private static boolean extractAndLoadLibraryFile()

in native/src/main/java/org/mvndaemon/mvnd/nativ/MvndNativeLoader.java [161:215]
43 lines of code
5 McCabe index (conditional complexity)

    private static boolean extractAndLoadLibraryFile(
            String libFolderForCurrentOS, String libraryFileName, String targetFolder) {
        String nativeLibraryFilePath = libFolderForCurrentOS + "/" + libraryFileName;
        // Include architecture name in temporary filename in order to avoid conflicts
        // when multiple JVMs with different architectures running at the same time
        String uuid = randomUUID();
        String extractedLibFileName = String.format("mvndnative-%s-%s-%s", getVersion(), uuid, libraryFileName);
        String extractedLckFileName = extractedLibFileName + ".lck";

        File extractedLibFile = new File(targetFolder, extractedLibFileName);
        File extractedLckFile = new File(targetFolder, extractedLckFileName);

        try {
            // Extract a native library file into the target directory
            try (InputStream in = MvndNativeLoader.class.getResourceAsStream(nativeLibraryFilePath)) {
                if (!extractedLckFile.exists()) {
                    new FileOutputStream(extractedLckFile).close();
                }
                try (OutputStream out = new FileOutputStream(extractedLibFile)) {
                    copy(in, out);
                }
            } finally {
                // Delete the extracted lib file on JVM exit.
                extractedLibFile.deleteOnExit();
                extractedLckFile.deleteOnExit();
            }

            // Set executable (x) flag to enable Java to load the native library
            extractedLibFile.setReadable(true);
            extractedLibFile.setWritable(true);
            extractedLibFile.setExecutable(true);

            // Check whether the contents are properly copied from the resource folder
            try (InputStream nativeIn = MvndNativeLoader.class.getResourceAsStream(nativeLibraryFilePath)) {
                try (InputStream extractedLibIn = new FileInputStream(extractedLibFile)) {
                    String eq = contentsEquals(nativeIn, extractedLibIn);
                    if (eq != null) {
                        throw new RuntimeException(String.format(
                                "Failed to write a native library file at %s because %s", extractedLibFile, eq));
                    }
                }
            }

            // Load library
            if (loadNativeLibrary(extractedLibFile)) {
                nativeLibrarySourceUrl = MvndNativeLoader.class
                        .getResource(nativeLibraryFilePath)
                        .toExternalForm();
                return true;
            }
        } catch (IOException e) {
            System.err.println(e.getMessage());
        }
        return false;
    }