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1   /*
2    * Copyright 2014 The Netty Project
3    *
4    * The Netty Project licenses this file to you under the Apache License, version 2.0 (the
5    * "License"); you may not use this file except in compliance with the License. You may obtain a
6    * 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 distributed under the License
11   * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
12   * or implied. See the License for the specific language governing permissions and limitations under
13   * the License.
14   */
15  package io.netty5.handler.codec.http2;
16  
17  import io.netty5.buffer.api.Buffer;
18  import io.netty5.util.internal.UnstableApi;
19  
20  /**
21   * Encodes {@link Http2Headers} into HPACK-encoded headers blocks.
22   */
23  @UnstableApi
24  public interface Http2HeadersEncoder {
25      /**
26       * Configuration related elements for the {@link Http2HeadersEncoder} interface
27       */
28      interface Configuration {
29          /**
30           * Represents the value for
31           * <a href="https://tools.ietf.org/html/rfc7540#section-6.5.2">SETTINGS_HEADER_TABLE_SIZE</a>.
32           * This method should only be called by Netty (not users) as a result of a receiving a {@code SETTINGS} frame.
33           */
34          void maxHeaderTableSize(long max) throws Http2Exception;
35  
36          /**
37           * Represents the value for
38           * <a href="https://tools.ietf.org/html/rfc7540#section-6.5.2">SETTINGS_HEADER_TABLE_SIZE</a>.
39           * The initial value returned by this method must be {@link Http2CodecUtil#DEFAULT_HEADER_TABLE_SIZE}.
40           */
41          long maxHeaderTableSize();
42  
43          /**
44           * Represents the value for
45           * <a href="https://tools.ietf.org/html/rfc7540#section-6.5.2">SETTINGS_MAX_HEADER_LIST_SIZE</a>.
46           * This method should only be called by Netty (not users) as a result of a receiving a {@code SETTINGS} frame.
47           */
48          void maxHeaderListSize(long max) throws Http2Exception;
49  
50          /**
51           * Represents the value for
52           * <a href="https://tools.ietf.org/html/rfc7540#section-6.5.2">SETTINGS_MAX_HEADER_LIST_SIZE</a>.
53           */
54          long maxHeaderListSize();
55      }
56  
57      /**
58       * Determine if a header name/value pair is treated as
59       * <a href="https://tools.ietf.org/html/rfc7541#section-7.1.3">sensitive</a>.
60       * If the object can be dynamically modified and shared across multiple connections it may need to be thread safe.
61       */
62      interface SensitivityDetector {
63          /**
64           * Determine if a header {@code name}/{@code value} pair should be treated as
65           * <a href="https://tools.ietf.org/html/rfc7541#section-7.1.3">sensitive</a>.
66           *
67           * @param name The name for the header.
68           * @param value The value of the header.
69           * @return {@code true} if a header {@code name}/{@code value} pair should be treated as
70           * <a href="https://tools.ietf.org/html/rfc7541#section-7.1.3">sensitive</a>.
71           * {@code false} otherwise.
72           */
73          boolean isSensitive(CharSequence name, CharSequence value);
74      }
75  
76      /**
77       * Encodes the given headers and writes the output headers block to the given output buffer.
78       *
79       * @param streamId  the identifier of the stream for which the headers are encoded.
80       * @param headers the headers to be encoded.
81       * @param buffer the buffer to receive the encoded headers.
82       */
83      void encodeHeaders(int streamId, Http2Headers headers, Buffer buffer) throws Http2Exception;
84  
85      /**
86       * Get the {@link Configuration} for this {@link Http2HeadersEncoder}
87       */
88      Configuration configuration();
89  
90      /**
91       * Always return {@code false} for {@link SensitivityDetector#isSensitive(CharSequence, CharSequence)}.
92       */
93      SensitivityDetector NEVER_SENSITIVE = (name, value) -> false;
94  
95      /**
96       * Always return {@code true} for {@link SensitivityDetector#isSensitive(CharSequence, CharSequence)}.
97       */
98      SensitivityDetector ALWAYS_SENSITIVE = (name, value) -> true;
99  }