linq4j/src/test/java/org/apache/calcite/linq4j/test/BlockBuilderTest.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to you 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.
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package org.apache.calcite.linq4j.test;

import org.apache.calcite.linq4j.tree.BinaryExpression;
import org.apache.calcite.linq4j.tree.BlockBuilder;
import org.apache.calcite.linq4j.tree.Expression;
import org.apache.calcite.linq4j.tree.ExpressionType;
import org.apache.calcite.linq4j.tree.Expressions;
import org.apache.calcite.linq4j.tree.OptimizeShuttle;
import org.apache.calcite.linq4j.tree.ParameterExpression;
import org.apache.calcite.linq4j.tree.Shuttle;

import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;

import java.lang.reflect.Method;
import java.util.function.Function;

import static org.apache.calcite.linq4j.test.BlockBuilderBase.FOUR;
import static org.apache.calcite.linq4j.test.BlockBuilderBase.ONE;
import static org.apache.calcite.linq4j.test.BlockBuilderBase.TWO;

import static org.junit.jupiter.api.Assertions.assertEquals;

/**
 * Tests BlockBuilder.
 */
class BlockBuilderTest {
  BlockBuilder b;

  @BeforeEach
  public void prepareBuilder() {
    b = new BlockBuilder(true);
  }

  @Test void testReuseExpressionsFromUpperLevel() {
    Expression x = b.append("x", Expressions.add(ONE, TWO));
    BlockBuilder nested = new BlockBuilder(true, b);
    Expression y = nested.append("y", Expressions.add(ONE, TWO));
    nested.add(Expressions.return_(null, Expressions.add(y, y)));
    b.add(nested.toBlock());
    assertEquals(
        "{\n"
            + "  final int x = 1 + 2;\n"
            + "  {\n"
            + "    return x + x;\n"
            + "  }\n"
            + "}\n",
        b.toBlock().toString());
  }

  @Test void testTestCustomOptimizer() {
    BlockBuilder b = new BlockBuilder() {
      @Override protected Shuttle createOptimizeShuttle() {
        return new OptimizeShuttle() {
          @Override public Expression visit(BinaryExpression binary,
              Expression expression0, Expression expression1) {
            if (binary.getNodeType() == ExpressionType.Add
                && ONE.equals(expression0) && TWO.equals(expression1)) {
              return FOUR;
            }
            return super.visit(binary, expression0, expression1);
          }
        };
      }
    };
    b.add(Expressions.return_(null, Expressions.add(ONE, TWO)));
    assertEquals("{\n  return 4;\n}\n", b.toBlock().toString());
  }

  private BlockBuilder appendBlockWithSameVariable(
      Expression initializer1, Expression initializer2) {
    BlockBuilder outer = new BlockBuilder();
    ParameterExpression outerX = Expressions.parameter(int.class, "x");
    outer.add(Expressions.declare(0, outerX, initializer1));
    outer.add(Expressions.statement(Expressions.assign(outerX, Expressions.constant(1))));

    BlockBuilder inner = new BlockBuilder();
    ParameterExpression innerX = Expressions.parameter(int.class, "x");
    inner.add(Expressions.declare(0, innerX, initializer2));
    inner.add(Expressions.statement(Expressions.assign(innerX, Expressions.constant(42))));
    inner.add(Expressions.return_(null, innerX));
    outer.append("x", inner.toBlock());
    return outer;
  }

  @Test void testRenameVariablesWithEmptyInitializer() {
    BlockBuilder outer = appendBlockWithSameVariable(null, null);

    assertEquals("{\n"
            + "  int x;\n"
            + "  x = 1;\n"
            + "  int x0;\n"
            + "  x0 = 42;\n"
            + "}\n", Expressions.toString(outer.toBlock()),
        "x in the second block should be renamed to avoid name clash");
  }

  @Test void testRenameVariablesWithInitializer() {
    BlockBuilder outer = appendBlockWithSameVariable(
        Expressions.constant(7), Expressions.constant(8));

    assertEquals("{\n"
            + "  int x = 7;\n"
            + "  x = 1;\n"
            + "  int x0 = 8;\n"
            + "  x0 = 42;\n"
            + "}\n", Expressions.toString(outer.toBlock()),
        "x in the second block should be renamed to avoid name clash");
  }

  /** Test case for
   * <a href="https://issues.apache.org/jira/browse/CALCITE-2413">[CALCITE-2413]
   * RexToLixTranslator does not generate correct declaration of Methods with
   * generic return types</a>. */
  @Test void genericMethodCall() throws NoSuchMethodException {
    BlockBuilder bb = new BlockBuilder();
    bb.append("_i",
        Expressions.call(
            Expressions.new_(Identity.class),
            Identity.class.getMethod("apply", Object.class),
            Expressions.constant("test")));

    assertEquals(
        "{\n"
            + "  final Object _i = new org.apache.calcite.linq4j.test.BlockBuilderTest.Identity()"
            + ".apply(\"test\");\n"
            + "}\n",
        Expressions.toString(bb.toBlock()));

  }

  /** Test case for
   * <a href="https://issues.apache.org/jira/browse/CALCITE-2611">[CALCITE-2611]
   * Linq4j code generation failure if one side of an OR contains
   * UNKNOWN</a>. */
  @Test void testOptimizeBoxedFalseEqNull() {
    BlockBuilder outer = new BlockBuilder();
    outer.append(
        Expressions.equal(
            OptimizeShuttle.BOXED_FALSE_EXPR,
            Expressions.constant(null)));

    assertEquals("{\n"
            + "  return false;\n"
            + "}\n", Expressions.toString(outer.toBlock()),
        "Expected to optimize Boolean.FALSE = null to false");
  }

  /**
   * Class with generics to validate if {@link Expressions#call(Method, Expression...)} works.
   * @param <I> result type
   */
  static class Identity<I> implements Function<I, I> {
    @Override public I apply(I i) {
      return i;
    }
  }

}