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* version 2 for more details (a copy is included in the LICENSE file that
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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;
}
}