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ratel api,used for developer on ratel system,an extension for xposed framewrok,ratel api compatable with original xposed framework

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/*
 * 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.
 */
package external.org.apache.commons.io.output;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.nio.charset.Charset;

import external.org.apache.commons.io.Charsets;
import external.org.apache.commons.io.FileUtils;

/**
 * FileWriter that will create and honor lock files to allow simple
 * cross thread file lock handling.
 * 

* This class provides a simple alternative to FileWriter * that will use a lock file to prevent duplicate writes. *

* N.B. the lock file is deleted when {@link #close()} is called * - or if the main file cannot be opened initially. * In the (unlikely) event that the lockfile cannot be deleted, * this is not reported, and subsequent requests using * the same lockfile will fail. *

* By default, the file will be overwritten, but this may be changed to append. * The lock directory may be specified, but defaults to the system property * java.io.tmpdir. * The encoding may also be specified, and defaults to the platform default. * */ public class LockableFileWriter extends Writer { // Cannot extend ProxyWriter, as requires writer to be // known when super() is called /** The extension for the lock file. */ private static final String LCK = ".lck"; /** The writer to decorate. */ private final Writer out; /** The lock file. */ private final File lockFile; /** * Constructs a LockableFileWriter. * If the file exists, it is overwritten. * * @param fileName the file to write to, not null * @throws NullPointerException if the file is null * @throws IOException in case of an I/O error */ public LockableFileWriter(final String fileName) throws IOException { this(fileName, false, null); } /** * Constructs a LockableFileWriter. * * @param fileName file to write to, not null * @param append true if content should be appended, false to overwrite * @throws NullPointerException if the file is null * @throws IOException in case of an I/O error */ public LockableFileWriter(final String fileName, final boolean append) throws IOException { this(fileName, append, null); } /** * Constructs a LockableFileWriter. * * @param fileName the file to write to, not null * @param append true if content should be appended, false to overwrite * @param lockDir the directory in which the lock file should be held * @throws NullPointerException if the file is null * @throws IOException in case of an I/O error */ public LockableFileWriter(final String fileName, final boolean append, final String lockDir) throws IOException { this(new File(fileName), append, lockDir); } /** * Constructs a LockableFileWriter. * If the file exists, it is overwritten. * * @param file the file to write to, not null * @throws NullPointerException if the file is null * @throws IOException in case of an I/O error */ public LockableFileWriter(final File file) throws IOException { this(file, false, null); } /** * Constructs a LockableFileWriter. * * @param file the file to write to, not null * @param append true if content should be appended, false to overwrite * @throws NullPointerException if the file is null * @throws IOException in case of an I/O error */ public LockableFileWriter(final File file, final boolean append) throws IOException { this(file, append, null); } /** * Constructs a LockableFileWriter. * * @param file the file to write to, not null * @param append true if content should be appended, false to overwrite * @param lockDir the directory in which the lock file should be held * @throws NullPointerException if the file is null * @throws IOException in case of an I/O error * @deprecated 2.5 use {@link #LockableFileWriter(File, Charset, boolean, String)} instead */ @Deprecated public LockableFileWriter(final File file, final boolean append, final String lockDir) throws IOException { this(file, Charset.defaultCharset(), append, lockDir); } /** * Constructs a LockableFileWriter with a file encoding. * * @param file the file to write to, not null * @param encoding the encoding to use, null means platform default * @throws NullPointerException if the file is null * @throws IOException in case of an I/O error * @since 2.3 */ public LockableFileWriter(final File file, final Charset encoding) throws IOException { this(file, encoding, false, null); } /** * Constructs a LockableFileWriter with a file encoding. * * @param file the file to write to, not null * @param encoding the encoding to use, null means platform default * @throws NullPointerException if the file is null * @throws IOException in case of an I/O error * @throws java.nio.charset.UnsupportedCharsetException * thrown instead of {@link java.io.UnsupportedEncodingException} in version 2.2 if the encoding is not * supported. */ public LockableFileWriter(final File file, final String encoding) throws IOException { this(file, encoding, false, null); } /** * Constructs a LockableFileWriter with a file encoding. * * @param file the file to write to, not null * @param encoding the encoding to use, null means platform default * @param append true if content should be appended, false to overwrite * @param lockDir the directory in which the lock file should be held * @throws NullPointerException if the file is null * @throws IOException in case of an I/O error * @since 2.3 */ public LockableFileWriter(File file, final Charset encoding, final boolean append, String lockDir) throws IOException { super(); // init file to create/append file = file.getAbsoluteFile(); if (file.getParentFile() != null) { FileUtils.forceMkdir(file.getParentFile()); } if (file.isDirectory()) { throw new IOException("File specified is a directory"); } // init lock file if (lockDir == null) { lockDir = System.getProperty("java.io.tmpdir"); } final File lockDirFile = new File(lockDir); FileUtils.forceMkdir(lockDirFile); testLockDir(lockDirFile); lockFile = new File(lockDirFile, file.getName() + LCK); // check if locked createLock(); // init wrapped writer out = initWriter(file, encoding, append); } /** * Constructs a LockableFileWriter with a file encoding. * * @param file the file to write to, not null * @param encoding the encoding to use, null means platform default * @param append true if content should be appended, false to overwrite * @param lockDir the directory in which the lock file should be held * @throws NullPointerException if the file is null * @throws IOException in case of an I/O error * @throws java.nio.charset.UnsupportedCharsetException * thrown instead of {@link java.io.UnsupportedEncodingException} in version 2.2 if the encoding is not * supported. */ public LockableFileWriter(final File file, final String encoding, final boolean append, final String lockDir) throws IOException { this(file, Charsets.toCharset(encoding), append, lockDir); } //----------------------------------------------------------------------- /** * Tests that we can write to the lock directory. * * @param lockDir the File representing the lock directory * @throws IOException if we cannot write to the lock directory * @throws IOException if we cannot find the lock file */ private void testLockDir(final File lockDir) throws IOException { if (!lockDir.exists()) { throw new IOException( "Could not find lockDir: " + lockDir.getAbsolutePath()); } if (!lockDir.canWrite()) { throw new IOException( "Could not write to lockDir: " + lockDir.getAbsolutePath()); } } /** * Creates the lock file. * * @throws IOException if we cannot create the file */ private void createLock() throws IOException { synchronized (LockableFileWriter.class) { if (!lockFile.createNewFile()) { throw new IOException("Can't write file, lock " + lockFile.getAbsolutePath() + " exists"); } lockFile.deleteOnExit(); } } /** * Initialise the wrapped file writer. * Ensure that a cleanup occurs if the writer creation fails. * * @param file the file to be accessed * @param encoding the encoding to use * @param append true to append * @return The initialised writer * @throws IOException if an error occurs */ private Writer initWriter(final File file, final Charset encoding, final boolean append) throws IOException { final boolean fileExistedAlready = file.exists(); try { return new OutputStreamWriter(new FileOutputStream(file.getAbsolutePath(), append), Charsets.toCharset(encoding)); } catch (final IOException | RuntimeException ex) { FileUtils.deleteQuietly(lockFile); if (fileExistedAlready == false) { FileUtils.deleteQuietly(file); } throw ex; } } //----------------------------------------------------------------------- /** * Closes the file writer and deletes the lockfile (if possible). * * @throws IOException if an I/O error occurs */ @Override public void close() throws IOException { try { out.close(); } finally { lockFile.delete(); } } //----------------------------------------------------------------------- /** * Write a character. * @param idx the character to write * @throws IOException if an I/O error occurs */ @Override public void write(final int idx) throws IOException { out.write(idx); } /** * Write the characters from an array. * @param chr the characters to write * @throws IOException if an I/O error occurs */ @Override public void write(final char[] chr) throws IOException { out.write(chr); } /** * Write the specified characters from an array. * @param chr the characters to write * @param st The start offset * @param end The number of characters to write * @throws IOException if an I/O error occurs */ @Override public void write(final char[] chr, final int st, final int end) throws IOException { out.write(chr, st, end); } /** * Write the characters from a string. * @param str the string to write * @throws IOException if an I/O error occurs */ @Override public void write(final String str) throws IOException { out.write(str); } /** * Write the specified characters from a string. * @param str the string to write * @param st The start offset * @param end The number of characters to write * @throws IOException if an I/O error occurs */ @Override public void write(final String str, final int st, final int end) throws IOException { out.write(str, st, end); } /** * Flush the stream. * @throws IOException if an I/O error occurs */ @Override public void flush() throws IOException { out.flush(); } }





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