// 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
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//
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package com.google.protobuf;
import com.google.protobuf.
Descriptors.
Descriptor;
import com.google.protobuf.
Descriptors.
FieldDescriptor;
import java.util.
Collection;
import java.util.
Collections;
import java.util.
HashMap;
import java.util.
HashSet;
import java.util.
Map;
import java.util.
Set;
/**
* A table of known extensions, searchable by name or field number. When
* parsing a protocol message that might have extensions, you must provide
* an {@code ExtensionRegistry} in which you have registered any extensions
* that you want to be able to parse. Otherwise, those extensions will just
* be treated like unknown fields.
*
* <p>For example, if you had the {@code .proto} file:
*
* <pre>
* option java_class = "MyProto";
*
* message Foo {
* extensions 1000 to max;
* }
*
* extend Foo {
* optional int32 bar;
* }
* </pre>
*
* Then you might write code like:
*
* <pre>
* ExtensionRegistry registry = ExtensionRegistry.newInstance();
* registry.add(MyProto.bar);
* MyProto.Foo message = MyProto.Foo.parseFrom(input, registry);
* </pre>
*
* <p>Background:
*
* <p>You might wonder why this is necessary. Two alternatives might come to
* mind. First, you might imagine a system where generated extensions are
* automatically registered when their containing classes are loaded. This
* is a popular technique, but is bad design; among other things, it creates a
* situation where behavior can change depending on what classes happen to be
* loaded. It also introduces a security vulnerability, because an
* unprivileged class could cause its code to be called unexpectedly from a
* privileged class by registering itself as an extension of the right type.
*
* <p>Another option you might consider is lazy parsing: do not parse an
* extension until it is first requested, at which point the caller must
* provide a type to use. This introduces a different set of problems. First,
* it would require a mutex lock any time an extension was accessed, which
* would be slow. Second, corrupt data would not be detected until first
* access, at which point it would be much harder to deal with it. Third, it
* could violate the expectation that message objects are immutable, since the
* type provided could be any arbitrary message class. An unprivileged user
* could take advantage of this to inject a mutable object into a message
* belonging to privileged code and create mischief.
*
* @author kenton@google.com Kenton Varda
*/
public class
ExtensionRegistry extends
ExtensionRegistryLite {
/** Construct a new, empty instance. */
public static
ExtensionRegistry newInstance() {
return new
ExtensionRegistry();
}
/** Get the unmodifiable singleton empty instance. */
public static
ExtensionRegistry getEmptyRegistry() {
return
EMPTY_REGISTRY;
}
/** Returns an unmodifiable view of the registry. */
@
Override
public
ExtensionRegistry getUnmodifiable() {
return new
ExtensionRegistry(this);
}
/** A (Descriptor, Message) pair, returned by lookup methods. */
public static final class
ExtensionInfo {
/** The extension's descriptor. */
public final
FieldDescriptor descriptor;
/**
* A default instance of the extension's type, if it has a message type.
* Otherwise, {@code null}.
*/
public final
Message defaultInstance;
private
ExtensionInfo(final
FieldDescriptor descriptor) {
this.
descriptor =
descriptor;
defaultInstance = null;
}
private
ExtensionInfo(final
FieldDescriptor descriptor,
final
Message defaultInstance) {
this.
descriptor =
descriptor;
this.
defaultInstance =
defaultInstance;
}
}
/**
* Deprecated. Use {@link #findImmutableExtensionByName(String)} instead.
*/
public
ExtensionInfo findExtensionByName(final
String fullName) {
return
findImmutableExtensionByName(
fullName);
}
/**
* Find an extension for immutable APIs by fully-qualified field name,
* in the proto namespace. i.e. {@code result.descriptor.fullName()} will
* match {@code fullName} if a match is found.
*
* @return Information about the extension if found, or {@code null}
* otherwise.
*/
public
ExtensionInfo findImmutableExtensionByName(final
String fullName) {
return
immutableExtensionsByName.
get(
fullName);
}
/**
* Find an extension for mutable APIs by fully-qualified field name,
* in the proto namespace. i.e. {@code result.descriptor.fullName()} will
* match {@code fullName} if a match is found.
*
* @return Information about the extension if found, or {@code null}
* otherwise.
*/
public
ExtensionInfo findMutableExtensionByName(final
String fullName) {
return
mutableExtensionsByName.
get(
fullName);
}
/**
* Deprecated. Use {@link #findImmutableExtensionByNumber(
* Descriptors.Descriptor, int)}
*/
public
ExtensionInfo findExtensionByNumber(
final
Descriptor containingType, final int
fieldNumber) {
return
findImmutableExtensionByNumber(
containingType,
fieldNumber);
}
/**
* Find an extension by containing type and field number for immutable APIs.
*
* @return Information about the extension if found, or {@code null}
* otherwise.
*/
public
ExtensionInfo findImmutableExtensionByNumber(
final
Descriptor containingType, final int
fieldNumber) {
return
immutableExtensionsByNumber.
get(
new
DescriptorIntPair(
containingType,
fieldNumber));
}
/**
* Find an extension by containing type and field number for mutable APIs.
*
* @return Information about the extension if found, or {@code null}
* otherwise.
*/
public
ExtensionInfo findMutableExtensionByNumber(
final
Descriptor containingType, final int
fieldNumber) {
return
mutableExtensionsByNumber.
get(
new
DescriptorIntPair(
containingType,
fieldNumber));
}
/**
* Find all extensions for mutable APIs by fully-qualified name of
* extended class. Note that this method is more computationally expensive
* than getting a single extension by name or number.
*
* @return Information about the extensions found, or {@code null} if there
* are none.
*/
public
Set<
ExtensionInfo>
getAllMutableExtensionsByExtendedType(final
String fullName) {
HashSet<
ExtensionInfo>
extensions = new
HashSet<
ExtensionInfo>();
for (
DescriptorIntPair pair :
mutableExtensionsByNumber.
keySet()) {
if (
pair.
descriptor.
getFullName().
equals(
fullName)) {
extensions.
add(
mutableExtensionsByNumber.
get(
pair));
}
}
return
extensions;
}
/**
* Find all extensions for immutable APIs by fully-qualified name of
* extended class. Note that this method is more computationally expensive
* than getting a single extension by name or number.
*
* @return Information about the extensions found, or {@code null} if there
* are none.
*/
public
Set<
ExtensionInfo>
getAllImmutableExtensionsByExtendedType(final
String fullName) {
HashSet<
ExtensionInfo>
extensions = new
HashSet<
ExtensionInfo>();
for (
DescriptorIntPair pair :
immutableExtensionsByNumber.
keySet()) {
if (
pair.
descriptor.
getFullName().
equals(
fullName)) {
extensions.
add(
immutableExtensionsByNumber.
get(
pair));
}
}
return
extensions;
}
/** Add an extension from a generated file to the registry. */
public void
add(final
Extension<?, ?>
extension) {
if (
extension.
getExtensionType() !=
Extension.
ExtensionType.
IMMUTABLE &&
extension.
getExtensionType() !=
Extension.
ExtensionType.
MUTABLE) {
// do not support other extension types. ignore
return;
}
add(
newExtensionInfo(
extension),
extension.
getExtensionType());
}
/** Add an extension from a generated file to the registry. */
public void
add(final
GeneratedMessage.
GeneratedExtension<?, ?>
extension) {
add((
Extension<?, ?>)
extension);
}
static
ExtensionInfo newExtensionInfo(final
Extension<?, ?>
extension) {
if (
extension.
getDescriptor().
getJavaType() ==
FieldDescriptor.
JavaType.
MESSAGE) {
if (
extension.
getMessageDefaultInstance() == null) {
throw new
IllegalStateException(
"Registered message-type extension had null default instance: " +
extension.
getDescriptor().
getFullName());
}
return new
ExtensionInfo(
extension.
getDescriptor(),
(
Message)
extension.
getMessageDefaultInstance());
} else {
return new
ExtensionInfo(
extension.
getDescriptor(), null);
}
}
/** Add a non-message-type extension to the registry by descriptor. */
public void
add(final
FieldDescriptor type) {
if (
type.
getJavaType() ==
FieldDescriptor.
JavaType.
MESSAGE) {
throw new
IllegalArgumentException(
"ExtensionRegistry.add() must be provided a default instance when " +
"adding an embedded message extension.");
}
ExtensionInfo info = new
ExtensionInfo(
type, null);
add(
info,
Extension.
ExtensionType.
IMMUTABLE);
add(
info,
Extension.
ExtensionType.
MUTABLE);
}
/** Add a message-type extension to the registry by descriptor. */
public void
add(final
FieldDescriptor type, final
Message defaultInstance) {
if (
type.
getJavaType() !=
FieldDescriptor.
JavaType.
MESSAGE) {
throw new
IllegalArgumentException(
"ExtensionRegistry.add() provided a default instance for a " +
"non-message extension.");
}
add(new
ExtensionInfo(
type,
defaultInstance),
Extension.
ExtensionType.
IMMUTABLE);
}
// =================================================================
// Private stuff.
private
ExtensionRegistry() {
this.
immutableExtensionsByName = new
HashMap<
String,
ExtensionInfo>();
this.
mutableExtensionsByName = new
HashMap<
String,
ExtensionInfo>();
this.
immutableExtensionsByNumber =
new
HashMap<
DescriptorIntPair,
ExtensionInfo>();
this.
mutableExtensionsByNumber =
new
HashMap<
DescriptorIntPair,
ExtensionInfo>();
}
private
ExtensionRegistry(
ExtensionRegistry other) {
super(
other);
this.
immutableExtensionsByName =
Collections.
unmodifiableMap(
other.
immutableExtensionsByName);
this.
mutableExtensionsByName =
Collections.
unmodifiableMap(
other.
mutableExtensionsByName);
this.
immutableExtensionsByNumber =
Collections.
unmodifiableMap(
other.
immutableExtensionsByNumber);
this.
mutableExtensionsByNumber =
Collections.
unmodifiableMap(
other.
mutableExtensionsByNumber);
}
private final
Map<
String,
ExtensionInfo>
immutableExtensionsByName;
private final
Map<
String,
ExtensionInfo>
mutableExtensionsByName;
private final
Map<
DescriptorIntPair,
ExtensionInfo>
immutableExtensionsByNumber;
private final
Map<
DescriptorIntPair,
ExtensionInfo>
mutableExtensionsByNumber;
ExtensionRegistry(boolean
empty) {
super(
EMPTY_REGISTRY_LITE);
this.
immutableExtensionsByName =
Collections.<
String,
ExtensionInfo>
emptyMap();
this.
mutableExtensionsByName =
Collections.<
String,
ExtensionInfo>
emptyMap();
this.
immutableExtensionsByNumber =
Collections.<
DescriptorIntPair,
ExtensionInfo>
emptyMap();
this.
mutableExtensionsByNumber =
Collections.<
DescriptorIntPair,
ExtensionInfo>
emptyMap();
}
static final
ExtensionRegistry EMPTY_REGISTRY = new
ExtensionRegistry(true);
private void
add(
final
ExtensionInfo extension,
final
Extension.
ExtensionType extensionType) {
if (!
extension.
descriptor.
isExtension()) {
throw new
IllegalArgumentException(
"ExtensionRegistry.add() was given a FieldDescriptor for a regular " +
"(non-extension) field.");
}
Map<
String,
ExtensionInfo>
extensionsByName;
Map<
DescriptorIntPair,
ExtensionInfo>
extensionsByNumber;
switch (
extensionType) {
case
IMMUTABLE:
extensionsByName =
immutableExtensionsByName;
extensionsByNumber =
immutableExtensionsByNumber;
break;
case
MUTABLE:
extensionsByName =
mutableExtensionsByName;
extensionsByNumber =
mutableExtensionsByNumber;
break;
default:
// Ignore the unknown supported type.
return;
}
extensionsByName.
put(
extension.
descriptor.
getFullName(),
extension);
extensionsByNumber.
put(
new
DescriptorIntPair(
extension.
descriptor.
getContainingType(),
extension.
descriptor.
getNumber()),
extension);
final
FieldDescriptor field =
extension.
descriptor;
if (
field.
getContainingType().
getOptions().
getMessageSetWireFormat() &&
field.
getType() ==
FieldDescriptor.
Type.
MESSAGE &&
field.
isOptional() &&
field.
getExtensionScope() ==
field.
getMessageType()) {
// This is an extension of a MessageSet type defined within the extension
// type's own scope. For backwards-compatibility, allow it to be looked
// up by type name.
extensionsByName.
put(
field.
getMessageType().
getFullName(),
extension);
}
}
/** A (GenericDescriptor, int) pair, used as a map key. */
private static final class
DescriptorIntPair {
private final
Descriptor descriptor;
private final int
number;
DescriptorIntPair(final
Descriptor descriptor, final int
number) {
this.
descriptor =
descriptor;
this.
number =
number;
}
@
Override
public int
hashCode() {
return
descriptor.
hashCode() * ((1 << 16) - 1) +
number;
}
@
Override
public boolean
equals(final
Object obj) {
if (!(
obj instanceof
DescriptorIntPair)) {
return false;
}
final
DescriptorIntPair other = (
DescriptorIntPair)
obj;
return
descriptor ==
other.
descriptor &&
number ==
other.
number;
}
}
}