com.google.protobuf.MessageLiteToString Maven / Gradle / Ivy
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// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc. All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file or at
// https://developers.google.com/open-source/licenses/bsd
package com.google.protobuf;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.Arrays;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import java.util.TreeMap;
/** Helps generate {@link String} representations of {@link MessageLite} protos. */
final class MessageLiteToString {
private static final String LIST_SUFFIX = "List";
private static final String BUILDER_LIST_SUFFIX = "OrBuilderList";
private static final String MAP_SUFFIX = "Map";
private static final String BYTES_SUFFIX = "Bytes";
private static final char[] INDENT_BUFFER = new char[80];
static {
Arrays.fill(INDENT_BUFFER, ' ');
}
private MessageLiteToString() {
// Classes which are not intended to be instantiated should be made non-instantiable with a
// private constructor. This includes utility classes (classes with only static members).
}
/**
* Returns a {@link String} representation of the {@link MessageLite} object. The first line of
* the {@code String} representation includes a comment string to uniquely identify
* the object instance. This acts as an indicator that this should not be relied on for
* comparisons.
*/
static String toString(MessageLite messageLite, String commentString) {
StringBuilder buffer = new StringBuilder();
buffer.append("# ").append(commentString);
reflectivePrintWithIndent(messageLite, buffer, 0);
return buffer.toString();
}
/**
* Reflectively prints the {@link MessageLite} to the buffer at given {@code indent} level.
*
* @param buffer the buffer to write to
* @param indent the number of spaces to indent the proto by
*/
private static void reflectivePrintWithIndent(
MessageLite messageLite, StringBuilder buffer, int indent) {
// Build a map of method name to method. We're looking for methods like getFoo(), hasFoo(),
// getFooList() and getFooMap() which might be useful for building an object's string
// representation.
Set setters = new HashSet<>();
Map hazzers = new HashMap<>();
Map getters = new TreeMap<>();
for (Method method : messageLite.getClass().getDeclaredMethods()) {
if (Modifier.isStatic(method.getModifiers())) {
continue;
}
if (method.getName().length() < 3) {
continue;
}
if (method.getName().startsWith("set")) {
setters.add(method.getName());
continue;
}
if (!Modifier.isPublic(method.getModifiers())) {
continue;
}
if (method.getParameterTypes().length != 0) {
continue;
}
if (method.getName().startsWith("has")) {
hazzers.put(method.getName(), method);
} else if (method.getName().startsWith("get")) {
getters.put(method.getName(), method);
}
}
for (Entry getter : getters.entrySet()) {
String suffix = getter.getKey().substring(3);
if (suffix.endsWith(LIST_SUFFIX)
&& !suffix.endsWith(BUILDER_LIST_SUFFIX)
// Sometimes people have fields named 'list' that aren't repeated.
&& !suffix.equals(LIST_SUFFIX)) {
// Try to reflectively get the value and toString() the field as if it were repeated. This
// only works if the method names have not been proguarded out or renamed.
Method listMethod = getter.getValue();
if (listMethod != null && listMethod.getReturnType().equals(List.class)) {
printField(
buffer,
indent,
suffix.substring(0, suffix.length() - LIST_SUFFIX.length()),
GeneratedMessageLite.invokeOrDie(listMethod, messageLite));
continue;
}
}
if (suffix.endsWith(MAP_SUFFIX)
// Sometimes people have fields named 'map' that aren't maps.
&& !suffix.equals(MAP_SUFFIX)) {
// Try to reflectively get the value and toString() the field as if it were a map. This only
// works if the method names have not been proguarded out or renamed.
Method mapMethod = getter.getValue();
if (mapMethod != null
&& mapMethod.getReturnType().equals(Map.class)
// Skip the deprecated getter method with no prefix "Map" when the field name ends with
// "map".
&& !mapMethod.isAnnotationPresent(Deprecated.class)
// Skip the internal mutable getter method.
&& Modifier.isPublic(mapMethod.getModifiers())) {
printField(
buffer,
indent,
suffix.substring(0, suffix.length() - MAP_SUFFIX.length()),
GeneratedMessageLite.invokeOrDie(mapMethod, messageLite));
continue;
}
}
if (!setters.contains("set" + suffix)) {
continue;
}
if (suffix.endsWith(BYTES_SUFFIX)
&& getters.containsKey("get" + suffix.substring(0, suffix.length() - "Bytes".length()))) {
// Heuristic to skip bytes based accessors for string fields.
continue;
}
// Try to reflectively get the value and toString() the field as if it were optional. This
// only works if the method names have not been proguarded out or renamed.
Method getMethod = getter.getValue();
Method hasMethod = hazzers.get("has" + suffix);
// TODO: Fix proto3 semantics.
if (getMethod != null) {
Object value = GeneratedMessageLite.invokeOrDie(getMethod, messageLite);
final boolean hasValue =
hasMethod == null
? !isDefaultValue(value)
: (Boolean) GeneratedMessageLite.invokeOrDie(hasMethod, messageLite);
// TODO: This doesn't stop printing oneof case twice: value and enum style.
if (hasValue) {
printField(buffer, indent, suffix, value);
}
continue;
}
}
if (messageLite instanceof GeneratedMessageLite.ExtendableMessage) {
Iterator> iter =
((GeneratedMessageLite.ExtendableMessage) messageLite).extensions.iterator();
while (iter.hasNext()) {
Map.Entry entry = iter.next();
printField(buffer, indent, "[" + entry.getKey().getNumber() + "]", entry.getValue());
}
}
if (((GeneratedMessageLite) messageLite).unknownFields != null) {
((GeneratedMessageLite) messageLite).unknownFields.printWithIndent(buffer, indent);
}
}
private static boolean isDefaultValue(Object o) {
if (o instanceof Boolean) {
return !((Boolean) o);
}
if (o instanceof Integer) {
return ((Integer) o) == 0;
}
if (o instanceof Float) {
return Float.floatToRawIntBits((Float) o) == 0;
}
if (o instanceof Double) {
return Double.doubleToRawLongBits((Double) o) == 0;
}
if (o instanceof String) {
return o.equals("");
}
if (o instanceof ByteString) {
return o.equals(ByteString.EMPTY);
}
if (o instanceof MessageLite) { // Can happen in oneofs.
return o == ((MessageLite) o).getDefaultInstanceForType();
}
if (o instanceof java.lang.Enum) { // Catches oneof enums.
return ((java.lang.Enum) o).ordinal() == 0;
}
return false;
}
/**
* Formats a text proto field.
*
* For use by generated code only.
*
* @param buffer the buffer to write to
* @param indent the number of spaces the proto should be indented by
* @param name the field name (in PascalCase)
* @param object the object value of the field
*/
static void printField(StringBuilder buffer, int indent, String name, Object object) {
if (object instanceof List) {
List list = (List) object;
for (Object entry : list) {
printField(buffer, indent, name, entry);
}
return;
}
if (object instanceof Map) {
Map map = (Map) object;
for (Map.Entry entry : map.entrySet()) {
printField(buffer, indent, name, entry);
}
return;
}
buffer.append('\n');
indent(indent, buffer);
buffer.append(pascalCaseToSnakeCase(name));
if (object instanceof String) {
buffer.append(": \"").append(TextFormatEscaper.escapeText((String) object)).append('"');
} else if (object instanceof ByteString) {
buffer.append(": \"").append(TextFormatEscaper.escapeBytes((ByteString) object)).append('"');
} else if (object instanceof GeneratedMessageLite) {
buffer.append(" {");
reflectivePrintWithIndent((GeneratedMessageLite) object, buffer, indent + 2);
buffer.append("\n");
indent(indent, buffer);
buffer.append("}");
} else if (object instanceof Map.Entry) {
buffer.append(" {");
Map.Entry entry = (Map.Entry) object;
printField(buffer, indent + 2, "key", entry.getKey());
printField(buffer, indent + 2, "value", entry.getValue());
buffer.append("\n");
indent(indent, buffer);
buffer.append("}");
} else {
buffer.append(": ").append(object);
}
}
private static void indent(int indent, StringBuilder buffer) {
while (indent > 0) {
int partialIndent = indent;
if (partialIndent > INDENT_BUFFER.length) {
partialIndent = INDENT_BUFFER.length;
}
buffer.append(INDENT_BUFFER, 0, partialIndent);
indent -= partialIndent;
}
}
private static String pascalCaseToSnakeCase(String pascalCase) {
if (pascalCase.isEmpty()) {
return pascalCase;
}
StringBuilder builder = new StringBuilder();
builder.append(Character.toLowerCase(pascalCase.charAt(0)));
for (int i = 1; i < pascalCase.length(); i++) {
char ch = pascalCase.charAt(i);
if (Character.isUpperCase(ch)) {
builder.append("_");
}
builder.append(Character.toLowerCase(ch));
}
return builder.toString();
}
}