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// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc. All rights reserved.
// https://developers.google.com/protocol-buffers/
//
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// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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package com.google.protobuf.util;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import com.google.protobuf.Descriptors.Descriptor;
import com.google.protobuf.Descriptors.FieldDescriptor;
import com.google.protobuf.FieldMask;
import com.google.protobuf.Message;
import java.util.ArrayList;
import java.util.List;
import java.util.Map.Entry;
import java.util.SortedMap;
import java.util.TreeMap;
import java.util.logging.Logger;
/**
* A tree representation of a FieldMask. Each leaf node in this tree represent
* a field path in the FieldMask.
*
* For example, FieldMask "foo.bar,foo.baz,bar.baz" as a tree will be:
*
* [root] -+- foo -+- bar
* | |
* | +- baz
* |
* +- bar --- baz
*
*
* By representing FieldMasks with this tree structure we can easily convert
* a FieldMask to a canonical form, merge two FieldMasks, calculate the
* intersection to two FieldMasks and traverse all fields specified by the
* FieldMask in a message tree.
*/
final class FieldMaskTree {
private static final Logger logger = Logger.getLogger(FieldMaskTree.class.getName());
private static final String FIELD_PATH_SEPARATOR_REGEX = "\\.";
private static final class Node {
final SortedMap children = new TreeMap();
}
private final Node root = new Node();
/**
* Creates an empty FieldMaskTree.
*/
FieldMaskTree() {}
/**
* Creates a FieldMaskTree for a given FieldMask.
*/
FieldMaskTree(FieldMask mask) {
mergeFromFieldMask(mask);
}
@Override
public String toString() {
return FieldMaskUtil.toString(toFieldMask());
}
/**
* Adds a field path to the tree. In a FieldMask, every field path matches the specified field as
* well as all its sub-fields. For example, a field path "foo.bar" matches field "foo.bar" and
* also "foo.bar.baz", etc. When adding a field path to the tree, redundant sub-paths will be
* removed. That is, after adding "foo.bar" to the tree, "foo.bar.baz" will be removed if it
* exists, which will turn the tree node for "foo.bar" to a leaf node. Likewise, if the field path
* to add is a sub-path of an existing leaf node, nothing will be changed in the tree.
*/
@CanIgnoreReturnValue
FieldMaskTree addFieldPath(String path) {
String[] parts = path.split(FIELD_PATH_SEPARATOR_REGEX);
if (parts.length == 0) {
return this;
}
Node node = root;
boolean createNewBranch = false;
// Find the matching node in the tree.
for (String part : parts) {
// Check whether the path matches an existing leaf node.
if (!createNewBranch && node != root && node.children.isEmpty()) {
// The path to add is a sub-path of an existing leaf node.
return this;
}
if (node.children.containsKey(part)) {
node = node.children.get(part);
} else {
createNewBranch = true;
Node tmp = new Node();
node.children.put(part, tmp);
node = tmp;
}
}
// Turn the matching node into a leaf node (i.e., remove sub-paths).
node.children.clear();
return this;
}
/** Merges all field paths in a FieldMask into this tree. */
@CanIgnoreReturnValue
FieldMaskTree mergeFromFieldMask(FieldMask mask) {
for (String path : mask.getPathsList()) {
addFieldPath(path);
}
return this;
}
/**
* Converts this tree to a FieldMask.
*/
FieldMask toFieldMask() {
if (root.children.isEmpty()) {
return FieldMask.getDefaultInstance();
}
List paths = new ArrayList();
getFieldPaths(root, "", paths);
return FieldMask.newBuilder().addAllPaths(paths).build();
}
/**
* Gathers all field paths in a sub-tree.
*/
private void getFieldPaths(Node node, String path, List paths) {
if (node.children.isEmpty()) {
paths.add(path);
return;
}
for (Entry entry : node.children.entrySet()) {
String childPath = path.isEmpty() ? entry.getKey() : path + "." + entry.getKey();
getFieldPaths(entry.getValue(), childPath, paths);
}
}
/**
* Adds the intersection of this tree with the given {@code path} to {@code output}.
*/
void intersectFieldPath(String path, FieldMaskTree output) {
if (root.children.isEmpty()) {
return;
}
String[] parts = path.split(FIELD_PATH_SEPARATOR_REGEX);
if (parts.length == 0) {
return;
}
Node node = root;
for (String part : parts) {
if (node != root && node.children.isEmpty()) {
// The given path is a sub-path of an existing leaf node in the tree.
output.addFieldPath(path);
return;
}
if (node.children.containsKey(part)) {
node = node.children.get(part);
} else {
return;
}
}
// We found a matching node for the path. All leaf children of this matching
// node is in the intersection.
List paths = new ArrayList();
getFieldPaths(node, path, paths);
for (String value : paths) {
output.addFieldPath(value);
}
}
/**
* Merges all fields specified by this FieldMaskTree from {@code source} to {@code destination}.
*/
void merge(Message source, Message.Builder destination, FieldMaskUtil.MergeOptions options) {
if (source.getDescriptorForType() != destination.getDescriptorForType()) {
throw new IllegalArgumentException("Cannot merge messages of different types.");
}
if (root.children.isEmpty()) {
return;
}
merge(root, "", source, destination, options);
}
/**
* Merges all fields specified by a sub-tree from {@code source} to {@code destination}.
*/
private void merge(
Node node,
String path,
Message source,
Message.Builder destination,
FieldMaskUtil.MergeOptions options) {
if (source.getDescriptorForType() != destination.getDescriptorForType()) {
throw new IllegalArgumentException(
String.format(
"source (%s) and destination (%s) descriptor must be equal",
source.getDescriptorForType(), destination.getDescriptorForType()));
}
Descriptor descriptor = source.getDescriptorForType();
for (Entry entry : node.children.entrySet()) {
FieldDescriptor field = descriptor.findFieldByName(entry.getKey());
if (field == null) {
logger.warning(
"Cannot find field \""
+ entry.getKey()
+ "\" in message type "
+ descriptor.getFullName());
continue;
}
if (!entry.getValue().children.isEmpty()) {
if (field.isRepeated() || field.getJavaType() != FieldDescriptor.JavaType.MESSAGE) {
logger.warning(
"Field \""
+ field.getFullName()
+ "\" is not a "
+ "singular message field and cannot have sub-fields.");
continue;
}
if (!source.hasField(field) && !destination.hasField(field)) {
// If the message field is not present in both source and destination, skip recursing
// so we don't create unnecessary empty messages.
continue;
}
String childPath = path.isEmpty() ? entry.getKey() : path + "." + entry.getKey();
Message.Builder childBuilder = ((Message) destination.getField(field)).toBuilder();
merge(entry.getValue(), childPath, (Message) source.getField(field), childBuilder, options);
destination.setField(field, childBuilder.buildPartial());
continue;
}
if (field.isRepeated()) {
if (options.replaceRepeatedFields()) {
destination.setField(field, source.getField(field));
} else {
for (Object element : (List) source.getField(field)) {
destination.addRepeatedField(field, element);
}
}
} else {
if (field.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
if (options.replaceMessageFields()) {
if (!source.hasField(field)) {
destination.clearField(field);
} else {
destination.setField(field, source.getField(field));
}
} else {
if (source.hasField(field)) {
destination.setField(
field,
((Message) destination.getField(field))
.toBuilder()
.mergeFrom((Message) source.getField(field))
.build());
}
}
} else {
if (source.hasField(field) || !options.replacePrimitiveFields()) {
destination.setField(field, source.getField(field));
} else {
destination.clearField(field);
}
}
}
}
}
}