84 lines
3.5 KiB
Java
84 lines
3.5 KiB
Java
/*
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* This file is part of BlueMap, licensed under the MIT License (MIT).
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*
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* Copyright (c) Blue (Lukas Rieger) <https://bluecolored.de>
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* Copyright (c) contributors
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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package de.bluecolored.bluemap.core.util;
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import de.bluecolored.bluemap.core.util.stream.OnCloseOutputStream;
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import java.io.FileNotFoundException;
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import java.io.IOException;
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import java.io.OutputStream;
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import java.nio.file.*;
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import java.nio.file.attribute.FileAttribute;
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public class FileHelper {
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/**
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* Creates an OutputStream that writes to a ".filepart"-file first and then atomically moves (overwrites) to the final target atomically
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* once the stream gets closed.
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*/
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public static OutputStream createFilepartOutputStream(final Path file) throws IOException {
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final Path partFile = getPartFile(file);
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FileHelper.createDirectories(partFile.getParent());
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OutputStream os = Files.newOutputStream(partFile, StandardOpenOption.WRITE, StandardOpenOption.TRUNCATE_EXISTING, StandardOpenOption.CREATE);
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return new OnCloseOutputStream(os, () -> {
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if (!Files.exists(partFile)) return;
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FileHelper.createDirectories(file.getParent());
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FileHelper.move(partFile, file);
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});
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}
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/**
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* Tries to move the file atomically, but fallbacks to a normal move operation if moving atomically fails
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*/
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public static void move(Path from, Path to) throws IOException {
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try {
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Files.move(from, to, StandardCopyOption.ATOMIC_MOVE, StandardCopyOption.REPLACE_EXISTING);
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} catch (FileNotFoundException | NoSuchFileException ignore) {
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} catch (IOException ex) {
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try {
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Files.move(from, to, StandardCopyOption.REPLACE_EXISTING);
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} catch (FileNotFoundException | NoSuchFileException ignore) {
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} catch (Throwable t) {
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t.addSuppressed(ex);
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throw t;
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}
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}
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}
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/**
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* Same as {@link Files#createDirectories(Path, FileAttribute[])} but accepts symlinked folders.
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* @see Files#createDirectories(Path, FileAttribute[])
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*/
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public static Path createDirectories(Path dir, FileAttribute<?>... attrs) throws IOException {
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if (Files.isDirectory(dir)) return dir;
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return Files.createDirectories(dir, attrs);
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}
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private static Path getPartFile(Path file) {
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return file.normalize().getParent().resolve(file.getFileName() + ".filepart");
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}
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}
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