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// Copyright (c) 2017 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 <list>
#include <set>
#include <unordered_map>
#include "base/memory/weak_ptr.h"
#include "base/timer/timer.h"
#include "net/http/http_server_properties.h"
namespace base {
class TickClock;
namespace net {
// This class tracks HTTP alternative services that have been marked as broken.
// The brokenness of an alt-svc will expire after some time according to an
// exponential back-off formula: each time an alt-svc is marked broken, the
// expiration delay will be some constant multiple of its previous expiration
// delay. This prevents broken alt-svcs from being retried too often by the
// network stack.
class NET_EXPORT_PRIVATE BrokenAlternativeServices {
// Delegate to be used by owner so it can be notified when the brokenness of
// an AlternativeService expires.
class NET_EXPORT Delegate {
// Called when a broken alternative service's expiration time is reached.
virtual void OnExpireBrokenAlternativeService(
const AlternativeService& expired_alternative_service) = 0;
virtual ~Delegate() {}
// |delegate| will be notified when a broken alternative service expires. It
// must not be null.
// |clock| is used for setting expiration times and scheduling the
// expiration of broken alternative services. It must not be null.
// |delegate| and |clock| are both unowned and must outlive this.
BrokenAlternativeServices(Delegate* delegate, const base::TickClock* clock);
BrokenAlternativeServices(const BrokenAlternativeServices&) = delete;
void operator=(const BrokenAlternativeServices&) = delete;
// Clears all broken and recently-broken alternative services (i.e. mark all
// as not broken nor recently-broken).
void Clear();
// Marks |alternative_service| as broken until an expiration delay (determined
// by how many consecutive times it's been marked broken before). After the
// delay, it will be in the recently broken state. However, when the default
// network changes, the service will immediately be in the working state.
void MarkBrokenUntilDefaultNetworkChanges(
const AlternativeService& alternative_service);
// Marks |alternative_service| as broken until an expiration delay (determined
// by how many consecutive times it's been marked broken before). After the
// delay, it will be in the recently broken state. When the default network
// changes, the brokenness state of this service remains unchanged.
void MarkBroken(const AlternativeService& alternative_service);
// Marks |alternative_service| as recently broken. Being recently broken will
// cause WasAlternativeServiceRecentlyBroken(alternative_service) to return
// true until Confirm(alternative_service) is called.
void MarkRecentlyBroken(const AlternativeService& alternative_service);
// Returns true if the alternative service is considered broken.
bool IsBroken(const AlternativeService& alternative_service) const;
// If the alternative service is considered broken, returns true and sets
// |brokenness_expiration| to the expiration time for that service.
// Returns false otherwise.
bool IsBroken(const AlternativeService& alternative_service,
base::TimeTicks* brokenness_expiration) const;
// Returns true if MarkRecentlyBroken(alternative_service)
// or MarkBroken(alternative_service) has been called and
// Confirm(alternative_service) has not been called
// afterwards (even if brokenness of |alternative_service| has expired).
bool WasRecentlyBroken(const AlternativeService& alternative_service);
// Changes the alternative service to be considered as working.
void Confirm(const AlternativeService& alternative_service);
// Clears all alternative services which were marked as broken until the
// default network changed, those services will now be considered working.
// Returns true if there was any broken alternative service affected by this
// network change.
bool OnDefaultNetworkChanged();
// Sets broken and recently broken alternative services.
// |broken_alternative_service_list|, |recently_broken_alternative_services|
// must not be nullptr.
// If a broken/recently-broken alt svc that's being added is already stored,
// the stored expiration/broken-count for that alt svc will be overwritten
// with the new value.
void SetBrokenAndRecentlyBrokenAlternativeServices(
const BrokenAlternativeServiceList& broken_alternative_service_list() const;
const RecentlyBrokenAlternativeServices&
recently_broken_alternative_services() const;
// TODO (wangyix): modify HttpServerPropertiesImpl unit tests so this
// friendness is no longer required.
friend class HttpServerPropertiesImplPeer;
struct AlternativeServiceHash {
size_t operator()(const net::AlternativeService& entry) const {
return entry.protocol ^ std::hash<std::string>()( ^ entry.port;
typedef std::unordered_map<AlternativeService,
// Helper method that marks |alternative_service| as broken until an
// expiration delay (determined by how many consecutive times it's been marked
// broken before). After the delay, it will be in the recently broken state.
void MarkBrokenImpl(const AlternativeService& alternative_service);
// Inserts |alternative_service| and its |expiration| time into
// |broken_alternative_service_list_| and |broken_alternative_service_map_|.
// |it| is the position in |broken_alternative_service_list_| where it was
// inserted.
bool AddToBrokenListAndMap(const AlternativeService& alternative_service,
base::TimeTicks expiration,
BrokenAlternativeServiceList::iterator* it);
void ExpireBrokenAlternateProtocolMappings();
void ScheduleBrokenAlternateProtocolMappingsExpiration();
Delegate* delegate_; // Unowned
const base::TickClock* clock_; // Unowned
// List of <broken alt svc, expiration time> pairs sorted by expiration time.
BrokenAlternativeServiceList broken_alternative_service_list_;
// A map from broken alt-svcs to their iterator pointing to that alt-svc's
// position in |broken_alternative_service_list_|.
BrokenMap broken_alternative_service_map_;
// A set of broken alternative services on the current default
// network. This will be cleared every time the default network changes.
std::set<AlternativeService> broken_alternative_services_on_default_network_;
// Maps broken alternative services to how many times they've been marked
// broken.
RecentlyBrokenAlternativeServices recently_broken_alternative_services_;
// Used for scheduling the task that expires the brokenness of alternative
// services.
base::OneShotTimer expiration_timer_;
base::WeakPtrFactory<BrokenAlternativeServices> weak_ptr_factory_;
} // namespace net