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Diffstat (limited to 'third_party/protobuf/java/core/src/main/java/com/google/protobuf/LazyFieldLite.java')
| -rw-r--r-- | third_party/protobuf/java/core/src/main/java/com/google/protobuf/LazyFieldLite.java | 437 |
1 files changed, 0 insertions, 437 deletions
diff --git a/third_party/protobuf/java/core/src/main/java/com/google/protobuf/LazyFieldLite.java b/third_party/protobuf/java/core/src/main/java/com/google/protobuf/LazyFieldLite.java deleted file mode 100644 index 4b0ba0fd6b..0000000000 --- a/third_party/protobuf/java/core/src/main/java/com/google/protobuf/LazyFieldLite.java +++ /dev/null @@ -1,437 +0,0 @@ -// 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 java.io.IOException; - -/** - * LazyFieldLite encapsulates the logic of lazily parsing message fields. It stores - * the message in a ByteString initially and then parses it on-demand. - * - * LazyFieldLite is thread-compatible: concurrent reads are safe once the proto that this - * LazyFieldLite is a part of is no longer being mutated by its Builder. However, explicit - * synchronization is needed under read/write situations. - * - * When a LazyFieldLite is used in the context of a MessageLite object, its behavior is considered - * to be immutable and none of the setter methods in its API are expected to be invoked. All of the - * getters are expected to be thread-safe. When used in the context of a MessageLite.Builder, - * setters can be invoked, but there is no guarantee of thread safety. - * - * TODO(yatin,dweis): Consider splitting this class's functionality and put the mutable methods - * into a separate builder class to allow us to give stronger compile-time guarantees. - * - * This class is internal implementation detail of the protobuf library, so you don't need to use it - * directly. - * - * @author xiangl@google.com (Xiang Li) - */ -public class LazyFieldLite { - private static final ExtensionRegistryLite EMPTY_REGISTRY = - ExtensionRegistryLite.getEmptyRegistry(); - - /** - * The value associated with the LazyFieldLite object is stored in one or more of the following - * three fields (delayedBytes, value, memoizedBytes). They should together be interpreted as - * follows. - * 1) delayedBytes can be non-null, while value and memoizedBytes is null. The object will be in - * this state while the value for the object has not yet been parsed. - * 2) Both delayedBytes and value are non-null. The object transitions to this state as soon as - * some caller needs to access the value (by invoking getValue()). - * 3) memoizedBytes is merely an optimization for calls to LazyFieldLite.toByteString() to avoid - * recomputing the ByteString representation on each call. Instead, when the value is parsed - * from delayedBytes, we will also assign the contents of delayedBytes to memoizedBytes (since - * that is the ByteString representation of value). - * 4) Finally, if the LazyFieldLite was created directly with a parsed MessageLite value, then - * delayedBytes will be null, and memoizedBytes will be initialized only upon the first call to - * LazyFieldLite.toByteString(). - * - * Given the above conditions, any caller that needs a serialized representation of this object - * must first check if the memoizedBytes or delayedBytes ByteString is non-null and use it - * directly; if both of those are null, it can look at the parsed value field. Similarly, any - * caller that needs a parsed value must first check if the value field is already non-null, if - * not it must parse the value from delayedBytes. - */ - - /** - * A delayed-parsed version of the contents of this field. When this field is non-null, then the - * "value" field is allowed to be null until the time that the value needs to be read. - * - * When delayedBytes is non-null then {@code extensionRegistry} is required to also be non-null. - * {@code value} and {@code memoizedBytes} will be initialized lazily. - */ - private ByteString delayedBytes; - - /** - * An {@code ExtensionRegistryLite} for parsing bytes. It is non-null on a best-effort basis. It - * is only guaranteed to be non-null if this message was initialized using bytes and an - * {@code ExtensionRegistry}. If it directly had a value set then it will be null, unless it has - * been merged with another {@code LazyFieldLite} that had an {@code ExtensionRegistry}. - */ - private ExtensionRegistryLite extensionRegistry; - - /** - * The parsed value. When this is null and a caller needs access to the MessageLite value, then - * {@code delayedBytes} will be parsed lazily at that time. - */ - protected volatile MessageLite value; - - /** - * The memoized bytes for {@code value}. This is an optimization for the toByteString() method to - * not have to recompute its return-value on each invocation. - * TODO(yatin): Figure out whether this optimization is actually necessary. - */ - private volatile ByteString memoizedBytes; - - /** - * Constructs a LazyFieldLite with bytes that will be parsed lazily. - */ - public LazyFieldLite(ExtensionRegistryLite extensionRegistry, ByteString bytes) { - checkArguments(extensionRegistry, bytes); - this.extensionRegistry = extensionRegistry; - this.delayedBytes = bytes; - } - - /** - * Constructs a LazyFieldLite with no contents, and no ability to parse extensions. - */ - public LazyFieldLite() { - } - - /** - * Constructs a LazyFieldLite instance with a value. The LazyFieldLite may not be able to parse - * the extensions in the value as it has no ExtensionRegistry. - */ - public static LazyFieldLite fromValue(MessageLite value) { - LazyFieldLite lf = new LazyFieldLite(); - lf.setValue(value); - return lf; - } - - @Override - public boolean equals(Object o) { - if (this == o) { - return true; - } - - if (!(o instanceof LazyFieldLite)) { - return false; - } - - LazyFieldLite other = (LazyFieldLite) o; - - // Lazy fields do not work well with equals... If both are delayedBytes, we do not have a - // mechanism to deserialize them so we rely on bytes equality. Otherwise we coerce into an - // actual message (if necessary) and call equals on the message itself. This implies that two - // messages can by unequal but then be turned equal simply be invoking a getter on a lazy field. - MessageLite value1 = value; - MessageLite value2 = other.value; - if (value1 == null && value2 == null) { - return toByteString().equals(other.toByteString()); - } else if (value1 != null && value2 != null) { - return value1.equals(value2); - } else if (value1 != null) { - return value1.equals(other.getValue(value1.getDefaultInstanceForType())); - } else { - return getValue(value2.getDefaultInstanceForType()).equals(value2); - } - } - - @Override - public int hashCode() { - // We can't provide a memoizable hash code for lazy fields. The byte strings may have different - // hash codes but evaluate to equivalent messages. And we have no facility for constructing - // a message here if we were not already holding a value. - return 1; - } - - /** - * Determines whether this LazyFieldLite instance represents the default instance of this type. - */ - public boolean containsDefaultInstance() { - return memoizedBytes == ByteString.EMPTY - || value == null && (delayedBytes == null || delayedBytes == ByteString.EMPTY); - } - - /** - * Clears the value state of this instance. - * - * <p>LazyField is not thread-safe for write access. Synchronizations are needed - * under read/write situations. - */ - public void clear() { - // Don't clear the ExtensionRegistry. It might prove useful later on when merging in another - // value, but there is no guarantee that it will contain all extensions that were directly set - // on the values that need to be merged. - delayedBytes = null; - value = null; - memoizedBytes = null; - } - - /** - * Overrides the contents of this LazyField. - * - * <p>LazyField is not thread-safe for write access. Synchronizations are needed - * under read/write situations. - */ - public void set(LazyFieldLite other) { - this.delayedBytes = other.delayedBytes; - this.value = other.value; - this.memoizedBytes = other.memoizedBytes; - // If the other LazyFieldLite was created by directly setting the value rather than first by - // parsing, then it will not have an extensionRegistry. In this case we hold on to the existing - // extensionRegistry, which has no guarantees that it has all the extensions that will be - // directly set on the value. - if (other.extensionRegistry != null) { - this.extensionRegistry = other.extensionRegistry; - } - } - - /** - * Returns message instance. It may do some thread-safe delayed parsing of bytes. - * - * @param defaultInstance its message's default instance. It's also used to get parser for the - * message type. - */ - public MessageLite getValue(MessageLite defaultInstance) { - ensureInitialized(defaultInstance); - return value; - } - - /** - * Sets the value of the instance and returns the old value without delay parsing anything. - * - * <p>LazyField is not thread-safe for write access. Synchronizations are needed - * under read/write situations. - */ - public MessageLite setValue(MessageLite value) { - MessageLite originalValue = this.value; - this.delayedBytes = null; - this.memoizedBytes = null; - this.value = value; - return originalValue; - } - - /** - * Merges another instance's contents. In some cases may drop some extensions if both fields - * contain data. If the other field has an {@code ExtensionRegistry} but this does not, then this - * field will copy over that {@code ExtensionRegistry}. - * - * <p>LazyField is not thread-safe for write access. Synchronizations are needed - * under read/write situations. - */ - public void merge(LazyFieldLite other) { - if (other.containsDefaultInstance()) { - return; - } - - if (this.containsDefaultInstance()) { - set(other); - return; - } - - // If the other field has an extension registry but this does not, copy over the other extension - // registry. - if (this.extensionRegistry == null) { - this.extensionRegistry = other.extensionRegistry; - } - - // In the case that both of them are not parsed we simply concatenate the bytes to save time. In - // the (probably rare) case that they have different extension registries there is a chance that - // some of the extensions may be dropped, but the tradeoff of making this operation fast seems - // to outway the benefits of combining the extension registries, which is not normally done for - // lite protos anyways. - if (this.delayedBytes != null && other.delayedBytes != null) { - this.delayedBytes = this.delayedBytes.concat(other.delayedBytes); - return; - } - - // At least one is parsed and both contain data. We won't drop any extensions here directly, but - // in the case that the extension registries are not the same then we might in the future if we - // need to serialze and parse a message again. - if (this.value == null && other.value != null) { - setValue(mergeValueAndBytes(other.value, this.delayedBytes, this.extensionRegistry)); - return; - } else if (this.value != null && other.value == null) { - setValue(mergeValueAndBytes(this.value, other.delayedBytes, other.extensionRegistry)); - return; - } - - // At this point we have two fully parsed messages. - setValue(this.value.toBuilder().mergeFrom(other.value).build()); - } - - /** - * Merges another instance's contents from a stream. - * - * <p>LazyField is not thread-safe for write access. Synchronizations are needed - * under read/write situations. - */ - public void mergeFrom(CodedInputStream input, ExtensionRegistryLite extensionRegistry) - throws IOException { - if (this.containsDefaultInstance()) { - setByteString(input.readBytes(), extensionRegistry); - return; - } - - // If the other field has an extension registry but this does not, copy over the other extension - // registry. - if (this.extensionRegistry == null) { - this.extensionRegistry = extensionRegistry; - } - - // In the case that both of them are not parsed we simply concatenate the bytes to save time. In - // the (probably rare) case that they have different extension registries there is a chance that - // some of the extensions may be dropped, but the tradeoff of making this operation fast seems - // to outway the benefits of combining the extension registries, which is not normally done for - // lite protos anyways. - if (this.delayedBytes != null) { - setByteString(this.delayedBytes.concat(input.readBytes()), this.extensionRegistry); - return; - } - - // We are parsed and both contain data. We won't drop any extensions here directly, but in the - // case that the extension registries are not the same then we might in the future if we - // need to serialize and parse a message again. - try { - setValue(value.toBuilder().mergeFrom(input, extensionRegistry).build()); - } catch (InvalidProtocolBufferException e) { - // Nothing is logged and no exceptions are thrown. Clients will be unaware that a proto - // was invalid. - } - } - - private static MessageLite mergeValueAndBytes( - MessageLite value, ByteString otherBytes, ExtensionRegistryLite extensionRegistry) { - try { - return value.toBuilder().mergeFrom(otherBytes, extensionRegistry).build(); - } catch (InvalidProtocolBufferException e) { - // Nothing is logged and no exceptions are thrown. Clients will be unaware that a proto - // was invalid. - return value; - } - } - - /** - * Sets this field with bytes to delay-parse. - */ - public void setByteString(ByteString bytes, ExtensionRegistryLite extensionRegistry) { - checkArguments(extensionRegistry, bytes); - this.delayedBytes = bytes; - this.extensionRegistry = extensionRegistry; - this.value = null; - this.memoizedBytes = null; - } - - /** - * Due to the optional field can be duplicated at the end of serialized - * bytes, which will make the serialized size changed after LazyField - * parsed. Be careful when using this method. - */ - public int getSerializedSize() { - // We *must* return delayed bytes size if it was ever set because the dependent messages may - // have memoized serialized size based off of it. - if (memoizedBytes != null) { - return memoizedBytes.size(); - } else if (delayedBytes != null) { - return delayedBytes.size(); - } else if (value != null) { - return value.getSerializedSize(); - } else { - return 0; - } - } - - /** - * Returns a BytesString for this field in a thread-safe way. - */ - public ByteString toByteString() { - if (memoizedBytes != null) { - return memoizedBytes; - } - // We *must* return delayed bytes if it was set because the dependent messages may have - // memoized serialized size based off of it. - if (delayedBytes != null) { - return delayedBytes; - } - synchronized (this) { - if (memoizedBytes != null) { - return memoizedBytes; - } - if (value == null) { - memoizedBytes = ByteString.EMPTY; - } else { - memoizedBytes = value.toByteString(); - } - return memoizedBytes; - } - } - - /** - * Might lazily parse the bytes that were previously passed in. Is thread-safe. - */ - protected void ensureInitialized(MessageLite defaultInstance) { - if (value != null) { - return; - } - synchronized (this) { - if (value != null) { - return; - } - try { - if (delayedBytes != null) { - // The extensionRegistry shouldn't be null here since we have delayedBytes. - MessageLite parsedValue = defaultInstance.getParserForType() - .parseFrom(delayedBytes, extensionRegistry); - this.value = parsedValue; - this.memoizedBytes = delayedBytes; - } else { - this.value = defaultInstance; - this.memoizedBytes = ByteString.EMPTY; - } - } catch (InvalidProtocolBufferException e) { - // Nothing is logged and no exceptions are thrown. Clients will be unaware that this proto - // was invalid. - this.value = defaultInstance; - this.memoizedBytes = ByteString.EMPTY; - } - } - } - - - private static void checkArguments(ExtensionRegistryLite extensionRegistry, ByteString bytes) { - if (extensionRegistry == null) { - throw new NullPointerException("found null ExtensionRegistry"); - } - if (bytes == null) { - throw new NullPointerException("found null ByteString"); - } - } -} |