Remove HpackHuffmanAggregator.

net/spdy/hpack_huffman_aggregator.cc

-// Copyright 2014 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.
-#include "net/spdy/hpack_huffman_aggregator.h"
-
-#include "base/metrics/bucket_ranges.h"
-#include "base/metrics/field_trial.h"
-#include "base/metrics/histogram.h"
-#include "base/metrics/sample_vector.h"
-#include "base/stl_util.h"
-#include "base/strings/string_number_conversions.h"
-#include "base/strings/string_util.h"
-#include "net/base/load_flags.h"
-#include "net/http/http_request_headers.h"
-#include "net/http/http_request_info.h"
-#include "net/http/http_response_headers.h"
-#include "net/spdy/hpack_encoder.h"
-#include "net/spdy/spdy_http_utils.h"
-
-namespace net {
-
-namespace {
-
-const char kHistogramName[] = "Net.SpdyHpackEncodedCharacterFrequency";
-
-const size_t kTotalCountsPublishThreshold = 50000;
-
-// Each encoder uses the default dynamic table size of 4096 total bytes.
-const size_t kMaxEncoders = 20;
-
-}  // namespace
-
-HpackHuffmanAggregator::HpackHuffmanAggregator()
-  : counts_(256, 0),
-    total_counts_(0),
-    max_encoders_(kMaxEncoders) {
-}
-
-HpackHuffmanAggregator::~HpackHuffmanAggregator() {
-  STLDeleteContainerPairSecondPointers(encoders_.begin(), encoders_.end());
-  encoders_.clear();
-}
-
-void HpackHuffmanAggregator::AggregateTransactionCharacterCounts(
-    const HttpRequestInfo& request,
-    const HttpRequestHeaders& request_headers,
-    const ProxyServer& proxy,
-    const HttpResponseHeaders& response_headers) {
-  if (IsCrossOrigin(request)) {
-    return;
-  }
-  HpackEncoder* encoder = ObtainEncoder(SpdySessionKey(
-      HostPortPair::FromURL(request.url), proxy, request.privacy_mode));
-
-  // Convert and encode the request and response header sets.
-  {
-    SpdyHeaderBlock headers;
-    CreateSpdyHeadersFromHttpRequest(
-        request, request_headers, SPDY4, false, &headers);
-
-    std::string tmp_out;
-    encoder->EncodeHeaderSet(headers, &tmp_out);
-  }
-  {
-    SpdyHeaderBlock headers;
-    CreateSpdyHeadersFromHttpResponse(response_headers, &headers);
-
-    std::string tmp_out;
-    encoder->EncodeHeaderSet(headers, &tmp_out);
-  }
-  if (total_counts_ >= kTotalCountsPublishThreshold) {
-    PublishCounts();
-  }
-}
-
-// static
-bool HpackHuffmanAggregator::UseAggregator() {
-  const std::string group_name =
-      base::FieldTrialList::FindFullName("HpackHuffmanAggregator");
-  if (group_name == "Enabled") {
-    return true;
-  }
-  return false;
-}
-
-// static
-void HpackHuffmanAggregator::CreateSpdyHeadersFromHttpResponse(
-    const HttpResponseHeaders& headers,
-    SpdyHeaderBlock* headers_out) {
-  // Lower-case header names, and coalesce multiple values delimited by \0.
-  // Also add the fixed status header.
-  std::string name, value;
-  void* it = NULL;
-  while (headers.EnumerateHeaderLines(&it, &name, &value)) {
-    base::StringToLowerASCII(&name);
-    if (headers_out->find(name) == headers_out->end()) {
-      (*headers_out)[name] = value;
-    } else {
-      (*headers_out)[name] += std::string(1, '\0') + value;
-    }
-  }
-  (*headers_out)[":status"] = base::IntToString(headers.response_code());
-}
-
-// static
-bool HpackHuffmanAggregator::IsCrossOrigin(const HttpRequestInfo& request) {
-  // Require that the request is top-level, or that it shares
-  // an origin with its referer.
-  if ((request.load_flags & LOAD_MAIN_FRAME) == 0) {
-    std::string referer_str;
-    if (!request.extra_headers.GetHeader(HttpRequestHeaders::kReferer,
-                                         &referer_str)) {
-      // Require a referer.
-      return true;
-    }
-    GURL referer(referer_str);
-    if (!HostPortPair::FromURL(request.url).Equals(
-        HostPortPair::FromURL(referer))) {
-      // Cross-origin request.
-      return true;
-    }
-  }
-  return false;
-}
-
-HpackEncoder* HpackHuffmanAggregator::ObtainEncoder(const SpdySessionKey& key) {
-  for (OriginEncoders::iterator it = encoders_.begin();
-       it != encoders_.end(); ++it) {
-    if (key.Equals(it->first)) {
-      // Move to head of list and return.
-      OriginEncoder origin_encoder = *it;
-      encoders_.erase(it);
-      encoders_.push_front(origin_encoder);
-      return origin_encoder.second;
-    }
-  }
-  // Not found. Create a new encoder, evicting one if needed.
-  encoders_.push_front(std::make_pair(
-      key, new HpackEncoder(ObtainHpackHuffmanTable())));
-  if (encoders_.size() > max_encoders_) {
-    delete encoders_.back().second;
-    encoders_.pop_back();
-  }
-  encoders_.front().second->SetCharCountsStorage(&counts_, &total_counts_);
-  return encoders_.front().second;
-}
-
-void HpackHuffmanAggregator::PublishCounts() {
-  // base::Histogram requires that values be 1-indexed.
-  const size_t kRangeMin = 1;
-  const size_t kRangeMax = counts_.size() + 1;
-  const size_t kBucketCount = kRangeMax + 1;
-
-  base::BucketRanges ranges(kBucketCount + 1);
-  for (size_t i = 0; i != ranges.size(); ++i) {
-    ranges.set_range(i, i);
-  }
-  ranges.ResetChecksum();
-
-  // Copy |counts_| into a SampleVector.
-  base::SampleVector samples(&ranges);
-  for (size_t i = 0; i != counts_.size(); ++i) {
-    samples.Accumulate(i + 1, counts_[i]);
-  }
-
-  STATIC_HISTOGRAM_POINTER_BLOCK(
-      kHistogramName,
-      AddSamples(samples),
-      base::LinearHistogram::FactoryGet(
-          kHistogramName, kRangeMin, kRangeMax, kBucketCount,
-          base::HistogramBase::kUmaTargetedHistogramFlag));
-
-  // Clear counts.
-  counts_.assign(counts_.size(), 0);
-  total_counts_ = 0;
-}
-
-}  // namespace net