/*
* The Alluxio Open Foundation licenses this work under the Apache License, version 2.0
* (the "License"). You may not use this work except in compliance with the License, which is
* available at www.apache.org/licenses/LICENSE-2.0
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
* either express or implied, as more fully set forth in the License.
*
* See the NOTICE file distributed with this work for information regarding copyright ownership.
*/
package alluxio.util.io;
import alluxio.AlluxioURI;
import alluxio.exception.ExceptionMessage;
import alluxio.exception.InvalidPathException;
import alluxio.util.OSUtils;
import com.google.common.base.CharMatcher;
import com.google.common.base.Joiner;
import com.google.common.base.Preconditions;
import org.apache.commons.io.FilenameUtils;
import java.util.ArrayList;
import java.util.List;
import javax.annotation.concurrent.ThreadSafe;
/**
* Utilities related to both Alluxio paths like {@link AlluxioURI} and local file paths.
*/
@ThreadSafe
public final class PathUtils {
private static final String TEMPORARY_SUFFIX_FORMAT = ".alluxio.0x%016X.tmp";
private static final int TEMPORARY_SUFFIX_LENGTH =
String.format(TEMPORARY_SUFFIX_FORMAT, 0).length();
/**
* Checks and normalizes the given path.
*
* @param path The path to clean up
* @return a normalized version of the path, with single separators between path components and
* dot components resolved
* @throws InvalidPathException if the path is invalid
*/
public static String cleanPath(String path) throws InvalidPathException {
validatePath(path);
return FilenameUtils.separatorsToUnix(FilenameUtils.normalizeNoEndSeparator(path));
}
/**
* Joins each element in paths in order, separated by {@link AlluxioURI#SEPARATOR}.
* <p>
* For example,
*
* <pre>
* {@code
* concatPath("/myroot/", "dir", 1L, "filename").equals("/myroot/dir/1/filename");
* concatPath("alluxio://myroot", "dir", "filename").equals("alluxio://myroot/dir/filename");
* concatPath("myroot/", "/dir/", "filename").equals("myroot/dir/filename");
* concatPath("/", "dir", "filename").equals("/dir/filename");
* }
* </pre>
*
* Note that empty element in base or paths is ignored.
*
* @param base base path
* @param paths paths to concatenate
* @return joined path
* @throws IllegalArgumentException if base or paths is null
*/
public static String concatPath(Object base, Object... paths) throws IllegalArgumentException {
Preconditions.checkArgument(base != null, "Failed to concatPath: base is null");
Preconditions.checkArgument(paths != null, "Failed to concatPath: a null set of paths");
List<String> trimmedPathList = new ArrayList<>();
String trimmedBase =
CharMatcher.is(AlluxioURI.SEPARATOR.charAt(0)).trimTrailingFrom(base.toString().trim());
trimmedPathList.add(trimmedBase);
for (Object path : paths) {
if (path == null) {
continue;
}
String trimmedPath =
CharMatcher.is(AlluxioURI.SEPARATOR.charAt(0)).trimFrom(path.toString().trim());
if (!trimmedPath.isEmpty()) {
trimmedPathList.add(trimmedPath);
}
}
if (trimmedPathList.size() == 1 && trimmedBase.isEmpty()) {
// base must be "[/]+"
return AlluxioURI.SEPARATOR;
}
return Joiner.on(AlluxioURI.SEPARATOR).join(trimmedPathList);
}
/**
* Gets the parent of the file at a path.
*
* @param path The path
* @return the parent path of the file; this is "/" if the given path is the root
* @throws InvalidPathException if the path is invalid
*/
public static String getParent(String path) throws InvalidPathException {
String cleanedPath = cleanPath(path);
String name = FilenameUtils.getName(cleanedPath);
String parent = cleanedPath.substring(0, cleanedPath.length() - name.length() - 1);
if (parent.isEmpty()) {
// The parent is the root path.
return AlluxioURI.SEPARATOR;
}
return parent;
}
/**
* Gets the path components of the given path. The first component will be an empty string.
*
* "/a/b/c" => {"", "a", "b", "c"}
* "/" => {""}
*
* @param path The path to split
* @return the path split into components
* @throws InvalidPathException if the path is invalid
*/
public static String[] getPathComponents(String path) throws InvalidPathException {
path = cleanPath(path);
if (isRoot(path)) {
return new String[]{""};
}
return path.split(AlluxioURI.SEPARATOR);
}
/**
* Removes the prefix from the path, yielding a relative path from the second path to the first.
*
* If the paths are the same, this method returns the empty string.
*
* @param path the full path
* @param prefix the prefix to remove
* @return the path with the prefix removed
* @throws InvalidPathException if either of the arguments are not valid paths
*/
public static String subtractPaths(String path, String prefix) throws InvalidPathException {
String cleanedPath = cleanPath(path);
String cleanedPrefix = cleanPath(prefix);
if (cleanedPath.equals(cleanedPrefix)) {
return "";
}
if (!hasPrefix(cleanedPath, cleanedPrefix)) {
throw new RuntimeException(
String.format("Cannot subtract %s from %s because it is not a prefix", prefix, path));
}
// The only clean path which ends in '/' is the root.
int prefixLen = cleanedPrefix.length();
int charsToDrop = PathUtils.isRoot(cleanedPrefix) ? prefixLen : prefixLen + 1;
return cleanedPath.substring(charsToDrop, cleanedPath.length());
}
/**
* Checks whether the given path contains the given prefix. The comparison happens at a component
* granularity; for example, {@code hasPrefix(/dir/file, /dir)} should evaluate to true, while
* {@code hasPrefix(/dir/file, /d)} should evaluate to false.
*
* @param path a path
* @param prefix a prefix
* @return whether the given path has the given prefix
* @throws InvalidPathException when the path or prefix is invalid
*/
public static boolean hasPrefix(String path, String prefix) throws InvalidPathException {
String[] pathComponents = getPathComponents(path);
String[] prefixComponents = getPathComponents(prefix);
if (pathComponents.length < prefixComponents.length) {
return false;
}
for (int i = 0; i < prefixComponents.length; i++) {
if (!pathComponents[i].equals(prefixComponents[i])) {
return false;
}
}
return true;
}
/**
* Checks if the given path is the root.
*
* @param path The path to check
* @return true if the path is the root
* @throws InvalidPathException if the path is invalid
*/
public static boolean isRoot(String path) throws InvalidPathException {
return AlluxioURI.SEPARATOR.equals(cleanPath(path));
}
/**
* Checks if the given path is properly formed.
*
* @param path The path to check
* @throws InvalidPathException If the path is not properly formed
*/
public static void validatePath(String path) throws InvalidPathException {
boolean invalid = (path == null || path.isEmpty() || path.contains(" "));
if (!OSUtils.isWindows()) {
invalid = (invalid || !path.startsWith(AlluxioURI.SEPARATOR));
}
if (invalid) {
throw new InvalidPathException(ExceptionMessage.PATH_INVALID.getMessage(path));
}
}
/**
* Generates a deterministic temporary file name for the a path and a file id and a nonce.
*
* @param nonce a nonce token
* @param path a file path
* @return a deterministic temporary file name
*/
public static String temporaryFileName(long nonce, String path) {
return path + String.format(TEMPORARY_SUFFIX_FORMAT, nonce);
}
/**
* @param path the path of the file, possibly temporary
* @return the permanent path of the file if it was temporary, or the original path if it was not
*/
public static String getPermanentFileName(String path) {
if (isTemporaryFileName(path)) {
return path.substring(0, path.length() - TEMPORARY_SUFFIX_LENGTH);
}
return path;
}
/**
* Determines whether the given path is a temporary file name generated by Alluxio.
*
* @param path the path to check
* @return whether the given path is a temporary file name generated by Alluxio
*/
public static boolean isTemporaryFileName(String path) {
return path.matches("^.*\\.alluxio\\.0x[0-9A-F]{16}\\.tmp$");
}
/**
* Creates a unique path based off the caller.
*
* @return unique path based off the caller
*/
public static String uniqPath() {
StackTraceElement caller = new Throwable().getStackTrace()[1];
long time = System.nanoTime();
return "/" + caller.getClassName() + "/" + caller.getMethodName() + "/" + time;
}
/**
* Adds a trailing separator if it does not exist in path.
*
* @param path the file name
* @param separator trailing separator to add
* @return updated path with trailing separator
*/
public static String normalizePath(String path, String separator) {
return path.endsWith(separator) ? path : path + separator;
}
private PathUtils() {} // prevent instantiation
}