| Index: net/filter/sdch_filter.cc
 | 
| diff --git a/net/filter/sdch_filter.cc b/net/filter/sdch_filter.cc
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| deleted file mode 100644
 | 
| index 85be8905fa76cb179dbbcfb3b629a9b6e48b381a..0000000000000000000000000000000000000000
 | 
| --- a/net/filter/sdch_filter.cc
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| +++ /dev/null
 | 
| @@ -1,568 +0,0 @@
 | 
| -// 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/filter/sdch_filter.h"
 | 
| -
 | 
| -#include <ctype.h>
 | 
| -#include <limits.h>
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| -#include <algorithm>
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| -#include <utility>
 | 
| -
 | 
| -#include "base/logging.h"
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| -#include "base/metrics/histogram_macros.h"
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| -#include "base/values.h"
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| -#include "net/base/sdch_manager.h"
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| -#include "net/base/sdch_net_log_params.h"
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| -#include "net/base/sdch_problem_codes.h"
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| -#include "net/url_request/url_request_context.h"
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| -#include "sdch/open-vcdiff/src/google/vcdecoder.h"
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| -
 | 
| -namespace net {
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| -
 | 
| -namespace {
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| -
 | 
| -const size_t kServerIdLength = 9;  // Dictionary hash plus null from server.
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| -
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| -// Disambiguate various types of responses that trigger a meta-refresh,
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| -// failure, or fallback to pass-through.
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| -enum ResponseCorruptionDetectionCause {
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| -  RESPONSE_NONE,
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| -
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| -  // 404 Http Response Code
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| -  RESPONSE_404 = 1,
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| -
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| -  // Not a 200 Http Response Code
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| -  RESPONSE_NOT_200 = 2,
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| -
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| -  // Cached before dictionary retrieved.
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| -  RESPONSE_OLD_UNENCODED = 3,
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| -
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| -  // Speculative but incorrect SDCH filtering was added added.
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| -  RESPONSE_TENTATIVE_SDCH = 4,
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| -
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| -  // Missing correct dict for decoding.
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| -  RESPONSE_NO_DICTIONARY = 5,
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| -
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| -  // Not an SDCH response but should be.
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| -  RESPONSE_CORRUPT_SDCH = 6,
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| -
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| -  // No dictionary was advertised with the request, the server claims
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| -  // to have encoded with SDCH anyway, but it isn't an SDCH response.
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| -  RESPONSE_ENCODING_LIE = 7,
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| -
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| -  RESPONSE_MAX,
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| -};
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| -
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| -const char* ResponseCorruptionDetectionCauseToString(
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| -    ResponseCorruptionDetectionCause cause) {
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| -  const char* cause_string = "<unknown>";
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| -  switch (cause) {
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| -    case RESPONSE_NONE:
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| -      cause_string = "NONE";
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| -      break;
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| -    case RESPONSE_404:
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| -      cause_string = "404";
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| -      break;
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| -    case RESPONSE_NOT_200:
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| -      cause_string = "NOT_200";
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| -      break;
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| -    case RESPONSE_OLD_UNENCODED:
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| -      cause_string = "OLD_UNENCODED";
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| -      break;
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| -    case RESPONSE_TENTATIVE_SDCH:
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| -      cause_string = "TENTATIVE_SDCH";
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| -      break;
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| -    case RESPONSE_NO_DICTIONARY:
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| -      cause_string = "NO_DICTIONARY";
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| -      break;
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| -    case RESPONSE_CORRUPT_SDCH:
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| -      cause_string = "CORRUPT_SDCH";
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| -      break;
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| -    case RESPONSE_ENCODING_LIE:
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| -      cause_string = "ENCODING_LIE";
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| -      break;
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| -    case RESPONSE_MAX:
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| -      cause_string = "<Error: max enum value>";
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| -      break;
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| -  }
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| -  return cause_string;
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| -}
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| -
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| -std::unique_ptr<base::Value> NetLogSdchResponseCorruptionDetectionCallback(
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| -    ResponseCorruptionDetectionCause cause,
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| -    bool cached,
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| -    NetLogCaptureMode capture_mode) {
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| -  std::unique_ptr<base::DictionaryValue> dict(new base::DictionaryValue());
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| -  dict->SetString("cause", ResponseCorruptionDetectionCauseToString(cause));
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| -  dict->SetBoolean("cached", cached);
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| -  return std::move(dict);
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| -}
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| -
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| -}  // namespace
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| -
 | 
| -SdchFilter::SdchFilter(FilterType type, const FilterContext& filter_context)
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| -    : Filter(type),
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| -      filter_context_(filter_context),
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| -      decoding_status_(DECODING_UNINITIALIZED),
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| -      dictionary_hash_(),
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| -      dictionary_hash_is_plausible_(false),
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| -      url_request_context_(filter_context.GetURLRequestContext()),
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| -      dest_buffer_excess_(),
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| -      dest_buffer_excess_index_(0),
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| -      source_bytes_(0),
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| -      output_bytes_(0),
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| -      possible_pass_through_(false) {
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| -  bool success = filter_context.GetMimeType(&mime_type_);
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| -  DCHECK(success);
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| -  success = filter_context.GetURL(&url_);
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| -  DCHECK(success);
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| -  DCHECK(url_request_context_->sdch_manager());
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| -}
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| -
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| -SdchFilter::~SdchFilter() {
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| -  // All code here is for gathering stats, and can be removed when SDCH is
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| -  // considered stable.
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| -
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| -  // References to filter_context_ and vcdiff_streaming_decoder_ (which
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| -  // contains a reference to the dictionary text) are safe because
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| -  // ~URLRequestHttpJob calls URLRequestJob::DestroyFilters, destroying
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| -  // this object before the filter context in URLRequestHttpJob and its
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| -  // members go out of scope.
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| -
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| -  static int filter_use_count = 0;
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| -  ++filter_use_count;
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| -  if (META_REFRESH_RECOVERY == decoding_status_) {
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| -    UMA_HISTOGRAM_COUNTS("Sdch3.FilterUseBeforeDisabling", filter_use_count);
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| -  }
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| -
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| -  if (vcdiff_streaming_decoder_.get()) {
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| -    if (!vcdiff_streaming_decoder_->FinishDecoding()) {
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| -      decoding_status_ = DECODING_ERROR;
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| -      LogSdchProblem(SDCH_INCOMPLETE_SDCH_CONTENT);
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| -      // Make it possible for the user to hit reload, and get non-sdch content.
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| -      // Note this will "wear off" quickly enough, and is just meant to assure
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| -      // in some rare case that the user is not stuck.
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| -      url_request_context_->sdch_manager()->BlacklistDomain(
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| -          url_, SDCH_INCOMPLETE_SDCH_CONTENT);
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| -      UMA_HISTOGRAM_COUNTS("Sdch3.PartialBytesIn",
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| -           static_cast<int>(filter_context_.GetByteReadCount()));
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| -      UMA_HISTOGRAM_COUNTS("Sdch3.PartialVcdiffIn", source_bytes_);
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| -      UMA_HISTOGRAM_COUNTS("Sdch3.PartialVcdiffOut", output_bytes_);
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| -    }
 | 
| -  }
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| -
 | 
| -  if (!dest_buffer_excess_.empty()) {
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| -    // Filter chaining error, or premature teardown.
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| -    LogSdchProblem(SDCH_UNFLUSHED_CONTENT);
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| -    UMA_HISTOGRAM_COUNTS("Sdch3.UnflushedBytesIn",
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| -         static_cast<int>(filter_context_.GetByteReadCount()));
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| -    UMA_HISTOGRAM_COUNTS("Sdch3.UnflushedBufferSize",
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| -                         dest_buffer_excess_.size());
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| -    UMA_HISTOGRAM_COUNTS("Sdch3.UnflushedVcdiffIn", source_bytes_);
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| -    UMA_HISTOGRAM_COUNTS("Sdch3.UnflushedVcdiffOut", output_bytes_);
 | 
| -  }
 | 
| -
 | 
| -  if (filter_context_.IsCachedContent()) {
 | 
| -    // Not a real error, but it is useful to have this tally.
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| -    // TODO(jar): Remove this stat after SDCH stability is validated.
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| -    LogSdchProblem(SDCH_CACHE_DECODED);
 | 
| -    return;  // We don't need timing stats, and we aready got ratios.
 | 
| -  }
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| -
 | 
| -  switch (decoding_status_) {
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| -    case DECODING_IN_PROGRESS: {
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| -      if (output_bytes_) {
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| -        UMA_HISTOGRAM_PERCENTAGE("Sdch3.Network_Decode_Ratio_a",
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| -            static_cast<int>(
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| -                (filter_context_.GetByteReadCount() * 100) / output_bytes_));
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| -        UMA_HISTOGRAM_COUNTS("Sdch3.NetworkBytesSavedByCompression",
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| -            output_bytes_ - source_bytes_);
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| -      }
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| -      UMA_HISTOGRAM_COUNTS("Sdch3.Network_Decode_Bytes_VcdiffOut_a",
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| -                           output_bytes_);
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| -      filter_context_.RecordPacketStats(FilterContext::SDCH_DECODE);
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| -
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| -      // Allow latency experiments to proceed.
 | 
| -      url_request_context_->sdch_manager()->SetAllowLatencyExperiment(
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| -          url_, true);
 | 
| -
 | 
| -      // Notify successful dictionary usage.
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| -      url_request_context_->sdch_manager()->OnDictionaryUsed(
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| -          std::string(dictionary_hash_, 0, kServerIdLength - 1));
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| -
 | 
| -      return;
 | 
| -    }
 | 
| -    case PASS_THROUGH: {
 | 
| -      filter_context_.RecordPacketStats(FilterContext::SDCH_PASSTHROUGH);
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| -      return;
 | 
| -    }
 | 
| -    case DECODING_UNINITIALIZED: {
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| -      LogSdchProblem(SDCH_UNINITIALIZED);
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| -      return;
 | 
| -    }
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| -    case WAITING_FOR_DICTIONARY_SELECTION: {
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| -      LogSdchProblem(SDCH_PRIOR_TO_DICTIONARY);
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| -      return;
 | 
| -    }
 | 
| -    case DECODING_ERROR: {
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| -      LogSdchProblem(SDCH_DECODE_ERROR);
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| -      return;
 | 
| -    }
 | 
| -    case META_REFRESH_RECOVERY: {
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| -      // Already accounted for when set.
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| -      return;
 | 
| -    }
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| -  }  // end of switch.
 | 
| -}
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| -
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| -bool SdchFilter::InitDecoding(Filter::FilterType filter_type) {
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| -  if (decoding_status_ != DECODING_UNINITIALIZED)
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| -    return false;
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| -
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| -  // Handle case  where sdch filter is guessed, but not required.
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| -  if (FILTER_TYPE_SDCH_POSSIBLE == filter_type)
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| -    possible_pass_through_ = true;
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| -
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| -  // Initialize decoder only after we have a dictionary in hand.
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| -  decoding_status_ = WAITING_FOR_DICTIONARY_SELECTION;
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| -  return true;
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| -}
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| -
 | 
| -#ifndef NDEBUG
 | 
| -static const char* kDecompressionErrorHtml =
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| -  "<head><META HTTP-EQUIV=\"Refresh\" CONTENT=\"0\"></head>"
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| -  "<div style=\"position:fixed;top:0;left:0;width:100%;border-width:thin;"
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| -  "border-color:black;border-style:solid;text-align:left;font-family:arial;"
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| -  "font-size:10pt;foreground-color:black;background-color:white\">"
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| -  "An error occurred. This page will be reloaded shortly. "
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| -  "Or press the \"reload\" button now to reload it immediately."
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| -  "</div>";
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| -#else
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| -static const char* kDecompressionErrorHtml =
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| -  "<head><META HTTP-EQUIV=\"Refresh\" CONTENT=\"0\"></head>";
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| -#endif
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| -
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| -Filter::FilterStatus SdchFilter::ReadFilteredData(char* dest_buffer,
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| -                                                  int* dest_len) {
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| -  int available_space = *dest_len;
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| -  *dest_len = 0;  // Nothing output yet.
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| -
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| -  if (!dest_buffer || available_space <= 0)
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| -    return FILTER_ERROR;
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| -
 | 
| -  if (WAITING_FOR_DICTIONARY_SELECTION == decoding_status_) {
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| -    FilterStatus status = InitializeDictionary();
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| -    if (FILTER_NEED_MORE_DATA == status)
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| -      return FILTER_NEED_MORE_DATA;
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| -    if (FILTER_ERROR == status) {
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| -      DCHECK_EQ(DECODING_ERROR, decoding_status_);
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| -      DCHECK_EQ(0u, dest_buffer_excess_index_);
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| -      DCHECK(dest_buffer_excess_.empty());
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| -      // This is where we try very hard to do error recovery, and make this
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| -      // protocol robust in the face of proxies that do many different things.
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| -      // If we decide that things are looking very bad (too hard to recover),
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| -      // we may even issue a "meta-refresh" to reload the page without an SDCH
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| -      // advertisement (so that we are sure we're not hurting anything).
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| -      //
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| -      // Watch out for an error page inserted by the proxy as part of a 40x
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| -      // error response. When we see such content molestation, we certainly
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| -      // need to fall into the meta-refresh case.
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| -      ResponseCorruptionDetectionCause cause = RESPONSE_NONE;
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| -      if (filter_context_.GetResponseCode() == 404) {
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| -        // We could be more generous, but for now, only a "NOT FOUND" code will
 | 
| -        // cause a pass through. All other bad codes will fall into a
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| -        // meta-refresh.
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| -        LogSdchProblem(SDCH_PASS_THROUGH_404_CODE);
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| -        cause = RESPONSE_404;
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| -        decoding_status_ = PASS_THROUGH;
 | 
| -      } else if (filter_context_.GetResponseCode() != 200) {
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| -        // We need to meta-refresh, with SDCH disabled.
 | 
| -        cause = RESPONSE_NOT_200;
 | 
| -      } else if (filter_context_.IsCachedContent()
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| -                 && !dictionary_hash_is_plausible_) {
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| -        // We must have hit the back button, and gotten content that was fetched
 | 
| -        // before we *really* advertised SDCH and a dictionary.
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| -        LogSdchProblem(SDCH_PASS_THROUGH_OLD_CACHED);
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| -        decoding_status_ = PASS_THROUGH;
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| -        cause = RESPONSE_OLD_UNENCODED;
 | 
| -      } else if (possible_pass_through_) {
 | 
| -        // This is the potentially most graceful response. There really was no
 | 
| -        // error. We were just overly cautious when we added a TENTATIVE_SDCH.
 | 
| -        // We added the sdch coding tag, and it should not have been added.
 | 
| -        // This can happen in server experiments, where the server decides
 | 
| -        // not to use sdch, even though there is a dictionary. To be
 | 
| -        // conservative, we locally added the tentative sdch (fearing that a
 | 
| -        // proxy stripped it!) and we must now recant (pass through).
 | 
| -        //
 | 
| -        // However.... just to be sure we don't get burned by proxies that
 | 
| -        // re-compress with gzip or other system, we can sniff to see if this
 | 
| -        // is compressed data etc. For now, we do nothing, which gets us into
 | 
| -        // the meta-refresh result.
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| -        // TODO(jar): Improve robustness by sniffing for valid text that we can
 | 
| -        // actual use re: decoding_status_ = PASS_THROUGH;
 | 
| -        cause = RESPONSE_TENTATIVE_SDCH;
 | 
| -      } else if (dictionary_hash_is_plausible_) {
 | 
| -        // We need a meta-refresh since we don't have the dictionary.
 | 
| -        // The common cause is a restart of the browser, where we try to render
 | 
| -        // cached content that was saved when we had a dictionary.
 | 
| -        cause = RESPONSE_NO_DICTIONARY;
 | 
| -      } else if (filter_context_.SdchDictionariesAdvertised()) {
 | 
| -        // This is a very corrupt SDCH request response. We can't decode it.
 | 
| -        // We'll use a meta-refresh, and get content without asking for SDCH.
 | 
| -        // This will also progressively disable SDCH for this domain.
 | 
| -        cause = RESPONSE_CORRUPT_SDCH;
 | 
| -      } else {
 | 
| -        // One of the first 9 bytes precluded consideration as a hash.
 | 
| -        // This can't be an SDCH payload, even though the server said it was.
 | 
| -        // This is a major error, as the server or proxy tagged this SDCH even
 | 
| -        // though it is not!
 | 
| -        // Meta-refresh won't help, as we didn't advertise an SDCH dictionary!!
 | 
| -        // Worse yet, meta-refresh could lead to an infinite refresh loop.
 | 
| -        LogSdchProblem(SDCH_PASSING_THROUGH_NON_SDCH);
 | 
| -        decoding_status_ = PASS_THROUGH;
 | 
| -        // ... but further back-off on advertising SDCH support.
 | 
| -        url_request_context_->sdch_manager()->BlacklistDomain(
 | 
| -            url_, SDCH_PASSING_THROUGH_NON_SDCH);
 | 
| -        cause = RESPONSE_ENCODING_LIE;
 | 
| -      }
 | 
| -      DCHECK_NE(RESPONSE_NONE, cause);
 | 
| -
 | 
| -      // Use if statement rather than ?: because UMA_HISTOGRAM_ENUMERATION
 | 
| -      // caches the histogram name based on the call site.
 | 
| -      if (filter_context_.IsCachedContent()) {
 | 
| -        UMA_HISTOGRAM_ENUMERATION(
 | 
| -            "Sdch3.ResponseCorruptionDetection.Cached", cause, RESPONSE_MAX);
 | 
| -      } else {
 | 
| -        UMA_HISTOGRAM_ENUMERATION(
 | 
| -            "Sdch3.ResponseCorruptionDetection.Uncached", cause, RESPONSE_MAX);
 | 
| -      }
 | 
| -      filter_context_.GetNetLog().AddEvent(
 | 
| -          NetLog::TYPE_SDCH_RESPONSE_CORRUPTION_DETECTION,
 | 
| -          base::Bind(&NetLogSdchResponseCorruptionDetectionCallback, cause,
 | 
| -                     filter_context_.IsCachedContent()));
 | 
| -
 | 
| -      if (decoding_status_ == PASS_THROUGH) {
 | 
| -        dest_buffer_excess_ = dictionary_hash_;  // Send what we scanned.
 | 
| -      } else {
 | 
| -        // This is where we try to do the expensive meta-refresh.
 | 
| -        if (std::string::npos == mime_type_.find("text/html")) {
 | 
| -          // Since we can't do a meta-refresh (along with an exponential
 | 
| -          // backoff), we'll just make sure this NEVER happens again.
 | 
| -          SdchProblemCode problem = (filter_context_.IsCachedContent()
 | 
| -                                         ? SDCH_CACHED_META_REFRESH_UNSUPPORTED
 | 
| -                                         : SDCH_META_REFRESH_UNSUPPORTED);
 | 
| -          url_request_context_->sdch_manager()->BlacklistDomainForever(
 | 
| -              url_, problem);
 | 
| -          LogSdchProblem(problem);
 | 
| -          return FILTER_ERROR;
 | 
| -        }
 | 
| -        // HTML content means we can issue a meta-refresh, and get the content
 | 
| -        // again, perhaps without SDCH (to be safe).
 | 
| -        if (filter_context_.IsCachedContent()) {
 | 
| -          // Cached content is probably a startup tab, so we'll just get fresh
 | 
| -          // content and try again, without disabling sdch.
 | 
| -          LogSdchProblem(SDCH_META_REFRESH_CACHED_RECOVERY);
 | 
| -        } else {
 | 
| -          // Since it wasn't in the cache, we definately need at least some
 | 
| -          // period of blacklisting to get the correct content.
 | 
| -          url_request_context_->sdch_manager()->BlacklistDomain(
 | 
| -              url_, SDCH_META_REFRESH_RECOVERY);
 | 
| -          LogSdchProblem(SDCH_META_REFRESH_RECOVERY);
 | 
| -        }
 | 
| -        decoding_status_ = META_REFRESH_RECOVERY;
 | 
| -        // Issue a meta redirect with SDCH disabled.
 | 
| -        dest_buffer_excess_ = kDecompressionErrorHtml;
 | 
| -      }
 | 
| -    } else {
 | 
| -      DCHECK_EQ(DECODING_IN_PROGRESS, decoding_status_);
 | 
| -    }
 | 
| -  }
 | 
| -
 | 
| -  int amount = OutputBufferExcess(dest_buffer, available_space);
 | 
| -  *dest_len += amount;
 | 
| -  dest_buffer += amount;
 | 
| -  available_space -= amount;
 | 
| -  DCHECK_GE(available_space, 0);
 | 
| -
 | 
| -  if (available_space <= 0)
 | 
| -    return FILTER_OK;
 | 
| -  DCHECK(dest_buffer_excess_.empty());
 | 
| -  DCHECK_EQ(0u, dest_buffer_excess_index_);
 | 
| -
 | 
| -  if (decoding_status_ != DECODING_IN_PROGRESS) {
 | 
| -    if (META_REFRESH_RECOVERY == decoding_status_) {
 | 
| -      // Absorb all input data. We've already output page reload HTML.
 | 
| -      next_stream_data_ = NULL;
 | 
| -      stream_data_len_ = 0;
 | 
| -      return FILTER_NEED_MORE_DATA;
 | 
| -    }
 | 
| -    if (PASS_THROUGH == decoding_status_) {
 | 
| -      // We must pass in available_space, but it will be changed to bytes_used.
 | 
| -      FilterStatus result = CopyOut(dest_buffer, &available_space);
 | 
| -      // Accumulate the returned count of bytes_used (a.k.a., available_space).
 | 
| -      *dest_len += available_space;
 | 
| -      return result;
 | 
| -    }
 | 
| -    DCHECK(false);
 | 
| -    decoding_status_ = DECODING_ERROR;
 | 
| -    return FILTER_ERROR;
 | 
| -  }
 | 
| -
 | 
| -  if (!next_stream_data_ || stream_data_len_ <= 0)
 | 
| -    return FILTER_NEED_MORE_DATA;
 | 
| -
 | 
| -  // A note on accounting: DecodeChunk() appends to its output buffer, so any
 | 
| -  // preexisting data in |dest_buffer_excess_| could skew the value of
 | 
| -  // |output_bytes_|. However, OutputBufferExcess guarantees that it will
 | 
| -  // consume all of |dest_buffer_excess_| when called above unless the
 | 
| -  // destination buffer runs out of space, and if the destination buffer runs
 | 
| -  // out of space, this code returns FILTER_OK early above. Therefore, if
 | 
| -  // execution reaches this point, |dest_buffer_excess_| is empty, which is
 | 
| -  // DCHECKed above.
 | 
| -  bool ret = vcdiff_streaming_decoder_->DecodeChunk(
 | 
| -    next_stream_data_, stream_data_len_, &dest_buffer_excess_);
 | 
| -  // Assume all data was used in decoding.
 | 
| -  next_stream_data_ = NULL;
 | 
| -  source_bytes_ += stream_data_len_;
 | 
| -  stream_data_len_ = 0;
 | 
| -  output_bytes_ += dest_buffer_excess_.size();
 | 
| -  if (!ret) {
 | 
| -    vcdiff_streaming_decoder_.reset(NULL);  // Don't call it again.
 | 
| -    decoding_status_ = DECODING_ERROR;
 | 
| -    LogSdchProblem(SDCH_DECODE_BODY_ERROR);
 | 
| -    return FILTER_ERROR;
 | 
| -  }
 | 
| -
 | 
| -  amount = OutputBufferExcess(dest_buffer, available_space);
 | 
| -  *dest_len += amount;
 | 
| -  dest_buffer += amount;
 | 
| -  available_space -= amount;
 | 
| -  if (0 == available_space && !dest_buffer_excess_.empty())
 | 
| -      return FILTER_OK;
 | 
| -  return FILTER_NEED_MORE_DATA;
 | 
| -}
 | 
| -
 | 
| -Filter::FilterStatus SdchFilter::InitializeDictionary() {
 | 
| -  size_t bytes_needed = kServerIdLength - dictionary_hash_.size();
 | 
| -  DCHECK_GT(bytes_needed, 0u);
 | 
| -  if (!next_stream_data_)
 | 
| -    return FILTER_NEED_MORE_DATA;
 | 
| -  if (static_cast<size_t>(stream_data_len_) < bytes_needed) {
 | 
| -    dictionary_hash_.append(next_stream_data_, stream_data_len_);
 | 
| -    next_stream_data_ = NULL;
 | 
| -    stream_data_len_ = 0;
 | 
| -    return FILTER_NEED_MORE_DATA;
 | 
| -  }
 | 
| -  dictionary_hash_.append(next_stream_data_, bytes_needed);
 | 
| -  DCHECK(kServerIdLength == dictionary_hash_.size());
 | 
| -  stream_data_len_ -= bytes_needed;
 | 
| -  DCHECK_LE(0, stream_data_len_);
 | 
| -  if (stream_data_len_ > 0)
 | 
| -    next_stream_data_ += bytes_needed;
 | 
| -  else
 | 
| -    next_stream_data_ = NULL;
 | 
| -
 | 
| -  const std::string* dictionary_text = nullptr;
 | 
| -  dictionary_hash_is_plausible_ = true;  // Assume plausible, but check.
 | 
| -
 | 
| -  SdchProblemCode rv = SDCH_OK;
 | 
| -  if ('\0' == dictionary_hash_[kServerIdLength - 1]) {
 | 
| -    std::string server_hash(dictionary_hash_, 0, kServerIdLength - 1);
 | 
| -    SdchManager::DictionarySet* handle =
 | 
| -        filter_context_.SdchDictionariesAdvertised();
 | 
| -    if (handle)
 | 
| -      dictionary_text = handle->GetDictionaryText(server_hash);
 | 
| -    if (!dictionary_text) {
 | 
| -      // This is a hack. Naively, the dictionaries available for
 | 
| -      // decoding should be only the ones advertised. However, there are
 | 
| -      // cases, specifically resources encoded with old dictionaries living
 | 
| -      // in the cache, that mean the full set of dictionaries should be made
 | 
| -      // available for decoding. It's not known how often this happens;
 | 
| -      // if it happens rarely enough, this code can be removed.
 | 
| -      //
 | 
| -      // TODO(rdsmith): Long-term, a better solution is necessary, since
 | 
| -      // an entry in the cache being encoded with the dictionary doesn't
 | 
| -      // guarantee that the dictionary is present. That solution probably
 | 
| -      // involves storing unencoded resources in the cache, but might
 | 
| -      // involve evicting encoded resources on dictionary removal.
 | 
| -      // See http://crbug.com/383405.
 | 
| -      unexpected_dictionary_handle_ =
 | 
| -          url_request_context_->sdch_manager()->GetDictionarySetByHash(
 | 
| -              url_, server_hash, &rv);
 | 
| -      if (unexpected_dictionary_handle_) {
 | 
| -        dictionary_text =
 | 
| -            unexpected_dictionary_handle_->GetDictionaryText(server_hash);
 | 
| -        // Override SDCH_OK rv; this is still worth logging.
 | 
| -        rv = (filter_context_.IsCachedContent() ?
 | 
| -              SDCH_UNADVERTISED_DICTIONARY_USED_CACHED :
 | 
| -              SDCH_UNADVERTISED_DICTIONARY_USED);
 | 
| -      } else {
 | 
| -        // Since dictionary was not found, check to see if hash was
 | 
| -        // even plausible.
 | 
| -        DCHECK(dictionary_hash_.size() == kServerIdLength);
 | 
| -        rv = SDCH_DICTIONARY_HASH_NOT_FOUND;
 | 
| -        for (size_t i = 0; i < kServerIdLength - 1; ++i) {
 | 
| -          char base64_char = dictionary_hash_[i];
 | 
| -          if (!isalnum(base64_char) &&
 | 
| -              '-' != base64_char && '_' != base64_char) {
 | 
| -            dictionary_hash_is_plausible_ = false;
 | 
| -            rv = SDCH_DICTIONARY_HASH_MALFORMED;
 | 
| -            break;
 | 
| -          }
 | 
| -        }
 | 
| -      }
 | 
| -    }
 | 
| -  } else {
 | 
| -    dictionary_hash_is_plausible_ = false;
 | 
| -    rv = SDCH_DICTIONARY_HASH_MALFORMED;
 | 
| -  }
 | 
| -
 | 
| -  if (rv != SDCH_OK)
 | 
| -    LogSdchProblem(rv);
 | 
| -
 | 
| -  if (!dictionary_text) {
 | 
| -    decoding_status_ = DECODING_ERROR;
 | 
| -    return FILTER_ERROR;
 | 
| -  }
 | 
| -
 | 
| -  vcdiff_streaming_decoder_.reset(new open_vcdiff::VCDiffStreamingDecoder);
 | 
| -  vcdiff_streaming_decoder_->SetAllowVcdTarget(false);
 | 
| -
 | 
| -  // The validity of the dictionary_text pointer is guaranteed for the
 | 
| -  // lifetime of the SdchFilter by the ownership of the DictionarySet by
 | 
| -  // the FilterContext/URLRequestHttpJob.  All URLRequestJob filters are
 | 
| -  // torn down in ~URLRequestHttpJob by a call to
 | 
| -  // URLRequestJob::DestroyFilters.
 | 
| -  vcdiff_streaming_decoder_->StartDecoding(dictionary_text->data(),
 | 
| -                                           dictionary_text->size());
 | 
| -  decoding_status_ = DECODING_IN_PROGRESS;
 | 
| -  return FILTER_OK;
 | 
| -}
 | 
| -
 | 
| -int SdchFilter::OutputBufferExcess(char* const dest_buffer,
 | 
| -                                   size_t available_space) {
 | 
| -  if (dest_buffer_excess_.empty())
 | 
| -    return 0;
 | 
| -  DCHECK(dest_buffer_excess_.size() > dest_buffer_excess_index_);
 | 
| -  size_t amount = std::min(available_space,
 | 
| -      dest_buffer_excess_.size() - dest_buffer_excess_index_);
 | 
| -  memcpy(dest_buffer, dest_buffer_excess_.data() + dest_buffer_excess_index_,
 | 
| -         amount);
 | 
| -  dest_buffer_excess_index_ += amount;
 | 
| -  if (dest_buffer_excess_.size() <= dest_buffer_excess_index_) {
 | 
| -    DCHECK(dest_buffer_excess_.size() == dest_buffer_excess_index_);
 | 
| -    dest_buffer_excess_.clear();
 | 
| -    dest_buffer_excess_index_ = 0;
 | 
| -  }
 | 
| -  return amount;
 | 
| -}
 | 
| -
 | 
| -void SdchFilter::LogSdchProblem(SdchProblemCode problem) {
 | 
| -  SdchManager::SdchErrorRecovery(problem);
 | 
| -  filter_context_.GetNetLog().AddEvent(
 | 
| -      NetLog::TYPE_SDCH_DECODING_ERROR,
 | 
| -      base::Bind(&NetLogSdchResourceProblemCallback, problem));
 | 
| -}
 | 
| -
 | 
| -}  // namespace net
 | 
| 
 |