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1   /*
2    * Copyright 2012 The Netty Project
3    *
4    * The Netty Project licenses this file to you under the Apache License,
5    * version 2.0 (the "License"); you may not use this file except in compliance
6    * with the License. You may obtain a copy of the License at:
7    *
8    *   https://www.apache.org/licenses/LICENSE-2.0
9    *
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
12   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13   * License for the specific language governing permissions and limitations
14   * under the License.
15   */
16  package io.netty5.handler.stream;
17  
18  import io.netty5.buffer.api.BufferAllocator;
19  
20  /**
21   * A data stream of indefinite length which is consumed by {@link ChunkedWriteHandler}.
22   */
23  public interface ChunkedInput<B> extends AutoCloseable {
24      /**
25       * Return {@code true} if and only if there is no data left in the stream
26       * and the stream has reached at its end.
27       */
28      boolean isEndOfInput() throws Exception;
29  
30      /**
31       * Fetches a chunked data from the stream. Once this method returns the last chunk
32       * and thus the stream has reached at its end, any subsequent {@link #isEndOfInput()}
33       * call must return {@code true}.
34       *
35       * @param allocator {@link BufferAllocator} if buffer allocation is necessary.
36       * @return the fetched chunk.
37       *         {@code null} if there is no data left in the stream.
38       *         Please note that {@code null} does not necessarily mean that the
39       *         stream has reached at its end.  In a slow stream, the next chunk
40       *         might be unavailable just momentarily.
41       */
42      B readChunk(BufferAllocator allocator) throws Exception;
43  
44      /**
45       * Returns the length of the input.
46       * @return  the length of the input if the length of the input is known.
47       *          a negative value if the length of the input is unknown.
48       */
49      long length();
50  
51      /**
52       * Returns current transfer progress.
53       */
54      long progress();
55  }