private void scandir()

in src/main/org/apache/tools/ant/DirectoryScanner.java [1201:1294]
84 lines of code
27 McCabe index (conditional complexity)

    private void scandir(final File dir, final TokenizedPath path, final boolean fast,
                         String[] newFiles, final Deque<String> directoryNamesFollowed) {
        String vpath = path.toString();
        if (!vpath.isEmpty() && !vpath.endsWith(File.separator)) {
            vpath += File.separator;
        }

        // avoid double scanning of directories, can only happen in fast mode
        if (fast && hasBeenScanned(vpath)) {
            return;
        }
        if (!followSymlinks) {
            final ArrayList<String> noLinks = new ArrayList<>();
            for (final String newFile : newFiles) {
                final Path filePath;
                if (dir == null) {
                    filePath = Paths.get(newFile);
                } else {
                    filePath = Paths.get(dir.toPath().toString(), newFile);
                }
                if (Files.isSymbolicLink(filePath)) {
                    final String name = vpath + newFile;
                    final File file = new File(dir, newFile);
                    if (file.isDirectory()) {
                        dirsExcluded.addElement(name);
                    } else if (file.isFile()) {
                        filesExcluded.addElement(name);
                    }
                    accountForNotFollowedSymlink(name, file);
                } else {
                    noLinks.add(newFile);
                }
            }
            newFiles = noLinks.toArray(new String[0]);
        } else {
            directoryNamesFollowed.addFirst(dir.getName());
        }

        for (String newFile : newFiles) {
            final String name = vpath + newFile;
            final TokenizedPath newPath = new TokenizedPath(path, newFile);
            final File file = new File(dir, newFile);
            final String[] children;

            // don't invoke file.list() if we know we never use the children
            if (fast // slow scan scans everything anyway
                && file.isDirectory() // otherwise we need list() to know whether this is a directory
                && !scanDuringFastScan(newPath) // otherwise we'd invoke scandir
                ) {
                children = new String[0];
            } else {
                children = file.list();
            }

            if (children == null || (children.length == 0 && file.isFile())) {
                if (isIncluded(newPath)) {
                    accountForIncludedFile(newPath, file);
                } else {
                    everythingIncluded = false;
                    filesNotIncluded.addElement(name);
                }
            } else if (file.isDirectory()) { // dir

                if (followSymlinks
                        && causesIllegalSymlinkLoop(newFile, dir, directoryNamesFollowed)) {
                    // will be caught and redirected to Ant's logging system
                    System.err.println("skipping symbolic link "
                                       + file.getAbsolutePath()
                                       + " -- too many levels of symbolic"
                                       + " links.");
                    notFollowedSymlinks.add(file.getAbsolutePath());
                    continue;
                }

                if (isIncluded(newPath)) {
                    accountForIncludedDir(newPath, file, fast, children,
                                          directoryNamesFollowed);
                } else {
                    everythingIncluded = false;
                    dirsNotIncluded.addElement(name);
                    if (fast && scanDuringFastScan(newPath)) {
                        scandir(file, newPath, fast, children, directoryNamesFollowed);
                    }
                }
                if (!fast) {
                    scandir(file, newPath, fast, children, directoryNamesFollowed);
                }
            }
        }

        if (followSymlinks) {
            directoryNamesFollowed.removeFirst();
        }
    }