton;
 Create_func_intersects Create_func_intersects::s_singleton;
 Create_func_isclosed Create_func_isclosed::s_singleton;
 Create_func_isempty Create_func_isempty::s_singleton;
+Create_func_isvalid Create_func_isvalid::s_singleton;
 Create_func_isring Create_func_isring::s_singleton;
 Create_func_issimple Create_func_issimple::s_singleton;
 Create_func_mbr_contains Create_func_mbr_contains::s_singleton;
@@ -4585,6 +4582,7 @@ static Native_func_registry func_array_geom[] =
   { { STRING_WITH_LEN("INTERSECTS") }, GEOM_BUILDER(Create_func_mbr_intersects)},
   { { STRING_WITH_LEN("ISCLOSED") }, GEOM_BUILDER(Create_func_isclosed)},
   { { STRING_WITH_LEN("ISEMPTY") }, GEOM_BUILDER(Create_func_isempty)},
+  { { STRING_WITH_LEN("ISVALID") }, GEOM_BUILDER(Create_func_isvalid)},
   { { STRING_WITH_LEN("ISRING") }, GEOM_BUILDER(Create_func_isring)},
   { { STRING_WITH_LEN("ISSIMPLE") }, GEOM_BUILDER(Create_func_issimple)},
   { { STRING_WITH_LEN("LINEFROMTEXT") }, GEOM_BUILDER(Create_func_geometry_from_text)},
@@ -4668,6 +4666,7 @@ static Native_func_registry func_array_geom[] =
   { { STRING_WITH_LEN("ST_INTERSECTS") }, GEOM_BUILDER(Create_func_intersects)},
   { { STRING_WITH_LEN("ST_ISCLOSED") }, GEOM_BUILDER(Create_func_isclosed)},
   { { STRING_WITH_LEN("ST_ISEMPTY") }, GEOM_BUILDER(Create_func_isempty)},
+  { { STRING_WITH_LEN("ST_ISVALID") }, GEOM_BUILDER(Create_func_isvalid)},
   { { STRING_WITH_LEN("ST_ISRING") }, GEOM_BUILDER(Create_func_isring)},
   { { STRING_WITH_LEN("ST_ISSIMPLE") }, GEOM_BUILDER(Create_func_issimple)},
   { { STRING_WITH_LEN("ST_LENGTH") }, GEOM_BUILDER(Create_func_glength)},

sql/item_geofunc.h

@@ -955,9 +955,6 @@ class Item_func_isempty: public Item_bool_func_args_geometry
 
 class Item_func_issimple: public Item_long_func_args_geometry
 {
-  Gcalc_heap collector;
-  Gcalc_function func;
-  Gcalc_scan_iterator scan_it;
   String tmp;
 public:
   Item_func_issimple(THD *thd, Item *a)
@@ -1005,6 +1002,21 @@ class Item_func_isring: public Item_func_issimple
   { return get_item_copy<Item_func_isring>(thd, this); }
 };
 
+class Item_func_isvalid: public Item_long_func_args_geometry
+{
+public:
+  String tmp;
+  Item_func_isvalid(THD *thd, Item *a): Item_long_func_args_geometry(thd, a) {}
+  longlong val_int() override;
+  LEX_CSTRING func_name_cstring() const override
+  {
+    static LEX_CSTRING name= {STRING_WITH_LEN("st_isvalid") };
+    return name;
+  }
+  Item *do_get_copy(THD *thd) const override
+  { return get_item_copy<Item_func_isvalid>(thd, this); }
+};
+
 class Item_func_dimension: public Item_long_func_args_geometry
 {
 public:

sql/spatial.cc

@@ -750,6 +750,56 @@ bool Geometry::envelope(String *result) const
   return 0;
 }
 
+int Geometry::is_simple(int *simple) const {
+  Gcalc_scan_iterator scan_it;
+  Gcalc_heap collector;
+  Gcalc_function func;
+  Gcalc_operation_transporter trn(&func, &collector);
+  const char *c_end;
+  MBR mbr;
+  *simple= 0;
+
+ if(this->get_mbr(&mbr, &c_end))
+    return 1;
+
+  collector.set_extent(mbr.xmin, mbr.xmax, mbr.ymin, mbr.ymax);
+  if (this->store_shapes(&trn))
+    return 1;
+
+  collector.prepare_operation();
+  scan_it.init(&collector);
+
+  while (scan_it.more_points())
+  {
+    const Gcalc_scan_iterator::event_point *ev, *next_ev;
+
+    if (scan_it.step())
+      return 1;
+
+    ev= scan_it.get_events();
+    if (ev->simple_event())
+      continue;
+
+    next_ev= ev->get_next();
+    if ((ev->event & (scev_thread | scev_single_point)) && !next_ev)
+      continue;
+
+    if ((ev->event == scev_two_threads) && !next_ev->get_next())
+      continue;
+
+    /* If the first and last points of a curve coincide - that is     */
+    /* an exception to the rule and the line is considered as simple. */
+    if ((next_ev && !next_ev->get_next()) &&
+        (ev->event & (scev_thread | scev_end)) &&
+        (next_ev->event & (scev_thread | scev_end)))
+      continue;
+
+    return 0;
+  }
+
+  *simple= 1;
+  return 0;
+}
 
 /*
   Create a point from data.
@@ -763,7 +813,6 @@ bool Geometry::envelope(String *result) const
     0	ok
     1	Can't reallocate 'result'
 */
-
 bool Geometry::create_point(String *result, const char *data) const
 {
   if (no_data(data, POINT_DATA_SIZE) ||
@@ -1045,6 +1094,17 @@ bool Gis_point::get_mbr(MBR *mbr, const char **end) const
 }
 
 
+int Gis_point::is_valid(int *valid) const
+{
+  double x, y;
+  if (get_xy(&x, &y))
+    return 1;
+
+  *valid= 1;
+  return 0;
+}
+
+
 int Gis_point::area(double *ar, const char **end) const
 {
   *ar= 0;
@@ -1444,6 +1504,47 @@ int Gis_line_string::is_closed(int *closed) const
 }
 
 
+int Gis_line_string::is_valid(int *valid) const
+{
+  Geometry_buffer buffer;
+  Geometry *geometry;
+  uint32 num_points;
+  *valid= 0;
+
+  if (no_data(m_data, 4))
+    return 1;
+
+  num_points= uint4korr(m_data);
+  if (not_enough_points(m_data, num_points))
+    return 1;
+
+  double x, y, previous_x, previous_y;
+  for (uint32 i = 1; i <= num_points; i++)
+  {
+    String wkb= 0;
+
+    if (wkb.reserve(SRID_SIZE + BYTE_ORDER_SIZE + WKB_HEADER_SIZE))
+      return 1;
+
+    wkb.q_append(SRID_PLACEHOLDER);
+    this->point_n(i, &wkb);
+    if (!(geometry= Geometry::construct(&buffer, wkb.ptr(), wkb.length()))||
+        ((Gis_point *) geometry)->get_xy(&x, &y))
+      return 1;
+
+    if ((i != 1) && (x != previous_x || y != previous_y))
+    {
+      *valid= 1;
+      return 0;
+    }
+
+    previous_x = x;
+    previous_y = y;
+  }
+  return 0;
+}
+
+
 int Gis_line_string::num_points(uint32 *n_points) const
 {
   *n_points= uint4korr(m_data);
@@ -1801,6 +1902,75 @@ bool Gis_polygon::get_mbr(MBR *mbr, const char **end) const
 }
 
 
+int Gis_polygon::is_valid(int *valid) const
+{
+  Geometry *exterior_ring, *interior_ring;
+  MBR exterior_mbr, interior_mbr;
+  uint32 num_interior_ring;
+  Geometry_buffer buffer;
+  const char *c_end;
+  String wkb= 0;
+  *valid= 0;
+
+  if (wkb.reserve(SRID_SIZE + BYTE_ORDER_SIZE + WKB_HEADER_SIZE))
+    return 1;
+
+  wkb.q_append(SRID_PLACEHOLDER);
+  if (this->exterior_ring(&wkb) ||
+      !(exterior_ring= Geometry::construct(&buffer, wkb.ptr(), wkb.length())))
+    return 1;
+
+  int valid_ring, simple;
+  if (exterior_ring->is_valid(&valid_ring) ||
+      exterior_ring->is_simple(&simple))
+    return 1;
+
+  if (!valid_ring || !simple)
+    return 0;
+
+  if (exterior_ring->get_mbr(&exterior_mbr, &c_end) ||
+      this->num_interior_ring(&num_interior_ring))
+    return 1;
+
+  std::vector<MBR> interior_mbrs;
+  for(uint32 i= 1; i <= num_interior_ring; i++)
+  {
+    String interior_wkb= 0;
+    if (interior_wkb.reserve(SRID_SIZE + BYTE_ORDER_SIZE + WKB_HEADER_SIZE))
+      return 1;
+
+    interior_wkb.q_append(SRID_PLACEHOLDER);
+    if (this->interior_ring_n(i, &interior_wkb))
+      break;
+
+    if (!(interior_ring= Geometry::construct(&buffer, interior_wkb.ptr(),
+                                             interior_wkb.length())) ||
+        interior_ring->get_mbr(&interior_mbr, &c_end))
+      return 1;
+
+    if (!exterior_mbr.contains(&interior_mbr) ||
+        exterior_mbr.equals(&interior_mbr))
+      return 0;
+
+    if (interior_ring->is_simple(&simple))
+      return 1;
+
+    if (!simple)
+      return 0;
+
+    for (const auto &mbr : interior_mbrs)
+    {
+      if (interior_mbr.equals(&mbr) || interior_mbr.within(&mbr))
+        return 0;
+    }
+    interior_mbrs.push_back(interior_mbr);
+  }
+
+  *valid= 1;
+  return 0;
+}
+
+
 int Gis_polygon::area(double *ar, const char **end_of_data) const
 {
   uint32 n_linear_rings;
@@ -2265,6 +2435,21 @@ bool Gis_multi_point::get_data_as_json(String *txt, uint max_dec_digits,
 }
 
 
+int Gis_multi_point::is_valid(int *valid) const
+{
+  uint32 num_points;
+  if (no_data(m_data, 4))
+    return 1;
+
+  num_points= uint4korr(m_data);
+  if (not_enough_points(m_data, num_points))
+    return 1;
+
+  *valid= 1;
+  return 0;
+}
+
+
 bool Gis_multi_point::get_mbr(MBR *mbr, const char **end) const
 {
   return (*end= get_mbr_for_points(mbr, m_data, WKB_HEADER_SIZE)) == 0;
@@ -2656,6 +2841,39 @@ bool Gis_multi_line_string::get_data_as_json(String *txt, uint max_dec_digits,
 }
 
 
+int Gis_multi_line_string::is_valid(int *valid) const
+{
+  uint32 num_linestring;
+  Geometry_buffer buffer;
+  Geometry *geometry= NULL;
+  *valid= 0;
+
+  if (no_data(m_data, 4))
+    return 1;
+  num_linestring= uint4korr(m_data);
+
+  for (uint32 i = 1; i <= num_linestring; i++)
+  {
+    String wkb = 0;
+
+    wkb.q_append(SRID_PLACEHOLDER);
+    if (this->geometry_n(i, &wkb) ||
+        !(geometry= Geometry::construct(&buffer, wkb.ptr(), wkb.length())))
+      return 1;
+
+    int line_valid;
+    if(geometry->is_valid(&line_valid))
+      return 1;
+
+    if (!line_valid)
+      return 0;
+  }
+
+  *valid= 1;
+  return 0;
+}
+
+
 bool Gis_multi_line_string::get_mbr(MBR *mbr, const char **end) const
 {
   uint32 n_line_strings;
@@ -3079,6 +3297,51 @@ bool Gis_multi_polygon::get_data_as_json(String *txt, uint max_dec_digits,
 }
 
 
+int Gis_multi_polygon::is_valid(int *valid) const
+{
+  Geometry_buffer buffer;
+  uint32 num_geometries;
+  std::vector<MBR> mbrs;
+  Geometry *geometry;
+  *valid= 0;
+
+  if (this->num_geometries(&num_geometries))
+    return 1;
+
+  for (uint32 i= 1; i <= num_geometries; i++)
+  {
+    String wkb= 0;
+    if (wkb.reserve(SRID_SIZE + BYTE_ORDER_SIZE + WKB_HEADER_SIZE))
+      return 0;
+
+    wkb.q_append(SRID_PLACEHOLDER);
+    if (this->geometry_n(i, &wkb) ||
+        !(geometry= Geometry::construct(&buffer, wkb.ptr(), wkb.length())))
+      return 1;
+
+    int internal_valid;
+    const char *c_end;
+    MBR interior_mbr;
+    if (geometry->is_valid(&internal_valid) ||
+        geometry->get_mbr(&interior_mbr, &c_end))
+      return 1;
+
+    if (!internal_valid)
+      return 0;
+
+    for (const auto &mbr : mbrs)
+    {
+      if (interior_mbr.intersects(&mbr) && !interior_mbr.touches(&mbr))
+        return 0;
+    }
+    mbrs.push_back(interior_mbr);
+  }
+
+  *valid= 1;
+  return 0;
+}
+
+
 bool Gis_multi_polygon::get_mbr(MBR *mbr, const char **end) const
 {
   uint32 n_polygons;
@@ -3307,7 +3570,7 @@ bool Gis_geometry_collection::init_from_wkt(Gis_read_stream *trs, String *wkb)
       return 1;
 
     if (next_word.length != 5 ||
-	(my_charset_latin1.strnncoll("empty", 5, next_word.str, 5) != 0))
+	     (my_charset_latin1.strnncoll("empty", 5, next_word.str, 5) != 0))
     {
       for (;;)
       {
@@ -3551,6 +3814,41 @@ bool Gis_geometry_collection::get_data_as_json(String *txt, uint max_dec_digits,
 }
 
 
+int Gis_geometry_collection::is_valid(int *valid) const
+{
+  Geometry_buffer buffer;
+  uint32 num_geometries;
+  Geometry *geometry;
+  *valid= 0;
+
+  if (this->num_geometries(&num_geometries))
+    return 1;
+
+  for (uint32 i= 1; i <= num_geometries; i++)
+  {
+    String wkb= 0;
+
+    if (wkb.reserve(SRID_SIZE + BYTE_ORDER_SIZE + WKB_HEADER_SIZE))
+      return 1;
+
+    wkb.q_append(SRID_PLACEHOLDER);
+    if(this->geometry_n(i, &wkb) ||
+       !(geometry= Geometry::construct(&buffer, wkb.ptr(), wkb.length())))
+      return 1;
+
+    int internal_valid;
+    if (geometry->is_valid(&internal_valid))
+      return 1;
+
+    if (!internal_valid)
+      return 0;
+  }
+
+  *valid= 1;
+  return 0;
+}
+
+
 bool Gis_geometry_collection::get_mbr(MBR *mbr, const char **end) const
 {
   uint32 n_objects;

sql/spatial.h

@@ -19,6 +19,7 @@
 #define SPATIAL_INCLUDED
 
 #include "sql_string.h"                         /* String, LEX_STRING */
+#include <vector>
 #include <my_compiler.h>
 #include <json_lib.h>
 
@@ -27,8 +28,10 @@ class Gis_read_stream;
 #include "gcalc_tools.h"
 
 const uint SRID_SIZE= 4;
+const uint32 SRID_PLACEHOLDER= 0;
 const uint SIZEOF_STORED_DOUBLE= 8;
-const uint POINT_DATA_SIZE= (SIZEOF_STORED_DOUBLE * 2); 
+const uint BYTE_ORDER_SIZE= 1;
+const uint POINT_DATA_SIZE= (SIZEOF_STORED_DOUBLE * 2);
 const uint WKB_HEADER_SIZE= 1+4;
 const uint32 GET_SIZE_ERROR= ((uint32) -1);
 
@@ -289,6 +292,7 @@ class Geometry
   virtual int geom_length(double *len, const char **end) const  { return -1; }
   virtual int area(double *ar, const char **end) const { return -1;}
   virtual int is_closed(int *closed) const { return -1; }
+  virtual int is_valid(int *valid) const { return -1; }
   virtual int num_interior_ring(uint32 *n_int_rings) const { return -1; }
   virtual int num_points(uint32 *n_points) const { return -1; }
   virtual int num_geometries(uint32 *num) const { return -1; }
@@ -337,6 +341,7 @@ class Geometry
   }
 
   bool envelope(String *result) const;
+  int is_simple(int *simple) const;
   static Class_info *ci_collection[wkb_last+1];
 
   static bool create_point(String *result, double x, double y);
@@ -405,7 +410,7 @@ class Gis_point: public Geometry
   bool get_data_as_json(String *txt, uint max_dec_digits,
                         const char **end) const override;
   bool get_mbr(MBR *mbr, const char **end) const override;
-  
+  int is_valid(int *valid) const override;
   int get_xy(double *x, double *y) const
   {
     const char *data= m_data;
@@ -479,6 +484,7 @@ class Gis_line_string: public Geometry
   int area(double *ar, const char **end) const override;
   int is_closed(int *closed) const override;
   int num_points(uint32 *n_points) const override;
+  int is_valid(int *valid) const override;
   int start_point(String *point) const override;
   int end_point(String *point) const override;
   int point_n(uint32 n, String *result) const override;
@@ -509,6 +515,7 @@ class Gis_polygon: public Geometry
   bool get_data_as_json(String *txt, uint max_dec_digits,
                         const char **end) const override;
   bool get_mbr(MBR *mbr, const char **end) const override;
+  int is_valid(int *valid) const override;
   int area(double *ar, const char **end) const override;
   int exterior_ring(String *result) const override;
   int num_interior_ring(uint32 *n_int_rings) const override;
@@ -545,6 +552,7 @@ class Gis_multi_point: public Geometry
   bool get_data_as_wkt(String *txt, const char **end) const override;
   bool get_data_as_json(String *txt, uint max_dec_digits,
                         const char **end) const override;
+  int is_valid(int *valid) const override;
   bool get_mbr(MBR *mbr, const char **end) const override;
   int num_geometries(uint32 *num) const override;
   int geometry_n(uint32 num, String *result) const override;
@@ -576,6 +584,7 @@ class Gis_multi_line_string: public Geometry
   bool get_data_as_wkt(String *txt, const char **end) const override;
   bool get_data_as_json(String *txt, uint max_dec_digits,
                         const char **end) const override;
+  int is_valid(int *valid) const override;
   bool get_mbr(MBR *mbr, const char **end) const override;
   int num_geometries(uint32 *num) const override;
   int geometry_n(uint32 num, String *result) const override;
@@ -606,6 +615,7 @@ class Gis_multi_polygon: public Geometry
   bool get_data_as_wkt(String *txt, const char **end) const override;
   bool get_data_as_json(String *txt, uint max_dec_digits,
                         const char **end) const override;
+  int is_valid(int *valid) const override;
   bool get_mbr(MBR *mbr, const char **end) const override;
   int num_geometries(uint32 *num) const override;
   int geometry_n(uint32 num, String *result) const override;
@@ -638,6 +648,7 @@ class Gis_geometry_collection: public Geometry
   bool get_data_as_wkt(String *txt, const char **end) const override;
   bool get_data_as_json(String *txt, uint max_dec_digits,
                         const char **end) const override;
+  int is_valid(int *valid) const override;
   bool get_mbr(MBR *mbr, const char **end) const override;
   int area(double *ar, const char **end) const override;
   int geom_length(double *len, const char **end) const override;