1 // Copyright 2020 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4 
5 #ifndef QUICHE_HTTP2_DECODER_PAYLOAD_DECODERS_PRIORITY_UPDATE_PAYLOAD_DECODER_H_
6 #define QUICHE_HTTP2_DECODER_PAYLOAD_DECODERS_PRIORITY_UPDATE_PAYLOAD_DECODER_H_
7 
8 // Decodes the payload of a PRIORITY_UPDATE frame.
9 
10 #include "quiche/http2/decoder/decode_buffer.h"
11 #include "quiche/http2/decoder/decode_status.h"
12 #include "quiche/http2/decoder/frame_decoder_state.h"
13 #include "quiche/http2/http2_structures.h"
14 #include "quiche/common/platform/api/quiche_export.h"
15 
16 namespace http2 {
17 namespace test {
18 class PriorityUpdatePayloadDecoderPeer;
19 }  // namespace test
20 
21 class QUICHE_EXPORT PriorityUpdatePayloadDecoder {
22  public:
23   // States during decoding of a PRIORITY_UPDATE frame.
24   enum class PayloadState {
25     // At the start of the PRIORITY_UPDATE frame payload, ready to start
26     // decoding the fixed size fields into priority_update_fields_.
27     kStartDecodingFixedFields,
28 
29     // The fixed size fields weren't all available when the decoder first
30     // tried to decode them; this state resumes the decoding when
31     // ResumeDecodingPayload is called later.
32     kResumeDecodingFixedFields,
33 
34     // Handle the DecodeStatus returned from starting or resuming the decoding
35     // of Http2PriorityUpdateFields into priority_update_fields_. If complete,
36     // calls OnPriorityUpdateStart.
37     kHandleFixedFieldsStatus,
38 
39     // Report the Priority Field Value portion of the payload to the listener's
40     // OnPriorityUpdatePayload method, and call OnPriorityUpdateEnd when the end
41     // of the payload is reached.
42     kReadPriorityFieldValue,
43   };
44 
45   // Starts the decoding of a PRIORITY_UPDATE frame's payload, and completes it
46   // if the entire payload is in the provided decode buffer.
47   DecodeStatus StartDecodingPayload(FrameDecoderState* state, DecodeBuffer* db);
48 
49   // Resumes decoding a PRIORITY_UPDATE frame that has been split across decode
50   // buffers.
51   DecodeStatus ResumeDecodingPayload(FrameDecoderState* state,
52                                      DecodeBuffer* db);
53 
54  private:
55   friend class test::PriorityUpdatePayloadDecoderPeer;
56 
57   Http2PriorityUpdateFields priority_update_fields_;
58   PayloadState payload_state_;
59 };
60 
61 }  // namespace http2
62 
63 #endif  // QUICHE_HTTP2_DECODER_PAYLOAD_DECODERS_PRIORITY_UPDATE_PAYLOAD_DECODER_H_
64