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add Files walk alternative without AccessDeniedException

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This commit is contained in:
Jörg Prante 2023-11-20 16:59:34 +01:00
parent 720640f8aa
commit 94cea9ae79
6 changed files with 101 additions and 147 deletions
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1
files-api/src/main/java/module-info.java
View file

@ -5,4 +5,5 @@ module org.xbib.files {
exports org.xbib.files;
uses FileServiceProvider;
provides FileServiceProvider with DefaultFileServiceProvider;
requires java.logging;
}

27
files-api/src/main/java/org/xbib/files/FileService.java
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@ -18,6 +18,8 @@ import java.util.Objects;
import java.util.Optional;
import java.util.ServiceLoader;
import java.util.Set;
import java.util.logging.Level;
import java.util.logging.Logger;
import java.util.stream.Stream;
public interface FileService {
@ -115,4 +117,29 @@ public interface FileService {
Stream<Path> walk(String path, FileVisitOption... options) throws IOException;
Stream<Path> walk(String path, int maxdepth, FileVisitOption... options) throws IOException;
/**
* Replacement for Files.walk() without AccessDeniedException.
* @param p the path
* @return a stream of readable files under the path
*/
static Stream<Path> walk(Path p) {
if (Files.isReadable(p)) {
if (Files.isDirectory(p)) {
try (Stream<Path> stream = Files.list(p)) {
return stream.flatMap(FileService::walk);
} catch (IOException e) {
Logger.getLogger(FileService.class.getName())
.log(Level.FINE,"skipped " + p + " because of " + e.getMessage());
return Stream.empty();
}
} else {
return Stream.of(p);
}
} else {
Logger.getLogger(FileService.class.getName())
.log(Level.WARNING, "unreadable: " + p);
}
return Stream.empty();
}
}

25
files-api/src/main/java/org/xbib/files/FileTreeIterator.java
View file

@ -12,7 +12,6 @@ import org.xbib.files.FileTreeWalker.Event;
/**
* This source is a copy taken from java.nio.file.FileTreeIterator which is inaccessible.
*
* An {@code Iterator} to iterate over the nodes of a file tree.
*
* <pre>{@code
@ -27,7 +26,9 @@ import org.xbib.files.FileTreeWalker.Event;
*/
class FileTreeIterator implements Iterator<Event>, Closeable {
private final FileTreeWalker walker;
private Event next;
/**
@ -37,21 +38,15 @@ class FileTreeIterator implements Iterator<Event>, Closeable {
* if {@code maxDepth} is negative
* @throws IOException
* if an I/O errors occurs opening the starting file
* @throws SecurityException
* if the security manager denies access to the starting file
* @throws NullPointerException
* if {@code start} or {@code options} is {@code null} or
* the options array contains a {@code null} element
*/
FileTreeIterator(Path start, int maxDepth, FileVisitOption... options)
throws IOException
{
FileTreeIterator(Path start, int maxDepth, FileVisitOption... options) throws IOException {
this.walker = new FileTreeWalker(Arrays.asList(options), maxDepth);
this.next = walker.walk(start);
assert next.type() == FileTreeWalker.EventType.ENTRY ||
next.type() == FileTreeWalker.EventType.START_DIRECTORY;
// IOException if there a problem accessing the starting file
IOException ioe = next.ioeException();
if (ioe != null)
throw ioe;
@ -62,10 +57,9 @@ class FileTreeIterator implements Iterator<Event>, Closeable {
FileTreeWalker.Event ev = walker.next();
while (ev != null) {
IOException ioe = ev.ioeException();
if (ioe != null)
if (ioe != null) {
throw new UncheckedIOException(ioe);
// END_DIRECTORY events are ignored
}
if (ev.type() != FileTreeWalker.EventType.END_DIRECTORY) {
next = ev;
return;
@ -77,19 +71,22 @@ class FileTreeIterator implements Iterator<Event>, Closeable {
@Override
public boolean hasNext() {
if (!walker.isOpen())
if (!walker.isOpen()) {
throw new IllegalStateException();
}
fetchNextIfNeeded();
return next != null;
}
@Override
public Event next() {
if (!walker.isOpen())
if (!walker.isOpen()) {
throw new IllegalStateException();
}
fetchNextIfNeeded();
if (next == null)
if (next == null) {
throw new NoSuchElementException();
}
Event result = next;
next = null;
return result;

172
files-api/src/main/java/org/xbib/files/FileTreeWalker.java
View file

@ -12,11 +12,12 @@ import java.io.Closeable;
import java.io.IOException;
import java.util.ArrayDeque;
import java.util.Collection;
import java.util.Deque;
import java.util.Iterator;
import java.util.Objects;
/**
* This source is a copy taken from java.nio.file.FileTreeWalker which is inaccessible.
*
* Walks a file tree, generating a sequence of events corresponding to the files
* in the tree.
*
@ -38,10 +39,11 @@ import java.util.Iterator;
*/
class FileTreeWalker implements Closeable {
private final boolean followLinks;
private final LinkOption[] linkOptions;
private final int maxDepth;
private final ArrayDeque<DirectoryNode> stack = new ArrayDeque<>();
private final Deque<DirectoryNode> stack = new ArrayDeque<>();
private boolean closed;
/**
@ -89,7 +91,7 @@ class FileTreeWalker implements Closeable {
/**
* The event types.
*/
static enum EventType {
enum EventType {
/**
* Start of a directory
*/
@ -109,13 +111,13 @@ class FileTreeWalker implements Closeable {
*/
static class Event {
private final EventType type;
private final Path file;
private final Path path;
private final BasicFileAttributes attrs;
private final IOException ioe;
private Event(EventType type, Path file, BasicFileAttributes attrs, IOException ioe) {
private Event(EventType type, Path path, BasicFileAttributes attrs, IOException ioe) {
this.type = type;
this.file = file;
this.path = path;
this.attrs = attrs;
this.ioe = ioe;
}
@ -132,8 +134,8 @@ class FileTreeWalker implements Closeable {
return type;
}
Path file() {
return file;
Path path() {
return path;
}
BasicFileAttributes attributes() {
@ -161,18 +163,17 @@ class FileTreeWalker implements Closeable {
boolean fl = false;
for (FileVisitOption option: options) {
// will throw NPE if options contains null
switch (option) {
case FOLLOW_LINKS : fl = true; break;
default:
throw new AssertionError("Should not get here");
if (Objects.requireNonNull(option) == FileVisitOption.FOLLOW_LINKS) {
fl = true;
} else {
throw new AssertionError("Should not get here");
}
}
if (maxDepth < 0)
throw new IllegalArgumentException("'maxDepth' is negative");
this.followLinks = fl;
this.linkOptions = (fl) ? new LinkOption[0] :
new LinkOption[] { LinkOption.NOFOLLOW_LINKS };
this.linkOptions = (fl) ? new LinkOption[0] : new LinkOption[] { LinkOption.NOFOLLOW_LINKS };
this.maxDepth = maxDepth;
}
@ -181,22 +182,18 @@ class FileTreeWalker implements Closeable {
* the walk is following sym links is not. The {@code canUseCached}
* argument determines whether this method can use cached attributes.
*/
private BasicFileAttributes getAttributes(Path file, boolean canUseCached)
throws IOException
{
private BasicFileAttributes getAttributes(Path file)
throws IOException {
// attempt to get attributes of file. If fails and we are following
// links then a link target might not exist so get attributes of link
BasicFileAttributes attrs;
try {
attrs = Files.readAttributes(file, BasicFileAttributes.class, linkOptions);
} catch (IOException ioe) {
if (!followLinks)
if (!followLinks) {
throw ioe;
// attempt to get attrmptes without following links
attrs = Files.readAttributes(file,
BasicFileAttributes.class,
LinkOption.NOFOLLOW_LINKS);
}
attrs = Files.readAttributes(file, BasicFileAttributes.class, LinkOption.NOFOLLOW_LINKS);
}
return attrs;
}
@ -232,70 +229,39 @@ class FileTreeWalker implements Closeable {
/**
* Visits the given file, returning the {@code Event} corresponding to that
* visit.
*
* The {@code ignoreSecurityException} parameter determines whether
* any SecurityException should be ignored or not. If a SecurityException
* is thrown, and is ignored, then this method returns {@code null} to
* mean that there is no event corresponding to a visit to the file.
*
* The {@code canUseCached} parameter determines whether cached attributes
* for the file can be used or not.
*/
private Event visit(Path entry, boolean ignoreSecurityException, boolean canUseCached) {
// need the file attributes
private Event visit(Path entry) {
BasicFileAttributes attrs;
try {
attrs = getAttributes(entry, canUseCached);
attrs = getAttributes(entry);
} catch (IOException ioe) {
return new Event(EventType.ENTRY, entry, ioe);
} catch (SecurityException se) {
if (ignoreSecurityException)
return null;
throw se;
}
// at maximum depth or file is not a directory
int depth = stack.size();
if (depth >= maxDepth || !attrs.isDirectory()) {
return new Event(EventType.ENTRY, entry, attrs);
}
// check for cycles when following links
if (followLinks && wouldLoop(entry, attrs.fileKey())) {
return new Event(EventType.ENTRY, entry,
new FileSystemLoopException(entry.toString()));
return new Event(EventType.ENTRY, entry, new FileSystemLoopException(entry.toString()));
}
// file is a directory, attempt to open it
DirectoryStream<Path> stream = null;
DirectoryStream<Path> stream;
try {
stream = Files.newDirectoryStream(entry);
} catch (IOException ioe) {
return new Event(EventType.ENTRY, entry, ioe);
} catch (SecurityException se) {
if (ignoreSecurityException)
return null;
throw se;
}
// push a directory node to the stack and return an event
stack.push(new DirectoryNode(entry, attrs.fileKey(), stream));
return new Event(EventType.START_DIRECTORY, entry, attrs);
}
/**
* Start walking from the given file.
*/
Event walk(Path file) {
if (closed)
if (closed) {
throw new IllegalStateException("Closed");
Event ev = visit(file,
false, // ignoreSecurityException
false); // canUseCached
assert ev != null;
return ev;
}
return visit(file);
}
/**
@ -304,51 +270,35 @@ class FileTreeWalker implements Closeable {
*/
Event next() {
DirectoryNode top = stack.peek();
if (top == null)
return null; // stack is empty, we are done
// continue iteration of the directory at the top of the stack
Event ev;
do {
Path entry = null;
IOException ioe = null;
// get next entry in the directory
if (!top.skipped()) {
Iterator<Path> iterator = top.iterator();
try {
if (iterator.hasNext()) {
entry = iterator.next();
}
} catch (DirectoryIteratorException x) {
ioe = x.getCause();
if (top == null) {
return null;
}
Path entry = null;
IOException ioe = null;
if (!top.skipped()) {
Iterator<Path> iterator = top.iterator();
try {
if (iterator.hasNext()) {
entry = iterator.next();
}
} catch (DirectoryIteratorException x) {
ioe = x.getCause();
}
}
if (entry == null) {
try {
top.stream().close();
} catch (IOException e) {
if (ioe == null) {
ioe = e;
} else {
ioe.addSuppressed(e);
}
}
// no next entry so close and pop directory,
// creating corresponding event
if (entry == null) {
try {
top.stream().close();
} catch (IOException e) {
if (ioe == null) {
ioe = e;
} else {
ioe.addSuppressed(e);
}
}
stack.pop();
return new Event(EventType.END_DIRECTORY, top.directory(), ioe);
}
// visit the entry
ev = visit(entry,
true, // ignoreSecurityException
true); // canUseCached
} while (ev == null);
return ev;
stack.pop();
return new Event(EventType.END_DIRECTORY, top.directory(), ioe);
}
return visit(entry);
}
/**
@ -362,17 +312,9 @@ class FileTreeWalker implements Closeable {
DirectoryNode node = stack.pop();
try {
node.stream().close();
} catch (IOException ignore) { }
}
}
/**
* Skips the remaining entries in the directory at the top of the stack.
* This method is a no-op if the stack is empty or the walker is closed.
*/
void skipRemainingSiblings() {
if (!stack.isEmpty()) {
stack.peek().skip();
} catch (IOException ignore) {
// ignore
}
}
}

21
files-api/src/main/java/org/xbib/files/FileWalker.java
View file

@ -7,7 +7,6 @@ import java.nio.file.DirectoryIteratorException;
import java.nio.file.DirectoryStream;
import java.nio.file.FileSystemLoopException;
import java.nio.file.FileVisitOption;
import java.nio.file.Files;
import java.nio.file.NotDirectoryException;
import java.nio.file.Path;
import java.nio.file.attribute.BasicFileAttributes;
@ -64,10 +63,6 @@ public class FileWalker {
* a directory <i>(optional specific exception)</i>
* @throws IOException
* if an I/O error occurs when opening the directory
* @throws SecurityException
* In the case of the default provider, and a security manager is
* installed, the {@link SecurityManager#checkRead(String) checkRead}
* method is invoked to check read access to the directory.
*/
public static Stream<Path> list(DirectoryStream<Path> ds) throws IOException {
try {
@ -90,10 +85,8 @@ public class FileWalker {
}
}
};
Spliterator<Path> spliterator =
Spliterators.spliteratorUnknownSize(iterator, Spliterator.DISTINCT);
return StreamSupport.stream(spliterator, false)
.onClose(asUncheckedRunnable(ds));
Spliterator<Path> spliterator = Spliterators.spliteratorUnknownSize(iterator, Spliterator.DISTINCT);
return StreamSupport.stream(spliterator, false).onClose(asUncheckedRunnable(ds));
} catch (Error|RuntimeException e) {
try {
ds.close();
@ -179,11 +172,6 @@ public class FileWalker {
*
* @throws IllegalArgumentException
* if the {@code maxDepth} parameter is negative
* @throws SecurityException
* If the security manager denies access to the starting file.
* In the case of the default provider, the {@link
* SecurityManager#checkRead(String) checkRead} method is invoked
* to check read access to the directory.
* @throws IOException
* if an I/O error is thrown when accessing the starting file.
*/
@ -204,7 +192,7 @@ public class FileWalker {
throw new UncheckedIOException(e);
}
})
.map(FileTreeWalker.Event::file);
.map(FileTreeWalker.Event::path);
} catch (Error|RuntimeException e) {
iterator.close();
closeable.close();
@ -213,8 +201,7 @@ public class FileWalker {
}
/**
* Convert a Closeable to a Runnable by converting checked IOException
* to UncheckedIOException
* Convert a Closeable to a Runnable by converting checked IOException to UncheckedIOException.
*/
private static Runnable asUncheckedRunnable(Closeable c) {
return () -> {

2
gradle.properties
View file

@ -1,5 +1,5 @@
group = org.xbib
name = files
version = 4.1.0
version = 4.2.0
org.gradle.warning.mode = ALL