/*
* Copyright (C) 2012 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.internal.util;
import java.io.PrintWriter;
import java.io.Writer;
/**
* Lightweight wrapper around {@link PrintWriter} that automatically indents
* newlines based on internal state. Delays writing indent until first actual
* write on a newline, enabling indent modification after newline.
*/
public class IndentingPrintWriter extends PrintWriter {
private final String mIndent;
private StringBuilder mBuilder = new StringBuilder();
private char[] mCurrent;
private boolean mEmptyLine = true;
public IndentingPrintWriter(Writer writer, String indent) {
super(writer);
mIndent = indent;
}
public void increaseIndent() {
mBuilder.append(mIndent);
mCurrent = null;
}
public void decreaseIndent() {
mBuilder.delete(0, mIndent.length());
mCurrent = null;
}
public void printPair(String key, Object value) {
print(key + "=" + String.valueOf(value) + " ");
}
@Override
public void write(char[] buf, int offset, int count) {
final int bufferEnd = offset + count;
int lineStart = offset;
int lineEnd = offset;
while (lineEnd < bufferEnd) {
char ch = buf[lineEnd++];
if (ch == '\n') {
writeIndent();
super.write(buf, lineStart, lineEnd - lineStart);
lineStart = lineEnd;
mEmptyLine = true;
}
}
if (lineStart != lineEnd) {
writeIndent();
super.write(buf, lineStart, lineEnd - lineStart);
}
}
private void writeIndent() {
if (mEmptyLine) {
mEmptyLine = false;
if (mBuilder.length() != 0) {
if (mCurrent == null) {
mCurrent = mBuilder.toString().toCharArray();
}
super.write(mCurrent, 0, mCurrent.length);
}
}
}
}