net/reporting/reporting_cache_impl.cc

// Copyright 2019 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/reporting/reporting_cache_impl.h"

#include <algorithm>
#include <set>
#include <unordered_map>
#include <unordered_set>
#include <utility>

#include "base/stl_util.h"
#include "base/time/clock.h"
#include "base/time/tick_clock.h"
#include "net/log/net_log.h"

namespace net {

namespace {
// TODO(chlily): Move this (and identical code in NEL) to net/base/url_util.h.

// Returns the superdomain of a given domain, or the empty string if the given
// domain is just a single label. Note that this does not take into account
// anything like the Public Suffix List, so the superdomain may end up being a
// bare TLD.
//
// Examples:
//
// GetSuperdomain("assets.example.com") -> "example.com"
// GetSuperdomain("example.net") -> "net"
// GetSuperdomain("littlebox") -> ""
std::string GetSuperdomain(const std::string& domain) {
  size_t dot_pos = domain.find('.');
  if (dot_pos == std::string::npos)
    return "";

  return domain.substr(dot_pos + 1);
}

}  // namespace

ReportingCacheImpl::ReportingCacheImpl(ReportingContext* context,
                                       PersistentReportingStore* store)
    : context_(context), store_(store) {
  DCHECK(context_);
}

ReportingCacheImpl::~ReportingCacheImpl() {
  base::TimeTicks now = tick_clock()->NowTicks();

  // Mark all undoomed reports as erased at shutdown, and record outcomes of
  // all remaining reports (doomed or not).
  for (auto it = reports_.begin(); it != reports_.end(); ++it) {
    ReportingReport* report = it->second.get();
    if (!base::Contains(doomed_reports_, report))
      report->outcome = ReportingReport::Outcome::ERASED_REPORTING_SHUT_DOWN;
    report->RecordOutcome(now);
  }

  reports_.clear();
}

void ReportingCacheImpl::AddReport(const GURL& url,
                                   const std::string& user_agent,
                                   const std::string& group_name,
                                   const std::string& type,
                                   std::unique_ptr<const base::Value> body,
                                   int depth,
                                   base::TimeTicks queued,
                                   int attempts) {
  auto report = std::make_unique<ReportingReport>(url, user_agent, group_name,
                                                  type, std::move(body), depth,
                                                  queued, attempts);

  auto inserted =
      reports_.insert(std::make_pair(report.get(), std::move(report)));
  DCHECK(inserted.second);

  if (reports_.size() > context_->policy().max_report_count) {
    // There should be at most one extra report (the one added above).
    DCHECK_EQ(context_->policy().max_report_count + 1, reports_.size());
    const ReportingReport* to_evict = FindReportToEvict();
    DCHECK_NE(nullptr, to_evict);
    // The newly-added report isn't pending, so even if all other reports are
    // pending, the cache should have a report to evict.
    DCHECK(!base::Contains(pending_reports_, to_evict));
    reports_[to_evict]->outcome = ReportingReport::Outcome::ERASED_EVICTED;
    RemoveReportInternal(to_evict);
  }

  context_->NotifyCachedReportsUpdated();
}

void ReportingCacheImpl::GetReports(
    std::vector<const ReportingReport*>* reports_out) const {
  reports_out->clear();
  for (const auto& it : reports_) {
    if (!base::Contains(doomed_reports_, it.first))
      reports_out->push_back(it.second.get());
  }
}

base::Value ReportingCacheImpl::GetReportsAsValue() const {
  // Sort the queued reports by origin and timestamp.
  std::vector<const ReportingReport*> sorted_reports;
  sorted_reports.reserve(reports_.size());
  for (const auto& it : reports_) {
    sorted_reports.push_back(it.second.get());
  }
  std::sort(sorted_reports.begin(), sorted_reports.end(),
            [](const ReportingReport* report1, const ReportingReport* report2) {
              if (report1->queued < report2->queued)
                return true;
              else if (report1->queued > report2->queued)
                return false;
              else
                return report1->url < report2->url;
            });

  std::vector<base::Value> report_list;
  for (const ReportingReport* report : sorted_reports) {
    base::Value report_dict(base::Value::Type::DICTIONARY);
    report_dict.SetKey("url", base::Value(report->url.spec()));
    report_dict.SetKey("group", base::Value(report->group));
    report_dict.SetKey("type", base::Value(report->type));
    report_dict.SetKey("depth", base::Value(report->depth));
    report_dict.SetKey("queued",
                       base::Value(NetLog::TickCountToString(report->queued)));
    report_dict.SetKey("attempts", base::Value(report->attempts));
    if (report->body) {
      report_dict.SetKey("body", report->body->Clone());
    }
    if (base::Contains(doomed_reports_, report)) {
      report_dict.SetKey("status", base::Value("doomed"));
    } else if (base::Contains(pending_reports_, report)) {
      report_dict.SetKey("status", base::Value("pending"));
    } else {
      report_dict.SetKey("status", base::Value("queued"));
    }
    report_list.push_back(std::move(report_dict));
  }
  return base::Value(std::move(report_list));
}

void ReportingCacheImpl::GetNonpendingReports(
    std::vector<const ReportingReport*>* reports_out) const {
  reports_out->clear();
  for (const auto& it : reports_) {
    if (!base::Contains(pending_reports_, it.first) &&
        !base::Contains(doomed_reports_, it.first)) {
      reports_out->push_back(it.second.get());
    }
  }
}

void ReportingCacheImpl::SetReportsPending(
    const std::vector<const ReportingReport*>& reports) {
  for (const ReportingReport* report : reports) {
    auto inserted = pending_reports_.insert(report);
    DCHECK(inserted.second);
  }
}

void ReportingCacheImpl::ClearReportsPending(
    const std::vector<const ReportingReport*>& reports) {
  std::vector<const ReportingReport*> reports_to_remove;

  for (const ReportingReport* report : reports) {
    size_t erased = pending_reports_.erase(report);
    DCHECK_EQ(1u, erased);
    if (base::Contains(doomed_reports_, report)) {
      reports_to_remove.push_back(report);
      doomed_reports_.erase(report);
    }
  }

  for (const ReportingReport* report : reports_to_remove)
    RemoveReportInternal(report);
}

void ReportingCacheImpl::IncrementReportsAttempts(
    const std::vector<const ReportingReport*>& reports) {
  for (const ReportingReport* report : reports) {
    DCHECK(base::Contains(reports_, report));
    reports_[report]->attempts++;
  }

  context_->NotifyCachedReportsUpdated();
}

void ReportingCacheImpl::IncrementEndpointDeliveries(
    const url::Origin& origin,
    const std::string& group_name,
    const GURL& url,
    int reports_delivered,
    bool successful) {
  EndpointMap::iterator endpoint_it =
      FindEndpointIt(ReportingEndpointGroupKey(origin, group_name), url);
  // The endpoint may have been removed while the upload was in progress. In
  // that case, we no longer care about the stats for the removed endpoint.
  if (endpoint_it == endpoints_.end())
    return;

  ReportingEndpoint::Statistics& stats = endpoint_it->second.stats;
  ++stats.attempted_uploads;
  stats.attempted_reports += reports_delivered;
  if (successful) {
    ++stats.successful_uploads;
    stats.successful_reports += reports_delivered;
  }
}

void ReportingCacheImpl::RemoveReports(
    const std::vector<const ReportingReport*>& reports,
    ReportingReport::Outcome outcome) {
  for (const ReportingReport* report : reports) {
    reports_[report]->outcome = outcome;
    if (base::Contains(pending_reports_, report)) {
      doomed_reports_.insert(report);
    } else {
      DCHECK(!base::Contains(doomed_reports_, report));
      RemoveReportInternal(report);
    }
  }

  context_->NotifyCachedReportsUpdated();
}

void ReportingCacheImpl::RemoveAllReports(ReportingReport::Outcome outcome) {
  std::vector<const ReportingReport*> reports_to_remove;
  for (auto it = reports_.begin(); it != reports_.end(); ++it) {
    ReportingReport* report = it->second.get();
    report->outcome = outcome;
    if (!base::Contains(pending_reports_, report))
      reports_to_remove.push_back(report);
    else
      doomed_reports_.insert(report);
  }

  for (const ReportingReport* report : reports_to_remove)
    RemoveReportInternal(report);

  context_->NotifyCachedReportsUpdated();
}

size_t ReportingCacheImpl::GetFullReportCountForTesting() const {
  return reports_.size();
}

bool ReportingCacheImpl::IsReportPendingForTesting(
    const ReportingReport* report) const {
  return base::Contains(pending_reports_, report);
}

bool ReportingCacheImpl::IsReportDoomedForTesting(
    const ReportingReport* report) const {
  return base::Contains(doomed_reports_, report);
}

void ReportingCacheImpl::OnParsedHeader(
    const url::Origin& origin,
    std::vector<ReportingEndpointGroup> parsed_header) {
  SanityCheckClients();

  OriginClient new_client(origin);
  base::Time now = clock()->Now();
  new_client.last_used = now;

  for (const auto& parsed_endpoint_group : parsed_header) {
    new_client.endpoint_group_names.insert(parsed_endpoint_group.name);
    new_client.endpoint_count += parsed_endpoint_group.endpoints.size();

    // Creates an endpoint group and sets its |last_used| to |now|.
    CachedReportingEndpointGroup new_group(new_client.origin,
                                           parsed_endpoint_group, now);

    std::set<GURL> new_endpoints;
    for (const auto& parsed_endpoint_info : parsed_endpoint_group.endpoints) {
      new_endpoints.insert(parsed_endpoint_info.url);
      ReportingEndpoint new_endpoint(origin, parsed_endpoint_group.name,
                                     std::move(parsed_endpoint_info));
      AddOrUpdateEndpoint(std::move(new_endpoint));
    }

    // Remove endpoints that may have been previously configured for this group,
    // but which were not specified in the current header.
    RemoveEndpointsInGroupOtherThan(new_group.group_key, new_endpoints);

    AddOrUpdateEndpointGroup(std::move(new_group));
  }

  // Remove endpoint groups that may have been configured for an existing client
  // for |origin|, but which are not specified in the current header.
  RemoveEndpointGroupsForOriginOtherThan(origin,
                                         new_client.endpoint_group_names);

  AddOrUpdateClient(std::move(new_client));

  EnforcePerOriginAndGlobalEndpointLimits(origin);
  SanityCheckClients();

  context_->NotifyCachedClientsUpdated();
}

std::vector<url::Origin> ReportingCacheImpl::GetAllOrigins() const {
  SanityCheckClients();
  std::vector<url::Origin> origins_out;
  for (const auto& domain_and_client : origin_clients_) {
    origins_out.push_back(domain_and_client.second.origin);
  }
  return origins_out;
}

void ReportingCacheImpl::RemoveClient(const url::Origin& origin) {
  SanityCheckClients();
  OriginClientMap::iterator client_it = FindClientIt(origin);
  if (client_it == origin_clients_.end())
    return;
  RemoveClientInternal(client_it);
  SanityCheckClients();
  context_->NotifyCachedClientsUpdated();
}

void ReportingCacheImpl::RemoveAllClients() {
  SanityCheckClients();
  origin_clients_.clear();
  endpoint_groups_.clear();
  endpoints_.clear();
  endpoint_its_by_url_.clear();
  SanityCheckClients();
  context_->NotifyCachedClientsUpdated();
}

void ReportingCacheImpl::RemoveEndpointGroup(const url::Origin& origin,
                                             const std::string& group_name) {
  SanityCheckClients();
  EndpointGroupMap::iterator group_it =
      FindEndpointGroupIt(ReportingEndpointGroupKey(origin, group_name));
  if (group_it == endpoint_groups_.end())
    return;
  OriginClientMap::iterator client_it = FindClientIt(origin);
  DCHECK(client_it != origin_clients_.end());

  RemoveEndpointGroupInternal(client_it, group_it);
  SanityCheckClients();
  context_->NotifyCachedClientsUpdated();
}

void ReportingCacheImpl::RemoveEndpointsForUrl(const GURL& url) {
  SanityCheckClients();

  auto url_range = endpoint_its_by_url_.equal_range(url);
  if (url_range.first == url_range.second)
    return;

  // Make a copy of the EndpointMap::iterators matching |url|, to avoid deleting
  // while iterating
  std::vector<EndpointMap::iterator> endpoint_its_to_remove;
  for (auto index_it = url_range.first; index_it != url_range.second;
       ++index_it) {
    endpoint_its_to_remove.push_back(index_it->second);
  }
  DCHECK_GT(endpoint_its_to_remove.size(), 0u);

  // Delete from the index, since we have the |url_range| already. This saves
  // us from having to remove them one by one, which would involve
  // iterating over the |url_range| on each call to RemoveEndpointInternal().
  endpoint_its_by_url_.erase(url_range.first, url_range.second);

  for (EndpointMap::iterator endpoint_it : endpoint_its_to_remove) {
    DCHECK(endpoint_it->second.info.url == url);
    const ReportingEndpointGroupKey& group_key = endpoint_it->first;
    OriginClientMap::iterator client_it = FindClientIt(group_key.origin);
    DCHECK(client_it != origin_clients_.end());
    EndpointGroupMap::iterator group_it = FindEndpointGroupIt(group_key);
    DCHECK(group_it != endpoint_groups_.end());
    RemoveEndpointInternal(client_it, group_it, endpoint_it);
  }

  SanityCheckClients();
  context_->NotifyCachedClientsUpdated();
}

std::vector<ReportingEndpoint>
ReportingCacheImpl::GetCandidateEndpointsForDelivery(
    const url::Origin& origin,
    const std::string& group_name) {
  base::Time now = clock()->Now();
  SanityCheckClients();

  // Look for an exact origin match for |origin| and |group|.
  EndpointGroupMap::iterator group_it =
      FindEndpointGroupIt(ReportingEndpointGroupKey(origin, group_name));
  if (group_it != endpoint_groups_.end() && group_it->second.expires > now) {
    OriginClientMap::iterator client_it = FindClientIt(origin);
    MarkEndpointGroupAndClientUsed(client_it, group_it, now);
    SanityCheckClients();
    context_->NotifyCachedClientsUpdated();
    return GetEndpointsInGroup(group_it->first);
  }

  // If no endpoints were found for an exact match, look for superdomain matches
  // TODO(chlily): Limit the number of labels to go through when looking for a
  // superdomain match.
  std::string domain = origin.host();
  while (!domain.empty()) {
    const auto domain_range = origin_clients_.equal_range(domain);
    for (auto client_it = domain_range.first; client_it != domain_range.second;
         ++client_it) {
      // Client for a superdomain of |origin|
      const OriginClient& client = client_it->second;
      // Check if |client| has a group with the requested name.
      if (!base::Contains(client.endpoint_group_names, group_name))
        continue;

      ReportingEndpointGroupKey group_key(client.origin, group_name);
      group_it = FindEndpointGroupIt(group_key);
      DCHECK(group_it != endpoint_groups_.end());
      const CachedReportingEndpointGroup& endpoint_group = group_it->second;
      // Check if the group is valid (unexpired and includes subdomains).
      if (endpoint_group.include_subdomains == OriginSubdomains::INCLUDE &&
          endpoint_group.expires > now) {
        MarkEndpointGroupAndClientUsed(client_it, group_it, now);
        SanityCheckClients();
        context_->NotifyCachedClientsUpdated();
        return GetEndpointsInGroup(group_key);
      }
    }
    domain = GetSuperdomain(domain);
  }
  return std::vector<ReportingEndpoint>();
}

base::Value ReportingCacheImpl::GetClientsAsValue() const {
  SanityCheckClients();
  std::vector<base::Value> origin_client_list;
  for (const auto& domain_and_client : origin_clients_) {
    const OriginClient& client = domain_and_client.second;
    origin_client_list.push_back(GetOriginClientAsValue(client));
  }
  return base::Value(std::move(origin_client_list));
}

size_t ReportingCacheImpl::GetEndpointCount() const {
  return endpoints_.size();
}

ReportingEndpoint ReportingCacheImpl::GetEndpointForTesting(
    const url::Origin& origin,
    const std::string& group_name,
    const GURL& url) const {
  SanityCheckClients();
  for (const auto& group_key_and_endpoint : endpoints_) {
    const ReportingEndpoint& endpoint = group_key_and_endpoint.second;
    if (endpoint.group_key.origin == origin &&
        endpoint.group_key.group_name == group_name &&
        endpoint.info.url == url) {
      return endpoint;
    }
  }
  return ReportingEndpoint();
}

bool ReportingCacheImpl::EndpointGroupExistsForTesting(
    const url::Origin& origin,
    const std::string& group_name,
    OriginSubdomains include_subdomains,
    base::Time expires) const {
  for (const auto& key_and_group : endpoint_groups_) {
    const CachedReportingEndpointGroup& endpoint_group = key_and_group.second;
    if (endpoint_group.group_key.origin == origin &&
        endpoint_group.group_key.group_name == group_name &&
        endpoint_group.include_subdomains == include_subdomains) {
      if (expires != base::Time()) {
        return endpoint_group.expires == expires;
      } else {
        return true;
      }
    }
  }
  return false;
}

size_t ReportingCacheImpl::GetEndpointGroupCountForTesting() const {
  return endpoint_groups_.size();
}

void ReportingCacheImpl::SetEndpointForTesting(
    const url::Origin& origin,
    const std::string& group_name,
    const GURL& url,
    OriginSubdomains include_subdomains,
    base::Time expires,
    int priority,
    int weight) {
  OriginClientMap::iterator client_it = FindClientIt(origin);
  // If the client doesn't yet exist, add it.
  if (client_it == origin_clients_.end()) {
    OriginClient new_client(origin);
    std::string domain = origin.host();
    client_it =
        origin_clients_.insert(std::make_pair(domain, std::move(new_client)));
  }

  base::Time now = clock()->Now();

  ReportingEndpointGroupKey group_key(origin, group_name);
  EndpointGroupMap::iterator group_it = FindEndpointGroupIt(group_key);
  // If the endpoint group doesn't yet exist, add it.
  if (group_it == endpoint_groups_.end()) {
    CachedReportingEndpointGroup new_group(origin, group_name,
                                           include_subdomains, expires, now);
    group_it =
        endpoint_groups_.insert(std::make_pair(group_key, std::move(new_group)))
            .first;
    client_it->second.endpoint_group_names.insert(group_name);
  } else {
    // Otherwise, update the existing entry
    group_it->second.include_subdomains = include_subdomains;
    group_it->second.expires = expires;
    group_it->second.last_used = now;
  }

  MarkEndpointGroupAndClientUsed(client_it, group_it, now);

  EndpointMap::iterator endpoint_it = FindEndpointIt(group_key, url);
  // If the endpoint doesn't yet exist, add it.
  if (endpoint_it == endpoints_.end()) {
    ReportingEndpoint::EndpointInfo info;
    info.url = std::move(url);
    info.priority = priority;
    info.weight = weight;
    ReportingEndpoint new_endpoint(origin, group_name, info);
    endpoint_it =
        endpoints_.insert(std::make_pair(group_key, std::move(new_endpoint)));
    AddEndpointItToIndex(endpoint_it);
    ++client_it->second.endpoint_count;
  } else {
    // Otherwise, update the existing entry
    endpoint_it->second.info.priority = priority;
    endpoint_it->second.info.weight = weight;
  }

  EnforcePerOriginAndGlobalEndpointLimits(origin);
  SanityCheckClients();
  context_->NotifyCachedClientsUpdated();
}

ReportingCacheImpl::OriginClient::OriginClient(url::Origin origin)
    : origin(std::move(origin)) {}

ReportingCacheImpl::OriginClient::OriginClient(const OriginClient& other) =
    default;

ReportingCacheImpl::OriginClient::OriginClient(OriginClient&& other) = default;

ReportingCacheImpl::OriginClient::~OriginClient() = default;

bool ReportingCacheImpl::IsReportDataPersisted() const {
  return store_ && context_->policy().persist_reports_across_restarts;
}

bool ReportingCacheImpl::IsClientDataPersisted() const {
  return store_ && context_->policy().persist_clients_across_restarts;
}

void ReportingCacheImpl::RemoveReportInternal(const ReportingReport* report) {
  reports_[report]->RecordOutcome(tick_clock()->NowTicks());
  size_t erased = reports_.erase(report);
  DCHECK_EQ(1u, erased);
}

const ReportingReport* ReportingCacheImpl::FindReportToEvict() const {
  const ReportingReport* earliest_queued = nullptr;

  for (const auto& it : reports_) {
    const ReportingReport* report = it.first;
    if (base::Contains(pending_reports_, report))
      continue;
    if (!earliest_queued || report->queued < earliest_queued->queued) {
      earliest_queued = report;
    }
  }

  return earliest_queued;
}

void ReportingCacheImpl::SanityCheckClients() const {
#if DCHECK_IS_ON()
  DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);

  size_t total_endpoint_count = 0;
  size_t total_endpoint_group_count = 0;
  std::set<url::Origin> origins_in_cache;

  for (const auto& domain_and_client : origin_clients_) {
    const std::string& domain = domain_and_client.first;
    const OriginClient& client = domain_and_client.second;
    total_endpoint_count += client.endpoint_count;
    total_endpoint_group_count += SanityCheckOriginClient(domain, client);

    // We have not seen a duplicate client with the same origin.
    DCHECK(!base::Contains(origins_in_cache, client.origin));
    origins_in_cache.insert(client.origin);
  }

  // Global endpoint cap is respected.
  DCHECK_LE(GetEndpointCount(), context_->policy().max_endpoint_count);

  // All the endpoints and endpoint groups are accounted for.
  DCHECK_EQ(total_endpoint_count, endpoints_.size());
  DCHECK_EQ(total_endpoint_group_count, endpoint_groups_.size());

  // All the endpoints are indexed properly.
  DCHECK_EQ(total_endpoint_count, endpoint_its_by_url_.size());
  for (const auto& url_and_endpoint_it : endpoint_its_by_url_) {
    DCHECK_EQ(url_and_endpoint_it.first,
              url_and_endpoint_it.second->second.info.url);
  }
}

size_t ReportingCacheImpl::SanityCheckOriginClient(
    const std::string& domain,
    const OriginClient& client) const {
  // Each client is keyed by its domain name.
  DCHECK_EQ(domain, client.origin.host());
  // Client is not empty (has at least one group)
  DCHECK(!client.endpoint_group_names.empty());

  size_t endpoint_count_in_client = 0;
  size_t endpoint_group_count_in_client = 0;

  for (const std::string& group_name : client.endpoint_group_names) {
    ++endpoint_group_count_in_client;
    ReportingEndpointGroupKey group_key(client.origin, group_name);
    const CachedReportingEndpointGroup& group = endpoint_groups_.at(group_key);
    endpoint_count_in_client += SanityCheckEndpointGroup(group_key, group);
  }
  // Client has the correct endpoint count.
  DCHECK_EQ(client.endpoint_count, endpoint_count_in_client);
  // Per-client endpoint cap is respected.
  DCHECK_LE(client.endpoint_count, context_->policy().max_endpoints_per_origin);

  // Note: Not checking last_used time here because base::Time is not
  // guaranteed to be monotonically non-decreasing.

  return endpoint_group_count_in_client;
}

size_t ReportingCacheImpl::SanityCheckEndpointGroup(
    const ReportingEndpointGroupKey& key,
    const CachedReportingEndpointGroup& group) const {
  size_t endpoint_count_in_group = 0;

  // Each group is keyed by its origin and name.
  DCHECK(key == group.group_key);

  // Group is not empty (has at least one endpoint)
  DCHECK_LE(0u, GetEndpointCountInGroup(group.group_key));

  // Note: Not checking expiry here because expired groups are allowed to
  // linger in the cache until they are garbage collected.

  std::set<GURL> endpoint_urls_in_group;

  const auto group_range = endpoints_.equal_range(key);
  for (auto it = group_range.first; it != group_range.second; ++it) {
    const ReportingEndpoint& endpoint = it->second;

    SanityCheckEndpoint(key, endpoint, it);

    // We have not seen a duplicate endpoint with the same URL in this
    // group.
    DCHECK(!base::Contains(endpoint_urls_in_group, endpoint.info.url));
    endpoint_urls_in_group.insert(endpoint.info.url);

    ++endpoint_count_in_group;
  }

  return endpoint_count_in_group;
}

void ReportingCacheImpl::SanityCheckEndpoint(
    const ReportingEndpointGroupKey& key,
    const ReportingEndpoint& endpoint,
    EndpointMap::const_iterator endpoint_it) const {
  // Origin and group name match.
  DCHECK(key == endpoint.group_key);

  // Priority and weight are nonnegative integers.
  DCHECK_LE(0, endpoint.info.priority);
  DCHECK_LE(0, endpoint.info.weight);

  // The endpoint is in the |endpoint_its_by_url_| index.
  DCHECK(base::Contains(endpoint_its_by_url_, endpoint.info.url));
  auto url_range = endpoint_its_by_url_.equal_range(endpoint.info.url);
  std::vector<EndpointMap::iterator> endpoint_its_for_url;
  for (auto index_it = url_range.first; index_it != url_range.second;
       ++index_it) {
    endpoint_its_for_url.push_back(index_it->second);
  }
  DCHECK(base::Contains(endpoint_its_for_url, endpoint_it));
#endif  // DCHECK_IS_ON()
}

ReportingCacheImpl::OriginClientMap::iterator ReportingCacheImpl::FindClientIt(
    const url::Origin& origin) {
  // TODO(chlily): Limit the number of clients per domain to prevent an attacker
  // from installing many Reporting policies for different port numbers on the
  // same host.
  const auto domain_range = origin_clients_.equal_range(origin.host());
  for (auto it = domain_range.first; it != domain_range.second; ++it) {
    if (it->second.origin == origin)
      return it;
  }
  return origin_clients_.end();
}

ReportingCacheImpl::EndpointGroupMap::iterator
ReportingCacheImpl::FindEndpointGroupIt(
    const ReportingEndpointGroupKey& group_key) {
  return endpoint_groups_.find(group_key);
}

ReportingCacheImpl::EndpointMap::iterator ReportingCacheImpl::FindEndpointIt(
    const ReportingEndpointGroupKey& group_key,
    const GURL& url) {
  const auto group_range = endpoints_.equal_range(group_key);
  for (auto it = group_range.first; it != group_range.second; ++it) {
    if (it->second.info.url == url)
      return it;
  }
  return endpoints_.end();
}

void ReportingCacheImpl::AddOrUpdateClient(OriginClient new_client) {
  OriginClientMap::iterator client_it = FindClientIt(new_client.origin);

  // Add a new client for this origin.
  if (client_it == origin_clients_.end()) {
    std::string domain = new_client.origin.host();
    client_it = origin_clients_.insert(
        std::make_pair(std::move(domain), std::move(new_client)));
  } else {
    // If an entry already existed, just update it.
    OriginClient& old_client = client_it->second;
    old_client.endpoint_count = new_client.endpoint_count;
    old_client.endpoint_group_names =
        std::move(new_client.endpoint_group_names);
    old_client.last_used = new_client.last_used;
  }

  // Note: SanityCheckClients() may fail here because we may be over the
  // global/per-origin endpoint limits.
}

void ReportingCacheImpl::AddOrUpdateEndpointGroup(
    CachedReportingEndpointGroup new_group) {
  EndpointGroupMap::iterator group_it =
      FindEndpointGroupIt(new_group.group_key);

  // Add a new endpoint group for this origin and group name.
  if (group_it == endpoint_groups_.end()) {
    endpoint_groups_.insert(
        std::make_pair(new_group.group_key, std::move(new_group)));
    return;
  }

  // If an entry already existed, just update it.
  CachedReportingEndpointGroup& old_group = group_it->second;
  old_group.include_subdomains = new_group.include_subdomains;
  old_group.expires = new_group.expires;
  old_group.last_used = new_group.last_used;

  // Note: SanityCheckClients() may fail here because we have not yet
  // added/updated the OriginClient for |origin| yet.
}

void ReportingCacheImpl::AddOrUpdateEndpoint(ReportingEndpoint new_endpoint) {
  EndpointMap::iterator endpoint_it =
      FindEndpointIt(new_endpoint.group_key, new_endpoint.info.url);

  // Add a new endpoint for this origin, group, and url.
  if (endpoint_it == endpoints_.end()) {
    url::Origin origin = new_endpoint.group_key.origin;
    EndpointMap::iterator endpoint_it = endpoints_.insert(
        std::make_pair(new_endpoint.group_key, std::move(new_endpoint)));
    AddEndpointItToIndex(endpoint_it);

    // If the client already exists, update its endpoint count.
    OriginClientMap::iterator client_it = FindClientIt(origin);
    if (client_it != origin_clients_.end())
      ++client_it->second.endpoint_count;
    return;
  }

  // If an entry already existed, just update it.
  ReportingEndpoint& old_endpoint = endpoint_it->second;
  old_endpoint.info.priority = new_endpoint.info.priority;
  old_endpoint.info.weight = new_endpoint.info.weight;
  // |old_endpoint.stats| stays the same.

  // Note: SanityCheckClients() may fail here because we have not yet
  // added/updated the OriginClient for |origin| yet.
}

void ReportingCacheImpl::RemoveEndpointsInGroupOtherThan(
    const ReportingEndpointGroupKey& group_key,
    const std::set<GURL>& endpoints_to_keep_urls) {
  EndpointGroupMap::iterator group_it = FindEndpointGroupIt(group_key);
  if (group_it == endpoint_groups_.end())
    return;
  OriginClientMap::iterator client_it = FindClientIt(group_key.origin);
  // Normally a group would not exist without a client for that origin, but
  // this can actually happen during header parsing if a header for an origin
  // without a pre-existing configuration erroneously contains multiple groups
  // with the same name. In that case, we assume here that they meant to set all
  // of those same-name groups as one group, so we don't remove anything.
  if (client_it == origin_clients_.end())
    return;

  const auto group_range = endpoints_.equal_range(group_key);
  for (auto it = group_range.first; it != group_range.second;) {
    if (base::Contains(endpoints_to_keep_urls, it->second.info.url)) {
      ++it;
      continue;
    }

    // This may invalidate |group_it| (and also possibly |client_it|), but only
    // if we are processing the last remaining endpoint in the group.
    base::Optional<EndpointMap::iterator> next_it =
        RemoveEndpointInternal(client_it, group_it, it);
    if (!next_it.has_value())
      return;
    it = next_it.value();
  }
}

void ReportingCacheImpl::RemoveEndpointGroupsForOriginOtherThan(
    const url::Origin& origin,
    const std::set<std::string>& groups_to_keep_names) {
  OriginClientMap::iterator client_it = FindClientIt(origin);
  if (client_it == origin_clients_.end())
    return;

  std::set<std::string>& old_group_names =
      client_it->second.endpoint_group_names;
  std::vector<std::string> groups_to_remove_names =
      base::STLSetDifference<std::vector<std::string>>(old_group_names,
                                                       groups_to_keep_names);

  for (const std::string& group_name : groups_to_remove_names) {
    EndpointGroupMap::iterator group_it =
        FindEndpointGroupIt(ReportingEndpointGroupKey(origin, group_name));
    RemoveEndpointGroupInternal(client_it, group_it);
  }
}

std::vector<ReportingEndpoint> ReportingCacheImpl::GetEndpointsInGroup(
    const ReportingEndpointGroupKey& group_key) const {
  const auto group_range = endpoints_.equal_range(group_key);
  std::vector<ReportingEndpoint> endpoints_out;
  for (auto it = group_range.first; it != group_range.second; ++it) {
    endpoints_out.push_back(it->second);
  }
  return endpoints_out;
}

size_t ReportingCacheImpl::GetEndpointCountInGroup(
    const ReportingEndpointGroupKey& group_key) const {
  return endpoints_.count(group_key);
}

void ReportingCacheImpl::MarkEndpointGroupAndClientUsed(
    OriginClientMap::iterator client_it,
    EndpointGroupMap::iterator group_it,
    base::Time now) {
  group_it->second.last_used = now;
  client_it->second.last_used = now;
}

base::Optional<ReportingCacheImpl::EndpointMap::iterator>
ReportingCacheImpl::RemoveEndpointInternal(OriginClientMap::iterator client_it,
                                           EndpointGroupMap::iterator group_it,
                                           EndpointMap::iterator endpoint_it) {
  DCHECK(client_it != origin_clients_.end());
  DCHECK(group_it != endpoint_groups_.end());
  DCHECK(endpoint_it != endpoints_.end());

  const ReportingEndpointGroupKey& group_key = endpoint_it->first;
  // If this is the only endpoint in the group, then removing it will cause the
  // group to become empty, so just remove the whole group. The client may also
  // be removed if it becomes empty.
  if (endpoints_.count(group_key) == 1) {
    RemoveEndpointGroupInternal(client_it, group_it);
    return base::nullopt;
  }
  // Otherwise, there are other endpoints in the group, so there is no chance
  // of needing to remove the group/client. Just remove this endpoint and
  // update the client's endpoint count.
  DCHECK_GT(client_it->second.endpoint_count, 1u);
  RemoveEndpointItFromIndex(endpoint_it);
  --client_it->second.endpoint_count;
  return endpoints_.erase(endpoint_it);
}

base::Optional<ReportingCacheImpl::EndpointGroupMap::iterator>
ReportingCacheImpl::RemoveEndpointGroupInternal(
    OriginClientMap::iterator client_it,
    EndpointGroupMap::iterator group_it,
    size_t* num_endpoints_removed) {
  DCHECK(client_it != origin_clients_.end());
  DCHECK(group_it != endpoint_groups_.end());
  const ReportingEndpointGroupKey& group_key = group_it->first;

  // Remove the endpoints for this group.
  const auto group_range = endpoints_.equal_range(group_key);
  size_t endpoints_removed =
      std::distance(group_range.first, group_range.second);
  DCHECK_GT(endpoints_removed, 0u);
  if (num_endpoints_removed)
    *num_endpoints_removed += endpoints_removed;
  for (auto it = group_range.first; it != group_range.second; ++it) {
    RemoveEndpointItFromIndex(it);
  }
  endpoints_.erase(group_range.first, group_range.second);

  // Update the client's endpoint count.
  OriginClient& client = client_it->second;
  client.endpoint_count -= endpoints_removed;

  // Remove endpoint group from client.
  size_t erased_from_client =
      client.endpoint_group_names.erase(group_key.group_name);
  DCHECK_EQ(1u, erased_from_client);

  base::Optional<EndpointGroupMap::iterator> rv =
      endpoint_groups_.erase(group_it);

  // Delete client if empty.
  if (client.endpoint_count == 0) {
    DCHECK(client.endpoint_group_names.empty());
    origin_clients_.erase(client_it);
    rv = base::nullopt;
  }
  return rv;
}

ReportingCacheImpl::OriginClientMap::iterator
ReportingCacheImpl::RemoveClientInternal(OriginClientMap::iterator client_it) {
  DCHECK(client_it != origin_clients_.end());
  const OriginClient& client = client_it->second;

  // Erase all groups in this client, and all endpoints in those groups.
  for (const std::string& group_name : client.endpoint_group_names) {
    ReportingEndpointGroupKey group_key(client.origin, group_name);
    endpoint_groups_.erase(group_key);

    const auto group_range = endpoints_.equal_range(group_key);
    for (auto it = group_range.first; it != group_range.second; ++it) {
      RemoveEndpointItFromIndex(it);
    }
    endpoints_.erase(group_range.first, group_range.second);
  }

  return origin_clients_.erase(client_it);
}

void ReportingCacheImpl::EnforcePerOriginAndGlobalEndpointLimits(
    const url::Origin& origin) {
  OriginClientMap::iterator client_it = FindClientIt(origin);
  DCHECK(client_it != origin_clients_.end());
  size_t client_endpoint_count = client_it->second.endpoint_count;
  size_t max_endpoints_per_origin = context_->policy().max_endpoints_per_origin;
  if (client_endpoint_count > max_endpoints_per_origin) {
    EvictEndpointsFromClient(client_it,
                             client_endpoint_count - max_endpoints_per_origin);
  }

  size_t max_endpoint_count = context_->policy().max_endpoint_count;
  while (GetEndpointCount() > max_endpoint_count) {
    // Find the stalest client (arbitrarily pick the first one if there are
    // multiple).
    OriginClientMap::iterator to_evict = origin_clients_.end();
    for (auto it = origin_clients_.begin(); it != origin_clients_.end(); ++it) {
      const OriginClient& client = it->second;
      if (to_evict == origin_clients_.end() ||
          client.last_used < to_evict->second.last_used) {
        to_evict = it;
      }
    }

    DCHECK(to_evict != origin_clients_.end());

    // Evict endpoints from the chosen client.
    size_t num_to_evict = GetEndpointCount() - max_endpoint_count;
    EvictEndpointsFromClient(
        to_evict, std::min(to_evict->second.endpoint_count, num_to_evict));
  }
}

void ReportingCacheImpl::EvictEndpointsFromClient(
    OriginClientMap::iterator client_it,
    size_t endpoints_to_evict) {
  DCHECK_GT(endpoints_to_evict, 0u);
  DCHECK(client_it != origin_clients_.end());
  const OriginClient& client = client_it->second;
  // Cache this value as |client| may be deleted.
  size_t client_endpoint_count = client.endpoint_count;
  const url::Origin& origin = client.origin;

  DCHECK_GE(client_endpoint_count, endpoints_to_evict);
  if (endpoints_to_evict == client_endpoint_count) {
    RemoveClientInternal(client_it);
    return;
  }

  size_t endpoints_removed = 0;
  bool client_deleted =
      RemoveExpiredOrStaleGroups(client_it, &endpoints_removed);
  // If we deleted the whole client, there is nothing left to do.
  if (client_deleted) {
    DCHECK_EQ(endpoints_removed, client_endpoint_count);
    return;
  }

  DCHECK(!client.endpoint_group_names.empty());

  while (endpoints_removed < endpoints_to_evict) {
    DCHECK_GT(client_it->second.endpoint_count, 0u);
    // Find the stalest group with the most endpoints.
    EndpointGroupMap::iterator stalest_group_it = endpoint_groups_.end();
    size_t stalest_group_endpoint_count = 0;
    for (const std::string& group_name : client.endpoint_group_names) {
      ReportingEndpointGroupKey group_key(origin, group_name);
      EndpointGroupMap::iterator group_it = FindEndpointGroupIt(group_key);
      size_t group_endpoint_count = GetEndpointCountInGroup(group_key);

      const CachedReportingEndpointGroup& group = group_it->second;
      if (stalest_group_it == endpoint_groups_.end() ||
          group.last_used < stalest_group_it->second.last_used ||
          (group.last_used == stalest_group_it->second.last_used &&
           group_endpoint_count > stalest_group_endpoint_count)) {
        stalest_group_it = group_it;
        stalest_group_endpoint_count = group_endpoint_count;
      }
    }
    DCHECK(stalest_group_it != endpoint_groups_.end());

    // Evict the least important (lowest priority, lowest weight) endpoint.
    EvictEndpointFromGroup(client_it, stalest_group_it);
    ++endpoints_removed;
  }
}

void ReportingCacheImpl::EvictEndpointFromGroup(
    OriginClientMap::iterator client_it,
    EndpointGroupMap::iterator group_it) {
  const ReportingEndpointGroupKey& group_key = group_it->first;
  const auto group_range = endpoints_.equal_range(group_key);
  EndpointMap::iterator endpoint_to_evict_it = endpoints_.end();
  for (auto it = group_range.first; it != group_range.second; ++it) {
    const ReportingEndpoint& endpoint = it->second;
    if (endpoint_to_evict_it == endpoints_.end() ||
        // Lower priority = higher numerical value of |priority|.
        endpoint.info.priority > endpoint_to_evict_it->second.info.priority ||
        (endpoint.info.priority == endpoint_to_evict_it->second.info.priority &&
         endpoint.info.weight < endpoint_to_evict_it->second.info.weight)) {
      endpoint_to_evict_it = it;
    }
  }
  DCHECK(endpoint_to_evict_it != endpoints_.end());

  RemoveEndpointInternal(client_it, group_it, endpoint_to_evict_it);
}

bool ReportingCacheImpl::RemoveExpiredOrStaleGroups(
    OriginClientMap::iterator client_it,
    size_t* num_endpoints_removed) {
  base::Time now = clock()->Now();
  // Make a copy of this because |client_it| may be invalidated.
  std::set<std::string> groups_in_client_names(
      client_it->second.endpoint_group_names);

  for (const std::string& group_name : groups_in_client_names) {
    EndpointGroupMap::iterator group_it = FindEndpointGroupIt(
        ReportingEndpointGroupKey(client_it->second.origin, group_name));
    DCHECK(group_it != endpoint_groups_.end());
    const CachedReportingEndpointGroup& group = group_it->second;
    if (group.expires < now ||
        now - group.last_used > context_->policy().max_group_staleness) {
      // May delete the client, invalidating |client_it|, but only if we are
      // processing the last remaining group.
      if (!RemoveEndpointGroupInternal(client_it, group_it,
                                       num_endpoints_removed)
               .has_value()) {
        return true;
      }
    }
  }

  return false;
}

void ReportingCacheImpl::AddEndpointItToIndex(
    EndpointMap::iterator endpoint_it) {
  const GURL& url = endpoint_it->second.info.url;
  endpoint_its_by_url_.insert(std::make_pair(url, endpoint_it));
}

void ReportingCacheImpl::RemoveEndpointItFromIndex(
    EndpointMap::iterator endpoint_it) {
  const GURL& url = endpoint_it->second.info.url;
  auto url_range = endpoint_its_by_url_.equal_range(url);
  for (auto it = url_range.first; it != url_range.second; ++it) {
    if (it->second == endpoint_it) {
      endpoint_its_by_url_.erase(it);
      return;
    }
  }
}

base::Value ReportingCacheImpl::GetOriginClientAsValue(
    const OriginClient& client) const {
  base::Value origin_client_dict(base::Value::Type::DICTIONARY);
  origin_client_dict.SetKey("origin", base::Value(client.origin.Serialize()));

  std::vector<base::Value> group_list;
  for (const std::string& group_name : client.endpoint_group_names) {
    ReportingEndpointGroupKey group_key(client.origin, group_name);
    const CachedReportingEndpointGroup& group = endpoint_groups_.at(group_key);
    group_list.push_back(GetEndpointGroupAsValue(group));
  }

  origin_client_dict.SetKey("groups", base::Value(std::move(group_list)));

  return origin_client_dict;
}

base::Value ReportingCacheImpl::GetEndpointGroupAsValue(
    const CachedReportingEndpointGroup& group) const {
  base::Value group_dict(base::Value::Type::DICTIONARY);
  group_dict.SetKey("name", base::Value(group.group_key.group_name));
  group_dict.SetKey("expires",
                    base::Value(NetLog::TimeToString(group.expires)));
  group_dict.SetKey(
      "includeSubdomains",
      base::Value(group.include_subdomains == OriginSubdomains::INCLUDE));

  std::vector<base::Value> endpoint_list;

  const auto group_range = endpoints_.equal_range(group.group_key);
  for (auto it = group_range.first; it != group_range.second; ++it) {
    const ReportingEndpoint& endpoint = it->second;
    endpoint_list.push_back(GetEndpointAsValue(endpoint));
  }

  group_dict.SetKey("endpoints", base::Value(std::move(endpoint_list)));

  return group_dict;
}

base::Value ReportingCacheImpl::GetEndpointAsValue(
    const ReportingEndpoint& endpoint) const {
  base::Value endpoint_dict(base::Value::Type::DICTIONARY);
  endpoint_dict.SetKey("url", base::Value(endpoint.info.url.spec()));
  endpoint_dict.SetKey("priority", base::Value(endpoint.info.priority));
  endpoint_dict.SetKey("weight", base::Value(endpoint.info.weight));

  const ReportingEndpoint::Statistics& stats = endpoint.stats;
  base::Value successful_dict(base::Value::Type::DICTIONARY);
  successful_dict.SetKey("uploads", base::Value(stats.successful_uploads));
  successful_dict.SetKey("reports", base::Value(stats.successful_reports));
  endpoint_dict.SetKey("successful", std::move(successful_dict));
  base::Value failed_dict(base::Value::Type::DICTIONARY);
  failed_dict.SetKey("uploads", base::Value(stats.attempted_uploads -
                                            stats.successful_uploads));
  failed_dict.SetKey("reports", base::Value(stats.attempted_reports -
                                            stats.successful_reports));
  endpoint_dict.SetKey("failed", std::move(failed_dict));

  return endpoint_dict;
}

}  // namespace net