gRPC Protobuf Lite

import io.grpc.protobuf.lite.ProtoLiteUtils;
import io.grpc.MethodDescriptor.Marshaller;
import io.grpc.Metadata.BinaryMarshaller;
import com.google.protobuf.ExtensionRegistryLite;

import io.grpc.protobuf.lite.ProtoLiteUtils;
import io.grpc.MethodDescriptor.Marshaller;
import io.grpc.Metadata.BinaryMarshaller;
import com.google.protobuf.MessageLite;
import com.google.protobuf.ExtensionRegistryLite;

// Create a marshaller for a protobuf lite message
MyMessageLite defaultInstance = MyMessageLite.getDefaultInstance();
Marshaller<MyMessageLite> marshaller = ProtoLiteUtils.marshaller(defaultInstance);

// Create a marshaller with recursion limit
Marshaller<MyMessageLite> limitedMarshaller = ProtoLiteUtils.marshallerWithRecursionLimit(
    defaultInstance, 100);

// Create a metadata marshaller
BinaryMarshaller<MyMessageLite> metaMarshaller = ProtoLiteUtils.metadataMarshaller(defaultInstance);

// Set global extension registry (if needed)
ExtensionRegistryLite registry = ExtensionRegistryLite.newInstance();
// ... configure registry
ProtoLiteUtils.setExtensionRegistry(registry);

/**
 * Creates a Marshaller for protos of the same type as defaultInstance.
 * @param defaultInstance the default instance of the message type
 * @return Marshaller for the message type
 * @since 1.0.0
 */
public static <T extends MessageLite> Marshaller<T> marshaller(T defaultInstance);

/**
 * Creates a Marshaller with custom recursion depth limit.
 * @param defaultInstance the default instance of the message type  
 * @param recursionLimit custom limit for recursion depth, negative values use default
 * @return Marshaller for the message type with recursion limit
 * @since 1.56.0
 */
public static <T extends MessageLite> Marshaller<T> marshallerWithRecursionLimit(
    T defaultInstance, int recursionLimit);

/**
 * Produce a metadata marshaller for a protobuf type.
 * @param defaultInstance the default instance of the message type
 * @return BinaryMarshaller for metadata serialization
 * @since 1.0.0
 */
public static <T extends MessageLite> Metadata.BinaryMarshaller<T> metadataMarshaller(
    T defaultInstance);

/**
 * Sets the global registry for proto marshalling shared across all servers and clients.
 * Warning: This API will likely change over time. Do not modify registry after setting.
 * @param newRegistry the extension registry to set globally
 * @since 1.0.0
 */
public static void setExtensionRegistry(ExtensionRegistryLite newRegistry);

/**
 * Input stream backed by a protobuf message with zero-copy optimization.
 * Package-private class used internally by marshallers.
 */
final class ProtoInputStream extends InputStream implements Drainable, KnownLength {
    // Constructor
    ProtoInputStream(MessageLite message, Parser<?> parser);
    
    // InputStream methods
    public int read() throws IOException;
    public int read(byte[] b, int off, int len) throws IOException;
    public int available();
    
    // Drainable interface
    public int drainTo(OutputStream target) throws IOException;
    
    // Package-private access methods
    MessageLite message();
    Parser<?> parser();
}

/**
 * Internal marshaller implementation for protobuf messages.
 * Implements PrototypeMarshaller interface for efficient serialization.
 */
private static final class MessageMarshaller<T extends MessageLite> 
    implements PrototypeMarshaller<T> {
    
    public Class<T> getMessageClass();
    public T getMessagePrototype();  
    public InputStream stream(T value);
    public T parse(InputStream stream);
}

/**
 * Internal marshaller implementation for metadata.
 * Implements BinaryMarshaller interface for header serialization.
 */
private static final class MetadataMarshaller<T extends MessageLite>
    implements Metadata.BinaryMarshaller<T> {
    
    public byte[] toBytes(T value);
    public T parseBytes(byte[] serialized);
}