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Merge "Add wrapping support to IndentingPrintWriter."

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This commit is contained in:
Jeff Sharkey
2013-01-31 00:37:34 +00:00
committed by Android (Google) Code Review
parent 75d880dfb0 71cb446f01
commit ed1ad7fada
2 changed files with 191 additions and 18 deletions
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77
core/java/com/android/internal/util/IndentingPrintWriter.java
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@ -21,29 +21,47 @@ 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.
* newlines based on internal state. It also automatically wraps long lines
* based on given line length.
* <p>
* 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 final String mSingleIndent;
private final int mWrapLength;
private StringBuilder mBuilder = new StringBuilder();
private char[] mCurrent;
/** Mutable version of current indent */
private StringBuilder mIndentBuilder = new StringBuilder();
/** Cache of current {@link #mIndentBuilder} value */
private char[] mCurrentIndent;
/** Length of current line being built, excluding any indent */
private int mCurrentLength;
/**
* Flag indicating if we're currently sitting on an empty line, and that
* next write should be prefixed with the current indent.
*/
private boolean mEmptyLine = true;
public IndentingPrintWriter(Writer writer, String indent) {
public IndentingPrintWriter(Writer writer, String singleIndent) {
this(writer, singleIndent, -1);
}
public IndentingPrintWriter(Writer writer, String singleIndent, int wrapLength) {
super(writer);
mIndent = indent;
mSingleIndent = singleIndent;
mWrapLength = wrapLength;
}
public void increaseIndent() {
mBuilder.append(mIndent);
mCurrent = null;
mIndentBuilder.append(mSingleIndent);
mCurrentIndent = null;
}
public void decreaseIndent() {
mBuilder.delete(0, mIndent.length());
mCurrent = null;
mIndentBuilder.delete(0, mSingleIndent.length());
mCurrentIndent = null;
}
public void printPair(String key, Object value) {
@ -52,33 +70,56 @@ public class IndentingPrintWriter extends PrintWriter {
@Override
public void write(char[] buf, int offset, int count) {
final int indentLength = mIndentBuilder.length();
final int bufferEnd = offset + count;
int lineStart = offset;
int lineEnd = offset;
// March through incoming buffer looking for newlines
while (lineEnd < bufferEnd) {
char ch = buf[lineEnd++];
mCurrentLength++;
if (ch == '\n') {
writeIndent();
maybeWriteIndent();
super.write(buf, lineStart, lineEnd - lineStart);
lineStart = lineEnd;
mEmptyLine = true;
mCurrentLength = 0;
}
// Wrap if we've pushed beyond line length
if (mWrapLength > 0 && mCurrentLength >= mWrapLength - indentLength) {
if (!mEmptyLine) {
// Give ourselves a fresh line to work with
super.write('\n');
mEmptyLine = true;
mCurrentLength = lineEnd - lineStart;
} else {
// We need more than a dedicated line, slice it hard
maybeWriteIndent();
super.write(buf, lineStart, lineEnd - lineStart);
super.write('\n');
mEmptyLine = true;
lineStart = lineEnd;
mCurrentLength = 0;
}
}
}
if (lineStart != lineEnd) {
writeIndent();
maybeWriteIndent();
super.write(buf, lineStart, lineEnd - lineStart);
}
}
private void writeIndent() {
private void maybeWriteIndent() {
if (mEmptyLine) {
mEmptyLine = false;
if (mBuilder.length() != 0) {
if (mCurrent == null) {
mCurrent = mBuilder.toString().toCharArray();
if (mIndentBuilder.length() != 0) {
if (mCurrentIndent == null) {
mCurrentIndent = mIndentBuilder.toString().toCharArray();
}
super.write(mCurrent, 0, mCurrent.length);
super.write(mCurrentIndent, 0, mCurrentIndent.length);
}
}
}

132
core/tests/coretests/src/com/android/internal/util/IndentingPrintWriterTest.java Normal file
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@ -0,0 +1,132 @@
/*
* Copyright (C) 2013 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 junit.framework.TestCase;
import java.io.ByteArrayOutputStream;
import java.io.PrintWriter;
/**
* Tests for {@link IndentingPrintWriter}.
*/
public class IndentingPrintWriterTest extends TestCase {
private ByteArrayOutputStream mStream;
private PrintWriter mWriter;
@Override
protected void setUp() throws Exception {
super.setUp();
mStream = new ByteArrayOutputStream();
mWriter = new PrintWriter(mStream);
}
public void testMultipleIndents() throws Exception {
final IndentingPrintWriter pw = new IndentingPrintWriter(mWriter, " ");
pw.print("Hello");
pw.increaseIndent();
pw.println();
pw.print("World");
pw.increaseIndent();
pw.println();
pw.print("And");
pw.decreaseIndent();
pw.println();
pw.print("Goodbye");
pw.decreaseIndent();
pw.println();
pw.print("World");
pw.println();
pw.flush();
assertEquals("Hello\n World\n And\n Goodbye\nWorld\n", mStream.toString());
}
public void testAdjustIndentAfterNewline() throws Exception {
final IndentingPrintWriter pw = new IndentingPrintWriter(mWriter, " ");
pw.println("Hello");
pw.increaseIndent();
pw.println("World");
pw.flush();
assertEquals("Hello\n World\n", mStream.toString());
}
public void testWrapping() throws Exception {
final IndentingPrintWriter pw = new IndentingPrintWriter(mWriter, "", 10);
pw.print("dog ");
pw.print("cat ");
pw.print("cow ");
pw.print("meow ");
pw.flush();
assertEquals("dog cat \ncow meow ", mStream.toString());
}
public void testWrappingIndented() throws Exception {
final IndentingPrintWriter pw = new IndentingPrintWriter(mWriter, " ", 10);
pw.increaseIndent();
pw.print("dog ");
pw.print("meow ");
pw.print("a ");
pw.print("b ");
pw.print("cow ");
pw.flush();
assertEquals(" dog \n meow \n a b \n cow ", mStream.toString());
}
public void testWrappingEmbeddedNewlines() throws Exception {
final IndentingPrintWriter pw = new IndentingPrintWriter(mWriter, " ", 10);
pw.increaseIndent();
pw.print("Lorem ipsum \ndolor sit \namet, consectetur \nadipiscing elit.");
pw.flush();
assertEquals(" Lorem ip\n sum \n dolor si\n t \n amet, co\n"
+ " nsectetu\n r \n adipisci\n ng elit.\n", mStream.toString());
}
public void testWrappingSingleGiant() throws Exception {
final IndentingPrintWriter pw = new IndentingPrintWriter(mWriter, " ", 10);
pw.increaseIndent();
pw.print("Lorem ipsum dolor sit amet, consectetur adipiscing elit.");
pw.flush();
assertEquals(" Lorem ip\n sum dolo\n r sit am\n et, cons\n"
+ " ectetur \n adipisci\n ng elit.\n", mStream.toString());
}
public void testWrappingPrefixedGiant() throws Exception {
final IndentingPrintWriter pw = new IndentingPrintWriter(mWriter, " ", 10);
pw.increaseIndent();
pw.print("foo");
pw.print("Lorem ipsum dolor sit amet, consectetur adipiscing elit.");
pw.flush();
assertEquals(" foo\n Lorem ip\n sum dolo\n r sit am\n et, cons\n"
+ " ectetur \n adipisci\n ng elit.\n", mStream.toString());
}
}