333f55e9ce
Motivation: See #4855 Modifications: Unfortunately, unescapeCsv cannot be used here because the input could be a CSV line like `"a,b",c`. Hence this patch adds unescapeCsvFields to parse a CSV line and split it into multiple fields and unescaped them. The unit tests should define the behavior of unescapeCsvFields. Then this patch just uses unescapeCsvFields to implement `CombinedHttpHeaders.getAll`. Result: `CombinedHttpHeaders.getAll` will return the unescaped values of a header.
555 lines
20 KiB
Java
555 lines
20 KiB
Java
/*
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* Copyright 2012 The Netty Project
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*
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* The Netty Project licenses this file to you under the Apache License,
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* version 2.0 (the "License"); you may not use this file except in compliance
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* with the License. You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*/
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package io.netty.util.internal;
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import java.io.IOException;
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import java.util.ArrayList;
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import java.util.Formatter;
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import java.util.List;
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import static io.netty.util.internal.ObjectUtil.checkNotNull;
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/**
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* String utility class.
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*/
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public final class StringUtil {
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public static final String EMPTY_STRING = "";
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public static final String NEWLINE;
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public static final char DOUBLE_QUOTE = '\"';
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public static final char COMMA = ',';
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public static final char LINE_FEED = '\n';
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public static final char CARRIAGE_RETURN = '\r';
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public static final char TAB = '\t';
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private static final String[] BYTE2HEX_PAD = new String[256];
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private static final String[] BYTE2HEX_NOPAD = new String[256];
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/**
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* 2 - Quote character at beginning and end.
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* 5 - Extra allowance for anticipated escape characters that may be added.
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*/
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private static final int CSV_NUMBER_ESCAPE_CHARACTERS = 2 + 5;
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private static final char PACKAGE_SEPARATOR_CHAR = '.';
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static {
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// Determine the newline character of the current platform.
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String newLine;
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Formatter formatter = new Formatter();
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try {
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newLine = formatter.format("%n").toString();
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} catch (Exception e) {
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// Should not reach here, but just in case.
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newLine = "\n";
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} finally {
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formatter.close();
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}
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NEWLINE = newLine;
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// Generate the lookup table that converts a byte into a 2-digit hexadecimal integer.
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int i;
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for (i = 0; i < 10; i ++) {
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StringBuilder buf = new StringBuilder(2);
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buf.append('0');
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buf.append(i);
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BYTE2HEX_PAD[i] = buf.toString();
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BYTE2HEX_NOPAD[i] = String.valueOf(i);
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}
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for (; i < 16; i ++) {
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StringBuilder buf = new StringBuilder(2);
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char c = (char) ('a' + i - 10);
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buf.append('0');
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buf.append(c);
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BYTE2HEX_PAD[i] = buf.toString();
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BYTE2HEX_NOPAD[i] = String.valueOf(c);
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}
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for (; i < BYTE2HEX_PAD.length; i ++) {
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StringBuilder buf = new StringBuilder(2);
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buf.append(Integer.toHexString(i));
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String str = buf.toString();
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BYTE2HEX_PAD[i] = str;
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BYTE2HEX_NOPAD[i] = str;
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}
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}
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/**
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* Splits the specified {@link String} with the specified delimiter. This operation is a simplified and optimized
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* version of {@link String#split(String)}.
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*/
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public static String[] split(String value, char delim) {
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final int end = value.length();
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final List<String> res = InternalThreadLocalMap.get().arrayList();
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int start = 0;
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for (int i = 0; i < end; i ++) {
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if (value.charAt(i) == delim) {
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if (start == i) {
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res.add(EMPTY_STRING);
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} else {
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res.add(value.substring(start, i));
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}
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start = i + 1;
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}
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}
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if (start == 0) { // If no delimiter was found in the value
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res.add(value);
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} else {
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if (start != end) {
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// Add the last element if it's not empty.
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res.add(value.substring(start, end));
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} else {
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// Truncate trailing empty elements.
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for (int i = res.size() - 1; i >= 0; i --) {
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if (res.get(i).isEmpty()) {
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res.remove(i);
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} else {
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break;
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}
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}
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}
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}
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return res.toArray(new String[res.size()]);
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}
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/**
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* Splits the specified {@link String} with the specified delimiter in maxParts maximum parts.
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* This operation is a simplified and optimized
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* version of {@link String#split(String, int)}.
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*/
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public static String[] split(String value, char delim, int maxParts) {
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final int end = value.length();
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final List<String> res = InternalThreadLocalMap.get().arrayList();
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int start = 0;
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int cpt = 1;
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for (int i = 0; i < end && cpt < maxParts; i ++) {
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if (value.charAt(i) == delim) {
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if (start == i) {
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res.add(EMPTY_STRING);
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} else {
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res.add(value.substring(start, i));
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}
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start = i + 1;
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cpt++;
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}
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}
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if (start == 0) { // If no delimiter was found in the value
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res.add(value);
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} else {
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if (start != end) {
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// Add the last element if it's not empty.
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res.add(value.substring(start, end));
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} else {
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// Truncate trailing empty elements.
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for (int i = res.size() - 1; i >= 0; i --) {
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if (res.get(i).isEmpty()) {
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res.remove(i);
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} else {
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break;
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}
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}
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}
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}
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return res.toArray(new String[res.size()]);
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}
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/**
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* Get the item after one char delim if the delim is found (else null).
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* This operation is a simplified and optimized
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* version of {@link String#split(String, int)}.
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*/
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public static String substringAfter(String value, char delim) {
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int pos = value.indexOf(delim);
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if (pos >= 0) {
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return value.substring(pos + 1);
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}
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return null;
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}
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/**
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* Checks if two strings have the same suffix of specified length
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*
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* @param s string
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* @param p string
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* @param len length of the common suffix
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* @return true if both s and p are not null and both have the same suffix. Otherwise - false
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*/
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public static boolean commonSuffixOfLength(String s, String p, int len) {
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return s != null && p != null && len >= 0 && s.regionMatches(s.length() - len, p, p.length() - len, len);
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}
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/**
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* Converts the specified byte value into a 2-digit hexadecimal integer.
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*/
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public static String byteToHexStringPadded(int value) {
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return BYTE2HEX_PAD[value & 0xff];
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}
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/**
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* Converts the specified byte value into a 2-digit hexadecimal integer and appends it to the specified buffer.
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*/
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public static <T extends Appendable> T byteToHexStringPadded(T buf, int value) {
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try {
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buf.append(byteToHexStringPadded(value));
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} catch (IOException e) {
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PlatformDependent.throwException(e);
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}
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return buf;
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}
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/**
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* Converts the specified byte array into a hexadecimal value.
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*/
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public static String toHexStringPadded(byte[] src) {
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return toHexStringPadded(src, 0, src.length);
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}
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/**
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* Converts the specified byte array into a hexadecimal value.
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*/
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public static String toHexStringPadded(byte[] src, int offset, int length) {
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return toHexStringPadded(new StringBuilder(length << 1), src, offset, length).toString();
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}
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/**
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* Converts the specified byte array into a hexadecimal value and appends it to the specified buffer.
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*/
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public static <T extends Appendable> T toHexStringPadded(T dst, byte[] src) {
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return toHexStringPadded(dst, src, 0, src.length);
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}
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/**
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* Converts the specified byte array into a hexadecimal value and appends it to the specified buffer.
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*/
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public static <T extends Appendable> T toHexStringPadded(T dst, byte[] src, int offset, int length) {
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final int end = offset + length;
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for (int i = offset; i < end; i ++) {
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byteToHexStringPadded(dst, src[i]);
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}
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return dst;
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}
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/**
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* Converts the specified byte value into a hexadecimal integer.
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*/
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public static String byteToHexString(int value) {
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return BYTE2HEX_NOPAD[value & 0xff];
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}
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/**
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* Converts the specified byte value into a hexadecimal integer and appends it to the specified buffer.
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*/
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public static <T extends Appendable> T byteToHexString(T buf, int value) {
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try {
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buf.append(byteToHexString(value));
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} catch (IOException e) {
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PlatformDependent.throwException(e);
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}
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return buf;
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}
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/**
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* Converts the specified byte array into a hexadecimal value.
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*/
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public static String toHexString(byte[] src) {
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return toHexString(src, 0, src.length);
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}
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/**
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* Converts the specified byte array into a hexadecimal value.
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*/
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public static String toHexString(byte[] src, int offset, int length) {
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return toHexString(new StringBuilder(length << 1), src, offset, length).toString();
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}
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/**
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* Converts the specified byte array into a hexadecimal value and appends it to the specified buffer.
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*/
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public static <T extends Appendable> T toHexString(T dst, byte[] src) {
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return toHexString(dst, src, 0, src.length);
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}
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/**
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* Converts the specified byte array into a hexadecimal value and appends it to the specified buffer.
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*/
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public static <T extends Appendable> T toHexString(T dst, byte[] src, int offset, int length) {
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assert length >= 0;
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if (length == 0) {
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return dst;
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}
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final int end = offset + length;
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final int endMinusOne = end - 1;
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int i;
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// Skip preceding zeroes.
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for (i = offset; i < endMinusOne; i ++) {
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if (src[i] != 0) {
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break;
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}
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}
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byteToHexString(dst, src[i ++]);
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int remaining = end - i;
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toHexStringPadded(dst, src, i, remaining);
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return dst;
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}
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/**
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* The shortcut to {@link #simpleClassName(Class) simpleClassName(o.getClass())}.
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*/
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public static String simpleClassName(Object o) {
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if (o == null) {
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return "null_object";
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} else {
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return simpleClassName(o.getClass());
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}
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}
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/**
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* Generates a simplified name from a {@link Class}. Similar to {@link Class#getSimpleName()}, but it works fine
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* with anonymous classes.
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*/
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public static String simpleClassName(Class<?> clazz) {
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String className = ObjectUtil.checkNotNull(clazz, "clazz").getName();
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final int lastDotIdx = className.lastIndexOf(PACKAGE_SEPARATOR_CHAR);
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if (lastDotIdx > -1) {
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return className.substring(lastDotIdx + 1);
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}
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return className;
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}
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/**
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* Escapes the specified value, if necessary according to
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* <a href="https://tools.ietf.org/html/rfc4180#section-2">RFC-4180</a>.
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*
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* @param value The value which will be escaped according to
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* <a href="https://tools.ietf.org/html/rfc4180#section-2">RFC-4180</a>
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* @return {@link CharSequence} the escaped value if necessary, or the value unchanged
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*/
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public static CharSequence escapeCsv(CharSequence value) {
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int length = checkNotNull(value, "value").length();
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if (length == 0) {
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return value;
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}
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int last = length - 1;
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boolean quoted = isDoubleQuote(value.charAt(0)) && isDoubleQuote(value.charAt(last)) && length != 1;
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boolean foundSpecialCharacter = false;
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boolean escapedDoubleQuote = false;
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StringBuilder escaped = new StringBuilder(length + CSV_NUMBER_ESCAPE_CHARACTERS).append(DOUBLE_QUOTE);
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for (int i = 0; i < length; i++) {
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char current = value.charAt(i);
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switch (current) {
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case DOUBLE_QUOTE:
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if (i == 0 || i == last) {
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if (!quoted) {
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escaped.append(DOUBLE_QUOTE);
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} else {
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continue;
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}
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} else {
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boolean isNextCharDoubleQuote = isDoubleQuote(value.charAt(i + 1));
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if (!isDoubleQuote(value.charAt(i - 1)) &&
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(!isNextCharDoubleQuote || i + 1 == last)) {
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escaped.append(DOUBLE_QUOTE);
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escapedDoubleQuote = true;
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}
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break;
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}
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case LINE_FEED:
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case CARRIAGE_RETURN:
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case COMMA:
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foundSpecialCharacter = true;
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}
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escaped.append(current);
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}
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return escapedDoubleQuote || foundSpecialCharacter && !quoted ?
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escaped.append(DOUBLE_QUOTE) : value;
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}
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/**
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* Unescapes the specified escaped CSV field, if necessary according to
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* <a href="https://tools.ietf.org/html/rfc4180#section-2">RFC-4180</a>.
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*
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* @param value The escaped CSV field which will be unescaped according to
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* <a href="https://tools.ietf.org/html/rfc4180#section-2">RFC-4180</a>
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* @return {@link CharSequence} the unescaped value if necessary, or the value unchanged
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*/
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public static CharSequence unescapeCsv(CharSequence value) {
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int length = checkNotNull(value, "value").length();
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if (length == 0) {
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return value;
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}
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int last = length - 1;
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boolean quoted = isDoubleQuote(value.charAt(0)) && isDoubleQuote(value.charAt(last)) && length != 1;
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if (!quoted) {
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validateCsvFormat(value);
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return value;
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}
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StringBuilder unescaped = InternalThreadLocalMap.get().stringBuilder();
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for (int i = 1; i < last; i++) {
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char current = value.charAt(i);
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if (current == DOUBLE_QUOTE) {
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if (isDoubleQuote(value.charAt(i + 1)) && (i + 1) != last) {
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// Followed by a double-quote but not the last character
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// Just skip the next double-quote
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i++;
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} else {
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// Not followed by a double-quote or the following double-quote is the last character
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throw newInvalidEscapedCsvFieldException(value, i);
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}
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}
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unescaped.append(current);
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}
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return unescaped.toString();
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}
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/**
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* Unescapes the specified escaped CSV fields according to
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* <a href="https://tools.ietf.org/html/rfc4180#section-2">RFC-4180</a>.
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*
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* @param value A string with multiple CSV escaped fields which will be unescaped according to
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* <a href="https://tools.ietf.org/html/rfc4180#section-2">RFC-4180</a>
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* @return {@link List} the list of unescaped fields
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*/
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public static List<CharSequence> unescapeCsvFields(CharSequence value) {
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List<CharSequence> unescaped = new ArrayList<CharSequence>(2);
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StringBuilder current = InternalThreadLocalMap.get().stringBuilder();
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boolean quoted = false;
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int last = value.length() - 1;
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for (int i = 0; i <= last; i++) {
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char c = value.charAt(i);
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if (quoted) {
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switch (c) {
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case DOUBLE_QUOTE:
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if (i == last) {
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// Add the last field and return
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unescaped.add(current.toString());
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return unescaped;
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}
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char next = value.charAt(++i);
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if (next == DOUBLE_QUOTE) {
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// 2 double-quotes should be unescaped to one
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current.append(DOUBLE_QUOTE);
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break;
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}
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if (next == COMMA) {
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// This is the end of a field. Let's start to parse the next field.
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quoted = false;
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unescaped.add(current.toString());
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current.setLength(0);
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break;
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}
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// double-quote followed by other character is invalid
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throw newInvalidEscapedCsvFieldException(value, i - 1);
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default:
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current.append(c);
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}
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} else {
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switch (c) {
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case COMMA:
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// Start to parse the next field
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unescaped.add(current.toString());
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current.setLength(0);
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break;
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case DOUBLE_QUOTE:
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if (current.length() == 0) {
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quoted = true;
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break;
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}
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// double-quote appears without being enclosed with double-quotes
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case LINE_FEED:
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case CARRIAGE_RETURN:
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// special characters appears without being enclosed with double-quotes
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throw newInvalidEscapedCsvFieldException(value, i);
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default:
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current.append(c);
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}
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}
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}
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if (quoted) {
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throw newInvalidEscapedCsvFieldException(value, last);
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}
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unescaped.add(current.toString());
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return unescaped;
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}
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/**s
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* Validate if {@code value} is a valid csv field without double-quotes.
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*
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* @throws IllegalArgumentException if {@code value} needs to be encoded with double-quotes.
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*/
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private static void validateCsvFormat(CharSequence value) {
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int length = value.length();
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for (int i = 0; i < length; i++) {
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switch (value.charAt(i)) {
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case DOUBLE_QUOTE:
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case LINE_FEED:
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case CARRIAGE_RETURN:
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case COMMA:
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// If value contains any special character, it should be enclosed with double-quotes
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throw newInvalidEscapedCsvFieldException(value, i);
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default:
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}
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}
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}
|
|
|
|
private static IllegalArgumentException newInvalidEscapedCsvFieldException(CharSequence value, int index) {
|
|
return new IllegalArgumentException("invalid escaped CSV field: " + value + " index: " + index);
|
|
}
|
|
|
|
/**
|
|
* Get the length of a string, {@code null} input is considered {@code 0} length.
|
|
*/
|
|
public static int length(String s) {
|
|
return s == null ? 0 : s.length();
|
|
}
|
|
|
|
/**
|
|
* Determine if a string is {@code null} or {@link String#isEmpty()} returns {@code true}.
|
|
*/
|
|
public static boolean isNullOrEmpty(String s) {
|
|
return s == null || s.isEmpty();
|
|
}
|
|
|
|
/**
|
|
* Determine if {@code c} lies within the range of values defined for
|
|
* <a href="http://unicode.org/glossary/#surrogate_code_point">Surrogate Code Point</a>.
|
|
* @param c the character to check.
|
|
* @return {@code true} if {@code c} lies within the range of values defined for
|
|
* <a href="http://unicode.org/glossary/#surrogate_code_point">Surrogate Code Point</a>. {@code false} otherwise.
|
|
*/
|
|
public static boolean isSurrogate(char c) {
|
|
return c >= '\uD800' && c <= '\uDFFF';
|
|
}
|
|
|
|
private static boolean isDoubleQuote(char c) {
|
|
return c == DOUBLE_QUOTE;
|
|
}
|
|
|
|
private StringUtil() {
|
|
// Unused.
|
|
}
|
|
}
|