SQL: add folding to BinaryComparison (elastic/x-pack-elasticsearch#3529)

* SQL: add folding to BinaryComparison

Add missing folding to predicates and logical operators
relates elastic/x-pack-elasticsearch#3528

Original commit: elastic/x-pack-elasticsearch@4a7d3765e5

sql/server/src/main/java/org/elasticsearch/xpack/sql/expression/Order.java

@@ -5,10 +5,10 @@
  */
 package org.elasticsearch.xpack.sql.expression;
 
-import java.util.Objects;
-
 import org.elasticsearch.xpack.sql.tree.Location;
 
+import java.util.Objects;
+
 public class Order extends UnaryExpression {
 
     public enum OrderDirection {
@@ -26,6 +26,11 @@ public class Order extends UnaryExpression {
         return direction;
     }
 
+    @Override
+    public boolean foldable() {
+        return false;
+    }
+
     @Override
     public int hashCode() {
         return Objects.hash(child(), direction);

sql/server/src/main/java/org/elasticsearch/xpack/sql/expression/UnaryExpression.java

@@ -25,6 +25,11 @@ public abstract class UnaryExpression extends Expression {
         return child;
     }
 
+    @Override
+    public boolean foldable() {
+        return child.foldable();
+    }
+
     @Override
     public boolean nullable() {
         return child.nullable();

sql/server/src/main/java/org/elasticsearch/xpack/sql/expression/predicate/And.java

@@ -10,12 +10,19 @@ import org.elasticsearch.xpack.sql.expression.BinaryOperator.Negateable;
 import org.elasticsearch.xpack.sql.expression.Expression;
 import org.elasticsearch.xpack.sql.tree.Location;
 
+import java.util.Objects;
+
 public class And extends BinaryLogic implements Negateable {
     
     public And(Location location, Expression left, Expression right) {
         super(location, left, right);
     }
 
+    @Override
+    public Object fold() {
+        return Objects.equals(left().fold(), Boolean.TRUE) && Objects.equals(right().fold(), Boolean.TRUE);
+    }
+
     @Override
     public Or negate() {
         return new Or(location(), new Not(location(), left()), new Not(location(), right()));

sql/server/src/main/java/org/elasticsearch/xpack/sql/expression/predicate/BinaryComparison.java

@@ -32,4 +32,12 @@ public abstract class BinaryComparison extends BinaryOperator {
     public DataType dataType() {
         return DataTypes.BOOLEAN;
     }
+
+    @SuppressWarnings({ "rawtypes", "unchecked" })
+    static Integer compare(Object left, Object right) {
+        if (left instanceof Comparable && right instanceof Comparable) {
+            return Integer.valueOf(((Comparable) left).compareTo(right));
+        }
+        return null;
+    }
 }

sql/server/src/main/java/org/elasticsearch/xpack/sql/expression/predicate/Equals.java

@@ -8,12 +8,19 @@ package org.elasticsearch.xpack.sql.expression.predicate;
 import org.elasticsearch.xpack.sql.expression.Expression;
 import org.elasticsearch.xpack.sql.tree.Location;
 
+import java.util.Objects;
+
 public class Equals extends BinaryComparison {
 
     public Equals(Location location, Expression left, Expression right) {
         super(location, left, right);
     }
 
+    @Override
+    public Object fold() {
+        return Objects.equals(left().fold(), right().fold());
+    }
+
     @Override
     public Equals swapLeftAndRight() {
         return new Equals(location(), right(), left());

sql/server/src/main/java/org/elasticsearch/xpack/sql/expression/predicate/GreaterThan.java

@@ -15,6 +15,12 @@ public class GreaterThan extends BinaryComparison implements Negateable {
         super(location, left, right);
     }
 
+    @Override
+    public Object fold() {
+        Integer compare = compare(left().fold(), right().fold());
+        return compare != null && compare.intValue() > 0;
+    }
+
     @Override
     public LessThan swapLeftAndRight() {
         return new LessThan(location(), right(), left());

sql/server/src/main/java/org/elasticsearch/xpack/sql/expression/predicate/GreaterThanOrEqual.java

@@ -15,6 +15,12 @@ public class GreaterThanOrEqual extends BinaryComparison implements Negateable {
         super(location, left, right);
     }
 
+    @Override
+    public Object fold() {
+        Integer compare = compare(left().fold(), right().fold());
+        return compare != null && compare.intValue() >= 0;
+    }
+
     @Override
     public LessThanOrEqual swapLeftAndRight() {
         return new LessThanOrEqual(location(), right(), left());

sql/server/src/main/java/org/elasticsearch/xpack/sql/expression/predicate/IsNotNull.java

@@ -17,6 +17,11 @@ public class IsNotNull extends UnaryExpression {
         super(location, child);
     }
 
+    @Override
+    public Object fold() {
+        return child().fold() != null && !DataTypes.NULL.same(child().dataType());
+    }
+
     @Override
     public boolean nullable() {
         return false;

sql/server/src/main/java/org/elasticsearch/xpack/sql/expression/predicate/LessThan.java

@@ -15,6 +15,12 @@ public class LessThan extends BinaryComparison implements Negateable {
         super(location, left, right);
     }
 
+    @Override
+    public Object fold() {
+        Integer compare = compare(left().fold(), right().fold());
+        return compare != null && compare.intValue() < 0;
+    }
+
     @Override
     public GreaterThan swapLeftAndRight() {
         return new GreaterThan(location(), right(), left());

sql/server/src/main/java/org/elasticsearch/xpack/sql/expression/predicate/LessThanOrEqual.java

@@ -15,6 +15,12 @@ public class LessThanOrEqual extends BinaryComparison implements Negateable {
         super(location, left, right);
     }
 
+    @Override
+    public Object fold() {
+        Integer compare = compare(left().fold(), right().fold());
+        return compare != null && compare.intValue() <= 0;
+    }
+
     @Override
     public GreaterThanOrEqual swapLeftAndRight() {
         return new GreaterThanOrEqual(location(), right(), left());

sql/server/src/main/java/org/elasticsearch/xpack/sql/expression/predicate/Not.java

@@ -7,17 +7,34 @@ package org.elasticsearch.xpack.sql.expression.predicate;
 
 import org.elasticsearch.xpack.sql.expression.BinaryOperator.Negateable;
 import org.elasticsearch.xpack.sql.expression.Expression;
+import org.elasticsearch.xpack.sql.expression.Expressions;
 import org.elasticsearch.xpack.sql.expression.UnaryExpression;
 import org.elasticsearch.xpack.sql.tree.Location;
 import org.elasticsearch.xpack.sql.type.DataType;
 import org.elasticsearch.xpack.sql.type.DataTypes;
 
+import java.util.Objects;
+
 public class Not extends UnaryExpression {
 
     public Not(Location location, Expression child) {
         super(location, child);
     }
 
+    @Override
+    protected TypeResolution resolveType() {
+        if (DataTypes.BOOLEAN.same(child().dataType())) {
+            return TypeResolution.TYPE_RESOLVED;
+        }
+        return new TypeResolution("Cannot negate expression ([" + Expressions.name(child()) + "] of type ["
+                + child().dataType().esName() + "])");
+    }
+
+    @Override
+    public Object fold() {
+        return Objects.equals(child().fold(), Boolean.TRUE) ? Boolean.FALSE : Boolean.TRUE;
+    }
+
     @Override
     protected Expression canonicalize() {
         Expression canonicalChild = child().canonical();

sql/server/src/main/java/org/elasticsearch/xpack/sql/expression/predicate/Or.java

@@ -10,12 +10,19 @@ import org.elasticsearch.xpack.sql.expression.BinaryOperator.Negateable;
 import org.elasticsearch.xpack.sql.expression.Expression;
 import org.elasticsearch.xpack.sql.tree.Location;
 
+import java.util.Objects;
+
 public class Or extends BinaryLogic implements Negateable {
 
     public Or(Location location, Expression left, Expression right) {
         super(location, left, right);
     }
 
+    @Override
+    public Object fold() {
+        return Objects.equals(left().fold(), Boolean.TRUE) || Objects.equals(right().fold(), Boolean.TRUE);
+    }
+
     @Override
     public Or swapLeftAndRight() {
         return new Or(location(), right(), left());

sql/server/src/main/java/org/elasticsearch/xpack/sql/expression/predicate/Range.java

@@ -54,6 +54,16 @@ public class Range extends Expression {
         return value.foldable() && lower.foldable() && upper.foldable();
     }
 
+    @Override
+    public Object fold() {
+        Object val = value.fold();
+        Integer lowerCompare = BinaryComparison.compare(lower.fold(), val);
+        Integer upperCompare = BinaryComparison.compare(val, upper().fold());
+        boolean lowerComparsion = lowerCompare == null ? false : (includeLower ? lowerCompare <= 0 : lowerCompare < 0);
+        boolean upperComparsion = upperCompare == null ? false : (includeUpper ? upperCompare <= 0 : upperCompare < 0);
+        return lowerComparsion && upperComparsion;
+    }
+
     @Override
     public boolean nullable() {
         return value.nullable() && lower.nullable() && upper.nullable();

sql/server/src/main/java/org/elasticsearch/xpack/sql/expression/regex/Like.java

@@ -11,6 +11,8 @@ import org.elasticsearch.xpack.sql.tree.Location;
 import org.elasticsearch.xpack.sql.type.DataType;
 import org.elasticsearch.xpack.sql.type.DataTypes;
 
+import java.util.regex.Pattern;
+
 public class Like extends BinaryExpression {
 
     public Like(Location location, Expression left, LikePattern right) {
@@ -18,8 +20,9 @@ public class Like extends BinaryExpression {
     }
 
     @Override
-    public LikePattern right() {
+    public Object fold() {
-        return (LikePattern) super.right();
+        Pattern p = Pattern.compile(right().fold().toString());
+        return p.matcher(left().fold().toString()).matches();
     }
 
     @Override

sql/server/src/main/java/org/elasticsearch/xpack/sql/expression/regex/LikePattern.java

@@ -69,6 +69,17 @@ public class LikePattern extends LeafExpression {
         return indexNameWildcard;
     }
 
+    @Override
+    public boolean foldable() {
+        return true;
+    }
+
+    @Override
+    public Object fold() {
+        // being in Java, the Java regex is returned
+        return asJavaRegex();
+    }
+
     @Override
     public boolean nullable() {
         return false;

sql/server/src/main/java/org/elasticsearch/xpack/sql/expression/regex/RLike.java

@@ -12,6 +12,8 @@ import org.elasticsearch.xpack.sql.tree.Location;
 import org.elasticsearch.xpack.sql.type.DataType;
 import org.elasticsearch.xpack.sql.type.DataTypes;
 
+import java.util.regex.Pattern;
+
 public class RLike extends BinaryExpression {
 
     public RLike(Location location, Expression left, Literal right) {
@@ -19,8 +21,9 @@ public class RLike extends BinaryExpression {
     }
 
     @Override
-    public Literal right() {
+    public Object fold() {
-        return (Literal) super.right();
+        Pattern p = Pattern.compile(right().fold().toString());
+        return p.matcher(left().fold().toString()).matches();
     }
 
     @Override

sql/server/src/main/java/org/elasticsearch/xpack/sql/planner/QueryTranslator.java

@@ -441,7 +441,7 @@ abstract class QueryTranslator {
             }
 
             if (e instanceof Like) {
-                LikePattern p = ((Like) e).right();
+                LikePattern p = (LikePattern) ((Like) e).right();
                 if (inexact) {
                     q = new QueryStringQuery(e.location(), p.asLuceneWildcard(), target);
                 }

sql/server/src/main/java/org/elasticsearch/xpack/sql/type/NullType.java

@@ -10,7 +10,7 @@ import java.sql.JDBCType;
 public class NullType extends AbstractDataType {
 
     NullType() {
-        super(JDBCType.NULL, true);
+        super(JDBCType.NULL, false);
     }
 
     @Override

sql/server/src/test/java/org/elasticsearch/xpack/sql/optimizer/OptimizerTests.java

@@ -20,9 +20,15 @@ import org.elasticsearch.xpack.sql.expression.predicate.And;
 import org.elasticsearch.xpack.sql.expression.predicate.Equals;
 import org.elasticsearch.xpack.sql.expression.predicate.GreaterThan;
 import org.elasticsearch.xpack.sql.expression.predicate.GreaterThanOrEqual;
+import org.elasticsearch.xpack.sql.expression.predicate.IsNotNull;
 import org.elasticsearch.xpack.sql.expression.predicate.LessThan;
 import org.elasticsearch.xpack.sql.expression.predicate.LessThanOrEqual;
+import org.elasticsearch.xpack.sql.expression.predicate.Not;
 import org.elasticsearch.xpack.sql.expression.predicate.Or;
+import org.elasticsearch.xpack.sql.expression.predicate.Range;
+import org.elasticsearch.xpack.sql.expression.regex.Like;
+import org.elasticsearch.xpack.sql.expression.regex.LikePattern;
+import org.elasticsearch.xpack.sql.expression.regex.RLike;
 import org.elasticsearch.xpack.sql.optimizer.Optimizer.BinaryComparisonSimplification;
 import org.elasticsearch.xpack.sql.optimizer.Optimizer.BooleanLiteralsOnTheRight;
 import org.elasticsearch.xpack.sql.optimizer.Optimizer.BooleanSimplification;
@@ -205,6 +211,40 @@ public class OptimizerTests extends ESTestCase {
         assertEquals(5, ((Literal) c).value());
     }
 
+    public void testConstantFoldingBinaryComparison() {
+        assertEquals(Literal.FALSE, new ConstantFolding().rule(new GreaterThan(EMPTY, L(2), L(3))));
+        assertEquals(Literal.FALSE, new ConstantFolding().rule(new GreaterThanOrEqual(EMPTY, L(2), L(3))));
+        assertEquals(Literal.FALSE, new ConstantFolding().rule(new Equals(EMPTY, L(2), L(3))));
+        assertEquals(Literal.TRUE, new ConstantFolding().rule(new LessThanOrEqual(EMPTY, L(2), L(3))));
+        assertEquals(Literal.TRUE, new ConstantFolding().rule(new LessThan(EMPTY, L(2), L(3))));
+    }
+
+    public void testConstantFoldingBinaryLogic() {
+        assertEquals(Literal.FALSE, new ConstantFolding().rule(new And(EMPTY, new GreaterThan(EMPTY, L(2), L(3)), Literal.TRUE)));
+        assertEquals(Literal.TRUE, new ConstantFolding().rule(new Or(EMPTY, new GreaterThanOrEqual(EMPTY, L(2), L(3)), Literal.TRUE)));
+    }
+
+    public void testConstantFoldingRange() {
+        assertEquals(Literal.TRUE, new ConstantFolding().rule(new Range(EMPTY, L(5), L(5), true, L(10), false)));
+        assertEquals(Literal.FALSE, new ConstantFolding().rule(new Range(EMPTY, L(5), L(5), false, L(10), false)));
+    }
+
+    public void testConstantIsNotNull() {
+        assertEquals(Literal.FALSE, new ConstantFolding().rule(new IsNotNull(EMPTY, L(null))));
+        assertEquals(Literal.TRUE, new ConstantFolding().rule(new IsNotNull(EMPTY, L(5))));
+    }
+
+    public void testConstantNot() {
+        assertEquals(Literal.FALSE, new ConstantFolding().rule(new Not(EMPTY, Literal.TRUE)));
+        assertEquals(Literal.TRUE, new ConstantFolding().rule(new Not(EMPTY, Literal.FALSE)));
+    }
+
+    public void testConstantFoldingLikes() {
+        assertEquals(Literal.TRUE,
+                new ConstantFolding().rule(new Like(EMPTY, Literal.of(EMPTY, "test_emp"), new LikePattern(EMPTY, "test%", (char) 0))));
+        assertEquals(Literal.TRUE,
+                new ConstantFolding().rule(new RLike(EMPTY, Literal.of(EMPTY, "test_emp"), Literal.of(EMPTY, "test.emp"))));
+    }
 
     public void testBinaryComparisonSimplification() {
         assertEquals(Literal.TRUE, new BinaryComparisonSimplification().rule(new Equals(EMPTY, L(5), L(5))));
@@ -224,7 +264,6 @@ public class OptimizerTests extends ESTestCase {
         assertEquals(L(5), eq.right());
     }
 
-
     public void testBoolSimplifyOr() {
         BooleanSimplification simplification = new BooleanSimplification();
         

sql/server/src/test/java/org/elasticsearch/xpack/sql/parser/LikeEscapingParsingTests.java

@@ -31,7 +31,7 @@ public class LikeEscapingParsingTests extends ESTestCase {
         Expression exp = parser.createExpression(String.format(Locale.ROOT, "exp LIKE %s", pattern));
         assertThat(exp, instanceOf(Like.class));
         Like l = (Like) exp;
-        return l.right();
+        return (LikePattern) l.right();
     }
 
     public void testNoEscaping() {