Java tutorial
/* 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 de.sandroboehme.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 de.sandroboehme.lesscss.LessException; import de.sandroboehme.lesscss.LessSource; public class NodeJsLessCompiler { private static final List<String> resources = Arrays.asList("lessc.js", "less/visitor.js", "less/tree.js", "less/to-css-visitor.js", "less/source-map-output.js", "less/rhino.js", "less/parser.js", "less/lessc_helper.js", "less/join-selector-visitor.js", "less/index.js", "less/import-visitor.js", "less/functions.js", "less/extend-visitor.js", "less/env.js", "less/colors.js", "less/browser.js", "less/tree/variable.js", "less/tree/value.js", "less/tree/url.js", "less/tree/unicode-descriptor.js", "less/tree/selector.js", "less/tree/ruleset.js", "less/tree/rule.js", "less/tree/ratio.js", "less/tree/quoted.js", "less/tree/paren.js", "less/tree/operation.js", "less/tree/negative.js", "less/tree/mixin.js", "less/tree/media.js", "less/tree/keyword.js", "less/tree/javascript.js", "less/tree/import.js", "less/tree/extend.js", "less/tree/expression.js", "less/tree/element.js", "less/tree/directive.js", "less/tree/dimension.js", "less/tree/condition.js", "less/tree/comment.js", "less/tree/color.js", "less/tree/call.js", "less/tree/assignment.js", "less/tree/anonymous.js", "less/tree/alpha.js"); private final Log log; private final boolean compress; private final String encoding; private final File tempDir; private final String nodeExecutablePath; public NodeJsLessCompiler(boolean compress, String encoding, Log log) throws IOException { this("node", compress, encoding, log); } public NodeJsLessCompiler(String nodeExecutablePath, boolean compress, String encoding, Log log) throws IOException { this.compress = compress; this.encoding = encoding; this.log = log; this.nodeExecutablePath = nodeExecutablePath; tempDir = createTempDir("lessc"); new File(tempDir, "less/tree").mkdirs(); for (String resource : resources) { InputStream in = NodeJsLessCompiler.class.getClassLoader() .getResourceAsStream("de/sandroboehme/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(nodeExecutablePath, 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) + ')'); } }