partially implementing st_equals

sql/analyzer/indexes.go

@@ -37,6 +37,15 @@ type indexLookup struct {
 
 type indexLookupsByTable map[string]*indexLookup
 
+func isSpatialAnalysisFunc(e sql.Expression) bool {
+	switch e.(type) {
+	case *spatial.Intersects, *spatial.Within, *spatial.STEquals:
+		return true
+	default:
+		return false
+	}
+}
+
 // getIndexes returns indexes applicable to all tables in the node given for the expression given, keyed by the name of
 // the table (aliased as appropriate). If more than one index per table is usable for the expression given, chooses a
 // best match (typically the longest prefix by column count).
@@ -252,7 +261,7 @@ func getIndexes(
 		// Next try to match the remaining expressions individually
 		for _, e := range unusedExprs {
 			// TODO: eventually support merging spatial lookups
-			if _, ok := e.(*spatial.Intersects); ok {
+			if isSpatialAnalysisFunc(e) {
 				continue
 			}
 			indexes, err := getIndexes(ctx, ia, e, tableAliases)
@@ -279,7 +288,7 @@ func getIndexes(
 	// TODO (james): add all other spatial index supported functions here
 	// TODO: make generalizable to all functions?
 	switch e := e.(type) {
-	case *spatial.Intersects, *spatial.Within:
+	case *spatial.Intersects, *spatial.Within, *spatial.STEquals:
 		// don't pushdown functions with bindvars
 		if exprHasBindVar(e) {
 			return nil, nil

sql/expression/function/registry.go

@@ -211,6 +211,7 @@ var BuiltIns = []sql.Function{
 	sql.Function1{Name: "st_astext", Fn: spatial.NewAsWKT},
 	sql.FunctionN{Name: "st_distance", Fn: spatial.NewDistance},
 	sql.Function1{Name: "st_dimension", Fn: spatial.NewDimension},
+	sql.Function2{Name: "st_equal", Fn: spatial.NewSTEquals},
 	sql.Function1{Name: "st_endpoint", Fn: spatial.NewEndPoint},
 	sql.FunctionN{Name: "st_geomcollfromtext", Fn: spatial.NewGeomCollFromText},
 	sql.FunctionN{Name: "st_geomcollfromtxt", Fn: spatial.NewGeomCollFromText},

sql/expression/function/spatial/st_equals.go

@@ -0,0 +1,126 @@
+// Copyright 2023 Dolthub, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package spatial
+
+import (
+	"fmt"
+
+	"github.com/dolthub/go-mysql-server/sql"
+	"github.com/dolthub/go-mysql-server/sql/expression"
+	"github.com/dolthub/go-mysql-server/sql/types"
+)
+
+// STEquals is a function that returns the STEquals of a LineString
+type STEquals struct {
+	expression.BinaryExpression
+}
+
+var _ sql.FunctionExpression = (*STEquals)(nil)
+
+// NewSTEquals creates a new STEquals expression.
+func NewSTEquals(g1, g2 sql.Expression) sql.Expression {
+	return &STEquals{
+		expression.BinaryExpression{
+			Left:  g1,
+			Right: g2,
+		},
+	}
+}
+
+// FunctionName implements sql.FunctionExpression
+func (s *STEquals) FunctionName() string {
+	return "st_equals"
+}
+
+// Description implements sql.FunctionExpression
+func (s *STEquals) Description() string {
+	return "returns 1 or 0 to indicate whether g1 is spatially equal to g2."
+}
+
+// Type implements the sql.Expression interface.
+func (s *STEquals) Type() sql.Type {
+	return types.Boolean
+}
+
+func (s *STEquals) String() string {
+	return fmt.Sprintf("ST_EQUALS(%s, %s)", s.Left, s.Right)
+}
+
+// WithChildren implements the Expression interface.
+func (s *STEquals) WithChildren(children ...sql.Expression) (sql.Expression, error) {
+	if len(children) != 2 {
+		return nil, sql.ErrInvalidChildrenNumber.New(s, len(children), 2)
+	}
+	return NewSTEquals(children[0], children[1]), nil
+}
+
+// isEqual checks if the set of types.Points in g1 is spatially equal to g2
+// This is equivalent to checking if g1 within g2 and g2 within g1
+func isEqual(g1 types.GeometryValue, g2 types.GeometryValue) bool {
+	return isWithin(g1, g2) && isWithin(g2, g1)
+}
+
+// Eval implements the sql.Expression interface.
+func (s *STEquals) Eval(ctx *sql.Context, row sql.Row) (interface{}, error) {
+	geom1, err := s.Left.Eval(ctx, row)
+	if err != nil {
+		return nil, err
+	}
+	geom2, err := s.Right.Eval(ctx, row)
+	if err != nil {
+		return nil, err
+	}
+	g1, g2, err := validateGeomComp(geom1, geom2, s.FunctionName())
+	if err != nil {
+		return nil, err
+	}
+	if g1 == nil || g2 == nil {
+		return nil, nil
+	}
+
+	// TODO (james): remove this switch block when the other comparisons are implemented
+	switch geom1.(type) {
+	case types.LineString:
+		return nil, sql.ErrUnsupportedGISTypeForSpatialFunc.New("LineString", s.FunctionName())
+	case types.Polygon:
+		return nil, sql.ErrUnsupportedGISTypeForSpatialFunc.New("Polygon", s.FunctionName())
+	case types.MultiPoint:
+		return nil, sql.ErrUnsupportedGISTypeForSpatialFunc.New("MultiPoint", s.FunctionName())
+	case types.MultiLineString:
+		return nil, sql.ErrUnsupportedGISTypeForSpatialFunc.New("MultiLineString", s.FunctionName())
+	case types.MultiPolygon:
+		return nil, sql.ErrUnsupportedGISTypeForSpatialFunc.New("MultiPolygon", s.FunctionName())
+	case types.GeomColl:
+		return nil, sql.ErrUnsupportedGISTypeForSpatialFunc.New("GeomColl", s.FunctionName())
+	}
+
+	// TODO (james): remove this switch block when the other comparisons are implemented
+	switch geom2.(type) {
+	case types.LineString:
+		return nil, sql.ErrUnsupportedGISTypeForSpatialFunc.New("LineString", s.FunctionName())
+	case types.Polygon:
+		return nil, sql.ErrUnsupportedGISTypeForSpatialFunc.New("Polygon", s.FunctionName())
+	case types.MultiPoint:
+		return nil, sql.ErrUnsupportedGISTypeForSpatialFunc.New("MultiPoint", s.FunctionName())
+	case types.MultiLineString:
+		return nil, sql.ErrUnsupportedGISTypeForSpatialFunc.New("MultiLineString", s.FunctionName())
+	case types.MultiPolygon:
+		return nil, sql.ErrUnsupportedGISTypeForSpatialFunc.New("MultiPolygon", s.FunctionName())
+	case types.GeomColl:
+		return nil, sql.ErrUnsupportedGISTypeForSpatialFunc.New("GeomColl", s.FunctionName())
+	}
+
+	return isEqual(g1, g2), nil
+}

sql/expression/function/spatial/st_equals_test.go

@@ -0,0 +1,127 @@
+// Copyright 2023 Dolthub, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package spatial
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/dolthub/go-mysql-server/sql"
+	"github.com/dolthub/go-mysql-server/sql/expression"
+	"github.com/dolthub/go-mysql-server/sql/types"
+)
+
+func TestSTEquals(t *testing.T) {
+	t.Run("point vs point equals", func(t *testing.T) {
+		require := require.New(t)
+		p1 := types.Point{X: 123, Y: 456}
+		p2 := types.Point{X: 123, Y: 456}
+		f := NewSTEquals(expression.NewLiteral(p1, types.PointType{}), expression.NewLiteral(p2, types.PointType{}))
+		v, err := f.Eval(sql.NewEmptyContext(), nil)
+		require.NoError(err)
+		require.Equal(true, v)
+	})
+
+	t.Run("point vs point not equals", func(t *testing.T) {
+		require := require.New(t)
+		p1 := types.Point{X: 123, Y: 456}
+		p2 := types.Point{X: 789, Y: 321}
+		f := NewSTEquals(expression.NewLiteral(p1, types.PointType{}), expression.NewLiteral(p2, types.PointType{}))
+		v, err := f.Eval(sql.NewEmptyContext(), nil)
+		require.NoError(err)
+		require.Equal(false, v)
+	})
+
+	t.Run("null vs point is null", func(t *testing.T) {
+		require := require.New(t)
+		p := types.Point{X: 789, Y: 321}
+		f := NewSTEquals(expression.NewLiteral(nil, types.Null), expression.NewLiteral(p, types.PointType{}))
+		v, err := f.Eval(sql.NewEmptyContext(), nil)
+		require.NoError(err)
+		require.Equal(nil, v)
+	})
+
+	t.Run("different SRIDs error", func(t *testing.T) {
+		require := require.New(t)
+		p1 := types.Point{SRID: 0, X: 123, Y: 456}
+		p2 := types.Point{SRID: 4326, X: 123, Y: 456}
+		f := NewSTEquals(expression.NewLiteral(p1, types.PointType{}), expression.NewLiteral(p2, types.PointType{}))
+		_, err := f.Eval(sql.NewEmptyContext(), nil)
+		require.Error(err)
+	})
+}
+
+func TestSTEqualsSkipped(t *testing.T) {
+	t.Skip("comparisons that aren't point vs point are unsupported")
+
+	t.Run("linestring vs linestring equals", func(t *testing.T) {
+		require := require.New(t)
+		l1 := types.LineString{Points: []types.Point{{X: 12, Y: 34}, {X: 56, Y: 78}, {X: 56, Y: 78}}}
+		l2 := types.LineString{Points: []types.Point{{X: 56, Y: 78}, {X: 12, Y: 34}, {X: 12, Y: 34}}}
+		f := NewSTEquals(expression.NewLiteral(l1, types.LineStringType{}), expression.NewLiteral(l2, types.LineStringType{}))
+		v, err := f.Eval(sql.NewEmptyContext(), nil)
+		require.NoError(err)
+		require.Equal(true, v)
+	})
+
+	t.Run("linestring vs linestring not equals", func(t *testing.T) {
+		require := require.New(t)
+		l1 := types.LineString{Points: []types.Point{{X: 12, Y: 34}, {X: 56, Y: 78}}}
+		l2 := types.LineString{Points: []types.Point{{X: 56, Y: 78}, {X: 12, Y: 34}, {X: 123, Y: 349}}}
+		f := NewSTEquals(expression.NewLiteral(l1, types.LineStringType{}), expression.NewLiteral(l2, types.LineStringType{}))
+		v, err := f.Eval(sql.NewEmptyContext(), nil)
+		require.NoError(err)
+		require.Equal(false, v)
+	})
+
+	t.Run("polygon vs multilinestring not equal", func(t *testing.T) {
+		require := require.New(t)
+		p1 := types.Point{X: 0, Y: 0}
+		p2 := types.Point{X: 0, Y: 1}
+		p3 := types.Point{X: 1, Y: 0}
+		p4 := types.Point{X: 1, Y: 1}
+		l1 := types.LineString{Points: []types.Point{p1, p2, p3, p4}}
+		p := types.Polygon{Lines: []types.LineString{l1}}
+		ml := types.MultiLineString{Lines: []types.LineString{l1}}
+		f := NewSTEquals(expression.NewLiteral(p, types.PolygonType{}), expression.NewLiteral(ml, types.MultiLineStringType{}))
+		v, err := f.Eval(sql.NewEmptyContext(), nil)
+		require.NoError(err)
+		require.Equal(false, v)
+	})
+
+	t.Run("empty geometry vs empty geometry equal", func(t *testing.T) {
+		require := require.New(t)
+		g1 := types.GeomColl{}
+		g2 := types.GeomColl{}
+		f := NewSTEquals(expression.NewLiteral(g1, types.GeomCollType{}), expression.NewLiteral(g2, types.GeomCollType{}))
+		v, err := f.Eval(sql.NewEmptyContext(), nil)
+		require.NoError(err)
+		require.Equal(true, v)
+	})
+
+	t.Run("point geometry vs linestring geometry not equal", func(t *testing.T) {
+		require := require.New(t)
+		p1 := types.Point{X: 0, Y: 0}
+		p2 := types.Point{X: 0, Y: 1}
+		l1 := types.LineString{Points: []types.Point{p1, p2}}
+		g1 := types.GeomColl{Geoms: []types.GeometryValue{p1, p2}}
+		g2 := types.GeomColl{Geoms: []types.GeometryValue{l1}}
+		f := NewSTEquals(expression.NewLiteral(g1, types.GeomCollType{}), expression.NewLiteral(g2, types.GeomCollType{}))
+		v, err := f.Eval(sql.NewEmptyContext(), nil)
+		require.NoError(err)
+		require.Equal(false, v)
+	})
+}