/*
* Copyright (C) 2010 The Android Open Source Project
*
* Licensed 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 com.android.tradefed.util;
import com.android.ddmlib.Log;
import java.util.ArrayList;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class QuotationAwareTokenizer {
private static final String LOG_TAG = "TOKEN";
/**
* Tokenizes the string, splitting on spaces. Does not split between consecutive, unquoted
* double-quote marks.
* <p/>
* How the tokenizer works:
* <ol>
* <li> Split the string into "characters" where each "character" is either an escaped
* character like \" (that is, "\\\"") or a single real character like f (just "f").
* <li> For each "character"
* <ol>
* <li> If it's a space, finish a token unless we're being quoted
* <li> If it's a quotation mark, flip the "we're being quoted" bit
* <li> Otherwise, add it to the token being built
* </ol>
* <li> At EOL, we typically haven't added the final token to the (tokens) {@link ArrayList}
* <ol>
* <li> If the last "character" is an escape character, throw an exception; that's not
* valid
* <li> If we're in the middle of a quotation, throw an exception; that's not valid
* <li> Otherwise, add the final token to (tokens)
* </ol>
* <li> Return a String[] version of (tokens)
* </ol>
*
* @param line A {@link String} to be tokenized
* @return A tokenized version of the string
* @throws IllegalArgumentException if the line cannot be parsed
*/
public static String[] tokenizeLine(String line) throws IllegalArgumentException {
if (line == null) {
throw new IllegalArgumentException("line is null");
}
ArrayList<String> tokens = new ArrayList<String>();
StringBuilder token = new StringBuilder();
// This pattern matches an escaped character or a character. Escaped char takes precedence
final Pattern charPattern = Pattern.compile("\\\\.|.");
final Matcher charMatcher = charPattern.matcher(line);
String aChar = "";
boolean quotation = false;
Log.d(LOG_TAG, String.format("Trying to tokenize the line '%s'", line));
while (charMatcher.find()) {
aChar = charMatcher.group();
Log.v(LOG_TAG, String.format("Got a character: '%s'", aChar));
if (" ".equals(aChar)) {
if (quotation) {
// inside a quotation; treat spaces as part of the token
token.append(aChar);
} else {
if (token.length() > 0) {
// this is the end of a non-empty token; dump it in our list of tokens,
// clear our temp storage, and keep rolling
Log.v(LOG_TAG, String.format("Finished token '%s'", token.toString()));
tokens.add(token.toString());
token.delete(0, token.length());
}
// otherwise, this is the non-first in a sequence of spaces; ignore.
}
} else if ("\"".equals(aChar)) {
// unescaped quotation mark; flip quotation state
Log.v(LOG_TAG, "Flipped quotation state");
quotation ^= true;
} else {
// default case: add the character to the token being built
Log.v(LOG_TAG, String.format("Adding character '%s' to token '%s'", aChar, token));
token.append(aChar);
}
}
if (quotation || "\\".equals(aChar)) {
// We ended in a quotation or with an escape character; this is not valid
throw new IllegalArgumentException("Unexpected EOL in a quotation or after an escape " +
"character");
}
// Add the final token to the tokens array.
if (token.length() > 0) {
Log.v(LOG_TAG, String.format("Finished final token '%s'", token.toString()));
tokens.add(token.toString());
token.delete(0, token.length());
}
String[] tokensArray = new String[tokens.size()];
return tokens.toArray(tokensArray);
}
}