Add wrapping support to IndentingPrintWriter.
When created with a wrapping width, any content longer than the
requested width will be wrapped onto additional lines. This supports
use-cases like dumping lots of data with printPair().
Improve documentation and add tests to verify behavior.
Change-Id: Ibdfce198f0e69f4df7725544fd1cd02fa029c647
diff --git a/core/java/com/android/internal/util/IndentingPrintWriter.java b/core/java/com/android/internal/util/IndentingPrintWriter.java
index dd5918b..d01a817 100644
--- a/core/java/com/android/internal/util/IndentingPrintWriter.java
+++ b/core/java/com/android/internal/util/IndentingPrintWriter.java
@@ -21,29 +21,47 @@
/**
* 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 @@
@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);
}
}
}
diff --git a/core/tests/coretests/src/com/android/internal/util/IndentingPrintWriterTest.java b/core/tests/coretests/src/com/android/internal/util/IndentingPrintWriterTest.java
new file mode 100644
index 0000000..6773612
--- /dev/null
+++ b/core/tests/coretests/src/com/android/internal/util/IndentingPrintWriterTest.java
@@ -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());
+ }
+}