org.eolang.opeo.compilation.JeoCompiler Maven / Gradle / Ivy

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Bytecode decompiler to eolang and back
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/*
 * The MIT License (MIT)
 *
 * Copyright (c) 2016-2023 Objectionary.com
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
package org.eolang.opeo.compilation;

import com.jcabi.xml.XML;
import org.eolang.jeo.representation.xmir.AllLabels;
import org.eolang.jeo.representation.xmir.XmlClass;
import org.eolang.jeo.representation.xmir.XmlMethod;
import org.eolang.jeo.representation.xmir.XmlNode;
import org.eolang.jeo.representation.xmir.XmlProgram;

/**
 * Compiler of high-level EO programs to low-level EO suitable for jeo-maven-plugin.
 *
 * @since 0.1
 */
public final class JeoCompiler {

    /**
     * The high-level EO program generated by opeo-maven-plugin.
     */
    private final XML opeo;

    /**
     * Constructor.
     *
     * @param opeo The high-level EO program generated by opeo-maven-plugin.
     */
    public JeoCompiler(final XML opeo) {
        this.opeo = opeo;
    }

    /**
     * Compiles the high-level EO program to low-level EO suitable for jeo-maven-plugin.
     *
     * @return The low-level EO program suitable for jeo-maven-plugin.
     */
    public XML compile() {
        final XmlProgram program = new XmlProgram(this.opeo.node());
        final String pckg = program.toXml().xpath("//meta[head='package']/tail/text()").stream()
            .findFirst()
            .orElse("");
        final XmlClass clazz = program.top();
        final XmlMethod[] methods = clazz.methods().stream()
            .map(method -> JeoCompiler.compile(method, pckg))
            .toArray(XmlMethod[]::new);
        return program.replaceTopClass(
            clazz.replaceMethods(methods)
        ).toXml();
    }

    /**
     * Compiles a single method.
     *
     * @param method The method to compile.
     * @param pckg The package of the method.
     * @return The compiled method.
     * @todo #229:90min Refactor {@link #compile} method to handle exceptions appropriately.
     *  The method {@link #compile} is catching generic exceptions which is bad.
     *  We should refactor it to simplify the code and remove duplicated catch blocks.
     *  After, don't forget to remove the Checkstyle and PMD tags.
     * @todo #229:90min Optimize Labels Generation.
     *  Here we clean the cache of labels before compiling a method. This is a workaround
     *  to avoid a bug in the generation of labels. When we have lot's of methods, the cache grows
     *  and the compilation time increases significantly.
     * @todo #229:90min Calculate the Max Stack Size.
     *  We should calculate the max stack size of the method and set it into the compiled method.
     *  To enforce jeo to calculate the max stack size, we use 'withoutMaxs()' method.
     *  This is important to avoid runtime errors when running the compiled code.
     *  Currently we calculate max stack size only for methods in the org.eolang package.
     *  This is done intentionally because all the classes for the org.eolang package are
     *  placed in the classpath and we can actually calculate the max stack size.
     *  Other packages, for example, spring framework, have some 'optional' dependencies
     *  that are not in the classpath and byt this reason, jeo can't calculate the max stack size.
     * @checkstyle IllegalCatch (50 lines)
     */
    @SuppressWarnings({"PMD.AvoidCatchingGenericException", "PMD.IdenticalCatchBranches"})
    private static XmlMethod compile(final XmlMethod method, final String pckg) {
        try {
            final XmlMethod result;
            new AllLabels().clearCache();
            if (pckg.contains("org.eolang")) {
                result = method.withoutMaxs().withInstructions(
                    new XmirParser(method.nodes()).toJeoNodes().toArray(new XmlNode[0])
                );
            } else {
                result = method.withInstructions(
                    new XmirParser(method.nodes()).toJeoNodes().toArray(new XmlNode[0])
                );
            }
            return result;
        } catch (final ClassCastException exception) {
            throw new IllegalArgumentException(
                String.format(
                    "Failed to compile method %s: %s",
                    method.name(),
                    method
                ),
                exception
            );
        } catch (final IllegalArgumentException exception) {
            throw new IllegalArgumentException(
                String.format(
                    "Failed to compile method %s: %s",
                    method.name(),
                    method
                ),
                exception
            );
        } catch (final IllegalStateException exception) {
            throw new IllegalStateException(
                String.format(
                    "Failed to compile method %s: %s",
                    method.name(),
                    method
                ),
                exception
            );
        } catch (final Exception exception) {
            throw new IllegalStateException(
                String.format(
                    "Failed to compile method %s: %s",
                    method.name(),
                    method
                ),
                exception
            );
        }
    }
}