// Copyright (c) 2009 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
package org.chromium.debug.core.util;
import java.util.Collection;
import java.util.Map;
import java.util.SortedMap;
import org.chromium.sdk.JsArray;
import org.chromium.sdk.JsObject;
import org.chromium.sdk.JsValue;
import org.chromium.sdk.JsVariable;
import org.chromium.sdk.JsValue.Type;
/**
* A converter of JsValues into human-readable strings used in various contexts.
*/
public class JsValueStringifier {
/**
* A configuration class
*/
public static class Config {
/**
* The maximum length of the text to render. If the value length exceeds
* the limit, an ellipsis will be used to truncate the value.
* The default is 80 characters.
*/
public int maxLength = 80;
}
private static final String ELLIPSIS = "..."; //$NON-NLS-1$
private static final String UNKNOWN_VALUE = "<null>"; //$NON-NLS-1$
private final Config config;
/**
* Constructs a visible string for the given {@code value} (without exposing
* the value structure). Encloses JavaScript string values in double quotes.
*
* @param value to build a visible string for
* @return {@code value.getValueString()} (enclosed in double quotes if
* {@code value.getType() == TYPE_STRING}), or {@code null} if
* {@code value==null}
*/
public static String toVisibleString(JsValue value) {
return possiblyQuoteValueString(value);
}
private static String possiblyQuoteValueString(JsValue value) {
if (value == null) {
return UNKNOWN_VALUE;
}
String valueString = value.getValueString();
return value.getType() == JsValue.Type.TYPE_STRING
? "\"" + valueString + "\"" //$NON-NLS-1$ //$NON-NLS-2$
: valueString;
}
/**
* Use the default config values.
*/
public JsValueStringifier() {
this.config = new Config();
}
/**
* Use the specified {@code config} data.
* @param config to use when rendering values.
*/
public JsValueStringifier(Config config) {
this.config = config;
}
public String render(JsValue value) {
if (value == null) {
return UNKNOWN_VALUE;
}
StringBuilder output = new StringBuilder();
renderInternal(value, config.maxLength, true, output);
return output.toString();
}
/**
* @param value to render
* @param maxLength the maximum length of the {@code output}
* @param descend whether to descend into the object contents
* @param output to render into
*/
private void renderInternal(JsValue value, int maxLength, boolean descend, StringBuilder output) {
if (!descend) {
renderPrimitive(value, maxLength, output);
return;
}
Type type = value.getType();
// TODO(apavlov): implement good stringification of other types?
switch (type) {
case TYPE_ARRAY:
renderArray(value.asObject().asArray(), maxLength, output);
break;
case TYPE_OBJECT:
renderObject(value.asObject(), maxLength, output);
break;
default:
renderPrimitive(value, maxLength, output);
break;
}
}
private void renderPrimitive(JsValue value, int maxLength, StringBuilder output) {
output.append(possiblyQuoteValueString(value));
truncate(output, maxLength, ELLIPSIS);
}
private void truncate(StringBuilder valueBuilder, int maxLength, String suffix) {
int length = valueBuilder.length();
if (length > maxLength) {
valueBuilder.setLength(maxLength);
valueBuilder.replace(
maxLength - suffix.length(), maxLength, suffix);
}
}
private StringBuilder renderArray(JsArray value, int maxLength, StringBuilder output) {
output.append('[');
SortedMap<Long, ? extends JsVariable> indexToElement = value.toSparseArray();
boolean isFirst = true;
int maxLengthWithoutLastBracket = maxLength - 1;
StringBuilder elementBuilder = new StringBuilder();
int entriesWritten = 0;
for (Map.Entry<Long, ? extends JsVariable> entry : indexToElement.entrySet()) {
Long index = entry.getKey();
JsVariable var = entry.getValue();
if (!isFirst) {
output.append(',');
} else {
isFirst = false;
}
elementBuilder.setLength(0);
elementBuilder.append(index).append('=');
renderInternal(var.getValue(), maxLengthWithoutLastBracket /* essentially, no limit */,
false, elementBuilder);
if (output.length() + elementBuilder.length() >= maxLengthWithoutLastBracket) {
// reached max length
appendNMore(output, indexToElement.size() - entriesWritten);
break;
} else {
output.append(elementBuilder.toString());
entriesWritten++;
}
}
return output.append(']');
}
private StringBuilder renderObject(JsObject value, int maxLength, StringBuilder output) {
output.append('[');
Collection<? extends JsVariable> properties = value.getProperties();
boolean isFirst = true;
int maxLengthWithoutLastBracket = maxLength - 1;
StringBuilder elementBuilder = new StringBuilder();
int entriesWritten = 0;
for (JsVariable property : properties) {
String name = property.getName();
if (!isFirst) {
output.append(',');
} else {
isFirst = false;
}
elementBuilder.setLength(0);
elementBuilder.append(name).append('=');
renderInternal(property.getValue(), maxLengthWithoutLastBracket /* essentially, no limit */,
false, elementBuilder);
if (output.length() + elementBuilder.length() >= maxLengthWithoutLastBracket) {
// reached max length
appendNMore(output, properties.size() - entriesWritten);
break;
} else {
output.append(elementBuilder.toString());
entriesWritten++;
}
}
return output.append(']');
}
private StringBuilder appendNMore(StringBuilder output, int n) {
return output.append(" +").append(n).append(ELLIPSIS); //$NON-NLS-1$
}
}