jetbrains.exodus.vfs.File Maven / Gradle / Ivy
/**
* Copyright 2010 - 2022 JetBrains s.r.o.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package jetbrains.exodus.vfs;
import jetbrains.exodus.ArrayByteIterable;
import jetbrains.exodus.ByteIterable;
import jetbrains.exodus.ByteIterator;
import jetbrains.exodus.bindings.LongBinding;
import jetbrains.exodus.env.Transaction;
import jetbrains.exodus.util.LightOutputStream;
import org.jetbrains.annotations.NotNull;
import java.io.OutputStream;
/**
* Describes a file of a {@linkplain VirtualFileSystem}. {@code File} is identified by its {@linkplain #getPath()}.
* Path is an abstract string, it can be used to codify a hierarchy, though {@linkplain VirtualFileSystem} doesn't
* contain methods to enumerate files by a path prefix.
*
* In addition, {@code File} can be identified by a file descriptor which an internal {@linkplain VirtualFileSystem}
* {@code long} unique id. Identifying by file descriptor allows to
* {@linkplain VirtualFileSystem#renameFile(Transaction, File, String) rename} a file.
*
*
{@code File} has its {@linkplain #getCreated() created} and {@linkplain #getLastModified() last modified} time.
*
* @see VirtualFileSystem
* @see VirtualFileSystem#createFile(Transaction, String)
* @see VirtualFileSystem#openFile(Transaction, String, boolean)
*/
public class File {
@NotNull
private final String path;
private final long fd;
private final long created;
private final long lastModified;
File(@NotNull final String path, final long fd, final long created, final long lastModified) {
this.path = path;
this.fd = fd;
this.created = created;
this.lastModified = lastModified;
}
File(@NotNull final File origin) {
this(origin.path, origin.fd, origin.created, System.currentTimeMillis());
}
File(@NotNull final String path, @NotNull final ByteIterable iterable) {
this.path = path;
final ByteIterator iterator = iterable.iterator();
fd = LongBinding.readCompressed(iterator);
created = LongBinding.readCompressed(iterator);
lastModified = LongBinding.readCompressed(iterator);
}
/**
* Returns the path which the {@code File} is identified by. Path is an abstract string, it can be used to codify
* a hierarchy, though {@linkplain VirtualFileSystem} doesn't contain methods to enumerate files by a path prefix.
*
* @return path of the {@code File}
*/
@NotNull
public String getPath() {
return path;
}
/**
* @return the {@code File}'s internal unique id
*/
public long getDescriptor() {
return fd;
}
/**
* Returns the time when the {@code File} was created. This value never changes.
*
* @return the time when the {@code File} was created
* @see VirtualFileSystem#createFile(Transaction, String)
* @see VirtualFileSystem#createFile(Transaction, long, String)
* @see VirtualFileSystem#openFile(Transaction, String, boolean)
*/
public long getCreated() {
return created;
}
/**
* Returns the time when the {@code File} was modified last time or explicitly touched.
* {@linkplain VirtualFileSystem}'s methods that open {@linkplain OutputStream} by file descriptor, not
* {@linkplain File} instance, return the stream which doesn't update last modified time.
*
*
The returned value is actual to the moment of the {@code File} instance creation,
* {@linkplain VirtualFileSystem#openFile(Transaction, String, boolean) open} new {@code File} instance to get
* consistent value of last modified time.
*
* @return the time when the {@code File} was modified last time or explicitly touched
* @see VirtualFileSystem#touchFile(Transaction, File)
*/
public long getLastModified() {
return lastModified;
}
@Override
public String toString() {
return path + "[fd = " + fd + ']';
}
ArrayByteIterable toByteIterable() {
final LightOutputStream output = new LightOutputStream();
final int[] bytes = new int[8];
LongBinding.writeCompressed(output, fd, bytes);
LongBinding.writeCompressed(output, created, bytes);
LongBinding.writeCompressed(output, lastModified, bytes);
return output.asArrayByteIterable();
}
}