com.google.template.soy.jssrc.dsl.BinaryOperation.java Source code

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Here is the source code for com.google.template.soy.jssrc.dsl.BinaryOperation.java

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/*
 * Copyright 2016 Google 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 com.google.template.soy.jssrc.dsl;

import com.google.auto.value.AutoValue;
import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSet;
import com.google.errorprone.annotations.Immutable;
import com.google.template.soy.exprtree.Operator;
import com.google.template.soy.exprtree.Operator.Associativity;

/** Represents a JavaScript binary operation. */
@AutoValue
@Immutable
abstract class BinaryOperation extends Operation {
    abstract String operator();

    abstract CodeChunk.WithValue arg1();

    abstract CodeChunk.WithValue arg2();

    static CodeChunk.WithValue create(Operator operator, CodeChunk.WithValue arg1, CodeChunk.WithValue arg2) {
        Preconditions.checkState(operator != Operator.AND, "use BinaryOperation::and");
        Preconditions.checkState(operator != Operator.OR, "use BinaryOperation::or");
        return create(operator.getTokenString(), operator.getPrecedence(), operator.getAssociativity(), arg1, arg2);
    }

    static BinaryOperation create(String operator, int precedence, Associativity associativity,
            CodeChunk.WithValue arg1, CodeChunk.WithValue arg2) {
        return new AutoValue_BinaryOperation(ImmutableSet.<CodeChunk>builder().addAll(arg1.initialStatements())
                .addAll(arg2.initialStatements()).build(), precedence, associativity, operator, arg1, arg2);
    }

    static CodeChunk.WithValue and(CodeChunk.WithValue lhs, CodeChunk.WithValue rhs,
            CodeChunk.Generator codeGenerator) {
        // If rhs has no initial statements, use the JS && operator directly.
        // It's already short-circuiting.
        if (lhs.initialStatements().containsAll(rhs.initialStatements())) {
            return create("&&", Operator.AND.getPrecedence(), Operator.AND.getAssociativity(), lhs, rhs);
        }
        // Otherwise, generate explicit short-circuiting code.
        // rhs should be evaluated only if lhs evaluates to true.
        CodeChunk.WithValue tmp = codeGenerator.declare(lhs).ref();
        return Composite.create(ImmutableList.of(CodeChunk.ifStatement(tmp, tmp.assign(rhs)).build()), tmp);
    }

    static CodeChunk.WithValue or(CodeChunk.WithValue lhs, CodeChunk.WithValue rhs,
            CodeChunk.Generator codeGenerator) {
        // If rhs has no initial statements, use the JS || operator directly.
        // It's already short-circuiting.
        if (lhs.initialStatements().containsAll(rhs.initialStatements())) {
            return create("||", Operator.OR.getPrecedence(), Operator.OR.getAssociativity(), lhs, rhs);
        }
        // Otherwise, generate explicit short-circuiting code.
        // rhs should be evaluated only if lhs evaluates to false.
        CodeChunk.WithValue tmp = codeGenerator.declare(lhs).ref();
        return Composite.create(ImmutableList.of(CodeChunk.ifStatement(not(tmp), tmp.assign(rhs)).build()), tmp);
    }

    @Override
    public void collectRequires(RequiresCollector collector) {
        arg1().collectRequires(collector);
        arg2().collectRequires(collector);
    }

    @Override
    void doFormatOutputExpr(FormattingContext ctx) {
        formatOperand(arg1(), OperandPosition.LEFT, ctx);
        ctx.append(' ').append(operator()).append(' ');
        formatOperand(arg2(), OperandPosition.RIGHT, ctx);
    }

    @Override
    void doFormatInitialStatements(FormattingContext ctx) {
        ctx.appendInitialStatements(arg1()).appendInitialStatements(arg2());
    }
}