org.lesscss.mojo.NodeJsLessCompiler.java Source code

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Here is the source code for org.lesscss.mojo.NodeJsLessCompiler.java

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/* Copyright 2013 the original author or authors.
 *
 * 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 org.lesscss.mojo;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Arrays;
import java.util.List;

import org.apache.commons.io.FileUtils;
import org.apache.commons.io.IOUtils;
import org.apache.maven.plugin.logging.Log;
import org.lesscss.LessException;
import org.lesscss.LessSource;

public class NodeJsLessCompiler {

    private static final List<String> resources = Arrays.asList("lessc.js", "less/browser.js", "less/colors.js",
            "less/functions.js", "less/index.js", "less/lessc_helper.js", "less/parser.js", "less/rhino.js",
            "less/tree.js", "less/tree/alpha.js", "less/tree/anonymous.js", "less/tree/assignment.js",
            "less/tree/call.js", "less/tree/color.js", "less/tree/comment.js", "less/tree/condition.js",
            "less/tree/dimension.js", "less/tree/directive.js", "less/tree/element.js", "less/tree/expression.js",
            "less/tree/import.js", "less/tree/javascript.js", "less/tree/keyword.js", "less/tree/media.js",
            "less/tree/mixin.js", "less/tree/operation.js", "less/tree/paren.js", "less/tree/quoted.js",
            "less/tree/ratio.js", "less/tree/rule.js", "less/tree/ruleset.js", "less/tree/selector.js",
            "less/tree/unicode-descriptor.js", "less/tree/url.js", "less/tree/value.js", "less/tree/variable.js");

    private final Log log;
    private final boolean compress;
    private final String encoding;
    private final File tempDir;

    public NodeJsLessCompiler(boolean compress, String encoding, Log log) throws IOException {
        this.compress = compress;
        this.encoding = encoding;
        this.log = log;

        tempDir = createTempDir("lessc");
        new File(tempDir, "less/tree").mkdirs();
        for (String resource : resources) {
            InputStream in = NodeJsLessCompiler.class.getClassLoader()
                    .getResourceAsStream("org/lesscss/mojo/js/" + resource);
            FileOutputStream out = new FileOutputStream(new File(tempDir, resource));
            IOUtils.copy(in, out);
            in.close();
            out.close();
        }
    }

    public void close() {
        for (String resource : resources) {
            File tempFile = new File(tempDir, resource);
            if (!tempFile.delete()) {
                log.warn("Could not delete temp file: " + tempFile.getAbsolutePath());
            }
        }
        File lessSubdir = new File(tempDir, "less");
        File treeSubdir = new File(lessSubdir, "tree");
        if (!treeSubdir.delete()) {
            log.warn("Could not delete temp dir: " + treeSubdir.getAbsolutePath());
        }
        if (!lessSubdir.delete()) {
            log.warn("Could not delete temp dir: " + lessSubdir.getAbsolutePath());
        }
        if (!tempDir.delete()) {
            log.warn("Could not delete temp dir: " + tempDir.getAbsolutePath());
        }
    }

    public void compile(LessSource input, File output, boolean force)
            throws IOException, LessException, InterruptedException {
        if (force || !output.exists() || output.lastModified() < input.getLastModifiedIncludingImports()) {
            String data = compile(input.getNormalizedContent());
            FileUtils.writeStringToFile(output, data, encoding);
        }
    }

    private String compile(String input) throws LessException, IOException, InterruptedException {
        long start = System.currentTimeMillis();

        File inputFile = File.createTempFile("lessc-input-", ".less");
        FileOutputStream out = new FileOutputStream(inputFile);
        IOUtils.write(input, out);
        out.close();
        File outputFile = File.createTempFile("lessc-output-", ".css");
        File lesscJsFile = new File(tempDir, "lessc.js");

        ProcessBuilder pb = new ProcessBuilder("node", lesscJsFile.getAbsolutePath(), inputFile.getAbsolutePath(),
                outputFile.getAbsolutePath(), String.valueOf(compress));
        pb.redirectErrorStream(true);
        Process process = pb.start();
        IOUtils.copy(process.getInputStream(), System.out);

        int exitStatus = process.waitFor();

        FileInputStream in = new FileInputStream(outputFile);
        String result = IOUtils.toString(in);
        in.close();
        if (!inputFile.delete()) {
            log.warn("Could not delete temp file: " + inputFile.getAbsolutePath());
        }
        if (!outputFile.delete()) {
            log.warn("Could not delete temp file: " + outputFile.getAbsolutePath());
        }
        if (exitStatus != 0) {
            throw new LessException(result, null);
        }

        log.debug("Finished compilation of LESS source in " + (System.currentTimeMillis() - start) + " ms.");

        return result;
    }

    // copied from guava's Files.createTempDir, with added prefix
    private static File createTempDir(String prefix) {
        final int tempDirAttempts = 10000;
        File baseDir = new File(System.getProperty("java.io.tmpdir"));
        String baseName = prefix + "-" + System.currentTimeMillis() + "-";
        for (int counter = 0; counter < tempDirAttempts; counter++) {
            File tempDir = new File(baseDir, baseName + counter);
            if (tempDir.mkdir()) {
                return tempDir;
            }
        }
        throw new IllegalStateException("Failed to create directory within " + tempDirAttempts + " attempts (tried "
                + baseName + "0 to " + baseName + (tempDirAttempts - 1) + ')');
    }
}