/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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
*
* http://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 org.apache.hadoop.fs.swift.util;
import org.apache.commons.logging.Log;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import java.io.FileNotFoundException;
import java.io.IOException;
/**
* Various utility classes for SwiftFS support
*/
public final class SwiftUtils {
public static final String READ = "read(buffer, offset, length)";
/**
* Join two (non null) paths, inserting a forward slash between them
* if needed
*
* @param path1 first path
* @param path2 second path
* @return the combined path
*/
public static String joinPaths(String path1, String path2) {
StringBuilder result =
new StringBuilder(path1.length() + path2.length() + 1);
result.append(path1);
boolean insertSlash = true;
if (path1.endsWith("/")) {
insertSlash = false;
} else if (path2.startsWith("/")) {
insertSlash = false;
}
if (insertSlash) {
result.append("/");
}
result.append(path2);
return result.toString();
}
/**
* This test contains the is-directory logic for Swift, so if
* changed there is only one place for it.
*
* @param fileStatus status to examine
* @return true if we consider this status to be representative of a
* directory.
*/
public static boolean isDirectory(FileStatus fileStatus) {
return fileStatus.isDirectory() || isFilePretendingToBeDirectory(fileStatus);
}
/**
* Test for the entry being a file that is treated as if it is a
* directory
*
* @param fileStatus status
* @return true if it meets the rules for being a directory
*/
public static boolean isFilePretendingToBeDirectory(FileStatus fileStatus) {
return fileStatus.getLen() == 0;
}
/**
* Predicate: Is a swift object referring to the root direcory?
* @param swiftObject object to probe
* @return true iff the object refers to the root
*/
public static boolean isRootDir(SwiftObjectPath swiftObject) {
return swiftObject.objectMatches("") || swiftObject.objectMatches("/");
}
/**
* Sprintf() to the log iff the log is at debug level. If the log
* is not at debug level, the printf operation is skipped, so
* no time is spent generating the string.
* @param log log to use
* @param text text message
* @param args args arguments to the print statement
*/
public static void debug(Log log, String text, Object... args) {
if (log.isDebugEnabled()) {
log.debug(String.format(text, args));
}
}
/**
* Log an exception (in text and trace) iff the log is at debug
* @param log Log to use
* @param text text message
* @param ex exception
*/
public static void debugEx(Log log, String text, Exception ex) {
if (log.isDebugEnabled()) {
log.debug(text + ex, ex);
}
}
/**
* Sprintf() to the log iff the log is at trace level. If the log
* is not at trace level, the printf operation is skipped, so
* no time is spent generating the string.
* @param log log to use
* @param text text message
* @param args args arguments to the print statement
*/
public static void trace(Log log, String text, Object... args) {
if (log.isTraceEnabled()) {
log.trace(String.format(text, args));
}
}
/**
* Given a partition number, calculate the partition value.
* This is used in the SwiftNativeOutputStream, and is placed
* here for tests to be able to calculate the filename of
* a partition.
* @param partNumber part number
* @return a string to use as the filename
*/
public static String partitionFilenameFromNumber(int partNumber) {
return String.format("%06d", partNumber);
}
/**
* List a a path to string
* @param fileSystem filesystem
* @param path directory
* @return a listing of the filestatuses of elements in the directory, one
* to a line, precedeed by the full path of the directory
* @throws IOException connectivity problems
*/
public static String ls(FileSystem fileSystem, Path path) throws
IOException {
if (path == null) {
//surfaces when someone calls getParent() on something at the top of the path
return "/";
}
FileStatus[] stats;
String pathtext = "ls " + path;
try {
stats = fileSystem.listStatus(path);
} catch (FileNotFoundException e) {
return pathtext + " -file not found";
} catch (IOException e) {
return pathtext + " -failed: " + e;
}
return pathtext + fileStatsToString(stats, "\n");
}
/**
* Take an array of filestats and convert to a string (prefixed w/ a [01] counter
* @param stats array of stats
* @param separator separator after every entry
* @return a stringified set
*/
public static String fileStatsToString(FileStatus[] stats, String separator) {
StringBuilder buf = new StringBuilder(stats.length * 128);
for (int i = 0; i < stats.length; i++) {
buf.append(String.format("[%02d] %s", i, stats[i])).append(separator);
}
return buf.toString();
}
/**
* Verify that the basic args to a read operation are valid;
* throws an exception if not -with meaningful text includeing
* @param buffer destination buffer
* @param off offset
* @param len number of bytes to read
* @throws NullPointerException null buffer
* @throws IndexOutOfBoundsException on any invalid range.
*/
public static void validateReadArgs(byte[] buffer, int off, int len) {
if (buffer == null) {
throw new NullPointerException("Null byte array in"+ READ);
}
if (off < 0 ) {
throw new IndexOutOfBoundsException("Negative buffer offset "
+ off
+ " in " + READ);
}
if (len < 0 ) {
throw new IndexOutOfBoundsException("Negative read length "
+ len
+ " in " + READ);
}
if (off > buffer.length) {
throw new IndexOutOfBoundsException("Buffer offset of "
+ off
+ "beyond buffer size of "
+ buffer.length
+ " in " + READ);
}
}
}