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Diffstat (limited to 'java/core/src/main/java/com/google/protobuf/ExtensionRegistry.java')
-rw-r--r-- | java/core/src/main/java/com/google/protobuf/ExtensionRegistry.java | 397 |
1 files changed, 397 insertions, 0 deletions
diff --git a/java/core/src/main/java/com/google/protobuf/ExtensionRegistry.java b/java/core/src/main/java/com/google/protobuf/ExtensionRegistry.java new file mode 100644 index 00000000..1c2e7e6f --- /dev/null +++ b/java/core/src/main/java/com/google/protobuf/ExtensionRegistry.java @@ -0,0 +1,397 @@ +// Protocol Buffers - Google's data interchange format +// Copyright 2008 Google Inc. All rights reserved. +// https://developers.google.com/protocol-buffers/ +// +// Redistribution and use in source and binary forms, with or without +// 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 +// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +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; + } + } +} |