// 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/http/http_server_properties_manager.h"

#include <utility>

#include "base/bind.h"
#include "base/memory/ptr_util.h"
#include "base/metrics/histogram_macros.h"
#include "base/single_thread_task_runner.h"
#include "base/stl_util.h"
#include "base/strings/string_number_conversions.h"
#include "base/threading/thread_task_runner_handle.h"
#include "base/values.h"
#include "net/base/ip_address.h"
#include "net/base/port_util.h"
#include "net/quic/platform/api/quic_hostname_utils.h"
#include "url/gurl.h"

namespace net {

namespace {

// Time to wait before starting an update the http_server_properties_impl_ cache
// from preferences. Scheduling another update during this period will be a
// no-op.
constexpr base::TimeDelta kUpdateCacheDelay = base::TimeDelta::FromSeconds(1);

// Time to wait before starting an update the preferences from the
// http_server_properties_impl_ cache. Scheduling another update during this
// period will be a no-op.
constexpr base::TimeDelta kUpdatePrefsDelay = base::TimeDelta::FromSeconds(60);

// "version" 0 indicates, http_server_properties doesn't have "version"
// property.
const int kMissingVersion = 0;

// The version number of persisted http_server_properties.
const int kVersionNumber = 5;

// Persist 200 MRU AlternateProtocolHostPortPairs.
const int kMaxAlternateProtocolHostsToPersist = 200;

// Persist 300 MRU SupportsSpdyServerHostPortPairs.
const int kMaxSupportsSpdyServerHostsToPersist = 300;

// Persist 200 ServerNetworkStats.
const int kMaxServerNetworkStatsHostsToPersist = 200;

// TODO (wangyix): update values for how many broken alt svcs to persist after
// looking at histograms showing how many are persisted in the real world.
const int kMaxBrokenAlternativeServicesToPersist =
    std::numeric_limits<int>::max();

const int kMaxRecentlyBrokenAlternativeServicesToPersist =
    std::numeric_limits<int>::max();

const char kVersionKey[] = "version";
const char kServersKey[] = "servers";
const char kSupportsSpdyKey[] = "supports_spdy";
const char kSupportsQuicKey[] = "supports_quic";
const char kQuicServers[] = "quic_servers";
const char kServerInfoKey[] = "server_info";
const char kUsedQuicKey[] = "used_quic";
const char kAddressKey[] = "address";
const char kAlternativeServiceKey[] = "alternative_service";
const char kProtocolKey[] = "protocol_str";
const char kHostKey[] = "host";
const char kPortKey[] = "port";
const char kExpirationKey[] = "expiration";
const char kAdvertisedVersionsKey[] = "advertised_versions";
const char kNetworkStatsKey[] = "network_stats";
const char kSrttKey[] = "srtt";
const char kBrokenAlternativeServicesKey[] = "broken_alternative_services";
const char kBrokenUntilKey[] = "broken_until";
const char kBrokenCountKey[] = "broken_count";

void AddAlternativeServiceFieldsToDictionaryValue(
    const AlternativeService& alternative_service,
    base::DictionaryValue* dict) {
  dict->SetInteger(kPortKey, alternative_service.port);
  if (!alternative_service.host.empty()) {
    dict->SetString(kHostKey, alternative_service.host);
  }
  dict->SetString(kProtocolKey,
                  NextProtoToString(alternative_service.protocol));
}

std::unique_ptr<base::Value> NetLogCallback(
    const base::DictionaryValue& http_server_properties_dict,
    NetLogCaptureMode capture_mode) {
  return base::WrapUnique<base::DictionaryValue>(
      http_server_properties_dict.DeepCopy());
}

}  // namespace

////////////////////////////////////////////////////////////////////////////////
//  HttpServerPropertiesManager

HttpServerPropertiesManager::PrefDelegate::~PrefDelegate() {}

HttpServerPropertiesManager::HttpServerPropertiesManager(
    PrefDelegate* pref_delegate,
    scoped_refptr<base::SingleThreadTaskRunner> pref_task_runner,
    scoped_refptr<base::SingleThreadTaskRunner> network_task_runner,
    NetLog* net_log)
    : HttpServerPropertiesManager(pref_delegate,
                                  std::move(pref_task_runner),
                                  std::move(network_task_runner),
                                  net_log,
                                  nullptr) {}

HttpServerPropertiesManager::HttpServerPropertiesManager(
    PrefDelegate* pref_delegate,
    scoped_refptr<base::SingleThreadTaskRunner> pref_task_runner,
    scoped_refptr<base::SingleThreadTaskRunner> network_task_runner,
    NetLog* net_log,
    base::TickClock* clock)
    : pref_task_runner_(std::move(pref_task_runner)),
      pref_delegate_(pref_delegate),
      setting_prefs_(false),
      clock_(clock ? clock : &default_clock_),
      is_initialized_(false),
      network_task_runner_(std::move(network_task_runner)),
      net_log_(
          NetLogWithSource::Make(net_log,
                                 NetLogSourceType::HTTP_SERVER_PROPERTIES)) {
  DCHECK(pref_task_runner_->RunsTasksInCurrentSequence());
  DCHECK(pref_delegate_);
  DCHECK(clock_);
  pref_weak_ptr_factory_.reset(
      new base::WeakPtrFactory<HttpServerPropertiesManager>(this));
  pref_weak_ptr_ = pref_weak_ptr_factory_->GetWeakPtr();
  pref_cache_update_timer_.reset(new base::OneShotTimer);
  pref_cache_update_timer_->SetTaskRunner(pref_task_runner_);
  pref_delegate_->StartListeningForUpdates(
      base::Bind(&HttpServerPropertiesManager::OnHttpServerPropertiesChanged,
                 base::Unretained(this)));
}

HttpServerPropertiesManager::~HttpServerPropertiesManager() {
  DCHECK(network_task_runner_->RunsTasksInCurrentSequence());
  network_weak_ptr_factory_.reset();
}

void HttpServerPropertiesManager::InitializeOnNetworkSequence() {
  DCHECK(network_task_runner_->RunsTasksInCurrentSequence());
  net_log_.BeginEvent(NetLogEventType::HTTP_SERVER_PROPERTIES_INITIALIZATION);

  network_weak_ptr_factory_.reset(
      new base::WeakPtrFactory<HttpServerPropertiesManager>(this));
  http_server_properties_impl_.reset(new HttpServerPropertiesImpl(clock_));

  network_prefs_update_timer_.reset(new base::OneShotTimer);
  network_prefs_update_timer_->SetTaskRunner(network_task_runner_);
  // UpdateCacheFromPrefsOnPrefSequence() will post a task to network thread to
  // update server properties. SetInitialized() will be run after that task is
  // run as |network_task_runner_| is single threaded.
  pref_task_runner_->PostTaskAndReply(
      FROM_HERE,
      base::Bind(
          &HttpServerPropertiesManager::UpdateCacheFromPrefsOnPrefSequence,
          pref_weak_ptr_),
      base::Bind(&HttpServerPropertiesManager::SetInitialized,
                 network_weak_ptr_factory_->GetWeakPtr()));
}

void HttpServerPropertiesManager::ShutdownOnPrefSequence() {
  DCHECK(pref_task_runner_->RunsTasksInCurrentSequence());
  // Cancel any pending updates, and stop listening for pref change updates.
  pref_cache_update_timer_->Stop();
  pref_weak_ptr_factory_.reset();
  pref_delegate_->StopListeningForUpdates();
}

// static
void HttpServerPropertiesManager::SetVersion(
    base::DictionaryValue* http_server_properties_dict,
    int version_number) {
  if (version_number < 0)
    version_number = kVersionNumber;
  DCHECK_LE(version_number, kVersionNumber);
  if (version_number <= kVersionNumber)
    http_server_properties_dict->SetInteger(kVersionKey, version_number);
}

void HttpServerPropertiesManager::Clear() {
  Clear(base::Closure());
}

void HttpServerPropertiesManager::Clear(const base::Closure& completion) {
  DCHECK(network_task_runner_->RunsTasksInCurrentSequence());

  http_server_properties_impl_->Clear();
  UpdatePrefsFromCacheOnNetworkSequence(completion);
}

bool HttpServerPropertiesManager::SupportsRequestPriority(
    const url::SchemeHostPort& server) {
  DCHECK(network_task_runner_->RunsTasksInCurrentSequence());
  return http_server_properties_impl_->SupportsRequestPriority(server);
}

bool HttpServerPropertiesManager::GetSupportsSpdy(
    const url::SchemeHostPort& server) {
  DCHECK(network_task_runner_->RunsTasksInCurrentSequence());
  return http_server_properties_impl_->GetSupportsSpdy(server);
}

void HttpServerPropertiesManager::SetSupportsSpdy(
    const url::SchemeHostPort& server,
    bool support_spdy) {
  DCHECK(network_task_runner_->RunsTasksInCurrentSequence());

  bool old_support_spdy = http_server_properties_impl_->GetSupportsSpdy(server);
  http_server_properties_impl_->SetSupportsSpdy(server, support_spdy);
  bool new_support_spdy = http_server_properties_impl_->GetSupportsSpdy(server);
  if (old_support_spdy != new_support_spdy)
    ScheduleUpdatePrefsOnNetworkSequence(SUPPORTS_SPDY);
}

bool HttpServerPropertiesManager::RequiresHTTP11(const HostPortPair& server) {
  DCHECK(network_task_runner_->RunsTasksInCurrentSequence());
  return http_server_properties_impl_->RequiresHTTP11(server);
}

void HttpServerPropertiesManager::SetHTTP11Required(
    const HostPortPair& server) {
  DCHECK(network_task_runner_->RunsTasksInCurrentSequence());

  http_server_properties_impl_->SetHTTP11Required(server);
  ScheduleUpdatePrefsOnNetworkSequence(HTTP_11_REQUIRED);
}

void HttpServerPropertiesManager::MaybeForceHTTP11(const HostPortPair& server,
                                                   SSLConfig* ssl_config) {
  DCHECK(network_task_runner_->RunsTasksInCurrentSequence());
  http_server_properties_impl_->MaybeForceHTTP11(server, ssl_config);
}

AlternativeServiceInfoVector
HttpServerPropertiesManager::GetAlternativeServiceInfos(
    const url::SchemeHostPort& origin) {
  DCHECK(network_task_runner_->RunsTasksInCurrentSequence());
  return http_server_properties_impl_->GetAlternativeServiceInfos(origin);
}

bool HttpServerPropertiesManager::SetHttp2AlternativeService(
    const url::SchemeHostPort& origin,
    const AlternativeService& alternative_service,
    base::Time expiration) {
  DCHECK(network_task_runner_->RunsTasksInCurrentSequence());
  const bool changed = http_server_properties_impl_->SetHttp2AlternativeService(
      origin, alternative_service, expiration);
  if (changed) {
    ScheduleUpdatePrefsOnNetworkSequence(SET_ALTERNATIVE_SERVICES);
  }
  return changed;
}

bool HttpServerPropertiesManager::SetQuicAlternativeService(
    const url::SchemeHostPort& origin,
    const AlternativeService& alternative_service,
    base::Time expiration,
    const QuicVersionVector& advertised_versions) {
  DCHECK(network_task_runner_->RunsTasksInCurrentSequence());
  const bool changed = http_server_properties_impl_->SetQuicAlternativeService(
      origin, alternative_service, expiration, advertised_versions);
  if (changed) {
    ScheduleUpdatePrefsOnNetworkSequence(SET_ALTERNATIVE_SERVICES);
  }
  return changed;
}

bool HttpServerPropertiesManager::SetAlternativeServices(
    const url::SchemeHostPort& origin,
    const AlternativeServiceInfoVector& alternative_service_info_vector) {
  DCHECK(network_task_runner_->RunsTasksInCurrentSequence());
  const bool changed = http_server_properties_impl_->SetAlternativeServices(
      origin, alternative_service_info_vector);
  if (changed) {
    ScheduleUpdatePrefsOnNetworkSequence(SET_ALTERNATIVE_SERVICES);
  }
  return changed;
}

void HttpServerPropertiesManager::MarkAlternativeServiceBroken(
    const AlternativeService& alternative_service) {
  DCHECK(network_task_runner_->RunsTasksInCurrentSequence());
  http_server_properties_impl_->MarkAlternativeServiceBroken(
      alternative_service);
  ScheduleUpdatePrefsOnNetworkSequence(MARK_ALTERNATIVE_SERVICE_BROKEN);
}

void HttpServerPropertiesManager::MarkAlternativeServiceRecentlyBroken(
    const AlternativeService& alternative_service) {
  DCHECK(network_task_runner_->RunsTasksInCurrentSequence());
  http_server_properties_impl_->MarkAlternativeServiceRecentlyBroken(
      alternative_service);
  ScheduleUpdatePrefsOnNetworkSequence(
      MARK_ALTERNATIVE_SERVICE_RECENTLY_BROKEN);
}

bool HttpServerPropertiesManager::IsAlternativeServiceBroken(
    const AlternativeService& alternative_service) const {
  DCHECK(network_task_runner_->RunsTasksInCurrentSequence());
  return http_server_properties_impl_->IsAlternativeServiceBroken(
      alternative_service);
}

bool HttpServerPropertiesManager::WasAlternativeServiceRecentlyBroken(
    const AlternativeService& alternative_service) {
  DCHECK(network_task_runner_->RunsTasksInCurrentSequence());
  return http_server_properties_impl_->WasAlternativeServiceRecentlyBroken(
      alternative_service);
}

void HttpServerPropertiesManager::ConfirmAlternativeService(
    const AlternativeService& alternative_service) {
  DCHECK(network_task_runner_->RunsTasksInCurrentSequence());
  bool old_value = http_server_properties_impl_->IsAlternativeServiceBroken(
      alternative_service);
  http_server_properties_impl_->ConfirmAlternativeService(alternative_service);
  bool new_value = http_server_properties_impl_->IsAlternativeServiceBroken(
      alternative_service);
  // For persisting, we only care about the value returned by
  // IsAlternativeServiceBroken. If that value changes, then call persist.
  if (old_value != new_value)
    ScheduleUpdatePrefsOnNetworkSequence(CONFIRM_ALTERNATIVE_SERVICE);
}

const AlternativeServiceMap&
HttpServerPropertiesManager::alternative_service_map() const {
  DCHECK(network_task_runner_->RunsTasksInCurrentSequence());
  return http_server_properties_impl_->alternative_service_map();
}

std::unique_ptr<base::Value>
HttpServerPropertiesManager::GetAlternativeServiceInfoAsValue() const {
  DCHECK(network_task_runner_->RunsTasksInCurrentSequence());
  return http_server_properties_impl_->GetAlternativeServiceInfoAsValue();
}

bool HttpServerPropertiesManager::GetSupportsQuic(
    IPAddress* last_address) const {
  DCHECK(network_task_runner_->RunsTasksInCurrentSequence());
  return http_server_properties_impl_->GetSupportsQuic(last_address);
}

void HttpServerPropertiesManager::SetSupportsQuic(bool used_quic,
                                                  const IPAddress& address) {
  DCHECK(network_task_runner_->RunsTasksInCurrentSequence());
  IPAddress old_last_quic_addr;
  http_server_properties_impl_->GetSupportsQuic(&old_last_quic_addr);
  http_server_properties_impl_->SetSupportsQuic(used_quic, address);
  IPAddress new_last_quic_addr;
  http_server_properties_impl_->GetSupportsQuic(&new_last_quic_addr);
  if (old_last_quic_addr != new_last_quic_addr)
    ScheduleUpdatePrefsOnNetworkSequence(SET_SUPPORTS_QUIC);
}

void HttpServerPropertiesManager::SetServerNetworkStats(
    const url::SchemeHostPort& server,
    ServerNetworkStats stats) {
  DCHECK(network_task_runner_->RunsTasksInCurrentSequence());
  ServerNetworkStats old_stats;
  const ServerNetworkStats* old_stats_ptr =
      http_server_properties_impl_->GetServerNetworkStats(server);
  if (http_server_properties_impl_->GetServerNetworkStats(server))
    old_stats = *old_stats_ptr;
  http_server_properties_impl_->SetServerNetworkStats(server, stats);
  ServerNetworkStats new_stats =
      *(http_server_properties_impl_->GetServerNetworkStats(server));
  if (old_stats != new_stats)
    ScheduleUpdatePrefsOnNetworkSequence(SET_SERVER_NETWORK_STATS);
}

void HttpServerPropertiesManager::ClearServerNetworkStats(
    const url::SchemeHostPort& server) {
  DCHECK(network_task_runner_->RunsTasksInCurrentSequence());
  bool need_update =
      http_server_properties_impl_->GetServerNetworkStats(server) != nullptr;
  http_server_properties_impl_->ClearServerNetworkStats(server);
  if (need_update)
    ScheduleUpdatePrefsOnNetworkSequence(CLEAR_SERVER_NETWORK_STATS);
}

const ServerNetworkStats* HttpServerPropertiesManager::GetServerNetworkStats(
    const url::SchemeHostPort& server) {
  DCHECK(network_task_runner_->RunsTasksInCurrentSequence());
  return http_server_properties_impl_->GetServerNetworkStats(server);
}

const ServerNetworkStatsMap&
HttpServerPropertiesManager::server_network_stats_map() const {
  DCHECK(network_task_runner_->RunsTasksInCurrentSequence());
  return http_server_properties_impl_->server_network_stats_map();
}

bool HttpServerPropertiesManager::SetQuicServerInfo(
    const QuicServerId& server_id,
    const std::string& server_info) {
  DCHECK(network_task_runner_->RunsTasksInCurrentSequence());
  bool changed =
      http_server_properties_impl_->SetQuicServerInfo(server_id, server_info);
  if (changed)
    ScheduleUpdatePrefsOnNetworkSequence(SET_QUIC_SERVER_INFO);
  return changed;
}

const std::string* HttpServerPropertiesManager::GetQuicServerInfo(
    const QuicServerId& server_id) {
  DCHECK(network_task_runner_->RunsTasksInCurrentSequence());
  return http_server_properties_impl_->GetQuicServerInfo(server_id);
}

const QuicServerInfoMap& HttpServerPropertiesManager::quic_server_info_map()
    const {
  DCHECK(network_task_runner_->RunsTasksInCurrentSequence());
  return http_server_properties_impl_->quic_server_info_map();
}

size_t HttpServerPropertiesManager::max_server_configs_stored_in_properties()
    const {
  DCHECK(network_task_runner_->RunsTasksInCurrentSequence());
  return http_server_properties_impl_
      ->max_server_configs_stored_in_properties();
}

void HttpServerPropertiesManager::SetMaxServerConfigsStoredInProperties(
    size_t max_server_configs_stored_in_properties) {
  DCHECK(network_task_runner_->RunsTasksInCurrentSequence());
  return http_server_properties_impl_->SetMaxServerConfigsStoredInProperties(
      max_server_configs_stored_in_properties);
}

bool HttpServerPropertiesManager::IsInitialized() const {
  DCHECK(network_task_runner_->RunsTasksInCurrentSequence());

  return is_initialized_;
}

// static
base::TimeDelta HttpServerPropertiesManager::GetUpdateCacheDelayForTesting() {
  return kUpdateCacheDelay;
}

// static
base::TimeDelta HttpServerPropertiesManager::GetUpdatePrefsDelayForTesting() {
  return kUpdatePrefsDelay;
}

//
// Update the HttpServerPropertiesImpl's cache with data from preferences.
//
void HttpServerPropertiesManager::ScheduleUpdateCacheOnPrefThread() {
  DCHECK(pref_task_runner_->RunsTasksInCurrentSequence());
  // Do not schedule a new update if there is already one scheduled.
  if (pref_cache_update_timer_->IsRunning())
    return;

  pref_cache_update_timer_->Start(
      FROM_HERE, kUpdateCacheDelay, this,
      &HttpServerPropertiesManager::UpdateCacheFromPrefsOnPrefSequence);
}

void HttpServerPropertiesManager::UpdateCacheFromPrefsOnPrefSequence() {
  // The preferences can only be read on the pref thread.
  DCHECK(pref_task_runner_->RunsTasksInCurrentSequence());

  if (!pref_delegate_->HasServerProperties())
    return;

  bool detected_corrupted_prefs = false;
  const base::DictionaryValue& http_server_properties_dict =
      pref_delegate_->GetServerProperties();

  net_log_.AddEvent(NetLogEventType::HTTP_SERVER_PROPERTIES_UPDATE_CACHE,
                    base::Bind(&NetLogCallback, http_server_properties_dict));
  int version = kMissingVersion;
  if (!http_server_properties_dict.GetIntegerWithoutPathExpansion(kVersionKey,
                                                                  &version)) {
    DVLOG(1) << "Missing version. Clearing all properties.";
    return;
  }

  const base::DictionaryValue* servers_dict = nullptr;
  const base::ListValue* servers_list = nullptr;
  if (version < 4) {
    // The properties for a given server is in
    // http_server_properties_dict["servers"][server].
    // Before Version 4, server data was stored in the following format in
    // alphabetical order.
    //
    //   "http_server_properties": {
    //      "servers": {
    //         "0-edge-chat.facebook.com:443" : {...},
    //         "0.client-channel.google.com:443" : {...},
    //         "yt3.ggpht.com:80" : {...},
    //         ...
    //      }, ...
    // },
    if (!http_server_properties_dict.GetDictionaryWithoutPathExpansion(
            kServersKey, &servers_dict)) {
      DVLOG(1) << "Malformed http_server_properties for servers.";
      return;
    }
  } else {
    // For Version 4, data was stored in the following format.
    // |servers| are saved in MRU order.
    //
    // "http_server_properties": {
    //      "servers": [
    //          {"yt3.ggpht.com:443" : {...}},
    //          {"0.client-channel.google.com:443" : {...}},
    //          {"0-edge-chat.facebook.com:80" : {...}},
    //          ...
    //      ], ...
    // },
    // For Version 5, data was stored in the following format.
    // |servers| are saved in MRU order. |servers| are in the format flattened
    // representation of (scheme/host/port) where port might be ignored if is
    // default with scheme.
    //
    // "http_server_properties": {
    //      "servers": [
    //          {"https://yt3.ggpht.com" : {...}},
    //          {"http://0.client-channel.google.com:443" : {...}},
    //          {"http://0-edge-chat.facebook.com" : {...}},
    //          ...
    //      ], ...
    // },
    if (!http_server_properties_dict.GetListWithoutPathExpansion(
            kServersKey, &servers_list)) {
      DVLOG(1) << "Malformed http_server_properties for servers list.";
      return;
    }
  }

  std::unique_ptr<IPAddress> addr = base::MakeUnique<IPAddress>();
  ReadSupportsQuic(http_server_properties_dict, addr.get());

  // String is "scheme://host:port" tuple of spdy server.
  std::unique_ptr<SpdyServersMap> spdy_servers_map(
      new SpdyServersMap(SpdyServersMap::NO_AUTO_EVICT));
  std::unique_ptr<AlternativeServiceMap> alternative_service_map(
      new AlternativeServiceMap(kMaxAlternateProtocolHostsToPersist));
  std::unique_ptr<ServerNetworkStatsMap> server_network_stats_map(
      new ServerNetworkStatsMap(kMaxServerNetworkStatsHostsToPersist));
  std::unique_ptr<QuicServerInfoMap> quic_server_info_map(
      new QuicServerInfoMap(QuicServerInfoMap::NO_AUTO_EVICT));

  if (version < 4) {
    if (!AddServersData(*servers_dict, spdy_servers_map.get(),
                        alternative_service_map.get(),
                        server_network_stats_map.get(), version)) {
      detected_corrupted_prefs = true;
    }
  } else {
    // Iterate servers list in reverse MRU order so that entries are inserted
    // into |spdy_servers_map|, |alternative_service_map|, and
    // |server_network_stats_map| from oldest to newest.
    for (base::ListValue::const_iterator it = servers_list->end();
         it != servers_list->begin();) {
      --it;
      if (!it->GetAsDictionary(&servers_dict)) {
        DVLOG(1) << "Malformed http_server_properties for servers dictionary.";
        detected_corrupted_prefs = true;
        continue;
      }
      if (!AddServersData(*servers_dict, spdy_servers_map.get(),
                          alternative_service_map.get(),
                          server_network_stats_map.get(), version)) {
        detected_corrupted_prefs = true;
      }
    }
  }

  if (!AddToQuicServerInfoMap(http_server_properties_dict,
                              quic_server_info_map.get())) {
    detected_corrupted_prefs = true;
  }

  // Read list containing broken and recently-broken alternative services, if
  // it exists.
  std::unique_ptr<BrokenAlternativeServiceList> broken_alternative_service_list;
  std::unique_ptr<RecentlyBrokenAlternativeServices>
      recently_broken_alternative_services;
  const base::ListValue* broken_alt_svc_list;
  if (http_server_properties_dict.GetListWithoutPathExpansion(
          kBrokenAlternativeServicesKey, &broken_alt_svc_list)) {
    broken_alternative_service_list =
        base::MakeUnique<BrokenAlternativeServiceList>();
    recently_broken_alternative_services =
        base::MakeUnique<RecentlyBrokenAlternativeServices>(
            RecentlyBrokenAlternativeServices::NO_AUTO_EVICT);

    // Iterate list in reverse-MRU order
    for (base::ListValue::const_iterator it = broken_alt_svc_list->end();
         it != broken_alt_svc_list->begin();) {
      --it;
      const base::DictionaryValue* entry_dict;
      if (!it->GetAsDictionary(&entry_dict)) {
        DVLOG(1) << "Malformed broken alterantive service entry.";
        detected_corrupted_prefs = true;
        continue;
      }
      if (!AddToBrokenAlternativeServices(
              *entry_dict, broken_alternative_service_list.get(),
              recently_broken_alternative_services.get())) {
        detected_corrupted_prefs = true;
        continue;
      }
    }
  }

  network_task_runner_->PostTask(
      FROM_HERE,
      base::Bind(
          &HttpServerPropertiesManager::UpdateCacheFromPrefsOnNetworkSequence,
          base::Unretained(this), base::Passed(&spdy_servers_map),
          base::Passed(&alternative_service_map), base::Passed(&addr),
          base::Passed(&server_network_stats_map),
          base::Passed(&quic_server_info_map),
          base::Passed(&broken_alternative_service_list),
          base::Passed(&recently_broken_alternative_services),
          detected_corrupted_prefs));
}

bool HttpServerPropertiesManager::AddToBrokenAlternativeServices(
    const base::DictionaryValue& broken_alt_svc_entry_dict,
    BrokenAlternativeServiceList* broken_alternative_service_list,
    RecentlyBrokenAlternativeServices* recently_broken_alternative_services) {
  AlternativeService alt_service;
  if (!ParseAlternativeServiceDict(broken_alt_svc_entry_dict, false,
                                   "broken alternative services",
                                   &alt_service)) {
    return false;
  }

  // Each entry must contain either broken-count and/or broken-until fields.
  bool contains_broken_count_or_broken_until = false;

  // Read broken-count and add an entry for |alt_service| into
  // |recently_broken_alternative_services|.
  if (broken_alt_svc_entry_dict.HasKey(kBrokenCountKey)) {
    int broken_count;
    if (!broken_alt_svc_entry_dict.GetIntegerWithoutPathExpansion(
            kBrokenCountKey, &broken_count)) {
      DVLOG(1) << "Recently broken alternative service has malformed "
               << "broken-count.";
      return false;
    }
    if (broken_count < 0) {
      DVLOG(1) << "Broken alternative service has negative broken-count.";
      return false;
    }
    recently_broken_alternative_services->Put(alt_service, broken_count);
    contains_broken_count_or_broken_until = true;
  }

  // Read broken-until and add an entry for |alt_service| in
  // |broken_alternative_service_list|.
  if (broken_alt_svc_entry_dict.HasKey(kBrokenUntilKey)) {
    std::string expiration_string;
    int64_t expiration_int64;
    if (!broken_alt_svc_entry_dict.GetStringWithoutPathExpansion(
            kBrokenUntilKey, &expiration_string) ||
        !base::StringToInt64(expiration_string, &expiration_int64)) {
      DVLOG(1) << "Broken alternative service has malformed broken-until "
               << "string.";
      return false;
    }

    time_t expiration_time_t = static_cast<time_t>(expiration_int64);
    // Convert expiration from time_t to Time to TimeTicks
    base::TimeTicks expiration_time_ticks =
        clock_->NowTicks() +
        (base::Time::FromTimeT(expiration_time_t) - base::Time::Now());
    broken_alternative_service_list->push_back(
        std::make_pair(alt_service, expiration_time_ticks));
    contains_broken_count_or_broken_until = true;
  }

  if (!contains_broken_count_or_broken_until) {
    DVLOG(1) << "Broken alternative service has neither broken-count nor "
             << "broken-until specified.";
    return false;
  }

  return true;
}

bool HttpServerPropertiesManager::AddServersData(
    const base::DictionaryValue& servers_dict,
    SpdyServersMap* spdy_servers_map,
    AlternativeServiceMap* alternative_service_map,
    ServerNetworkStatsMap* network_stats_map,
    int version) {
  for (base::DictionaryValue::Iterator it(servers_dict); !it.IsAtEnd();
       it.Advance()) {
    // Get server's scheme/host/pair.
    const std::string& server_str = it.key();
    std::string spdy_server_url = server_str;
    if (version < 5) {
      // For old version disk data, always use HTTPS as the scheme.
      spdy_server_url.insert(0, "https://");
    }
    url::SchemeHostPort spdy_server((GURL(spdy_server_url)));
    if (spdy_server.host().empty()) {
      DVLOG(1) << "Malformed http_server_properties for server: " << server_str;
      return false;
    }

    const base::DictionaryValue* server_pref_dict = nullptr;
    if (!it.value().GetAsDictionary(&server_pref_dict)) {
      DVLOG(1) << "Malformed http_server_properties server: " << server_str;
      return false;
    }

    // Get if server supports Spdy.
    bool supports_spdy = false;
    if (server_pref_dict->GetBoolean(kSupportsSpdyKey, &supports_spdy) &&
        supports_spdy) {
      spdy_servers_map->Put(spdy_server.Serialize(), supports_spdy);
    }

    if (!AddToAlternativeServiceMap(spdy_server, *server_pref_dict,
                                    alternative_service_map) ||
        !AddToNetworkStatsMap(spdy_server, *server_pref_dict,
                              network_stats_map)) {
      return false;
    }
  }
  return true;
}

bool HttpServerPropertiesManager::ParseAlternativeServiceDict(
    const base::DictionaryValue& dict,
    bool host_optional,
    const std::string& parsing_under,
    AlternativeService* alternative_service) {
  // Protocol is mandatory.
  std::string protocol_str;
  if (!dict.GetStringWithoutPathExpansion(kProtocolKey, &protocol_str)) {
    DVLOG(1) << "Malformed alternative service protocol string under: "
             << parsing_under;
    return false;
  }
  NextProto protocol = NextProtoFromString(protocol_str);
  if (!IsAlternateProtocolValid(protocol)) {
    DVLOG(1) << "Invalid alternative service protocol string \"" << protocol_str
             << "\" under: " << parsing_under;
    return false;
  }
  alternative_service->protocol = protocol;

  // If host is optional, it defaults to "".
  std::string host = "";
  if (dict.HasKey(kHostKey)) {
    if (!dict.GetStringWithoutPathExpansion(kHostKey, &host)) {
      DVLOG(1) << "Malformed alternative service host string under: "
               << parsing_under;
      return false;
    }
  } else if (!host_optional) {
    DVLOG(1) << "alternative service missing host string under: "
             << parsing_under;
    return false;
  }
  alternative_service->host = host;

  // Port is mandatory.
  int port = 0;
  if (!dict.GetInteger(kPortKey, &port) || !IsPortValid(port)) {
    DVLOG(1) << "Malformed alternative service port under: " << parsing_under;
    return false;
  }
  alternative_service->port = static_cast<uint32_t>(port);

  return true;
}

bool HttpServerPropertiesManager::ParseAlternativeServiceInfoDictOfServer(
    const base::DictionaryValue& dict,
    const std::string& server_str,
    AlternativeServiceInfo* alternative_service_info) {
  AlternativeService alternative_service;
  if (!ParseAlternativeServiceDict(dict, true, "server " + server_str,
                                   &alternative_service)) {
    return false;
  }
  alternative_service_info->set_alternative_service(alternative_service);

  // Expiration is optional, defaults to one day.
  base::Time expiration;
  if (!dict.HasKey(kExpirationKey)) {
    alternative_service_info->set_expiration(base::Time::Now() +
                                             base::TimeDelta::FromDays(1));
  } else {
    std::string expiration_string;
    if (dict.GetStringWithoutPathExpansion(kExpirationKey,
                                           &expiration_string)) {
      int64_t expiration_int64 = 0;
      if (!base::StringToInt64(expiration_string, &expiration_int64)) {
        DVLOG(1) << "Malformed alternative service expiration for server: "
                 << server_str;
        return false;
      }
      alternative_service_info->set_expiration(
          base::Time::FromInternalValue(expiration_int64));
    } else {
      DVLOG(1) << "Malformed alternative service expiration for server: "
               << server_str;
      return false;
    }
  }

  // Advertised versions list is optional.
  if (dict.HasKey(kAdvertisedVersionsKey)) {
    const base::ListValue* versions_list = nullptr;
    if (!dict.GetListWithoutPathExpansion(kAdvertisedVersionsKey,
                                          &versions_list)) {
      DVLOG(1) << "Malformed alternative service advertised versions list for "
               << "server: " << server_str;
      return false;
    }
    QuicVersionVector advertised_versions;
    for (const auto& value : *versions_list) {
      int version;
      if (!value.GetAsInteger(&version)) {
        DVLOG(1) << "Malformed alternative service version for server: "
                 << server_str;
        return false;
      }
      advertised_versions.push_back(QuicVersion(version));
    }
    alternative_service_info->set_advertised_versions(advertised_versions);
  }

  return true;
}

bool HttpServerPropertiesManager::AddToAlternativeServiceMap(
    const url::SchemeHostPort& server,
    const base::DictionaryValue& server_pref_dict,
    AlternativeServiceMap* alternative_service_map) {
  DCHECK(alternative_service_map->Peek(server) ==
         alternative_service_map->end());
  const base::ListValue* alternative_service_list;
  if (!server_pref_dict.GetListWithoutPathExpansion(
          kAlternativeServiceKey, &alternative_service_list)) {
    return true;
  }
  if (server.scheme() != "https") {
    return false;
  }

  AlternativeServiceInfoVector alternative_service_info_vector;
  for (const auto& alternative_service_list_item : *alternative_service_list) {
    const base::DictionaryValue* alternative_service_dict;
    if (!alternative_service_list_item.GetAsDictionary(
            &alternative_service_dict))
      return false;
    AlternativeServiceInfo alternative_service_info;
    if (!ParseAlternativeServiceInfoDictOfServer(*alternative_service_dict,
                                                 server.Serialize(),
                                                 &alternative_service_info)) {
      return false;
    }
    if (base::Time::Now() < alternative_service_info.expiration()) {
      alternative_service_info_vector.push_back(alternative_service_info);
    }
  }

  if (alternative_service_info_vector.empty()) {
    return false;
  }

  alternative_service_map->Put(server, alternative_service_info_vector);
  return true;
}

bool HttpServerPropertiesManager::ReadSupportsQuic(
    const base::DictionaryValue& http_server_properties_dict,
    IPAddress* last_quic_address) {
  const base::DictionaryValue* supports_quic_dict = nullptr;
  if (!http_server_properties_dict.GetDictionaryWithoutPathExpansion(
          kSupportsQuicKey, &supports_quic_dict)) {
    return true;
  }
  bool used_quic = false;
  if (!supports_quic_dict->GetBooleanWithoutPathExpansion(kUsedQuicKey,
                                                          &used_quic)) {
    DVLOG(1) << "Malformed SupportsQuic";
    return false;
  }
  if (!used_quic)
    return false;

  std::string address;
  if (!supports_quic_dict->GetStringWithoutPathExpansion(kAddressKey,
                                                         &address) ||
      !last_quic_address->AssignFromIPLiteral(address)) {
    DVLOG(1) << "Malformed SupportsQuic";
    return false;
  }
  return true;
}

bool HttpServerPropertiesManager::AddToNetworkStatsMap(
    const url::SchemeHostPort& server,
    const base::DictionaryValue& server_pref_dict,
    ServerNetworkStatsMap* network_stats_map) {
  DCHECK(network_stats_map->Peek(server) == network_stats_map->end());
  const base::DictionaryValue* server_network_stats_dict = nullptr;
  if (!server_pref_dict.GetDictionaryWithoutPathExpansion(
          kNetworkStatsKey, &server_network_stats_dict)) {
    return true;
  }
  int srtt;
  if (!server_network_stats_dict->GetIntegerWithoutPathExpansion(kSrttKey,
                                                                 &srtt)) {
    DVLOG(1) << "Malformed ServerNetworkStats for server: "
             << server.Serialize();
    return false;
  }
  ServerNetworkStats server_network_stats;
  server_network_stats.srtt = base::TimeDelta::FromMicroseconds(srtt);
  // TODO(rtenneti): When QUIC starts using bandwidth_estimate, then persist
  // bandwidth_estimate.
  network_stats_map->Put(server, server_network_stats);
  return true;
}

bool HttpServerPropertiesManager::AddToQuicServerInfoMap(
    const base::DictionaryValue& http_server_properties_dict,
    QuicServerInfoMap* quic_server_info_map) {
  const base::DictionaryValue* quic_servers_dict = nullptr;
  if (!http_server_properties_dict.GetDictionaryWithoutPathExpansion(
          kQuicServers, &quic_servers_dict)) {
    DVLOG(1) << "Malformed http_server_properties for quic_servers.";
    return true;
  }

  bool detected_corrupted_prefs = false;
  for (base::DictionaryValue::Iterator it(*quic_servers_dict); !it.IsAtEnd();
       it.Advance()) {
    // Get quic_server_id.
    const std::string& quic_server_id_str = it.key();
    QuicServerId quic_server_id;
    QuicHostnameUtils::StringToQuicServerId(quic_server_id_str,
                                            &quic_server_id);
    if (quic_server_id.host().empty()) {
      DVLOG(1) << "Malformed http_server_properties for quic server: "
               << quic_server_id_str;
      detected_corrupted_prefs = true;
      continue;
    }

    const base::DictionaryValue* quic_server_pref_dict = nullptr;
    if (!it.value().GetAsDictionary(&quic_server_pref_dict)) {
      DVLOG(1) << "Malformed http_server_properties quic server dict: "
               << quic_server_id_str;
      detected_corrupted_prefs = true;
      continue;
    }

    std::string quic_server_info;
    if (!quic_server_pref_dict->GetStringWithoutPathExpansion(
            kServerInfoKey, &quic_server_info)) {
      DVLOG(1) << "Malformed http_server_properties quic server info: "
               << quic_server_id_str;
      detected_corrupted_prefs = true;
      continue;
    }
    quic_server_info_map->Put(quic_server_id, quic_server_info);
  }
  return !detected_corrupted_prefs;
}

void HttpServerPropertiesManager::UpdateCacheFromPrefsOnNetworkSequence(
    std::unique_ptr<SpdyServersMap> spdy_servers_map,
    std::unique_ptr<AlternativeServiceMap> alternative_service_map,
    std::unique_ptr<IPAddress> last_quic_address,
    std::unique_ptr<ServerNetworkStatsMap> server_network_stats_map,
    std::unique_ptr<QuicServerInfoMap> quic_server_info_map,
    std::unique_ptr<BrokenAlternativeServiceList>
        broken_alternative_service_list,
    std::unique_ptr<RecentlyBrokenAlternativeServices>
        recently_broken_alternative_services,
    bool detected_corrupted_prefs) {
  // Preferences have the master data because admins might have pushed new
  // preferences. Update the cached data with new data from preferences.
  DCHECK(network_task_runner_->RunsTasksInCurrentSequence());

  UMA_HISTOGRAM_COUNTS_1M("Net.CountOfSpdyServers", spdy_servers_map->size());
  http_server_properties_impl_->SetSpdyServers(std::move(spdy_servers_map));

  // Update the cached data and use the new alternative service list from
  // preferences.
  UMA_HISTOGRAM_COUNTS_1M("Net.CountOfAlternateProtocolServers",
                          alternative_service_map->size());
  http_server_properties_impl_->SetAlternativeServiceServers(
      std::move(alternative_service_map));

  http_server_properties_impl_->SetSupportsQuic(*last_quic_address);

  http_server_properties_impl_->SetServerNetworkStats(
      std::move(server_network_stats_map));

  UMA_HISTOGRAM_COUNTS_1000("Net.CountOfQuicServerInfos",
                            quic_server_info_map->size());

  http_server_properties_impl_->SetQuicServerInfoMap(
      std::move(quic_server_info_map));

  if (recently_broken_alternative_services) {
    DCHECK(broken_alternative_service_list);

    UMA_HISTOGRAM_COUNTS_1000("Net.CountOfBrokenAlternativeServices",
                              broken_alternative_service_list->size());
    UMA_HISTOGRAM_COUNTS_1000("Net.CountOfRecentlyBrokenAlternativeServices",
                              recently_broken_alternative_services->size());

    http_server_properties_impl_->SetBrokenAndRecentlyBrokenAlternativeServices(
        std::move(broken_alternative_service_list),
        std::move(recently_broken_alternative_services));
  }

  // Update the prefs with what we have read (delete all corrupted prefs).
  if (detected_corrupted_prefs)
    ScheduleUpdatePrefsOnNetworkSequence(DETECTED_CORRUPTED_PREFS);
}

//
// Update Preferences with data from the cached data.
//
void HttpServerPropertiesManager::ScheduleUpdatePrefsOnNetworkSequence(
    Location location) {
  DCHECK(network_task_runner_->RunsTasksInCurrentSequence());
  // Do not schedule a new update if there is already one scheduled.
  if (network_prefs_update_timer_->IsRunning())
    return;

  network_prefs_update_timer_->Start(
      FROM_HERE, kUpdatePrefsDelay, this,
      &HttpServerPropertiesManager::UpdatePrefsFromCacheOnNetworkSequence);

  // TODO(rtenneti): Delete the following histogram after collecting some data.
  UMA_HISTOGRAM_ENUMERATION("Net.HttpServerProperties.UpdatePrefs", location,
                            HttpServerPropertiesManager::NUM_LOCATIONS);
}

// This is required so we can set this as the callback for a timer.
void HttpServerPropertiesManager::UpdatePrefsFromCacheOnNetworkSequence() {
  UpdatePrefsFromCacheOnNetworkSequence(base::Closure());
}

void HttpServerPropertiesManager::UpdatePrefsFromCacheOnNetworkSequence(
    const base::Closure& completion) {
  DCHECK(network_task_runner_->RunsTasksInCurrentSequence());

  // It is in MRU order.
  std::unique_ptr<std::vector<std::string>> spdy_servers =
      base::MakeUnique<std::vector<std::string>>();
  http_server_properties_impl_->GetSpdyServerList(
      spdy_servers.get(), kMaxSupportsSpdyServerHostsToPersist);

  std::unique_ptr<AlternativeServiceMap> alternative_service_map =
      base::MakeUnique<AlternativeServiceMap>(
          kMaxAlternateProtocolHostsToPersist);
  const AlternativeServiceMap& map =
      http_server_properties_impl_->alternative_service_map();
  UMA_HISTOGRAM_COUNTS_1M("Net.CountOfAlternateProtocolServers.Memory",
                          map.size());
  int count = 0;
  typedef std::map<std::string, bool> CanonicalHostPersistedMap;
  CanonicalHostPersistedMap persisted_map;
  // Maintain MRU order.
  for (AlternativeServiceMap::const_reverse_iterator it = map.rbegin();
       it != map.rend() && count < kMaxAlternateProtocolHostsToPersist; ++it) {
    const url::SchemeHostPort& server = it->first;
    AlternativeServiceInfoVector notbroken_alternative_service_info_vector;
    for (const AlternativeServiceInfo& alternative_service_info : it->second) {
      // Do not persist expired entries.
      if (alternative_service_info.expiration() < base::Time::Now()) {
        continue;
      }
      AlternativeService alternative_service(
          alternative_service_info.alternative_service());
      if (!IsAlternateProtocolValid(alternative_service.protocol)) {
        continue;
      }
      if (alternative_service.host.empty()) {
        alternative_service.host = server.host();
      }
      notbroken_alternative_service_info_vector.push_back(
          alternative_service_info);
    }
    if (notbroken_alternative_service_info_vector.empty()) {
      continue;
    }
    const std::string* canonical_suffix =
        http_server_properties_impl_->GetCanonicalSuffix(server.host());
    if (canonical_suffix != nullptr) {
      if (persisted_map.find(*canonical_suffix) != persisted_map.end())
        continue;
      persisted_map[*canonical_suffix] = true;
    }
    alternative_service_map->Put(server,
                                 notbroken_alternative_service_info_vector);
    ++count;
  }

  std::unique_ptr<ServerNetworkStatsMap> server_network_stats_map =
      base::MakeUnique<ServerNetworkStatsMap>(
          kMaxServerNetworkStatsHostsToPersist);
  const ServerNetworkStatsMap& network_stats_map =
      http_server_properties_impl_->server_network_stats_map();
  count = 0;
  for (ServerNetworkStatsMap::const_reverse_iterator
           it = network_stats_map.rbegin();
       it != network_stats_map.rend() &&
       count < kMaxServerNetworkStatsHostsToPersist;
       ++it, ++count) {
    server_network_stats_map->Put(it->first, it->second);
  }

  std::unique_ptr<QuicServerInfoMap> quic_server_info_map;
  const QuicServerInfoMap& main_quic_server_info_map =
      http_server_properties_impl_->quic_server_info_map();
  if (main_quic_server_info_map.size() > 0) {
    quic_server_info_map = base::MakeUnique<QuicServerInfoMap>(
        max_server_configs_stored_in_properties());
    for (QuicServerInfoMap::const_reverse_iterator it =
             main_quic_server_info_map.rbegin();
         it != main_quic_server_info_map.rend(); ++it) {
      quic_server_info_map->Put(it->first, it->second);
    }
  }

  std::unique_ptr<BrokenAlternativeServiceList> broken_alt_svc_list;
  const BrokenAlternativeServiceList& broken_alternative_service_list =
      http_server_properties_impl_->broken_alternative_service_list();
  if (broken_alternative_service_list.size() > 0) {
    broken_alt_svc_list = base::MakeUnique<BrokenAlternativeServiceList>();
    size_t count = 0;
    for (auto it = broken_alternative_service_list.begin();
         it != broken_alternative_service_list.end() &&
         count < kMaxBrokenAlternativeServicesToPersist;
         ++it) {
      broken_alt_svc_list->push_back(*it);
      ++count;
    }
  }

  std::unique_ptr<RecentlyBrokenAlternativeServices> recently_broken_alt_svcs;
  const RecentlyBrokenAlternativeServices& recently_broken_alt_services =
      http_server_properties_impl_->recently_broken_alternative_services();
  if (recently_broken_alt_services.size() > 0) {
    recently_broken_alt_svcs =
        base::MakeUnique<RecentlyBrokenAlternativeServices>(
            kMaxRecentlyBrokenAlternativeServicesToPersist);
    size_t count = 0;
    for (auto it = recently_broken_alt_services.rbegin();
         it != recently_broken_alt_services.rend() &&
         count < kMaxRecentlyBrokenAlternativeServicesToPersist;
         ++it) {
      recently_broken_alt_svcs->Put(it->first, it->second);
      ++count;
    }
  }

  std::unique_ptr<IPAddress> last_quic_addr = base::MakeUnique<IPAddress>();
  http_server_properties_impl_->GetSupportsQuic(last_quic_addr.get());
  // Update the preferences on the pref thread.
  pref_task_runner_->PostTask(
      FROM_HERE,
      base::Bind(&HttpServerPropertiesManager::UpdatePrefsOnPrefThread,
                 pref_weak_ptr_, base::Passed(&spdy_servers),
                 base::Passed(&alternative_service_map),
                 base::Passed(&last_quic_addr),
                 base::Passed(&server_network_stats_map),
                 base::Passed(&quic_server_info_map),
                 base::Passed(&broken_alt_svc_list),
                 base::Passed(&recently_broken_alt_svcs), completion));
}

// A local or temporary data structure to hold preferences for a server.
// This is used only in UpdatePrefsOnPrefThread.
struct ServerPref {
  bool supports_spdy = false;
  const AlternativeServiceInfoVector* alternative_service_info_vector = nullptr;
  const SupportsQuic* supports_quic = nullptr;
  const ServerNetworkStats* server_network_stats = nullptr;
};

// All maps and lists are in MRU order.
void HttpServerPropertiesManager::UpdatePrefsOnPrefThread(
    std::unique_ptr<std::vector<std::string>> spdy_servers,
    std::unique_ptr<AlternativeServiceMap> alternative_service_map,
    std::unique_ptr<IPAddress> last_quic_address,
    std::unique_ptr<ServerNetworkStatsMap> server_network_stats_map,
    std::unique_ptr<QuicServerInfoMap> quic_server_info_map,
    std::unique_ptr<BrokenAlternativeServiceList>
        broken_alternative_service_list,
    std::unique_ptr<RecentlyBrokenAlternativeServices>
        recently_broken_alternative_services,
    const base::Closure& completion) {
  typedef base::MRUCache<url::SchemeHostPort, ServerPref> ServerPrefMap;
  ServerPrefMap server_pref_map(ServerPrefMap::NO_AUTO_EVICT);

  DCHECK(pref_task_runner_->RunsTasksInCurrentSequence());

  // Add servers that support spdy to server_pref_map in the MRU order.
  DCHECK(spdy_servers);
  for (size_t i = spdy_servers->size(); i > 0; --i) {
    url::SchemeHostPort server((GURL(spdy_servers->at(i - 1))));
    ServerPrefMap::iterator it = server_pref_map.Get(server);
    if (it == server_pref_map.end()) {
      ServerPref server_pref;
      server_pref.supports_spdy = true;
      server_pref_map.Put(server, server_pref);
    } else {
      it->second.supports_spdy = true;
    }
  }

  // Add alternative services to server_pref_map in the MRU order.
  DCHECK(alternative_service_map);
  for (AlternativeServiceMap::const_reverse_iterator map_it =
           alternative_service_map->rbegin();
       map_it != alternative_service_map->rend(); ++map_it) {
    const url::SchemeHostPort server = map_it->first;
    ServerPrefMap::iterator it = server_pref_map.Get(server);
    if (it == server_pref_map.end()) {
      ServerPref server_pref;
      server_pref.alternative_service_info_vector = &map_it->second;
      server_pref_map.Put(server, server_pref);
    } else {
      it->second.alternative_service_info_vector = &map_it->second;
    }
  }

  // Add ServerNetworkStats servers to server_pref_map in the MRU order.
  DCHECK(server_network_stats_map);
  for (ServerNetworkStatsMap::const_reverse_iterator map_it =
           server_network_stats_map->rbegin();
       map_it != server_network_stats_map->rend(); ++map_it) {
    const url::SchemeHostPort server = map_it->first;
    ServerPrefMap::iterator it = server_pref_map.Get(server);
    if (it == server_pref_map.end()) {
      ServerPref server_pref;
      server_pref.server_network_stats = &map_it->second;
      server_pref_map.Put(server, server_pref);
    } else {
      it->second.server_network_stats = &map_it->second;
    }
  }

  // Persist properties to the prefs in the MRU order.
  base::DictionaryValue http_server_properties_dict;
  auto servers_list = base::MakeUnique<base::ListValue>();
  for (ServerPrefMap::const_reverse_iterator map_it = server_pref_map.rbegin();
       map_it != server_pref_map.rend(); ++map_it) {
    const url::SchemeHostPort server = map_it->first;
    const ServerPref& server_pref = map_it->second;

    auto servers_dict = base::MakeUnique<base::DictionaryValue>();
    auto server_pref_dict = base::MakeUnique<base::DictionaryValue>();

    // Save supports_spdy.
    if (server_pref.supports_spdy) {
      server_pref_dict->SetBoolean(kSupportsSpdyKey, server_pref.supports_spdy);
    }
    if (server_pref.alternative_service_info_vector) {
      SaveAlternativeServiceToServerPrefs(
          *server_pref.alternative_service_info_vector, server_pref_dict.get());
    }
    if (server_pref.server_network_stats) {
      SaveNetworkStatsToServerPrefs(*server_pref.server_network_stats,
                                    server_pref_dict.get());
    }

    servers_dict->SetWithoutPathExpansion(server.Serialize(),
                                          std::move(server_pref_dict));
    bool value = servers_list->AppendIfNotPresent(std::move(servers_dict));
    DCHECK(value);  // Should never happen.
  }

  http_server_properties_dict.SetWithoutPathExpansion(kServersKey,
                                                      std::move(servers_list));
  SetVersion(&http_server_properties_dict, kVersionNumber);

  DCHECK(last_quic_address);
  SaveSupportsQuicToPrefs(*last_quic_address, &http_server_properties_dict);

  if (quic_server_info_map) {
    SaveQuicServerInfoMapToServerPrefs(*quic_server_info_map,
                                       &http_server_properties_dict);
  }

  SaveBrokenAlternativeServicesToPrefs(
      broken_alternative_service_list.get(),
      recently_broken_alternative_services.get(), &http_server_properties_dict);

  setting_prefs_ = true;
  pref_delegate_->SetServerProperties(http_server_properties_dict);
  setting_prefs_ = false;

  net_log_.AddEvent(NetLogEventType::HTTP_SERVER_PROPERTIES_UPDATE_PREFS,
                    base::Bind(&NetLogCallback, http_server_properties_dict));
  // Note that |completion| will be fired after we have written everything to
  // the Preferences, but likely before these changes are serialized to disk.
  // This is not a problem though, as JSONPrefStore guarantees that this will
  // happen, pretty soon, and even in the case we shut down immediately.
  if (!completion.is_null())
    completion.Run();
}

void HttpServerPropertiesManager::SaveAlternativeServiceToServerPrefs(
    const AlternativeServiceInfoVector& alternative_service_info_vector,
    base::DictionaryValue* server_pref_dict) {
  if (alternative_service_info_vector.empty()) {
    return;
  }
  std::unique_ptr<base::ListValue> alternative_service_list(
      new base::ListValue);
  for (const AlternativeServiceInfo& alternative_service_info :
       alternative_service_info_vector) {
    const AlternativeService& alternative_service =
        alternative_service_info.alternative_service();
    DCHECK(IsAlternateProtocolValid(alternative_service.protocol));
    std::unique_ptr<base::DictionaryValue> alternative_service_dict(
        new base::DictionaryValue);
    AddAlternativeServiceFieldsToDictionaryValue(
        alternative_service, alternative_service_dict.get());
    // JSON cannot store int64_t, so expiration is converted to a string.
    alternative_service_dict->SetString(
        kExpirationKey,
        base::Int64ToString(
            alternative_service_info.expiration().ToInternalValue()));
    std::unique_ptr<base::ListValue> advertised_versions_list =
        base::MakeUnique<base::ListValue>();
    for (const auto& version : alternative_service_info.advertised_versions()) {
      advertised_versions_list->AppendInteger(version);
    }
    alternative_service_dict->SetList(kAdvertisedVersionsKey,
                                      std::move(advertised_versions_list));
    alternative_service_list->Append(std::move(alternative_service_dict));
  }
  if (alternative_service_list->GetSize() == 0)
    return;
  server_pref_dict->SetWithoutPathExpansion(
      kAlternativeServiceKey, std::move(alternative_service_list));
}

void HttpServerPropertiesManager::SaveSupportsQuicToPrefs(
    const IPAddress& last_quic_address,
    base::DictionaryValue* http_server_properties_dict) {
  if (!last_quic_address.IsValid())
    return;

  auto supports_quic_dict = base::MakeUnique<base::DictionaryValue>();
  supports_quic_dict->SetBoolean(kUsedQuicKey, true);
  supports_quic_dict->SetString(kAddressKey, last_quic_address.ToString());
  http_server_properties_dict->SetWithoutPathExpansion(
      kSupportsQuicKey, std::move(supports_quic_dict));
}

void HttpServerPropertiesManager::SaveNetworkStatsToServerPrefs(
    const ServerNetworkStats& server_network_stats,
    base::DictionaryValue* server_pref_dict) {
  auto server_network_stats_dict = base::MakeUnique<base::DictionaryValue>();
  // Becasue JSON doesn't support int64_t, persist int64_t as a string.
  server_network_stats_dict->SetInteger(
      kSrttKey, static_cast<int>(server_network_stats.srtt.InMicroseconds()));
  // TODO(rtenneti): When QUIC starts using bandwidth_estimate, then persist
  // bandwidth_estimate.
  server_pref_dict->SetWithoutPathExpansion(
      kNetworkStatsKey, std::move(server_network_stats_dict));
}

void HttpServerPropertiesManager::SaveQuicServerInfoMapToServerPrefs(
    const QuicServerInfoMap& quic_server_info_map,
    base::DictionaryValue* http_server_properties_dict) {
  auto quic_servers_dict = base::MakeUnique<base::DictionaryValue>();
  for (QuicServerInfoMap::const_reverse_iterator it =
           quic_server_info_map.rbegin();
       it != quic_server_info_map.rend(); ++it) {
    const QuicServerId& server_id = it->first;
    auto quic_server_pref_dict = base::MakeUnique<base::DictionaryValue>();
    quic_server_pref_dict->SetStringWithoutPathExpansion(kServerInfoKey,
                                                         it->second);
    quic_servers_dict->SetWithoutPathExpansion(
        server_id.ToString(), std::move(quic_server_pref_dict));
  }
  http_server_properties_dict->SetWithoutPathExpansion(
      kQuicServers, std::move(quic_servers_dict));
}

void HttpServerPropertiesManager::SaveBrokenAlternativeServicesToPrefs(
    const BrokenAlternativeServiceList* broken_alternative_service_list,
    const RecentlyBrokenAlternativeServices*
        recently_broken_alternative_services,
    base::DictionaryValue* http_server_properties_dict) {
  // JSON list will be in MRU order according to
  // |recently_broken_alternative_services|.
  std::unique_ptr<base::ListValue> json_list =
      base::MakeUnique<base::ListValue>();

  // Maps recently-broken alternative services to the index where it's stored
  // in |json_list|.
  std::unordered_map<AlternativeService, size_t, AlternativeServiceHash>
      json_list_index_map;

  if (recently_broken_alternative_services) {
    for (auto it = recently_broken_alternative_services->rbegin();
         it != recently_broken_alternative_services->rend(); ++it) {
      const AlternativeService& alt_service = it->first;
      int broken_count = it->second;
      base::DictionaryValue entry_dict;
      AddAlternativeServiceFieldsToDictionaryValue(alt_service, &entry_dict);
      entry_dict.SetIntegerWithoutPathExpansion(kBrokenCountKey, broken_count);
      json_list_index_map[alt_service] = json_list->GetList().size();
      json_list->GetList().push_back(std::move(entry_dict));
    }
  }

  if (broken_alternative_service_list) {
    // Add expiration time info from |broken_alternative_service_list| to
    // the JSON list.
    for (auto entry : *broken_alternative_service_list) {
      const AlternativeService& alt_service = entry.first;
      base::TimeTicks expiration_time_ticks = entry.second;
      // Convert expiration from TimeTicks to Time to time_t
      time_t expiration_time_t =
          (base::Time::Now() + (expiration_time_ticks - clock_->NowTicks()))
              .ToTimeT();
      int64_t expiration_int64 = static_cast<int64_t>(expiration_time_t);

      auto it = json_list_index_map.find(alt_service);
      if (it != json_list_index_map.end()) {
        size_t json_list_index = it->second;
        base::DictionaryValue* entry_dict = nullptr;
        bool result = json_list->GetDictionary(json_list_index, &entry_dict);
        DCHECK(result);
        entry_dict->SetStringWithoutPathExpansion(
            kBrokenUntilKey, base::Int64ToString(expiration_int64));
      } else {
        base::DictionaryValue entry_dict;
        AddAlternativeServiceFieldsToDictionaryValue(alt_service, &entry_dict);
        entry_dict.SetStringWithoutPathExpansion(
            kBrokenUntilKey, base::Int64ToString(expiration_int64));
        json_list->GetList().push_back(std::move(entry_dict));
      }
    }
  }

  if (recently_broken_alternative_services || broken_alternative_service_list) {
    http_server_properties_dict->SetWithoutPathExpansion(
        kBrokenAlternativeServicesKey, std::move(json_list));
  }
}

void HttpServerPropertiesManager::OnHttpServerPropertiesChanged() {
  DCHECK(pref_task_runner_->RunsTasksInCurrentSequence());
  if (!setting_prefs_)
    ScheduleUpdateCacheOnPrefThread();
}

void HttpServerPropertiesManager::SetInitialized() {
  DCHECK(network_task_runner_->RunsTasksInCurrentSequence());
  is_initialized_ = true;
  net_log_.EndEvent(NetLogEventType::HTTP_SERVER_PROPERTIES_INITIALIZATION);
}

}  // namespace net