Add new HTTP/2 and HPACK decoder in net/http2/.

net/http2/decoder/payload_decoders/goaway_payload_decoder.h

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef NET_HTTP2_DECODER_PAYLOAD_DECODERS_GOAWAY_PAYLOAD_DECODER_H_
+#define NET_HTTP2_DECODER_PAYLOAD_DECODERS_GOAWAY_PAYLOAD_DECODER_H_
+
+// Decodes the payload of a GOAWAY frame.
+
+// TODO(jamessynge): Sweep through all payload decoders, changing the names of
+// the PayloadState enums so that they are really states, and not actions.
+
+#include "net/base/net_export.h"
+#include "net/http2/decoder/decode_buffer.h"
+#include "net/http2/decoder/decode_status.h"
+#include "net/http2/decoder/frame_decoder_state.h"
+#include "net/http2/http2_structures.h"
+
+namespace net {
+namespace test {
+class GoAwayPayloadDecoderPeer;
+}  // namespace test
+
+class NET_EXPORT_PRIVATE GoAwayPayloadDecoder {
+ public:
+  // States during decoding of a GOAWAY frame.
+  enum class PayloadState {
+    // At the start of the GOAWAY frame payload, ready to start decoding the
+    // fixed size fields into goaway_fields_.
+    kStartDecodingFixedFields,
+
+    // Handle the DecodeStatus returned from starting or resuming the
+    // decoding of Http2GoAwayFields into goaway_fields_. If complete,
+    // calls OnGoAwayStart.
+    kHandleFixedFieldsStatus,
+
+    // Report the Opaque Data portion of the payload to the listener's
+    // OnGoAwayOpaqueData method, and call OnGoAwayEnd when the end of the
+    // payload is reached.
+    kReadOpaqueData,
+
+    // The fixed size fields weren't all available when the decoder first
+    // tried to decode them (state kStartDecodingFixedFields); this state
+    // resumes the decoding when ResumeDecodingPayload is called later.
+    kResumeDecodingFixedFields,
+  };
+
+  // Starts the decoding of a GOAWAY frame's payload, and completes it if
+  // the entire payload is in the provided decode buffer.
+  DecodeStatus StartDecodingPayload(FrameDecoderState* state, DecodeBuffer* db);
+
+  // Resumes decoding a GOAWAY frame's payload that has been split across
+  // decode buffers.
+  DecodeStatus ResumeDecodingPayload(FrameDecoderState* state,
+                                     DecodeBuffer* db);
+
+ private:
+  friend class test::GoAwayPayloadDecoderPeer;
+
+  Http2GoAwayFields goaway_fields_;
+  PayloadState payload_state_;
+};
+
+}  // namespace net
+
+#endif  // NET_HTTP2_DECODER_PAYLOAD_DECODERS_GOAWAY_PAYLOAD_DECODER_H_