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| 1 | +/* |
| 2 | + * Class NativeUtils is published under the The MIT License: |
| 3 | + * |
| 4 | + * Copyright (c) 2012 Adam Heinrich <[email protected]> |
| 5 | + * |
| 6 | + * Permission is hereby granted, free of charge, to any person obtaining a copy |
| 7 | + * of this software and associated documentation files (the "Software"), to deal |
| 8 | + * in the Software without restriction, including without limitation the rights |
| 9 | + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
| 10 | + * copies of the Software, and to permit persons to whom the Software is |
| 11 | + * furnished to do so, subject to the following conditions: |
| 12 | + * |
| 13 | + * The above copyright notice and this permission notice shall be included in all |
| 14 | + * copies or substantial portions of the Software. |
| 15 | + * |
| 16 | + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| 17 | + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| 18 | + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
| 19 | + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| 20 | + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
| 21 | + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE |
| 22 | + * SOFTWARE. |
| 23 | + */ |
| 24 | +package go; |
| 25 | + |
| 26 | +import java.io.*; |
| 27 | +import java.nio.file.FileSystemNotFoundException; |
| 28 | +import java.nio.file.FileSystems; |
| 29 | +import java.nio.file.Files; |
| 30 | +import java.nio.file.ProviderNotFoundException; |
| 31 | +import java.nio.file.StandardCopyOption; |
| 32 | + |
| 33 | +/** |
| 34 | + * A simple library class which helps with loading dynamic libraries stored in the |
| 35 | + * JAR archive. These libraries usually contain implementation of some methods in |
| 36 | + * native code (using JNI - Java Native Interface). |
| 37 | + * |
| 38 | + * @see <a href="http://adamheinrich.com/blog/2012/how-to-load-native-jni-library-from-jar">http://adamheinrich.com/blog/2012/how-to-load-native-jni-library-from-jar</a> |
| 39 | + * @see <a href="https://github.com/adamheinrich/native-utils">https://github.com/adamheinrich/native-utils</a> |
| 40 | + * |
| 41 | + */ |
| 42 | +public class NativeUtils { |
| 43 | + |
| 44 | + /** |
| 45 | + * The minimum length a prefix for a file has to have according to {@link File#createTempFile(String, String)}}. |
| 46 | + */ |
| 47 | + private static final int MIN_PREFIX_LENGTH = 3; |
| 48 | + public static final String NATIVE_FOLDER_PATH_PREFIX = "nativeutils"; |
| 49 | + |
| 50 | + /** |
| 51 | + * Temporary directory which will contain the DLLs. |
| 52 | + */ |
| 53 | + private static File temporaryDir; |
| 54 | + |
| 55 | + /** |
| 56 | + * Private constructor - this class will never be instanced |
| 57 | + */ |
| 58 | + private NativeUtils() { |
| 59 | + } |
| 60 | + |
| 61 | + /** |
| 62 | + * Loads library from current JAR archive |
| 63 | + * |
| 64 | + * The file from JAR is copied into system temporary directory and then loaded. The temporary file is deleted after |
| 65 | + * exiting. |
| 66 | + * Method uses String as filename because the pathname is "abstract", not system-dependent. |
| 67 | + * |
| 68 | + * @param path The path of file inside JAR as absolute path (beginning with '/'), e.g. /package/File.ext |
| 69 | + * @throws IOException If temporary file creation or read/write operation fails |
| 70 | + * @throws IllegalArgumentException If source file (param path) does not exist |
| 71 | + * @throws IllegalArgumentException If the path is not absolute or if the filename is shorter than three characters |
| 72 | + * (restriction of {@link File#createTempFile(java.lang.String, java.lang.String)}). |
| 73 | + * @throws FileNotFoundException If the file could not be found inside the JAR. |
| 74 | + */ |
| 75 | + public static void loadLibraryFromJar(String path) throws IOException { |
| 76 | + |
| 77 | + if (null == path || !path.startsWith("/")) { |
| 78 | + throw new IllegalArgumentException("The path has to be absolute (start with '/')."); |
| 79 | + } |
| 80 | + |
| 81 | + // Obtain filename from path |
| 82 | + String[] parts = path.split("/"); |
| 83 | + String filename = (parts.length > 1) ? parts[parts.length - 1] : null; |
| 84 | + |
| 85 | + // Check if the filename is okay |
| 86 | + if (filename == null || filename.length() < MIN_PREFIX_LENGTH) { |
| 87 | + throw new IllegalArgumentException("The filename has to be at least 3 characters long."); |
| 88 | + } |
| 89 | + |
| 90 | + // Prepare temporary file |
| 91 | + if (temporaryDir == null) { |
| 92 | + temporaryDir = createTempDirectory(NATIVE_FOLDER_PATH_PREFIX); |
| 93 | + temporaryDir.deleteOnExit(); |
| 94 | + } |
| 95 | + |
| 96 | + File temp = new File(temporaryDir, filename); |
| 97 | + |
| 98 | + try (InputStream is = NativeUtils.class.getResourceAsStream(path)) { |
| 99 | + Files.copy(is, temp.toPath(), StandardCopyOption.REPLACE_EXISTING); |
| 100 | + } catch (IOException e) { |
| 101 | + temp.delete(); |
| 102 | + throw e; |
| 103 | + } catch (NullPointerException e) { |
| 104 | + temp.delete(); |
| 105 | + throw new FileNotFoundException("File " + path + " was not found inside JAR."); |
| 106 | + } |
| 107 | + |
| 108 | + try { |
| 109 | + System.load(temp.getAbsolutePath()); |
| 110 | + } finally { |
| 111 | + if (isPosixCompliant()) { |
| 112 | + // Assume POSIX compliant file system, can be deleted after loading |
| 113 | + temp.delete(); |
| 114 | + } else { |
| 115 | + // Assume non-POSIX, and don't delete until last file descriptor closed |
| 116 | + temp.deleteOnExit(); |
| 117 | + } |
| 118 | + } |
| 119 | + } |
| 120 | + |
| 121 | + private static boolean isPosixCompliant() { |
| 122 | + try { |
| 123 | + return FileSystems.getDefault() |
| 124 | + .supportedFileAttributeViews() |
| 125 | + .contains("posix"); |
| 126 | + } catch (FileSystemNotFoundException |
| 127 | + | ProviderNotFoundException |
| 128 | + | SecurityException e) { |
| 129 | + return false; |
| 130 | + } |
| 131 | + } |
| 132 | + |
| 133 | + private static File createTempDirectory(String prefix) throws IOException { |
| 134 | + String tempDir = System.getProperty("java.io.tmpdir"); |
| 135 | + File generatedDir = new File(tempDir, prefix + System.nanoTime()); |
| 136 | + |
| 137 | + if (!generatedDir.mkdir()) |
| 138 | + throw new IOException("Failed to create temp directory " + generatedDir.getName()); |
| 139 | + |
| 140 | + return generatedDir; |
| 141 | + } |
| 142 | +} |
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