/*
* Copyright 2010 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 org.gradle.api.internal.file.copy;
import org.gradle.api.Transformer;
import org.gradle.internal.SystemProperties;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.Reader;
public class LineFilter extends Reader {
private static enum State {
NORMAL,
SKIP_LINE,
EOF
};
private final Transformer<String, String> transformer;
private String transformedLine;
private int transformedIndex;
private final BufferedReader bufferedIn;
private final Reader in;
private State state = State.NORMAL;
/**
* Creates a new filtered reader.
*
* @param transformer a transformer to filter each line
* @throws NullPointerException if <code>in</code> is <code>null</code>
*/
public LineFilter(Reader in, Transformer<String, String> transformer) {
this.in = in;
this.bufferedIn = new BufferedReader(in);
this.transformer = transformer;
}
private void readTransformedLine() throws IOException {
StringBuilder line = new StringBuilder();
boolean eol = false;
int ch;
while (!eol && (ch = bufferedIn.read()) >= 0) {
if (ch == '\n') {
eol = true;
} else if (ch == '\r') {
eol = true;
bufferedIn.mark(1);
if (bufferedIn.read() != '\n') {
bufferedIn.reset();
}
} else {
line.append((char) ch);
}
}
if (line.length() == 0 && !eol) {
state = State.EOF;
return;
}
String result = transformer.transform(line.toString());
if (result == null) {
state = State.SKIP_LINE;
return;
}
StringBuilder builder = new StringBuilder();
builder.append(result);
if (eol) {
builder.append(SystemProperties.getInstance().getLineSeparator());
}
state = State.NORMAL;
transformedLine = builder.toString();
}
private void ensureData() throws IOException {
while (state == State.SKIP_LINE || state == State.NORMAL && (transformedLine == null || transformedIndex >= transformedLine.length())) {
readTransformedLine();
transformedIndex = 0;
}
}
@Override
public int read() throws IOException {
ensureData();
if (state == State.EOF) {
return -1;
}
return transformedLine.charAt(transformedIndex++);
}
@Override
public int read(char[] cbuf, int off, int len) throws IOException {
for (int i = 0; i < len; i++) {
final int c = read();
if (c == -1) {
if (i == 0) {
return -1;
} else {
return i;
}
}
cbuf[off + i] = (char) c;
}
return len;
}
public void close() throws IOException {
in.close();
}
}