xref: /aosp_15_r20/external/pigweed/pw_grpc/pw_grpc_private/hpack.h (revision 61c4878ac05f98d0ceed94b57d316916de578985)
1 // Copyright 2024 The Pigweed Authors
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License"); you may not
4 // use this file except in compliance with the License. You may obtain a copy of
5 // the License at
6 //
7 //     https://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
11 // WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
12 // License for the specific language governing permissions and limitations under
13 // the License.
14 
15 #pragma once
16 
17 #include <cstdint>
18 
19 #include "pw_bytes/span.h"
20 #include "pw_result/result.h"
21 #include "pw_string/string.h"
22 
23 namespace pw::grpc {
24 
25 // We disable the HPACK dynamic header table.
26 inline constexpr uint32_t kHpackDynamicHeaderTableSize = 0;
27 
28 // Maximum size of a string that can be returned by this API.
29 inline constexpr uint32_t kHpackMaxStringSize = 127;
30 
31 // Parses a request header field block, returning the grpc method name.
32 Result<InlineString<kHpackMaxStringSize>> HpackParseRequestHeaders(
33     ConstByteSpan payload);
34 
35 // Decodes an HPACK integer.
36 // Consumed bytes are removed from the `input` span.
37 Result<int> HpackIntegerDecode(ConstByteSpan& input, int bits_in_first_byte);
38 
39 // Decodes an HPACK string.
40 // Consumed bytes are removed from the `input` span.
41 Result<InlineString<kHpackMaxStringSize>> HpackStringDecode(
42     ConstByteSpan& input);
43 
44 // Decodes a Huffman-encoded string.
45 Result<InlineString<kHpackMaxStringSize>> HpackHuffmanDecode(
46     ConstByteSpan input);
47 
48 // Returns a HEADERS payload to use for grpc Response-Headers.
49 ConstByteSpan ResponseHeadersPayload();
50 
51 // Returns a HEADERS payload to use for grpc Trailers.
52 ConstByteSpan ResponseTrailersPayload(Status response_code);
53 
54 }  // namespace pw::grpc
55