| /* |
| * 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.tools.ant.filters; |
| |
| import java.io.IOException; |
| import java.io.Reader; |
| |
| /** |
| * This is a Java comment and string stripper reader that filters |
| * those lexical tokens out for purposes of simple Java parsing. |
| * (if you have more complex Java parsing needs, use a real lexer). |
| * Since this class heavily relies on the single char read function, |
| * you are recommended to make it work on top of a buffered reader. |
| * |
| */ |
| public final class StripJavaComments |
| extends BaseFilterReader |
| implements ChainableReader { |
| |
| /** |
| * The read-ahead character, used for effectively pushing a single |
| * character back. A value of -1 indicates that no character is in the |
| * buffer. |
| */ |
| private int readAheadCh = -1; |
| |
| /** |
| * Whether or not the parser is currently in the middle of a string |
| * literal. |
| */ |
| private boolean inString = false; |
| |
| /** |
| * Whether or not the last char has been a backslash. |
| */ |
| private boolean quoted = false; |
| |
| /** |
| * Constructor for "dummy" instances. |
| * |
| * @see BaseFilterReader#BaseFilterReader() |
| */ |
| public StripJavaComments() { |
| super(); |
| } |
| |
| /** |
| * Creates a new filtered reader. |
| * |
| * @param in A Reader object providing the underlying stream. |
| * Must not be <code>null</code>. |
| */ |
| public StripJavaComments(final Reader in) { |
| super(in); |
| } |
| |
| /** |
| * Returns the next character in the filtered stream, not including |
| * Java comments. |
| * |
| * @return the next character in the resulting stream, or -1 |
| * if the end of the resulting stream has been reached |
| * |
| * @exception IOException if the underlying stream throws an IOException |
| * during reading |
| */ |
| public int read() throws IOException { |
| int ch = -1; |
| if (readAheadCh != -1) { |
| ch = readAheadCh; |
| readAheadCh = -1; |
| } else { |
| ch = in.read(); |
| if (ch == '"' && !quoted) { |
| inString = !inString; |
| quoted = false; |
| } else if (ch == '\\') { |
| quoted = !quoted; |
| } else { |
| quoted = false; |
| if (!inString) { |
| if (ch == '/') { |
| ch = in.read(); |
| if (ch == '/') { |
| while (ch != '\n' && ch != -1 && ch != '\r') { |
| ch = in.read(); |
| } |
| } else if (ch == '*') { |
| while (ch != -1) { |
| ch = in.read(); |
| if (ch == '*') { |
| ch = in.read(); |
| while (ch == '*') { |
| ch = in.read(); |
| } |
| |
| if (ch == '/') { |
| ch = read(); |
| break; |
| } |
| } |
| } |
| } else { |
| readAheadCh = ch; |
| ch = '/'; |
| } |
| } |
| } |
| } |
| } |
| |
| return ch; |
| } |
| |
| /** |
| * Creates a new StripJavaComments using the passed in |
| * Reader for instantiation. |
| * |
| * @param rdr A Reader object providing the underlying stream. |
| * Must not be <code>null</code>. |
| * |
| * @return a new filter based on this configuration, but filtering |
| * the specified reader |
| */ |
| |
| public Reader chain(final Reader rdr) { |
| StripJavaComments newFilter = new StripJavaComments(rdr); |
| return newFilter; |
| } |
| } |