ninja.build.ArgumentTokenizer Maven / Gradle / Ivy
/**
* Copyright (C) 2012- the original author or authors.
*
* 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 ninja.build;
import java.util.List;
import java.util.LinkedList;
/**
* Utility class which can tokenize a String into a list of String arguments,
* with behavior similar to parsing command line arguments to a program.
* Quoted Strings are treated as single arguments, and escaped characters
* are translated so that the tokenized arguments have the same meaning.
* Since all methods are static, the class is declared abstract to prevent
* instantiation.
* @version $Id$
*/
public abstract class ArgumentTokenizer {
private static final int NO_TOKEN_STATE = 0;
private static final int NORMAL_TOKEN_STATE = 1;
private static final int SINGLE_QUOTE_STATE = 2;
private static final int DOUBLE_QUOTE_STATE = 3;
/** Tokenizes the given String into String tokens
* @param arguments A String containing one or more command-line style arguments to be tokenized.
* @return A list of parsed and properly escaped arguments.
*/
public static List tokenize(String arguments) {
return tokenize(arguments, false);
}
/** Tokenizes the given String into String tokens.
* @param arguments A String containing one or more command-line style arguments to be tokenized.
* @param stringify whether or not to include escape special characters
* @return A list of parsed and properly escaped arguments.
*/
public static List tokenize(String arguments, boolean stringify) {
LinkedList argList = new LinkedList<>();
StringBuilder currArg = new StringBuilder();
boolean escaped = false;
int state = NO_TOKEN_STATE; // start in the NO_TOKEN_STATE
int len = arguments.length();
// Loop over each character in the string
for (int i = 0; i < len; i++) {
char c = arguments.charAt(i);
if (escaped) {
// Escaped state: just append the next character to the current arg.
escaped = false;
currArg.append(c);
}
else {
switch(state) {
case SINGLE_QUOTE_STATE:
if (c == '\'') {
// Seen the close quote; continue this arg until whitespace is seen
state = NORMAL_TOKEN_STATE;
}
else {
currArg.append(c);
}
break;
case DOUBLE_QUOTE_STATE:
if (c == '"') {
// Seen the close quote; continue this arg until whitespace is seen
state = NORMAL_TOKEN_STATE;
}
else if (c == '\\') {
// Look ahead, and only escape quotes or backslashes
i++;
char next = arguments.charAt(i);
if (next == '"' || next == '\\') {
currArg.append(next);
}
else {
currArg.append(c);
currArg.append(next);
}
}
else {
currArg.append(c);
}
break;
// case NORMAL_TOKEN_STATE:
// if (Character.isWhitespace(c)) {
// // Whitespace ends the token; start a new one
// argList.add(currArg.toString());
// currArg = new StringBuffer();
// state = NO_TOKEN_STATE;
// }
// else if (c == '\\') {
// // Backslash in a normal token: escape the next character
// escaped = true;
// }
// else if (c == '\'') {
// state = SINGLE_QUOTE_STATE;
// }
// else if (c == '"') {
// state = DOUBLE_QUOTE_STATE;
// }
// else {
// currArg.append(c);
// }
// break;
case NO_TOKEN_STATE:
case NORMAL_TOKEN_STATE:
switch(c) {
case '\\':
escaped = true;
state = NORMAL_TOKEN_STATE;
break;
case '\'':
state = SINGLE_QUOTE_STATE;
break;
case '"':
state = DOUBLE_QUOTE_STATE;
break;
default:
if (!Character.isWhitespace(c)) {
currArg.append(c);
state = NORMAL_TOKEN_STATE;
}
else if (state == NORMAL_TOKEN_STATE) {
// Whitespace ends the token; start a new one
argList.add(currArg.toString());
currArg = new StringBuilder();
state = NO_TOKEN_STATE;
}
}
break;
default:
throw new IllegalStateException("ArgumentTokenizer state " + state + " is invalid!");
}
}
}
// If we're still escaped, put in the backslash
if (escaped) {
currArg.append('\\');
argList.add(currArg.toString());
}
// Close the last argument if we haven't yet
else if (state != NO_TOKEN_STATE) {
argList.add(currArg.toString());
}
// Format each argument if we've been told to stringify them
if (stringify) {
for (int i = 0; i < argList.size(); i++) {
argList.set(i, "\"" + _escapeQuotesAndBackslashes(argList.get(i)) + "\"");
}
}
return argList;
}
/** Inserts backslashes before any occurrences of a backslash or
* quote in the given string. Also converts any special characters
* appropriately.
*/
protected static String _escapeQuotesAndBackslashes(String s) {
final StringBuilder buf = new StringBuilder(s);
// Walk backwards, looking for quotes or backslashes.
// If we see any, insert an extra backslash into the buffer at
// the same index. (By walking backwards, the index into the buffer
// will remain correct as we change the buffer.)
for (int i = s.length()-1; i >= 0; i--) {
char c = s.charAt(i);
if ((c == '\\') || (c == '"')) {
buf.insert(i, '\\');
}
// Replace any special characters with escaped versions
else if (c == '\n') {
buf.deleteCharAt(i);
buf.insert(i, "\\n");
}
else if (c == '\t') {
buf.deleteCharAt(i);
buf.insert(i, "\\t");
}
else if (c == '\r') {
buf.deleteCharAt(i);
buf.insert(i, "\\r");
}
else if (c == '\b') {
buf.deleteCharAt(i);
buf.insert(i, "\\b");
}
else if (c == '\f') {
buf.deleteCharAt(i);
buf.insert(i, "\\f");
}
}
return buf.toString();
}
}