1 // Protocol Buffers - Google's data interchange format 2 // Copyright 2008 Google Inc. All rights reserved. 3 // https://developers.google.com/protocol-buffers/ 4 // 5 // Redistribution and use in source and binary forms, with or without 6 // modification, are permitted provided that the following conditions are 7 // met: 8 // 9 // * Redistributions of source code must retain the above copyright 10 // notice, this list of conditions and the following disclaimer. 11 // * Redistributions in binary form must reproduce the above 12 // copyright notice, this list of conditions and the following disclaimer 13 // in the documentation and/or other materials provided with the 14 // distribution. 15 // * Neither the name of Google Inc. nor the names of its 16 // contributors may be used to endorse or promote products derived from 17 // this software without specific prior written permission. 18 // 19 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 20 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 21 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 22 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 23 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 24 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 25 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 26 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 27 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 28 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 29 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 30 31 package com.google.protobuf; 32 33 import java.util.Collections; 34 import java.util.HashMap; 35 import java.util.Map; 36 37 /** 38 * Equivalent to {@link ExtensionRegistry} but supports only "lite" types. 39 * 40 * <p>If all of your types are lite types, then you only need to use {@code ExtensionRegistryLite}. 41 * Similarly, if all your types are regular types, then you only need {@link ExtensionRegistry}. 42 * Typically it does not make sense to mix the two, since if you have any regular types in your 43 * program, you then require the full runtime and lose all the benefits of the lite runtime, so you 44 * might as well make all your types be regular types. However, in some cases (e.g. when depending 45 * on multiple third-party libraries where one uses lite types and one uses regular), you may find 46 * yourself wanting to mix the two. In this case things get more complicated. 47 * 48 * <p>There are three factors to consider: Whether the type being extended is lite, whether the 49 * embedded type (in the case of a message-typed extension) is lite, and whether the extension 50 * itself is lite. Since all three are declared in different files, they could all be different. 51 * Here are all the combinations and which type of registry to use: 52 * 53 * <pre> 54 * Extended type Inner type Extension Use registry 55 * ======================================================================= 56 * lite lite lite ExtensionRegistryLite 57 * lite regular lite ExtensionRegistry 58 * regular regular regular ExtensionRegistry 59 * all other combinations not supported 60 * </pre> 61 * 62 * <p>Note that just as regular types are not allowed to contain lite-type fields, they are also not 63 * allowed to contain lite-type extensions. This is because regular types must be fully accessible 64 * via reflection, which in turn means that all the inner messages must also support reflection. On 65 * the other hand, since regular types implement the entire lite interface, there is no problem with 66 * embedding regular types inside lite types. 67 * 68 * @author kenton@google.com Kenton Varda 69 */ 70 public class ExtensionRegistryLite { 71 72 // Set true to enable lazy parsing feature for MessageSet. 73 // 74 // TODO(xiangl): Now we use a global flag to control whether enable lazy 75 // parsing feature for MessageSet, which may be too crude for some 76 // applications. Need to support this feature on smaller granularity. 77 private static volatile boolean eagerlyParseMessageSets = false; 78 79 // short circuit the ExtensionRegistryFactory via assumevalues trickery 80 @SuppressWarnings("JavaOptionalSuggestions") 81 private static boolean doFullRuntimeInheritanceCheck = true; 82 83 // Visible for testing. 84 static final String EXTENSION_CLASS_NAME = "com.google.protobuf.Extension"; 85 86 /* @Nullable */ resolveExtensionClass()87 static Class<?> resolveExtensionClass() { 88 try { 89 return Class.forName(EXTENSION_CLASS_NAME); 90 } catch (ClassNotFoundException e) { 91 // See comment in ExtensionRegistryFactory on the potential expense of this. 92 return null; 93 } 94 } 95 96 /* @Nullable */ 97 private static final Class<?> extensionClass = resolveExtensionClass(); 98 isEagerlyParseMessageSets()99 public static boolean isEagerlyParseMessageSets() { 100 return eagerlyParseMessageSets; 101 } 102 setEagerlyParseMessageSets(boolean isEagerlyParse)103 public static void setEagerlyParseMessageSets(boolean isEagerlyParse) { 104 eagerlyParseMessageSets = isEagerlyParse; 105 } 106 107 /** 108 * Construct a new, empty instance. 109 * 110 * <p>This may be an {@code ExtensionRegistry} if the full (non-Lite) proto libraries are 111 * available. 112 */ newInstance()113 public static ExtensionRegistryLite newInstance() { 114 return doFullRuntimeInheritanceCheck 115 ? ExtensionRegistryFactory.create() 116 : new ExtensionRegistryLite(); 117 } 118 119 private static volatile ExtensionRegistryLite emptyRegistry; 120 121 /** 122 * Get the unmodifiable singleton empty instance of either ExtensionRegistryLite or {@code 123 * ExtensionRegistry} (if the full (non-Lite) proto libraries are available). 124 */ getEmptyRegistry()125 public static ExtensionRegistryLite getEmptyRegistry() { 126 ExtensionRegistryLite result = emptyRegistry; 127 if (result == null) { 128 synchronized (ExtensionRegistryLite.class) { 129 result = emptyRegistry; 130 if (result == null) { 131 result = 132 emptyRegistry = 133 doFullRuntimeInheritanceCheck 134 ? ExtensionRegistryFactory.createEmpty() 135 : EMPTY_REGISTRY_LITE; 136 } 137 } 138 } 139 return result; 140 } 141 142 143 /** Returns an unmodifiable view of the registry. */ getUnmodifiable()144 public ExtensionRegistryLite getUnmodifiable() { 145 return new ExtensionRegistryLite(this); 146 } 147 148 /** 149 * Find an extension by containing type and field number. 150 * 151 * @return Information about the extension if found, or {@code null} otherwise. 152 */ 153 @SuppressWarnings("unchecked") 154 public <ContainingType extends MessageLite> findLiteExtensionByNumber( final ContainingType containingTypeDefaultInstance, final int fieldNumber)155 GeneratedMessageLite.GeneratedExtension<ContainingType, ?> findLiteExtensionByNumber( 156 final ContainingType containingTypeDefaultInstance, final int fieldNumber) { 157 return (GeneratedMessageLite.GeneratedExtension<ContainingType, ?>) 158 extensionsByNumber.get(new ObjectIntPair(containingTypeDefaultInstance, fieldNumber)); 159 } 160 161 /** Add an extension from a lite generated file to the registry. */ add(final GeneratedMessageLite.GeneratedExtension<?, ?> extension)162 public final void add(final GeneratedMessageLite.GeneratedExtension<?, ?> extension) { 163 extensionsByNumber.put( 164 new ObjectIntPair(extension.getContainingTypeDefaultInstance(), extension.getNumber()), 165 extension); 166 } 167 168 /** 169 * Add an extension from a lite generated file to the registry only if it is a non-lite extension 170 * i.e. {@link GeneratedMessageLite.GeneratedExtension}. 171 */ add(ExtensionLite<?, ?> extension)172 public final void add(ExtensionLite<?, ?> extension) { 173 if (GeneratedMessageLite.GeneratedExtension.class.isAssignableFrom(extension.getClass())) { 174 add((GeneratedMessageLite.GeneratedExtension<?, ?>) extension); 175 } 176 if (doFullRuntimeInheritanceCheck && ExtensionRegistryFactory.isFullRegistry(this)) { 177 try { 178 this.getClass().getMethod("add", extensionClass).invoke(this, extension); 179 } catch (Exception e) { 180 throw new IllegalArgumentException( 181 String.format("Could not invoke ExtensionRegistry#add for %s", extension), e); 182 } 183 } 184 } 185 186 // ================================================================= 187 // Private stuff. 188 189 // Constructors are package-private so that ExtensionRegistry can subclass 190 // this. 191 ExtensionRegistryLite()192 ExtensionRegistryLite() { 193 this.extensionsByNumber = 194 new HashMap<ObjectIntPair, GeneratedMessageLite.GeneratedExtension<?, ?>>(); 195 } 196 197 static final ExtensionRegistryLite EMPTY_REGISTRY_LITE = new ExtensionRegistryLite(true); 198 ExtensionRegistryLite(ExtensionRegistryLite other)199 ExtensionRegistryLite(ExtensionRegistryLite other) { 200 if (other == EMPTY_REGISTRY_LITE) { 201 this.extensionsByNumber = Collections.emptyMap(); 202 } else { 203 this.extensionsByNumber = Collections.unmodifiableMap(other.extensionsByNumber); 204 } 205 } 206 207 private final Map<ObjectIntPair, GeneratedMessageLite.GeneratedExtension<?, ?>> 208 extensionsByNumber; 209 ExtensionRegistryLite(boolean empty)210 ExtensionRegistryLite(boolean empty) { 211 this.extensionsByNumber = Collections.emptyMap(); 212 } 213 214 /** A (Object, int) pair, used as a map key. */ 215 private static final class ObjectIntPair { 216 private final Object object; 217 private final int number; 218 ObjectIntPair(final Object object, final int number)219 ObjectIntPair(final Object object, final int number) { 220 this.object = object; 221 this.number = number; 222 } 223 224 @Override hashCode()225 public int hashCode() { 226 return System.identityHashCode(object) * ((1 << 16) - 1) + number; 227 } 228 229 @Override equals(final Object obj)230 public boolean equals(final Object obj) { 231 if (!(obj instanceof ObjectIntPair)) { 232 return false; 233 } 234 final ObjectIntPair other = (ObjectIntPair) obj; 235 return object == other.object && number == other.number; 236 } 237 } 238 } 239