Add ByteBufEncoder and ByteBufDecoder

See gh-24866

spring-core/src/main/java/org/springframework/core/codec/ByteBufDecoder.java

@@ -0,0 +1,69 @@
+/*
+ * Copyright 2002-2020 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.core.codec;
+
+import io.netty.buffer.ByteBuf;
+import io.netty.buffer.Unpooled;
+import org.springframework.core.ResolvableType;
+import org.springframework.core.io.buffer.DataBuffer;
+import org.springframework.core.io.buffer.DataBufferUtils;
+import org.springframework.core.io.buffer.NettyDataBuffer;
+import org.springframework.lang.Nullable;
+import org.springframework.util.MimeType;
+import org.springframework.util.MimeTypeUtils;
+
+import java.util.Map;
+
+/**
+ * Decoder for {@link ByteBuf ByteBufs}.
+ *
+ * @author Vladislav Kisel
+ * @since 5.3
+ */
+public class ByteBufDecoder extends AbstractDataBufferDecoder<ByteBuf> {
+
+	public ByteBufDecoder() {
+		super(MimeTypeUtils.ALL);
+	}
+
+
+	@Override
+	public boolean canDecode(ResolvableType elementType, @Nullable MimeType mimeType) {
+		return (ByteBuf.class.isAssignableFrom(elementType.toClass()) &&
+				super.canDecode(elementType, mimeType));
+	}
+
+	@Override
+	public ByteBuf decode(DataBuffer dataBuffer, ResolvableType elementType,
+			@Nullable MimeType mimeType, @Nullable Map<String, Object> hints) {
+
+		// Copies the dataBuffer if needed only
+		ByteBuf byteBuf;
+		if (dataBuffer instanceof NettyDataBuffer) {
+			byteBuf = ((NettyDataBuffer) dataBuffer).getNativeBuffer();
+		} else {
+			byteBuf = Unpooled.wrappedBuffer(dataBuffer.asByteBuffer());
+			DataBufferUtils.release(dataBuffer);
+		}
+
+		if (logger.isDebugEnabled()) {
+			logger.debug(Hints.getLogPrefix(hints) + "Read " + byteBuf.readableBytes() + " bytes");
+		}
+		return byteBuf;
+	}
+
+}

spring-core/src/main/java/org/springframework/core/codec/ByteBufEncoder.java

@@ -0,0 +1,78 @@
+/*
+ * Copyright 2002-2020 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.core.codec;
+
+import io.netty.buffer.ByteBuf;
+import org.reactivestreams.Publisher;
+import org.springframework.core.ResolvableType;
+import org.springframework.core.io.buffer.DataBuffer;
+import org.springframework.core.io.buffer.DataBufferFactory;
+import org.springframework.core.io.buffer.NettyDataBufferFactory;
+import org.springframework.lang.Nullable;
+import org.springframework.util.MimeType;
+import org.springframework.util.MimeTypeUtils;
+import reactor.core.publisher.Flux;
+
+import java.util.Map;
+
+/**
+ * Encoder for {@link ByteBuf ByteBufs}.
+ *
+ * @author Vladislav Kisel
+ * @since 5.3
+ */
+public class ByteBufEncoder extends AbstractEncoder<ByteBuf> {
+
+	public ByteBufEncoder() {
+		super(MimeTypeUtils.ALL);
+	}
+
+
+	@Override
+	public boolean canEncode(ResolvableType elementType, @Nullable MimeType mimeType) {
+		Class<?> clazz = elementType.toClass();
+		return super.canEncode(elementType, mimeType) && ByteBuf.class.isAssignableFrom(clazz);
+	}
+
+	@Override
+	public Flux<DataBuffer> encode(Publisher<? extends ByteBuf> inputStream,
+			DataBufferFactory bufferFactory, ResolvableType elementType, @Nullable MimeType mimeType,
+			@Nullable Map<String, Object> hints) {
+
+		return Flux.from(inputStream).map(byteBuffer ->
+				encodeValue(byteBuffer, bufferFactory, elementType, mimeType, hints));
+	}
+
+	@Override
+	public DataBuffer encodeValue(ByteBuf byteBuf, DataBufferFactory bufferFactory,
+			ResolvableType valueType, @Nullable MimeType mimeType, @Nullable Map<String, Object> hints) {
+
+		DataBuffer dataBuffer;
+		if (bufferFactory instanceof NettyDataBufferFactory) {
+			dataBuffer = ((NettyDataBufferFactory) bufferFactory).wrap(byteBuf);
+		} else {
+			dataBuffer = bufferFactory.wrap(byteBuf.nioBuffer());
+		}
+
+		if (logger.isDebugEnabled() && !Hints.isLoggingSuppressed(hints)) {
+			String logPrefix = Hints.getLogPrefix(hints);
+			logger.debug(logPrefix + "Writing " + dataBuffer.readableByteCount() + " bytes");
+		}
+		return dataBuffer;
+	}
+
+}