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- // Copyright (c) 2012 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.
- #ifndef COMPONENTS_VARIATIONS_SERVICE_VARIATIONS_SERVICE_H_
- #define COMPONENTS_VARIATIONS_SERVICE_VARIATIONS_SERVICE_H_
- #include <memory>
- #include <string>
- #include <vector>
- #include "base/compiler_specific.h"
- #include "base/gtest_prod_util.h"
- #include "base/memory/raw_ptr.h"
- #include "base/memory/weak_ptr.h"
- #include "base/metrics/field_trial.h"
- #include "base/observer_list.h"
- #include "base/time/time.h"
- #include "build/chromeos_buildflags.h"
- #include "components/variations/client_filterable_state.h"
- #include "components/variations/service/safe_seed_manager.h"
- #include "components/variations/service/ui_string_overrider.h"
- #include "components/variations/service/variations_field_trial_creator.h"
- #include "components/variations/service/variations_service_client.h"
- #include "components/variations/variations_request_scheduler.h"
- #include "components/variations/variations_seed_simulator.h"
- #include "components/variations/variations_seed_store.h"
- #include "components/version_info/version_info.h"
- #include "components/web_resource/resource_request_allowed_notifier.h"
- #include "url/gurl.h"
- class PrefService;
- class PrefRegistrySimple;
- namespace base {
- class FeatureList;
- class Version;
- }
- namespace metrics {
- class MetricsStateManager;
- }
- namespace network {
- class SimpleURLLoader;
- }
- namespace user_prefs {
- class PrefRegistrySyncable;
- }
- namespace variations {
- class VariationsSeed;
- }
- namespace variations {
- #if BUILDFLAG(IS_CHROMEOS_ASH)
- class DeviceVariationsRestrictionByPolicyApplicator;
- #endif
- // Used to (a) set up field trials based on stored variations seed data and (b)
- // fetch new seed data from the variations server.
- class VariationsService
- : public web_resource::ResourceRequestAllowedNotifier::Observer {
- public:
- class Observer {
- public:
- // How critical a detected experiment change is. Whether it should be
- // handled on a "best-effort" basis or, for a more critical change, if it
- // should be given higher priority.
- enum Severity {
- BEST_EFFORT,
- CRITICAL,
- };
- // Called when the VariationsService detects that there will be significant
- // experiment changes on a restart. This notification can then be used to
- // update UI (i.e. badging an icon).
- virtual void OnExperimentChangesDetected(Severity severity) = 0;
- protected:
- virtual ~Observer() {}
- };
- VariationsService(const VariationsService&) = delete;
- VariationsService& operator=(const VariationsService&) = delete;
- ~VariationsService() override;
- // Enum used to choose whether GetVariationsServerURL will return an HTTPS
- // URL or an HTTP one. The HTTP URL is used as a fallback for seed retrieval
- // in cases where an HTTPS connection fails.
- enum HttpOptions { USE_HTTP, USE_HTTPS };
- // Should be called before startup of the main message loop.
- void PerformPreMainMessageLoopStartup();
- // Adds an observer to listen for detected experiment changes.
- void AddObserver(Observer* observer);
- // Removes a previously-added observer.
- void RemoveObserver(Observer* observer);
- // Called when the application enters foreground. This may trigger a
- // FetchVariationsSeed call.
- // TODO(rkaplow): Handle this and the similar event in metrics_service by
- // observing an 'OnAppEnterForeground' event instead of requiring the frontend
- // code to notify each service individually.
- void OnAppEnterForeground();
- // Sets the value of the "restrict" URL param to the variations service that
- // should be used for variation seed requests. This takes precedence over any
- // value coming from policy prefs. This should be called prior to any calls
- // to |StartRepeatedVariationsSeedFetch|.
- void SetRestrictMode(const std::string& restrict_mode);
- // Returns the variations server URL. |http_options| determines whether to
- // use the http or https URL. This function will return an empty GURL when
- // the restrict param exists for USE_HTTP, to indicate that no HTTP fallback
- // should happen in that case.
- GURL GetVariationsServerURL(HttpOptions http_options);
- // Returns the permanent overridden country code stored for this client. This
- // value will not be updated on Chrome updates.
- std::string GetOverriddenPermanentCountry();
- // Returns the permanent country code stored for this client. Country code is
- // in the format of lowercase ISO 3166-1 alpha-2. Example: us, br, in
- std::string GetStoredPermanentCountry();
- // Forces an override of the stored permanent country. Returns true
- // if the variable has been updated. Return false if the override country is
- // the same as the stored variable, or if the update failed for any other
- // reason.
- bool OverrideStoredPermanentCountry(const std::string& override_country);
- // Returns what variations will consider to be the latest country. Returns
- // empty if it is not available.
- std::string GetLatestCountry() const;
- // Ensures the locale that was used for evaluating variations matches the
- // passed |locale|. This is used to ensure that the locale determined after
- // loading the resource bundle (which is passed here) corresponds to what
- // was used for variations during an earlier stage of start up.
- void EnsureLocaleEquals(const std::string& locale);
- // Exposed for testing.
- static std::string GetDefaultVariationsServerURLForTesting();
- // Register Variations related prefs in Local State.
- static void RegisterPrefs(PrefRegistrySimple* registry);
- // Register Variations related prefs in the Profile prefs.
- static void RegisterProfilePrefs(user_prefs::PrefRegistrySyncable* registry);
- // Factory method for creating a VariationsService. Does not take ownership of
- // |state_manager|. Caller should ensure that |state_manager| is valid for the
- // lifetime of this class.
- static std::unique_ptr<VariationsService> Create(
- std::unique_ptr<VariationsServiceClient> client,
- PrefService* local_state,
- metrics::MetricsStateManager* state_manager,
- const char* disable_network_switch,
- const UIStringOverrider& ui_string_overrider,
- web_resource::ResourceRequestAllowedNotifier::
- NetworkConnectionTrackerGetter network_connection_tracker_getter);
- // Enables fetching the seed for testing, even for unofficial builds. This
- // should be used along with overriding |DoActualFetch| or using
- // |net::TestURLLoaderFactory|.
- static void EnableFetchForTesting();
- // Set the PrefService responsible for getting policy-related preferences,
- // such as the restrict parameter.
- void set_policy_pref_service(PrefService* service) {
- DCHECK(service);
- policy_pref_service_ = service;
- }
- // Exposed for testing.
- void GetClientFilterableStateForVersionCalledForTesting();
- web_resource::ResourceRequestAllowedNotifier*
- GetResourceRequestAllowedNotifierForTesting() {
- return resource_request_allowed_notifier_.get();
- }
- // Wrapper around VariationsFieldTrialCreator::SetUpFieldTrials().
- bool SetUpFieldTrials(
- const std::vector<std::string>& variation_ids,
- const std::string& command_line_variation_ids,
- const std::vector<base::FeatureList::FeatureOverrideInfo>&
- extra_overrides,
- std::unique_ptr<base::FeatureList> feature_list,
- variations::PlatformFieldTrials* platform_field_trials);
- // Overrides cached UI strings on the resource bundle once it is initialized.
- void OverrideCachedUIStrings();
- int request_count() const { return request_count_; }
- // Cancels the currently pending fetch request.
- void CancelCurrentRequestForTesting();
- // Exposes StartRepeatedVariationsSeedFetch for testing.
- void StartRepeatedVariationsSeedFetchForTesting();
- // Allows the embedder to override the platform and override the OS name in
- // the variations server url. This is useful for android webview and weblayer
- // which are distinct from regular android chrome.
- void OverridePlatform(Study::Platform platform,
- const std::string& osname_server_param_override);
- protected:
- // Gets the serial number of the most recent Finch seed. Virtual for testing.
- virtual const std::string& GetLatestSerialNumber();
- // Starts the fetching process once, where |OnURLFetchComplete| is called with
- // the response. This calls DoFetchToURL with the set url.
- virtual void DoActualFetch();
- // Attempts a seed fetch from the set |url|. Returns true if the fetch was
- // started successfully, false otherwise. |is_http_retry| should be true if
- // this is a retry over HTTP, false otherwise.
- virtual bool DoFetchFromURL(const GURL& url, bool is_http_retry);
- // Stores the seed to prefs. Set as virtual and protected so that it can be
- // overridden by tests.
- virtual bool StoreSeed(const std::string& seed_data,
- const std::string& seed_signature,
- const std::string& country_code,
- base::Time date_fetched,
- bool is_delta_compressed,
- bool is_gzip_compressed);
- // Create an entropy provider based on low entropy. This is used to create
- // trials for studies that should only depend on low entropy, such as studies
- // that send experiment IDs to Google web properties. Virtual for testing.
- virtual std::unique_ptr<const base::FieldTrial::EntropyProvider>
- CreateLowEntropyProvider();
- // Creates the VariationsService with the given |local_state| prefs service
- // and |state_manager|. Does not take ownership of |state_manager|. Caller
- // should ensure that |state_manager| is valid for the lifetime of this class.
- // Use the |Create| factory method to create a VariationsService.
- VariationsService(
- std::unique_ptr<VariationsServiceClient> client,
- std::unique_ptr<web_resource::ResourceRequestAllowedNotifier> notifier,
- PrefService* local_state,
- metrics::MetricsStateManager* state_manager,
- const UIStringOverrider& ui_string_overrider);
- // Sets the URL for querying the variations server. Used for testing.
- void set_variations_server_url(const GURL& url) {
- variations_server_url_ = url;
- }
- // Sets the URL for querying the variations server when doing HTTP retries.
- // Used for testing.
- void set_insecure_variations_server_url(const GURL& url) {
- insecure_variations_server_url_ = url;
- }
- // Sets the |last_request_was_http_retry_| flag. Used for testing.
- void set_last_request_was_http_retry(bool was_http_retry) {
- last_request_was_http_retry_ = was_http_retry;
- }
- // The client that provides access to the embedder's environment.
- // Protected so testing subclasses can access it.
- VariationsServiceClient* client() { return client_.get(); }
- // Exposes MaybeRetryOverHTTP for testing.
- bool CallMaybeRetryOverHTTPForTesting();
- // Records a successful fetch:
- // (1) Resets failure streaks for Safe Mode.
- // (2) Records the time of this fetch as the most recent successful fetch.
- // Protected so testing subclasses can call it.
- void RecordSuccessfulFetch();
- private:
- FRIEND_TEST_ALL_PREFIXES(VariationsServiceTest, Observer);
- FRIEND_TEST_ALL_PREFIXES(VariationsServiceTest, SeedStoredWhenOKStatus);
- FRIEND_TEST_ALL_PREFIXES(VariationsServiceTest, SeedNotStoredWhenNonOKStatus);
- FRIEND_TEST_ALL_PREFIXES(VariationsServiceTest, InstanceManipulations);
- FRIEND_TEST_ALL_PREFIXES(VariationsServiceTest,
- LoadPermanentConsistencyCountry);
- FRIEND_TEST_ALL_PREFIXES(VariationsServiceTest, CountryHeader);
- FRIEND_TEST_ALL_PREFIXES(VariationsServiceTest, GetVariationsServerURL);
- FRIEND_TEST_ALL_PREFIXES(VariationsServiceTest, VariationsURLHasParams);
- FRIEND_TEST_ALL_PREFIXES(VariationsServiceTest, RequestsInitiallyAllowed);
- FRIEND_TEST_ALL_PREFIXES(VariationsServiceTest, RequestsInitiallyNotAllowed);
- FRIEND_TEST_ALL_PREFIXES(VariationsServiceTest,
- SafeMode_SuccessfulFetchClearsFailureStreaks);
- FRIEND_TEST_ALL_PREFIXES(VariationsServiceTest,
- SafeMode_NotModifiedFetchClearsFailureStreaks);
- FRIEND_TEST_ALL_PREFIXES(VariationsServiceTest, InsecurelyFetchedSetWhenHTTP);
- FRIEND_TEST_ALL_PREFIXES(VariationsServiceTest,
- InsecurelyFetchedNotSetWhenHTTPS);
- FRIEND_TEST_ALL_PREFIXES(VariationsServiceTest, DoNotRetryAfterARetry);
- FRIEND_TEST_ALL_PREFIXES(VariationsServiceTest,
- DoNotRetryIfInsecureURLIsHTTPS);
- void InitResourceRequestedAllowedNotifier();
- // Calls FetchVariationsSeed once and repeats this periodically. See
- // implementation for details on the period.
- void StartRepeatedVariationsSeedFetch();
- // Checks if prerequisites for fetching the Variations seed are met, and if
- // so, performs the actual fetch using |DoActualFetch|.
- void FetchVariationsSeed();
- // Notify any observers of this service based on the simulation |result|.
- void NotifyObservers(
- const variations::VariationsSeedSimulator::Result& result);
- // Called by SimpleURLLoader when |pending_seed_request_| load completes.
- void OnSimpleLoaderComplete(std::unique_ptr<std::string> response_body);
- // Retry the fetch over HTTP, called by OnSimpleLoaderComplete when a request
- // fails. Returns true is the fetch was successfully started, this does not
- // imply the actual fetch was successful.
- bool MaybeRetryOverHTTP();
- // ResourceRequestAllowedNotifier::Observer implementation:
- void OnResourceRequestsAllowed() override;
- // Performs a variations seed simulation with the given |seed| and |version|
- // and logs the simulation results as histograms.
- void PerformSimulationWithVersion(
- std::unique_ptr<variations::VariationsSeed> seed,
- const base::Version& version);
- // Encrypts a string using the encrypted_messages component, input is passed
- // in as |plaintext|, outputs a serialized EncryptedMessage protobuf as
- // |encrypted|. Returns true on success, false on failure. The encryption can
- // be done in-place.
- bool EncryptString(const std::string& plaintext, std::string* encrypted);
- // Loads the country code to use for filtering permanent consistency studies,
- // updating the stored country code if the stored value was for a different
- // Chrome version. The country used for permanent consistency studies is kept
- // consistent between Chrome upgrades in order to avoid annoying the user due
- // to experiment churn while traveling.
- std::string LoadPermanentConsistencyCountry(
- const base::Version& version,
- const std::string& latest_country);
- std::unique_ptr<VariationsServiceClient> client_;
- // The pref service used to store persist the variations seed.
- raw_ptr<PrefService> local_state_;
- // Used for instantiating entropy providers for variations seed simulation.
- // Weak pointer.
- raw_ptr<metrics::MetricsStateManager> state_manager_;
- // Used to obtain policy-related preferences. Depending on the platform, will
- // either be Local State or Profile prefs.
- raw_ptr<PrefService> policy_pref_service_;
- // Contains the scheduler instance that handles timing for requests to the
- // server. Initially NULL and instantiated when the initial fetch is
- // requested.
- std::unique_ptr<VariationsRequestScheduler> request_scheduler_;
- // Contains the current seed request. Will only have a value while a request
- // is pending, and will be reset by |OnURLFetchComplete|.
- std::unique_ptr<network::SimpleURLLoader> pending_seed_request_;
- // The value of the "restrict" URL param to the variations server that has
- // been specified via |SetRestrictMode|. If empty, the URL param will be set
- // based on policy prefs.
- std::string restrict_mode_;
- // The URL to use for querying the variations server.
- GURL variations_server_url_;
- // HTTP URL used as a fallback if HTTPS fetches fail. If not set, retries
- // over HTTP will not be attempted.
- GURL insecure_variations_server_url_;
- // Tracks whether the initial request to the variations server had completed.
- bool initial_request_completed_ = false;
- // Tracks whether any errors resolving delta compression were encountered
- // since the last time a seed was fetched successfully.
- bool delta_error_since_last_success_ = false;
- // Helper class used to tell this service if it's allowed to make network
- // resource requests.
- std::unique_ptr<web_resource::ResourceRequestAllowedNotifier>
- resource_request_allowed_notifier_;
- // The start time of the last seed request. This is used to measure the
- // latency of seed requests. Initially zero.
- base::TimeTicks last_request_started_time_;
- // The number of requests to the variations server that have been performed.
- int request_count_ = 0;
- // List of observers of the VariationsService.
- base::ObserverList<Observer>::Unchecked observer_list_;
- // The main entry point for managing safe mode state.
- SafeSeedManager safe_seed_manager_;
- // Member responsible for creating trials from a variations seed.
- VariationsFieldTrialCreator field_trial_creator_;
- // True if the last request was a retry over http.
- bool last_request_was_http_retry_ = false;
- // When not empty, contains an override for the os name in the variations
- // server url.
- std::string osname_server_param_override_;
- #if BUILDFLAG(IS_CHROMEOS_ASH)
- std::unique_ptr<DeviceVariationsRestrictionByPolicyApplicator>
- device_variations_restrictions_by_policy_applicator_;
- #endif
- SEQUENCE_CHECKER(sequence_checker_);
- base::WeakPtrFactory<VariationsService> weak_ptr_factory_{this};
- };
- } // namespace variations
- #endif // COMPONENTS_VARIATIONS_SERVICE_VARIATIONS_SERVICE_H_
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