Pull new version of protobuf sources.

third_party/protobuf/java/src/main/java/com/google/protobuf/ExtensionRegistry.java

Index: third_party/protobuf/java/src/main/java/com/google/protobuf/ExtensionRegistry.java
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+// 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;
+  }
+
+
+  /** 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());
+  }
+
+  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(ExtensionRegistryLite.getEmptyRegistry());
+    this.immutableExtensionsByName =
+        Collections.<String, ExtensionInfo>emptyMap();
+    this.mutableExtensionsByName =
+        Collections.<String, ExtensionInfo>emptyMap();
+    this.immutableExtensionsByNumber =
+        Collections.<DescriptorIntPair, ExtensionInfo>emptyMap();
+    this.mutableExtensionsByNumber =
+            Collections.<DescriptorIntPair, ExtensionInfo>emptyMap();
+  }
+  private static final ExtensionRegistry EMPTY = 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;
+    }
+  }
+}