155 lines
5.4 KiB
Java
155 lines
5.4 KiB
Java
/*
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* Class NativeUtils is published under the The MIT License:
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*
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* Copyright (c) 2012 Adam Heinrich <adam@adamh.cz>
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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 all
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* 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 THE
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* SOFTWARE.
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*/
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package cz.adamh.utils;
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import java.io.File;
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import java.io.FileNotFoundException;
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import java.io.IOException;
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import java.io.InputStream;
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import java.nio.file.FileSystemNotFoundException;
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import java.nio.file.FileSystems;
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import java.nio.file.Files;
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import java.nio.file.ProviderNotFoundException;
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import java.nio.file.StandardCopyOption;
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/**
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* A simple library class which helps with loading dynamic libraries stored in
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* the
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* JAR archive. These libraries usualy contain implementation of some methods in
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* native code (using JNI - Java Native Interface).
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*
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* @see http://adamheinrich.com/blog/2012/how-to-load-native-jni-library-from-jar
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* @see https://github.com/adamheinrich/native-utils
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*
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*/
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public class NativeUtils {
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/**
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* The minimum length a prefix for a file has to have according to
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* {@link File#createTempFile(String, String)}}.
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*/
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private static final int MIN_PREFIX_LENGTH = 3;
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/**
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* Temporary directory which will contain the DLLs.
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*/
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private static File temporaryDir;
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/**
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* Private constructor - this class will never be instanced
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*/
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private NativeUtils() {}
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/**
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* Loads library from current JAR archive
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*
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* The file from JAR is copied into system temporary directory and then
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* loaded. The temporary file is deleted after
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* exiting.
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* Method uses String as filename because the pathname is "abstract", not
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* system-dependent.
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*
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* @param path
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* The path of file inside JAR as absolute path (beginning with
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* '/'), e.g. /package/File.ext
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* @throws IOException
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* If temporary file creation or read/write operation fails
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* @throws IllegalArgumentException
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* If source file (param path) does not exist
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* @throws IllegalArgumentException
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* If the path is not absolute or if the filename is shorter
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* than three characters
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* (restriction of
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* {@link File#createTempFile(java.lang.String, java.lang.String)}).
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* @throws FileNotFoundException
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* If the file could not be found inside the JAR.
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*/
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public static void loadLibraryFromJar(String path) throws IOException {
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if (!path.startsWith("/")) {
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throw new IllegalArgumentException("The path has to be absolute (start with '/').");
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}
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// Obtain filename from path
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final String[] parts = path.split("/");
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final String filename = (parts.length > 1) ? parts[parts.length - 1] : null;
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// Check if the filename is okay
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if (filename == null || filename.length() < MIN_PREFIX_LENGTH) {
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throw new IllegalArgumentException("The filename has to be at least 3 characters long.");
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}
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// Prepare temporary file
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if (temporaryDir == null) {
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temporaryDir = createTempDirectory("nativeutils");
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temporaryDir.deleteOnExit();
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}
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final File temp = new File(temporaryDir, filename);
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try (InputStream is = NativeUtils.class.getResourceAsStream(path)) {
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Files.copy(is, temp.toPath(), StandardCopyOption.REPLACE_EXISTING);
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} catch (final IOException e) {
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temp.delete();
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throw e;
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} catch (final NullPointerException e) {
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temp.delete();
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throw new FileNotFoundException("File " + path + " was not found inside JAR.");
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}
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try {
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System.load(temp.getAbsolutePath());
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} finally {
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if (isPosixCompliant()) {
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// Assume POSIX compliant file system, can be deleted after loading
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temp.delete();
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} else {
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// Assume non-POSIX, and don't delete until last file descriptor closed
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temp.deleteOnExit();
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}
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}
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}
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private static boolean isPosixCompliant() {
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try {
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if (FileSystems.getDefault().supportedFileAttributeViews().contains("posix")) {
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return true;
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}
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return false;
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} catch (FileSystemNotFoundException | ProviderNotFoundException | SecurityException e) {
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return false;
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}
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}
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private static File createTempDirectory(String prefix) throws IOException {
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final String tempDir = System.getProperty("java.io.tmpdir");
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final File generatedDir = new File(tempDir, prefix + System.nanoTime());
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if (!generatedDir.mkdir()) {
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throw new IOException("Failed to create temp directory " + generatedDir.getName());
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}
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return generatedDir;
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}
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} |