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

net/http2/hpack/decoder/hpack_varint_decoder.h

Index: net/http2/hpack/decoder/hpack_varint_decoder.h
diff --git a/net/http2/hpack/decoder/hpack_varint_decoder.h b/net/http2/hpack/decoder/hpack_varint_decoder.h
deleted file mode 100644
index b110fad23a983b40b0e7974e56bd43ca9bbf56e1..0000000000000000000000000000000000000000
--- a/net/http2/hpack/decoder/hpack_varint_decoder.h
+++ /dev/null
@@ -1,181 +0,0 @@
-// 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.
-
-// HpackVarintDecoder decodes HPACK variable length unsigned integers. These
-// integers are used to identify static or dynamic table index entries, to
-// specify string lengths, and to update the size limit of the dynamic table.
-//
-// The caller will need to validate that the decoded value is in an acceptable
-// range.
-//
-// In order to support naive encoders (i.e. which always output 5 extension
-// bytes for a uint32 that is >= prefix_mask), the decoder supports an an
-// encoding with up to 5 extension bytes, and a maximum value of 268,435,582
-// (4 "full" extension bytes plus the maximum for a prefix, 127). It could be
-// modified to support a lower maximum value (by requiring that extensions bytes
-// be "empty"), or a larger value if valuable for some reason I can't see.
-//
-// For details of the encoding, see:
-//        http://httpwg.org/specs/rfc7541.html#integer.representation
-//
-// TODO(jamessynge): Consider dropping support for encodings of more than 4
-// bytes, including the prefix byte, as in practice we only see at most 3 bytes,
-// and 4 bytes would cover any desire to support large (but not ridiculously
-// large) header values.
-
-#ifndef NET_HTTP2_HPACK_DECODER_HPACK_VARINT_DECODER_H_
-#define NET_HTTP2_HPACK_DECODER_HPACK_VARINT_DECODER_H_
-
-#include <string>
-
-#include "base/logging.h"
-#include "net/base/net_export.h"
-#include "net/http2/decoder/decode_buffer.h"
-#include "net/http2/decoder/decode_status.h"
-
-namespace net {
-// Decodes an HPACK variable length unsigned integer, in a resumable fashion
-// so it can handle running out of input in the DecodeBuffer. Call Start or
-// StartExtended the first time (when decoding the byte that contains the
-// prefix), then call Resume later if it is necessary to resume. When done,
-// call value() to retrieve the decoded value.
-//
-// No constructor or destructor. Holds no resources, so destruction isn't
-// needed. Start and StartExtended handles the initialization of member
-// variables. This is necessary in order for HpackVarintDecoder to be part
-// of a union.
-class NET_EXPORT_PRIVATE HpackVarintDecoder {
- public:
-  // |prefix_value| is the first byte of the encoded varint.
-  // |prefix_mask| is the mask of the valid bits, i.e. without the top 1 to 4
-  // high-bits set, as appropriate for the item being decoded; must be a
-  // contiguous sequence of set bits, starting with the low-order bits.
-  DecodeStatus Start(uint8_t prefix_value,
-                     uint8_t prefix_mask,
-                     DecodeBuffer* db) {
-    DCHECK_LE(15, prefix_mask) << std::hex << prefix_mask;
-    DCHECK_LE(prefix_mask, 127) << std::hex << prefix_mask;
-    // Confirm that |prefix_mask| is a contiguous sequence of bits.
-    DCHECK_EQ(0, (prefix_mask + 1) & prefix_mask) << std::hex << prefix_mask;
-
-    // Ignore the bits that aren't a part of the prefix of the varint.
-    value_ = prefix_value & prefix_mask;
-
-    if (value_ < prefix_mask) {
-      MarkDone();
-      return DecodeStatus::kDecodeDone;
-    }
-
-    offset_ = 0;
-    return Resume(db);
-  }
-
-  // The caller has already determined that the encoding requires multiple
-  // bytes, i.e. that the 4 to 7 low-order bits (the number determined by the
-  // prefix length, a value not passed into this function) of the first byte are
-  // are all 1. The caller passes in |prefix_mask|, which is 2^prefix_length-1.
-  DecodeStatus StartExtended(uint8_t prefix_mask, DecodeBuffer* db) {
-    DCHECK_LE(15, prefix_mask) << std::hex << prefix_mask;
-    DCHECK_LE(prefix_mask, 127) << std::hex << prefix_mask;
-    // Confirm that |prefix_mask| is a contiguous sequence of bits.
-    DCHECK_EQ(0, prefix_mask & (prefix_mask + 1)) << std::hex << prefix_mask;
-
-    value_ = prefix_mask;
-    offset_ = 0;
-    return Resume(db);
-  }
-
-  // Resume decoding a variable length integer after an earlier
-  // call to Start or StartExtended returned kDecodeInProgress.
-  DecodeStatus Resume(DecodeBuffer* db) {
-    CheckNotDone();
-    do {
-      if (db->Empty()) {
-        return DecodeStatus::kDecodeInProgress;
-      }
-      uint8_t byte = db->DecodeUInt8();
-      value_ += (byte & 0x7f) << offset_;
-      if ((byte & 0x80) == 0) {
-        if (offset_ < MaxOffset() || byte == 0) {
-          MarkDone();
-          return DecodeStatus::kDecodeDone;
-        }
-        break;
-      }
-      offset_ += 7;
-    } while (offset_ <= MaxOffset());
-    DLOG(WARNING) << "Variable length int encoding is too large or too long. "
-                  << DebugString();
-    MarkDone();
-    return DecodeStatus::kDecodeError;
-  }
-
-  uint32_t value() const {
-    CheckDone();
-    return value_;
-  }
-
-  // This supports optimizations for the case of a varint with zero extension
-  // bytes, where the handling of the prefix is done by the caller.
-  void set_value(uint32_t v) {
-    MarkDone();
-    value_ = v;
-  }
-
-  // All the public methods below are for supporting assertions and tests.
-
-  std::string DebugString() const;
-
-  // For benchmarking, these methods ensure the decoder
-  // is NOT inlined into the caller.
-  DecodeStatus StartForTest(uint8_t prefix_value,
-                            uint8_t prefix_mask,
-                            DecodeBuffer* db);
-  DecodeStatus StartExtendedForTest(uint8_t prefix_mask, DecodeBuffer* db);
-  DecodeStatus ResumeForTest(DecodeBuffer* db);
-
-  static constexpr uint32_t MaxExtensionBytes() { return 5; }
-
-  // Returns the highest value with the specified number of extension bytes and
-  // the specified prefix length (bits).
-  static uint64_t constexpr HiValueOfExtensionBytes(uint32_t extension_bytes,
-                                                    uint32_t prefix_length) {
-    return (1 << prefix_length) - 2 +
-           (extension_bytes == 0 ? 0 : (1LLU << (extension_bytes * 7)));
-  }
-
- private:
-  // Protection in case Resume is called when it shouldn't be.
-  void MarkDone() {
-#ifndef NDEBUG
-    // We support up to 5 extension bytes, so offset_ should never be > 28 when
-    // it makes sense to call Resume().
-    offset_ = MaxOffset() + 7;
-#endif
-  }
-  void CheckNotDone() const {
-#ifndef NDEBUG
-    DCHECK_LE(offset_, MaxOffset());
-#endif
-  }
-  void CheckDone() const {
-#ifndef NDEBUG
-    DCHECK_GT(offset_, MaxOffset());
-#endif
-  }
-  static constexpr uint32_t MaxOffset() {
-    return 7 * (MaxExtensionBytes() - 1);
-  }
-
-  // These fields are initialized just to keep ASAN happy about reading
-  // them from DebugString().
-  uint32_t value_ = 0;
-  uint32_t offset_ = 0;
-};
-
-std::ostream& operator<<(std::ostream& out, const HpackVarintDecoder& v);
-
-}  // namespace net
-
-#endif  // NET_HTTP2_HPACK_DECODER_HPACK_VARINT_DECODER_H_