ParseFileUtils.java

/*
 * 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 com.parse;

import org.json.JSONException;
import org.json.JSONObject;

import java.io.*;
import java.nio.channels.FileChannel;
import java.nio.charset.Charset;

/**
 * General file manipulation utilities.
 */
public class ParseFileUtils {

    /**
     * The number of bytes in a kilobyte.
     */
    public static final long ONE_KB = 1024;

    /**
     * The number of bytes in a megabyte.
     */
    public static final long ONE_MB = ONE_KB * ONE_KB;

    /**
     * The file copy buffer size (30 MB)
     */
    private static final long FILE_COPY_BUFFER_SIZE = ONE_MB * 30;

    /**
     * Reads the contents of a file into a byte array.
     * The file is always closed.
     *
     * @param file the file to read, must not be <code>null</code>
     * @return the file contents, never <code>null</code>
     * @throws IOException in case of an I/O error
     * @since Commons IO 1.1
     */
    public static byte[] readFileToByteArray(File file) throws IOException {
        InputStream in = null;
        try {
            in = openInputStream(file);
            return ParseIOUtils.toByteArray(in);
        } finally {
            ParseIOUtils.closeQuietly(in);
        }
    }

    //-----------------------------------------------------------------------

    /**
     * Opens a {@link FileInputStream} for the specified file, providing better
     * error messages than simply calling <code>new FileInputStream(file)</code>.
     * <p>
     * At the end of the method either the stream will be successfully opened,
     * or an exception will have been thrown.
     * <p>
     * An exception is thrown if the file does not exist.
     * An exception is thrown if the file object exists but is a directory.
     * An exception is thrown if the file exists but cannot be read.
     *
     * @param file the file to open for input, must not be <code>null</code>
     * @return a new {@link FileInputStream} for the specified file
     * @throws FileNotFoundException if the file does not exist
     * @throws IOException           if the file object is a directory
     * @throws IOException           if the file cannot be read
     * @since Commons IO 1.3
     */
    public static FileInputStream openInputStream(File file) throws IOException {
        if (file.exists()) {
            if (file.isDirectory()) {
                throw new IOException("File '" + file + "' exists but is a directory");
            }
            if (!file.canRead()) {
                throw new IOException("File '" + file + "' cannot be read");
            }
        } else {
            throw new FileNotFoundException("File '" + file + "' does not exist");
        }
        return new FileInputStream(file);
    }

    /**
     * Writes a byte array to a file creating the file if it does not exist.
     * <p>
     * NOTE: As from v1.3, the parent directories of the file will be created
     * if they do not exist.
     *
     * @param file the file to write to
     * @param data the content to write to the file
     * @throws IOException in case of an I/O error
     * @since Commons IO 1.1
     */
    public static void writeByteArrayToFile(File file, byte[] data) throws IOException {
        OutputStream out = null;
        try {
            out = openOutputStream(file);
            out.write(data);
        } finally {
            ParseIOUtils.closeQuietly(out);
        }
    }

    //-----------------------------------------------------------------------

    /**
     * Opens a {@link FileOutputStream} for the specified file, checking and
     * creating the parent directory if it does not exist.
     * <p>
     * At the end of the method either the stream will be successfully opened,
     * or an exception will have been thrown.
     * <p>
     * The parent directory will be created if it does not exist.
     * The file will be created if it does not exist.
     * An exception is thrown if the file object exists but is a directory.
     * An exception is thrown if the file exists but cannot be written to.
     * An exception is thrown if the parent directory cannot be created.
     *
     * @param file the file to open for output, must not be <code>null</code>
     * @return a new {@link FileOutputStream} for the specified file
     * @throws IOException if the file object is a directory
     * @throws IOException if the file cannot be written to
     * @throws IOException if a parent directory needs creating but that fails
     * @since Commons IO 1.3
     */
    public static FileOutputStream openOutputStream(File file) throws IOException {
        if (file.exists()) {
            if (file.isDirectory()) {
                throw new IOException("File '" + file + "' exists but is a directory");
            }
            if (!file.canWrite()) {
                throw new IOException("File '" + file + "' cannot be written to");
            }
        } else {
            File parent = file.getParentFile();
            if (parent != null && !parent.exists()) {
                if (!parent.mkdirs()) {
                    throw new IOException("File '" + file + "' could not be created");
                }
            }
        }
        return new FileOutputStream(file);
    }

    /**
     * Moves a file.
     * <p>
     * When the destination file is on another file system, do a "copy and delete".
     *
     * @param srcFile  the file to be moved
     * @param destFile the destination file
     * @throws NullPointerException if source or destination is {@code null}
     * @throws IOException          if source or destination is invalid
     * @throws IOException          if an IO error occurs moving the file
     * @since 1.4
     */
    public static void moveFile(final File srcFile, final File destFile) throws IOException {
        if (srcFile == null) {
            throw new NullPointerException("Source must not be null");
        }
        if (destFile == null) {
            throw new NullPointerException("Destination must not be null");
        }
        if (!srcFile.exists()) {
            throw new FileNotFoundException("Source '" + srcFile + "' does not exist");
        }
        if (srcFile.isDirectory()) {
            throw new IOException("Source '" + srcFile + "' is a directory");
        }
        if (destFile.exists()) {
            throw new IOException("Destination '" + destFile + "' already exists");
        }
        if (destFile.isDirectory()) {
            throw new IOException("Destination '" + destFile + "' is a directory");
        }
        final boolean rename = srcFile.renameTo(destFile);
        if (!rename) {
            copyFile(srcFile, destFile);
            if (!srcFile.delete()) {
                ParseFileUtils.deleteQuietly(destFile);
                throw new IOException("Failed to delete original file '" + srcFile +
                        "' after copy to '" + destFile + "'");
            }
        }
    }

    /**
     * Copies a file to a new location preserving the file date.
     * <p>
     * This method copies the contents of the specified source file to the
     * specified destination file. The directory holding the destination file is
     * created if it does not exist. If the destination file exists, then this
     * method will overwrite it.
     * <p>
     * <strong>Note:</strong> This method tries to preserve the file's last
     * modified date/times using {@link File#setLastModified(long)}, however
     * it is not guaranteed that the operation will succeed.
     * If the modification operation fails, no indication is provided.
     *
     * @param srcFile  an existing file to copy, must not be {@code null}
     * @param destFile the new file, must not be {@code null}
     * @throws NullPointerException if source or destination is {@code null}
     * @throws IOException          if source or destination is invalid
     * @throws IOException          if an IO error occurs during copying
     * @throws IOException          if the output file length is not the same as the input file length after the copy completes
     * @see #copyFile(File, File, boolean)
     */
    public static void copyFile(final File srcFile, final File destFile) throws IOException {
        copyFile(srcFile, destFile, true);
    }

    /**
     * Copies a file to a new location.
     * <p>
     * This method copies the contents of the specified source file
     * to the specified destination file.
     * The directory holding the destination file is created if it does not exist.
     * If the destination file exists, then this method will overwrite it.
     * <p>
     * <strong>Note:</strong> Setting <code>preserveFileDate</code> to
     * {@code true} tries to preserve the file's last modified
     * date/times using {@link File#setLastModified(long)}, however it is
     * not guaranteed that the operation will succeed.
     * If the modification operation fails, no indication is provided.
     *
     * @param srcFile          an existing file to copy, must not be {@code null}
     * @param destFile         the new file, must not be {@code null}
     * @param preserveFileDate true if the file date of the copy
     *                         should be the same as the original
     * @throws NullPointerException if source or destination is {@code null}
     * @throws IOException          if source or destination is invalid
     * @throws IOException          if an IO error occurs during copying
     * @throws IOException          if the output file length is not the same as the input file length after the copy completes
     * @see #doCopyFile(File, File, boolean)
     */
    public static void copyFile(final File srcFile, final File destFile,
                                final boolean preserveFileDate) throws IOException {
        if (srcFile == null) {
            throw new NullPointerException("Source must not be null");
        }
        if (destFile == null) {
            throw new NullPointerException("Destination must not be null");
        }
        if (!srcFile.exists()) {
            throw new FileNotFoundException("Source '" + srcFile + "' does not exist");
        }
        if (srcFile.isDirectory()) {
            throw new IOException("Source '" + srcFile + "' exists but is a directory");
        }
        if (srcFile.getCanonicalPath().equals(destFile.getCanonicalPath())) {
            throw new IOException("Source '" + srcFile + "' and destination '" + destFile + "' are the same");
        }
        final File parentFile = destFile.getParentFile();
        if (parentFile != null) {
            if (!parentFile.mkdirs() && !parentFile.isDirectory()) {
                throw new IOException("Destination '" + parentFile + "' directory cannot be created");
            }
        }
        if (destFile.exists() && !destFile.canWrite()) {
            throw new IOException("Destination '" + destFile + "' exists but is read-only");
        }
        doCopyFile(srcFile, destFile, preserveFileDate);
    }

    /**
     * Internal copy file method.
     * This caches the original file length, and throws an IOException
     * if the output file length is different from the current input file length.
     * So it may fail if the file changes size.
     * It may also fail with "IllegalArgumentException: Negative size" if the input file is truncated part way
     * through copying the data and the new file size is less than the current position.
     *
     * @param srcFile          the validated source file, must not be {@code null}
     * @param destFile         the validated destination file, must not be {@code null}
     * @param preserveFileDate whether to preserve the file date
     * @throws IOException              if an error occurs
     * @throws IOException              if the output file length is not the same as the input file length after the copy completes
     * @throws IllegalArgumentException "Negative size" if the file is truncated so that the size is less than the position
     */
    private static void doCopyFile(final File srcFile, final File destFile, final boolean preserveFileDate) throws IOException {
        if (destFile.exists() && destFile.isDirectory()) {
            throw new IOException("Destination '" + destFile + "' exists but is a directory");
        }

        FileInputStream fis = null;
        FileOutputStream fos = null;
        FileChannel input = null;
        FileChannel output = null;
        try {
            fis = new FileInputStream(srcFile);
            fos = new FileOutputStream(destFile);
            input = fis.getChannel();
            output = fos.getChannel();
            final long size = input.size(); // TODO See IO-386
            long pos = 0;
            long count;
            while (pos < size) {
                final long remain = size - pos;
                count = remain > FILE_COPY_BUFFER_SIZE ? FILE_COPY_BUFFER_SIZE : remain;
                final long bytesCopied = output.transferFrom(input, pos, count);
                if (bytesCopied == 0) { // IO-385 - can happen if file is truncated after caching the size
                    break; // ensure we don't loop forever
                }
                pos += bytesCopied;
            }
        } finally {
            ParseIOUtils.closeQuietly(output);
            ParseIOUtils.closeQuietly(fos);
            ParseIOUtils.closeQuietly(input);
            ParseIOUtils.closeQuietly(fis);
        }

        final long srcLen = srcFile.length(); // TODO See IO-386
        final long dstLen = destFile.length(); // TODO See IO-386
        if (srcLen != dstLen) {
            throw new IOException("Failed to copy full contents from '" +
                    srcFile + "' to '" + destFile + "' Expected length: " + srcLen + " Actual: " + dstLen);
        }
        if (preserveFileDate) {
            destFile.setLastModified(srcFile.lastModified());
        }
    }

    //-----------------------------------------------------------------------

    /**
     * Deletes a directory recursively.
     *
     * @param directory directory to delete
     * @throws IOException in case deletion is unsuccessful
     */
    public static void deleteDirectory(final File directory) throws IOException {
        if (!directory.exists()) {
            return;
        }

        if (!isSymlink(directory)) {
            cleanDirectory(directory);
        }

        if (!directory.delete()) {
            final String message =
                    "Unable to delete directory " + directory + ".";
            throw new IOException(message);
        }
    }

    /**
     * Deletes a file, never throwing an exception. If file is a directory, delete it and all sub-directories.
     * <p>
     * The difference between File.delete() and this method are:
     * <ul>
     * <li>A directory to be deleted does not have to be empty.</li>
     * <li>No exceptions are thrown when a file or directory cannot be deleted.</li>
     * </ul>
     *
     * @param file file or directory to delete, can be {@code null}
     * @return {@code true} if the file or directory was deleted, otherwise
     * {@code false}
     * @since 1.4
     */
    public static boolean deleteQuietly(final File file) {
        if (file == null) {
            return false;
        }
        try {
            if (file.isDirectory()) {
                cleanDirectory(file);
            }
        } catch (final Exception ignored) {
        }

        try {
            return file.delete();
        } catch (final Exception ignored) {
            return false;
        }
    }

    /**
     * Cleans a directory without deleting it.
     *
     * @param directory directory to clean
     * @throws IOException in case cleaning is unsuccessful
     */
    public static void cleanDirectory(final File directory) throws IOException {
        if (!directory.exists()) {
            final String message = directory + " does not exist";
            throw new IllegalArgumentException(message);
        }

        if (!directory.isDirectory()) {
            final String message = directory + " is not a directory";
            throw new IllegalArgumentException(message);
        }

        final File[] files = directory.listFiles();
        if (files == null) {  // null if security restricted
            throw new IOException("Failed to list contents of " + directory);
        }

        IOException exception = null;
        for (final File file : files) {
            try {
                forceDelete(file);
            } catch (final IOException ioe) {
                exception = ioe;
            }
        }

        if (null != exception) {
            throw exception;
        }
    }

    //-----------------------------------------------------------------------

    /**
     * Deletes a file. If file is a directory, delete it and all sub-directories.
     * <p>
     * The difference between File.delete() and this method are:
     * <ul>
     * <li>A directory to be deleted does not have to be empty.</li>
     * <li>You get exceptions when a file or directory cannot be deleted.
     * (java.io.File methods returns a boolean)</li>
     * </ul>
     *
     * @param file file or directory to delete, must not be {@code null}
     * @throws NullPointerException  if the directory is {@code null}
     * @throws FileNotFoundException if the file was not found
     * @throws IOException           in case deletion is unsuccessful
     */
    public static void forceDelete(final File file) throws IOException {
        if (file.isDirectory()) {
            deleteDirectory(file);
        } else {
            final boolean filePresent = file.exists();
            if (!file.delete()) {
                if (!filePresent) {
                    throw new FileNotFoundException("File does not exist: " + file);
                }
                final String message =
                        "Unable to delete file: " + file;
                throw new IOException(message);
            }
        }
    }

    /**
     * Determines whether the specified file is a Symbolic Link rather than an actual file.
     * <p>
     * Will not return true if there is a Symbolic Link anywhere in the path,
     * only if the specific file is.
     * <p>
     * For code that runs on Java 1.7 or later, use the following method instead:
     * <br>
     * {@code boolean java.nio.file.Files.isSymbolicLink(Path path)}
     *
     * @param file the file to check
     * @return true if the file is a Symbolic Link
     * @throws IOException if an IO error occurs while checking the file
     * @since 2.0
     */
    public static boolean isSymlink(final File file) throws IOException {
        if (file == null) {
            throw new NullPointerException("File must not be null");
        }
//    if (FilenameUtils.isSystemWindows()) {
//      return false;
//    }
        File fileInCanonicalDir;
        if (file.getParent() == null) {
            fileInCanonicalDir = file;
        } else {
            final File canonicalDir = file.getParentFile().getCanonicalFile();
            fileInCanonicalDir = new File(canonicalDir, file.getName());
        }

        return !fileInCanonicalDir.getCanonicalFile().equals(fileInCanonicalDir.getAbsoluteFile());
    }

    //region String

    public static String readFileToString(File file, Charset encoding) throws IOException {
        return new String(readFileToByteArray(file), encoding);
    }

    public static String readFileToString(File file, String encoding) throws IOException {
        return readFileToString(file, Charset.forName(encoding));
    }

    public static void writeStringToFile(File file, String string, Charset encoding)
            throws IOException {
        writeByteArrayToFile(file, string.getBytes(encoding));
    }

    public static void writeStringToFile(File file, String string, String encoding)
            throws IOException {
        writeStringToFile(file, string, Charset.forName(encoding));
    }

    //endregion

    //region JSONObject

    /**
     * Reads the contents of a file into a {@link JSONObject}. The file is always closed.
     */
    public static JSONObject readFileToJSONObject(File file) throws IOException, JSONException {
        String content = readFileToString(file, "UTF-8");
        return new JSONObject(content);
    }

    /**
     * Writes a {@link JSONObject} to a file creating the file if it does not exist.
     */
    public static void writeJSONObjectToFile(File file, JSONObject json) throws IOException {
        ParseFileUtils.writeByteArrayToFile(file, json.toString().getBytes(Charset.forName("UTF-8")));
    }

    //endregion
}