chrome/browser/prefetch/search_prefetch/search_prefetch_service.h - chromium/src - Git at Google

 // Copyright 2020 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 CHROME_BROWSER_PREFETCH_SEARCH_PREFETCH_SEARCH_PREFETCH_SERVICE_H_
 #define CHROME_BROWSER_PREFETCH_SEARCH_PREFETCH_SEARCH_PREFETCH_SERVICE_H_

 #include <map>
 #include <string>

 #include "base/callback.h"
 #include "base/callback_list.h"
 #include "base/memory/raw_ptr.h"
 #include "base/scoped_observation.h"
 #include "base/time/time.h"
 #include "base/timer/timer.h"
 #include "chrome/browser/prefetch/search_prefetch/base_search_prefetch_request.h"
 #include "components/keyed_service/core/keyed_service.h"
 #include "components/search_engines/template_url_data.h"
 #include "components/search_engines/template_url_service.h"
 #include "components/search_engines/template_url_service_observer.h"
 #include "third_party/abseil-cpp/absl/types/optional.h"
 #include "url/gurl.h"

 struct OmniboxLog;
 class PrefRegistrySimple;
 class Profile;
 class SearchPrefetchURLLoader;
 class AutocompleteResult;

 namespace network {
 struct ResourceRequest;
 }

 // Any updates to this class need to be propagated to enums.xml.
 enum class SearchPrefetchEligibilityReason {
   // The prefetch was started.
   kPrefetchStarted = 0,
   // The user has disabled prefetching and preconnecting in their client.
   kPrefetchDisabled = 1,
   // The user has disabled javascript overall or on the DSE.
   kJavascriptDisabled = 2,
   // The default search engine is not set.
   kSearchEngineNotValid = 3,
   // The entry has no search terms in the suggestion.
   kNotDefaultSearchWithTerms = 4,
   // We have seen an error in a network request recently.
   kErrorBackoff = 5,
   // This query was issued recently as a prefetch and was not served (can be
   // failed, cancelled, or complete).
   kAttemptedQueryRecently = 6,
   // Too many prefetches have been cancelled, failed, or not served recently.
   kMaxAttemptsReached = 7,
   // A URLLoaderThrottle decided this request should not be issued.
   kThrottled = 8,
   kMaxValue = kThrottled,
 };

 // Any updates to this class need to be propagated to enums.xml.
 enum class SearchPrefetchServingReason {
   // The prefetch was started.
   kServed = 0,
   // The default search engine is not set.
   kSearchEngineNotValid = 1,
   // The user has disabled javascript overall or on the DSE.
   kJavascriptDisabled = 2,
   // The entry has no search terms in the suggestion.
   kNotDefaultSearchWithTerms = 3,
   // There wasn't a prefetch issued for the search terms.
   kNoPrefetch = 4,
   // The prefetch for the search terms was for a different origin than the DSE.
   kPrefetchWasForDifferentOrigin = 5,
   // The request was canceled before completion.
   kRequestWasCancelled = 6,
   // The request failed due to some network/service error.
   kRequestFailed = 7,
   // The request wasn't served unexpectantly.
   kNotServedOtherReason = 8,
   // The navigation was a POST request, reload or link navigation.
   kPostReloadOrLink = 9,
   kMaxValue = kPostReloadOrLink,
 };

 class SearchPrefetchService : public KeyedService,
                               public TemplateURLServiceObserver {
  public:
   explicit SearchPrefetchService(Profile* profile);
   ~SearchPrefetchService() override;

   SearchPrefetchService(const SearchPrefetchService&) = delete;
   SearchPrefetchService& operator=(const SearchPrefetchService&) = delete;

   // KeyedService:
   void Shutdown() override;

   // TemplateURLServiceObserver:
   // Monitors changes to DSE. If a change occurs, clears prefetches.
   void OnTemplateURLServiceChanged() override;

   // Called when `AutocompleteController` receives updates on `result`.
   void OnResultChanged(const AutocompleteResult& result);

   // Returns whether the prefetch started or not.
   bool MaybePrefetchURL(const GURL& url);

   // Clear all prefetches from the service.
   void ClearPrefetches();

   // Clear the disk cache entry for |url|.
   void ClearCacheEntry(const GURL& navigation_url);

   // Update the last serving time of |url|, so it's eviction priority is
   // lowered.
   void UpdateServeTime(const GURL& navigation_url);

   // Takes the response from this object if |url| matches a prefetched URL.
   std::unique_ptr<SearchPrefetchURLLoader> TakePrefetchResponseFromMemoryCache(
       const network::ResourceRequest& tentative_resource_request);

   // Creates a cache loader to serve a cache only response with fallback to
   // network fetch.
   std::unique_ptr<SearchPrefetchURLLoader> TakePrefetchResponseFromDiskCache(
       const GURL& navigation_url);

   // Allows search prerender to use the BackForwardSearchPrefetchURLLoader.
   // Called on prerender activation. Search prerender emplaces a new mapping
   // relationship:
   // key  : The URL displayed on the location bar, The prerendered
   // page changes the `prerendering_url` by updating some parameters, so it
   // differs from `prerendering_url`.
   // value: The URL sent by a prerendering URL request.
   // TODO(https://crbug.com/1295170): This is a workaround. Remove this method
   // after the unification work is done.
   void AddCacheEntryForPrerender(const GURL& updated_prerendered_url,
                                  const GURL& prerendering_url);

   // Reports the status of a prefetch for a given search term.
   absl::optional<SearchPrefetchStatus> GetSearchPrefetchStatusForTesting(
       std::u16string search_terms);

   // Calls |LoadFromPrefs()|.
   bool LoadFromPrefsForTesting();

   static void RegisterProfilePrefs(PrefRegistrySimple* registry);

  private:
   // Records a cache entry for a navigation that is being served.
   void AddCacheEntry(const GURL& navigation_url, const GURL& prefetch_url);

   // Removes the prefetch and prefetch timers associated with |search_terms|.
   void DeletePrefetch(std::u16string search_terms);

   // Records metrics around the error rate of prefetches. When |error| is true,
   // records the current time to prevent prefetches for a set duration.
   void ReportFetchResult(bool error);

   // If the navigation URL matches with a prefetch that can be served, this
   // function marks that prefetch as clicked to prevent deletion when omnibox
   // closes.
   void OnURLOpenedFromOmnibox(OmniboxLog* log);

   // These methods serialize and deserialize |prefetch_cache_| to
   // |profile_| pref service in a dictionary value.
   //
   // Returns true iff loading the prefs removed at least one entry, so the pref
   // should be saved.
   bool LoadFromPrefs();
   void SaveToPrefs() const;

   // Prefetches that are started are stored using search terms as a key. Only
   // one prefetch should be started for a given search term until the old
   // prefetch expires.
   std::map<std::u16string, std::unique_ptr<BaseSearchPrefetchRequest>>
       prefetches_;

   // A group of timers to expire |prefetches_| based on the same key.
   std::map<std::u16string, std::unique_ptr<base::OneShotTimer>>
       prefetch_expiry_timers_;

   // The time of the last prefetch network/server error.
   base::TimeTicks last_error_time_ticks_;

   // The current state of the DSE.
   absl::optional<TemplateURLData> template_url_service_data_;

   // A subscription to the omnibox log service to track when a navigation is
   // about to happen.
   base::CallbackListSubscription omnibox_subscription_;

   base::ScopedObservation<TemplateURLService, TemplateURLServiceObserver>
       observer_{this};

   raw_ptr<Profile> profile_;

   // A map of previously handled URLs that allows certain navigations to be
   // served from cache. The value is the prefetch URL in cache and the latest
   // serving time of the response.
   std::map<GURL, std::pair<GURL, base::Time>> prefetch_cache_;
 };

 #endif  // CHROME_BROWSER_PREFETCH_SEARCH_PREFETCH_SEARCH_PREFETCH_SERVICE_H_
	// Copyright 2020 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 CHROME_BROWSER_PREFETCH_SEARCH_PREFETCH_SEARCH_PREFETCH_SERVICE_H_
	#define CHROME_BROWSER_PREFETCH_SEARCH_PREFETCH_SEARCH_PREFETCH_SERVICE_H_

	#include <map>
	#include <string>

	#include "base/callback.h"
	#include "base/callback_list.h"
	#include "base/memory/raw_ptr.h"
	#include "base/scoped_observation.h"
	#include "base/time/time.h"
	#include "base/timer/timer.h"
	#include "chrome/browser/prefetch/search_prefetch/base_search_prefetch_request.h"
	#include "components/keyed_service/core/keyed_service.h"
	#include "components/search_engines/template_url_data.h"
	#include "components/search_engines/template_url_service.h"
	#include "components/search_engines/template_url_service_observer.h"
	#include "third_party/abseil-cpp/absl/types/optional.h"
	#include "url/gurl.h"

	struct OmniboxLog;
	class PrefRegistrySimple;
	class Profile;
	class SearchPrefetchURLLoader;
	class AutocompleteResult;

	namespace network {
	struct ResourceRequest;
	}

	// Any updates to this class need to be propagated to enums.xml.
	enum class SearchPrefetchEligibilityReason {
	// The prefetch was started.
	kPrefetchStarted = 0,
	// The user has disabled prefetching and preconnecting in their client.
	kPrefetchDisabled = 1,
	// The user has disabled javascript overall or on the DSE.
	kJavascriptDisabled = 2,
	// The default search engine is not set.
	kSearchEngineNotValid = 3,
	// The entry has no search terms in the suggestion.
	kNotDefaultSearchWithTerms = 4,
	// We have seen an error in a network request recently.
	kErrorBackoff = 5,
	// This query was issued recently as a prefetch and was not served (can be
	// failed, cancelled, or complete).
	kAttemptedQueryRecently = 6,
	// Too many prefetches have been cancelled, failed, or not served recently.
	kMaxAttemptsReached = 7,
	// A URLLoaderThrottle decided this request should not be issued.
	kThrottled = 8,
	kMaxValue = kThrottled,
	};

	// Any updates to this class need to be propagated to enums.xml.
	enum class SearchPrefetchServingReason {
	// The prefetch was started.
	kServed = 0,
	// The default search engine is not set.
	kSearchEngineNotValid = 1,
	// The user has disabled javascript overall or on the DSE.
	kJavascriptDisabled = 2,
	// The entry has no search terms in the suggestion.
	kNotDefaultSearchWithTerms = 3,
	// There wasn't a prefetch issued for the search terms.
	kNoPrefetch = 4,
	// The prefetch for the search terms was for a different origin than the DSE.
	kPrefetchWasForDifferentOrigin = 5,
	// The request was canceled before completion.
	kRequestWasCancelled = 6,
	// The request failed due to some network/service error.
	kRequestFailed = 7,
	// The request wasn't served unexpectantly.
	kNotServedOtherReason = 8,
	// The navigation was a POST request, reload or link navigation.
	kPostReloadOrLink = 9,
	kMaxValue = kPostReloadOrLink,
	};

	class SearchPrefetchService : public KeyedService,
	public TemplateURLServiceObserver {
	public:
	explicit SearchPrefetchService(Profile* profile);
	~SearchPrefetchService() override;

	SearchPrefetchService(const SearchPrefetchService&) = delete;
	SearchPrefetchService& operator=(const SearchPrefetchService&) = delete;

	// KeyedService:
	void Shutdown() override;

	// TemplateURLServiceObserver:
	// Monitors changes to DSE. If a change occurs, clears prefetches.
	void OnTemplateURLServiceChanged() override;

	// Called when `AutocompleteController` receives updates on `result`.
	void OnResultChanged(const AutocompleteResult& result);

	// Returns whether the prefetch started or not.
	bool MaybePrefetchURL(const GURL& url);

	// Clear all prefetches from the service.
	void ClearPrefetches();

	// Clear the disk cache entry for \|url\|.
	void ClearCacheEntry(const GURL& navigation_url);

	// Update the last serving time of \|url\|, so it's eviction priority is
	// lowered.
	void UpdateServeTime(const GURL& navigation_url);

	// Takes the response from this object if \|url\| matches a prefetched URL.
	std::unique_ptr<SearchPrefetchURLLoader> TakePrefetchResponseFromMemoryCache(
	const network::ResourceRequest& tentative_resource_request);

	// Creates a cache loader to serve a cache only response with fallback to
	// network fetch.
	std::unique_ptr<SearchPrefetchURLLoader> TakePrefetchResponseFromDiskCache(
	const GURL& navigation_url);

	// Allows search prerender to use the BackForwardSearchPrefetchURLLoader.
	// Called on prerender activation. Search prerender emplaces a new mapping
	// relationship:
	// key : The URL displayed on the location bar, The prerendered
	// page changes the `prerendering_url` by updating some parameters, so it
	// differs from `prerendering_url`.
	// value: The URL sent by a prerendering URL request.
	// TODO(https://crbug.com/1295170): This is a workaround. Remove this method
	// after the unification work is done.
	void AddCacheEntryForPrerender(const GURL& updated_prerendered_url,
	const GURL& prerendering_url);

	// Reports the status of a prefetch for a given search term.
	absl::optional<SearchPrefetchStatus> GetSearchPrefetchStatusForTesting(
	std::u16string search_terms);

	// Calls \|LoadFromPrefs()\|.
	bool LoadFromPrefsForTesting();

	static void RegisterProfilePrefs(PrefRegistrySimple* registry);

	private:
	// Records a cache entry for a navigation that is being served.
	void AddCacheEntry(const GURL& navigation_url, const GURL& prefetch_url);

	// Removes the prefetch and prefetch timers associated with \|search_terms\|.
	void DeletePrefetch(std::u16string search_terms);

	// Records metrics around the error rate of prefetches. When \|error\| is true,
	// records the current time to prevent prefetches for a set duration.
	void ReportFetchResult(bool error);

	// If the navigation URL matches with a prefetch that can be served, this
	// function marks that prefetch as clicked to prevent deletion when omnibox
	// closes.
	void OnURLOpenedFromOmnibox(OmniboxLog* log);

	// These methods serialize and deserialize \|prefetch_cache_\| to
	// \|profile_\| pref service in a dictionary value.
	//
	// Returns true iff loading the prefs removed at least one entry, so the pref
	// should be saved.
	bool LoadFromPrefs();
	void SaveToPrefs() const;

	// Prefetches that are started are stored using search terms as a key. Only
	// one prefetch should be started for a given search term until the old
	// prefetch expires.
	std::map<std::u16string, std::unique_ptr<BaseSearchPrefetchRequest>>
	prefetches_;

	// A group of timers to expire \|prefetches_\| based on the same key.
	std::map<std::u16string, std::unique_ptr<base::OneShotTimer>>
	prefetch_expiry_timers_;

	// The time of the last prefetch network/server error.
	base::TimeTicks last_error_time_ticks_;

	// The current state of the DSE.
	absl::optional<TemplateURLData> template_url_service_data_;

	// A subscription to the omnibox log service to track when a navigation is
	// about to happen.
	base::CallbackListSubscription omnibox_subscription_;

	base::ScopedObservation<TemplateURLService, TemplateURLServiceObserver>
	observer_{this};

	raw_ptr<Profile> profile_;

	// A map of previously handled URLs that allows certain navigations to be
	// served from cache. The value is the prefetch URL in cache and the latest
	// serving time of the response.
	std::map<GURL, std::pair<GURL, base::Time>> prefetch_cache_;
	};

	#endif // CHROME_BROWSER_PREFETCH_SEARCH_PREFETCH_SEARCH_PREFETCH_SERVICE_H_