Java tutorial
/* * Copyright (C) 2008, 2019 Google Inc. * and other copyright owners as documented in the project's IP log. * * This program and the accompanying materials are made available * under the terms of the Eclipse Distribution License v1.0 which * accompanies this distribution, is reproduced below, and is * available at http://www.eclipse.org/org/documents/edl-v10.php * * All rights reserved. * * Redistribution and use in source and binary forms, with or * without modification, are permitted provided that the following * conditions are met: * * - Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * - Redistributions in binary form must reproduce the above * copyright notice, this list of conditions and the following * disclaimer in the documentation and/or other materials provided * with the distribution. * * - Neither the name of the Eclipse Foundation, Inc. nor the * names of its contributors may be used to endorse or promote * products derived from this software without specific prior * written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ package org.eclipse.jgit.util; import static java.nio.charset.StandardCharsets.UTF_8; import java.util.Arrays; import org.eclipse.jgit.lib.Constants; /** * Utility functions related to quoted string handling. */ public abstract class QuotedString { /** Quoting style that obeys the rules Git applies to file names */ public static final GitPathStyle GIT_PATH = new GitPathStyle(true); /** * Quoting style that obeys the rules Git applies to file names when * {@code core.quotePath = false}. * * @since 5.6 */ public static final QuotedString GIT_PATH_MINIMAL = new GitPathStyle(false); /** * Quoting style used by the Bourne shell. * <p> * Quotes are unconditionally inserted during {@link #quote(String)}. This * protects shell meta-characters like <code>$</code> or <code>~</code> from * being recognized as special. */ public static final BourneStyle BOURNE = new BourneStyle(); /** Bourne style, but permits <code>~user</code> at the start of the string. */ public static final BourneUserPathStyle BOURNE_USER_PATH = new BourneUserPathStyle(); /** * Quote an input string by the quoting rules. * <p> * If the input string does not require any quoting, the same String * reference is returned to the caller. * <p> * Otherwise a quoted string is returned, including the opening and closing * quotation marks at the start and end of the string. If the style does not * permit raw Unicode characters then the string will first be encoded in * UTF-8, with unprintable sequences possibly escaped by the rules. * * @param in * any non-null Unicode string. * @return a quoted string. See above for details. */ public abstract String quote(String in); /** * Clean a previously quoted input, decoding the result via UTF-8. * <p> * This method must match quote such that: * * <pre> * a.equals(dequote(quote(a))); * </pre> * * is true for any <code>a</code>. * * @param in * a Unicode string to remove quoting from. * @return the cleaned string. * @see #dequote(byte[], int, int) */ public String dequote(String in) { final byte[] b = Constants.encode(in); return dequote(b, 0, b.length); } /** * Decode a previously quoted input, scanning a UTF-8 encoded buffer. * <p> * This method must match quote such that: * * <pre> * a.equals(dequote(Constants.encode(quote(a)))); * </pre> * * is true for any <code>a</code>. * <p> * This method removes any opening/closing quotation marks added by * {@link #quote(String)}. * * @param in * the input buffer to parse. * @param offset * first position within <code>in</code> to scan. * @param end * one position past in <code>in</code> to scan. * @return the cleaned string. */ public abstract String dequote(byte[] in, int offset, int end); /** * Quoting style used by the Bourne shell. * <p> * Quotes are unconditionally inserted during {@link #quote(String)}. This * protects shell meta-characters like <code>$</code> or <code>~</code> from * being recognized as special. */ public static class BourneStyle extends QuotedString { @Override public String quote(String in) { final StringBuilder r = new StringBuilder(); r.append('\''); int start = 0, i = 0; for (; i < in.length(); i++) { switch (in.charAt(i)) { case '\'': case '!': r.append(in, start, i); r.append('\''); r.append('\\'); r.append(in.charAt(i)); r.append('\''); start = i + 1; break; } } r.append(in, start, i); r.append('\''); return r.toString(); } @Override public String dequote(byte[] in, int ip, int ie) { boolean inquote = false; final byte[] r = new byte[ie - ip]; int rPtr = 0; while (ip < ie) { final byte b = in[ip++]; switch (b) { case '\'': inquote = !inquote; continue; case '\\': if (inquote || ip == ie) r[rPtr++] = b; // literal within a quote else r[rPtr++] = in[ip++]; continue; default: r[rPtr++] = b; continue; } } return RawParseUtils.decode(UTF_8, r, 0, rPtr); } } /** Bourne style, but permits <code>~user</code> at the start of the string. */ public static class BourneUserPathStyle extends BourneStyle { @Override public String quote(String in) { if (in.matches("^~[A-Za-z0-9_-]+$")) { //$NON-NLS-1$ // If the string is just "~user" we can assume they // mean "~user/". // return in + "/"; //$NON-NLS-1$ } if (in.matches("^~[A-Za-z0-9_-]*/.*$")) { //$NON-NLS-1$ // If the string is of "~/path" or "~user/path" // we must not escape ~/ or ~user/ from the shell. // final int i = in.indexOf('/') + 1; if (i == in.length()) return in; return in.substring(0, i) + super.quote(in.substring(i)); } return super.quote(in); } } /** Quoting style that obeys the rules Git applies to file names */ public static final class GitPathStyle extends QuotedString { private static final byte[] quote; static { quote = new byte[128]; Arrays.fill(quote, (byte) -1); for (int i = '0'; i <= '9'; i++) quote[i] = 0; for (int i = 'a'; i <= 'z'; i++) quote[i] = 0; for (int i = 'A'; i <= 'Z'; i++) quote[i] = 0; quote[' '] = 0; quote['$'] = 0; quote['%'] = 0; quote['&'] = 0; quote['*'] = 0; quote['+'] = 0; quote[','] = 0; quote['-'] = 0; quote['.'] = 0; quote['/'] = 0; quote[':'] = 0; quote[';'] = 0; quote['='] = 0; quote['?'] = 0; quote['@'] = 0; quote['_'] = 0; quote['^'] = 0; quote['|'] = 0; quote['~'] = 0; quote['\u0007'] = 'a'; quote['\b'] = 'b'; quote['\f'] = 'f'; quote['\n'] = 'n'; quote['\r'] = 'r'; quote['\t'] = 't'; quote['\u000B'] = 'v'; quote['\\'] = '\\'; quote['"'] = '"'; } private final boolean quoteHigh; @Override public String quote(String instr) { if (instr.isEmpty()) { return "\"\""; //$NON-NLS-1$ } boolean reuse = true; final byte[] in = Constants.encode(instr); final byte[] out = new byte[4 * in.length + 2]; int o = 0; out[o++] = '"'; for (int i = 0; i < in.length; i++) { final int c = in[i] & 0xff; if (c < quote.length) { final byte style = quote[c]; if (style == 0) { out[o++] = (byte) c; continue; } if (style > 0) { reuse = false; out[o++] = '\\'; out[o++] = style; continue; } } else if (!quoteHigh) { out[o++] = (byte) c; continue; } reuse = false; out[o++] = '\\'; out[o++] = (byte) (((c >> 6) & 03) + '0'); out[o++] = (byte) (((c >> 3) & 07) + '0'); out[o++] = (byte) (((c >> 0) & 07) + '0'); } if (reuse) { return instr; } out[o++] = '"'; return new String(out, 0, o, UTF_8); } @Override public String dequote(byte[] in, int inPtr, int inEnd) { if (2 <= inEnd - inPtr && in[inPtr] == '"' && in[inEnd - 1] == '"') return dq(in, inPtr + 1, inEnd - 1); return RawParseUtils.decode(UTF_8, in, inPtr, inEnd); } private static String dq(byte[] in, int inPtr, int inEnd) { final byte[] r = new byte[inEnd - inPtr]; int rPtr = 0; while (inPtr < inEnd) { final byte b = in[inPtr++]; if (b != '\\') { r[rPtr++] = b; continue; } if (inPtr == inEnd) { // Lone trailing backslash. Treat it as a literal. // r[rPtr++] = '\\'; break; } switch (in[inPtr++]) { case 'a': r[rPtr++] = 0x07 /* \a = BEL */; continue; case 'b': r[rPtr++] = '\b'; continue; case 'f': r[rPtr++] = '\f'; continue; case 'n': r[rPtr++] = '\n'; continue; case 'r': r[rPtr++] = '\r'; continue; case 't': r[rPtr++] = '\t'; continue; case 'v': r[rPtr++] = 0x0B/* \v = VT */; continue; case '\\': case '"': r[rPtr++] = in[inPtr - 1]; continue; case '0': case '1': case '2': case '3': { int cp = in[inPtr - 1] - '0'; for (int n = 1; n < 3 && inPtr < inEnd; n++) { final byte c = in[inPtr]; if ('0' <= c && c <= '7') { cp <<= 3; cp |= c - '0'; inPtr++; } else { break; } } r[rPtr++] = (byte) cp; continue; } default: // Any other code is taken literally. // r[rPtr++] = '\\'; r[rPtr++] = in[inPtr - 1]; continue; } } return RawParseUtils.decode(UTF_8, r, 0, rPtr); } private GitPathStyle(boolean doQuote) { quoteHigh = doQuote; } } }