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 * <p> 40 * If all of your types are lite types, then you only need to use 41 * {@code ExtensionRegistryLite}. Similarly, if all your types are regular 42 * types, then you only need {@link ExtensionRegistry}. Typically it does not 43 * make sense to mix the two, since if you have any regular types in your 44 * program, you then require the full runtime and lose all the benefits of 45 * the lite runtime, so you might as well make all your types be regular types. 46 * However, in some cases (e.g. when depending on multiple third-party libraries 47 * where one uses lite types and one uses regular), you may find yourself 48 * wanting to mix the two. In this case things get more complicated. 49 * <p> 50 * There are three factors to consider: Whether the type being extended is 51 * lite, whether the embedded type (in the case of a message-typed extension) 52 * is lite, and whether the extension itself is lite. Since all three are 53 * declared in different files, they could all be different. Here are all 54 * the combinations and which type of registry to use: 55 * <pre> 56 * Extended type Inner type Extension Use registry 57 * ======================================================================= 58 * lite lite lite ExtensionRegistryLite 59 * lite regular lite ExtensionRegistry 60 * regular regular regular ExtensionRegistry 61 * all other combinations not supported 62 * </pre> 63 * <p> 64 * Note that just as regular types are not allowed to contain lite-type fields, 65 * they are also not allowed to contain lite-type extensions. This is because 66 * regular types must be fully accessible via reflection, which in turn means 67 * that all the inner messages must also support reflection. On the other hand, 68 * since regular types implement the entire lite interface, there is no problem 69 * with embedding regular types inside lite types. 70 * 71 * @author kenton@google.com Kenton Varda 72 */ 73 public class ExtensionRegistryLite { 74 75 // Set true to enable lazy parsing feature for MessageSet. 76 // 77 // TODO(xiangl): Now we use a global flag to control whether enable lazy 78 // parsing feature for MessageSet, which may be too crude for some 79 // applications. Need to support this feature on smaller granularity. 80 private static volatile boolean eagerlyParseMessageSets = false; 81 82 // Visible for testing. 83 static final String EXTENSION_CLASS_NAME = "com.google.protobuf.Extension"; 84 85 /* @Nullable */ resolveExtensionClass()86 static Class<?> resolveExtensionClass() { 87 try { 88 return Class.forName(EXTENSION_CLASS_NAME); 89 } catch (ClassNotFoundException e) { 90 // See comment in ExtensionRegistryFactory on the potential expense of this. 91 return null; 92 } 93 } 94 95 /* @Nullable */ 96 private static final Class<?> extensionClass = resolveExtensionClass(); 97 isEagerlyParseMessageSets()98 public static boolean isEagerlyParseMessageSets() { 99 return eagerlyParseMessageSets; 100 } 101 setEagerlyParseMessageSets(boolean isEagerlyParse)102 public static void setEagerlyParseMessageSets(boolean isEagerlyParse) { 103 eagerlyParseMessageSets = isEagerlyParse; 104 } 105 106 /** 107 * Construct a new, empty instance. 108 * 109 * <p> 110 * This may be an {@code ExtensionRegistry} if the full (non-Lite) proto libraries are available. 111 */ newInstance()112 public static ExtensionRegistryLite newInstance() { 113 return ExtensionRegistryFactory.create(); 114 } 115 116 /** 117 * Get the unmodifiable singleton empty instance of either ExtensionRegistryLite or 118 * {@code ExtensionRegistry} (if the full (non-Lite) proto libraries are available). 119 */ getEmptyRegistry()120 public static ExtensionRegistryLite getEmptyRegistry() { 121 return ExtensionRegistryFactory.createEmpty(); 122 } 123 124 /** Returns an unmodifiable view of the registry. */ getUnmodifiable()125 public ExtensionRegistryLite getUnmodifiable() { 126 return new ExtensionRegistryLite(this); 127 } 128 129 /** 130 * Find an extension by containing type and field number. 131 * 132 * @return Information about the extension if found, or {@code null} 133 * otherwise. 134 */ 135 @SuppressWarnings("unchecked") 136 public <ContainingType extends MessageLite> 137 GeneratedMessageLite.GeneratedExtension<ContainingType, ?> findLiteExtensionByNumber( final ContainingType containingTypeDefaultInstance, final int fieldNumber)138 findLiteExtensionByNumber( 139 final ContainingType containingTypeDefaultInstance, 140 final int fieldNumber) { 141 return (GeneratedMessageLite.GeneratedExtension<ContainingType, ?>) 142 extensionsByNumber.get( 143 new ObjectIntPair(containingTypeDefaultInstance, fieldNumber)); 144 } 145 146 /** Add an extension from a lite generated file to the registry. */ add( final GeneratedMessageLite.GeneratedExtension<?, ?> extension)147 public final void add( 148 final GeneratedMessageLite.GeneratedExtension<?, ?> extension) { 149 extensionsByNumber.put( 150 new ObjectIntPair(extension.getContainingTypeDefaultInstance(), 151 extension.getNumber()), 152 extension); 153 } 154 155 /** 156 * Add an extension from a lite generated file to the registry only if it is 157 * a non-lite extension i.e. {@link GeneratedMessageLite.GeneratedExtension}. */ add(ExtensionLite<?, ?> extension)158 public final void add(ExtensionLite<?, ?> extension) { 159 if (GeneratedMessageLite.GeneratedExtension.class.isAssignableFrom(extension.getClass())) { 160 add((GeneratedMessageLite.GeneratedExtension<?, ?>) extension); 161 } 162 if (ExtensionRegistryFactory.isFullRegistry(this)) { 163 try { 164 this.getClass().getMethod("add", extensionClass).invoke(this, extension); 165 } catch (Exception e) { 166 throw new IllegalArgumentException( 167 String.format("Could not invoke ExtensionRegistry#add for %s", extension), e); 168 } 169 } 170 } 171 172 // ================================================================= 173 // Private stuff. 174 175 // Constructors are package-private so that ExtensionRegistry can subclass 176 // this. 177 ExtensionRegistryLite()178 ExtensionRegistryLite() { 179 this.extensionsByNumber = 180 new HashMap<ObjectIntPair, 181 GeneratedMessageLite.GeneratedExtension<?, ?>>(); 182 } 183 static final ExtensionRegistryLite EMPTY_REGISTRY_LITE = 184 new ExtensionRegistryLite(true); 185 ExtensionRegistryLite(ExtensionRegistryLite other)186 ExtensionRegistryLite(ExtensionRegistryLite other) { 187 if (other == EMPTY_REGISTRY_LITE) { 188 this.extensionsByNumber = Collections.emptyMap(); 189 } else { 190 this.extensionsByNumber = 191 Collections.unmodifiableMap(other.extensionsByNumber); 192 } 193 } 194 195 private final Map<ObjectIntPair, 196 GeneratedMessageLite.GeneratedExtension<?, ?>> 197 extensionsByNumber; 198 ExtensionRegistryLite(boolean empty)199 ExtensionRegistryLite(boolean empty) { 200 this.extensionsByNumber = Collections.emptyMap(); 201 } 202 203 /** A (Object, int) pair, used as a map key. */ 204 private static final class ObjectIntPair { 205 private final Object object; 206 private final int number; 207 ObjectIntPair(final Object object, final int number)208 ObjectIntPair(final Object object, final int number) { 209 this.object = object; 210 this.number = number; 211 } 212 213 @Override hashCode()214 public int hashCode() { 215 return System.identityHashCode(object) * ((1 << 16) - 1) + number; 216 } 217 @Override equals(final Object obj)218 public boolean equals(final Object obj) { 219 if (!(obj instanceof ObjectIntPair)) { 220 return false; 221 } 222 final ObjectIntPair other = (ObjectIntPair)obj; 223 return object == other.object && number == other.number; 224 } 225 } 226 } 227