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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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package jdk.internal.module;

import java.io.File;
import java.io.IOException;
import java.nio.file.FileSystem;
import java.nio.file.Files;
import java.nio.file.NoSuchFileException;
import java.nio.file.Path;
import java.nio.file.attribute.BasicFileAttributes;

A helper class to support working with resources in modules. Also provides support for translating resource names to file paths.
/** * A helper class to support working with resources in modules. Also provides * support for translating resource names to file paths. */
public final class Resources { private Resources() { }
Return true if a resource can be encapsulated. Resource with names ending in ".class" or "/" cannot be encapsulated. Resource names that map to a legal package name can be encapsulated.
/** * Return true if a resource can be encapsulated. Resource with names * ending in ".class" or "/" cannot be encapsulated. Resource names * that map to a legal package name can be encapsulated. */
public static boolean canEncapsulate(String name) { int len = name.length(); if (len > 6 && name.endsWith(".class")) { return false; } else { return Checks.isPackageName(toPackageName(name)); } }
Derive a package name for a resource. The package name returned by this method may not be a legal package name. This method returns null if the resource name ends with a "/" (a directory) or the resource name does not contain a "/".
/** * Derive a <em>package name</em> for a resource. The package name * returned by this method may not be a legal package name. This method * returns null if the resource name ends with a "/" (a directory) * or the resource name does not contain a "/". */
public static String toPackageName(String name) { int index = name.lastIndexOf('/'); if (index == -1 || index == name.length()-1) { return ""; } else { return name.substring(0, index).replace('/', '.'); } }
Returns a resource name corresponding to the relative file path between dir and file. If the file is a directory then the name will end with a "/", except the top-level directory where the empty string is returned.
/** * Returns a resource name corresponding to the relative file path * between {@code dir} and {@code file}. If the file is a directory * then the name will end with a "/", except the top-level directory * where the empty string is returned. */
public static String toResourceName(Path dir, Path file) { String s = dir.relativize(file) .toString() .replace(File.separatorChar, '/'); if (!s.isEmpty() && Files.isDirectory(file)) s += "/"; return s; }
Returns a file path to a resource in a file tree. If the resource name has a trailing "/" then the file path will locate a directory. Returns null if the resource does not map to a file in the tree file.
/** * Returns a file path to a resource in a file tree. If the resource * name has a trailing "/" then the file path will locate a directory. * Returns {@code null} if the resource does not map to a file in the * tree file. */
public static Path toFilePath(Path dir, String name) throws IOException { boolean expectDirectory = name.endsWith("/"); if (expectDirectory) { name = name.substring(0, name.length() - 1); // drop trailing "/" } Path path = toSafeFilePath(dir.getFileSystem(), name); if (path != null) { Path file = dir.resolve(path); try { BasicFileAttributes attrs; attrs = Files.readAttributes(file, BasicFileAttributes.class); if (attrs.isDirectory() || (!attrs.isDirectory() && !expectDirectory)) return file; } catch (NoSuchFileException ignore) { } } return null; }
Map a resource name to a "safe" file path. Returns null if the resource name cannot be converted into a "safe" file path. Resource names with empty elements, or elements that are "." or ".." are rejected, as are resource names that translates to a file path with a root component.
/** * Map a resource name to a "safe" file path. Returns {@code null} if * the resource name cannot be converted into a "safe" file path. * * Resource names with empty elements, or elements that are "." or ".." * are rejected, as are resource names that translates to a file path * with a root component. */
private static Path toSafeFilePath(FileSystem fs, String name) { // scan elements of resource name int next; int off = 0; while ((next = name.indexOf('/', off)) != -1) { int len = next - off; if (!mayTranslate(name, off, len)) { return null; } off = next + 1; } int rem = name.length() - off; if (!mayTranslate(name, off, rem)) { return null; } // convert to file path Path path; if (File.separatorChar == '/') { path = fs.getPath(name); } else { // not allowed to embed file separators if (name.contains(File.separator)) return null; path = fs.getPath(name.replace('/', File.separatorChar)); } // file path not allowed to have root component return (path.getRoot() == null) ? path : null; }
Returns true if the element in a resource name is a candidate to translate to the element of a file path.
/** * Returns {@code true} if the element in a resource name is a candidate * to translate to the element of a file path. */
private static boolean mayTranslate(String name, int off, int len) { if (len <= 2) { if (len == 0) return false; boolean starsWithDot = (name.charAt(off) == '.'); if (len == 1 && starsWithDot) return false; if (len == 2 && starsWithDot && (name.charAt(off+1) == '.')) return false; } return true; } }