| /** |
| * 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; |
| |
| import java.io.IOException; |
| |
| import org.apache.commons.codec.DecoderException; |
| import org.apache.commons.codec.binary.Base64; |
| import org.apache.commons.codec.binary.Hex; |
| import org.apache.hadoop.classification.InterfaceAudience; |
| import org.apache.hadoop.classification.InterfaceStability; |
| |
| import com.google.common.base.Preconditions; |
| |
| /** |
| * The value of <code>XAttr</code> is byte[], this class is to |
| * covert byte[] to some kind of string representation or convert back. |
| * String representation is convenient for display and input. For example |
| * display in screen as shell response and json response, input as http |
| * or shell parameter. |
| */ |
| @InterfaceAudience.Public |
| @InterfaceStability.Stable |
| public enum XAttrCodec { |
| /** |
| * Value encoded as text |
| * string is enclosed in double quotes (\"). |
| */ |
| TEXT, |
| |
| /** |
| * Value encoded as hexadecimal string |
| * is prefixed with 0x. |
| */ |
| HEX, |
| |
| /** |
| * Value encoded as base64 string |
| * is prefixed with 0s. |
| */ |
| BASE64; |
| |
| private static final String HEX_PREFIX = "0x"; |
| private static final String BASE64_PREFIX = "0s"; |
| private static final Base64 base64 = new Base64(0); |
| |
| /** |
| * Decode string representation of a value and check whether it's |
| * encoded. If the given string begins with 0x or 0X, it expresses |
| * a hexadecimal number. If the given string begins with 0s or 0S, |
| * base64 encoding is expected. If the given string is enclosed in |
| * double quotes, the inner string is treated as text. Otherwise |
| * the given string is treated as text. |
| * @param value string representation of the value. |
| * @return byte[] the value |
| * @throws IOException |
| */ |
| public static byte[] decodeValue(String value) throws IOException { |
| byte[] result = null; |
| if (value != null) { |
| if (value.length() >= 2) { |
| String en = value.substring(0, 2); |
| if (value.startsWith("\"") && value.endsWith("\"")) { |
| value = value.substring(1, value.length()-1); |
| result = value.getBytes("utf-8"); |
| } else if (en.equalsIgnoreCase(HEX_PREFIX)) { |
| value = value.substring(2, value.length()); |
| try { |
| result = Hex.decodeHex(value.toCharArray()); |
| } catch (DecoderException e) { |
| throw new IOException(e); |
| } |
| } else if (en.equalsIgnoreCase(BASE64_PREFIX)) { |
| value = value.substring(2, value.length()); |
| result = base64.decode(value); |
| } |
| } |
| if (result == null) { |
| result = value.getBytes("utf-8"); |
| } |
| } |
| return result; |
| } |
| |
| /** |
| * Encode byte[] value to string representation with encoding. |
| * Values encoded as text strings are enclosed in double quotes (\"), |
| * while strings encoded as hexadecimal and base64 are prefixed with |
| * 0x and 0s, respectively. |
| * @param value byte[] value |
| * @param encoding |
| * @return String string representation of value |
| * @throws IOException |
| */ |
| public static String encodeValue(byte[] value, XAttrCodec encoding) |
| throws IOException { |
| Preconditions.checkNotNull(value, "Value can not be null."); |
| if (encoding == HEX) { |
| return HEX_PREFIX + Hex.encodeHexString(value); |
| } else if (encoding == BASE64) { |
| return BASE64_PREFIX + base64.encodeToString(value); |
| } else { |
| return "\"" + new String(value, "utf-8") + "\""; |
| } |
| } |
| } |