components/precache/content/precache_manager.h

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef COMPONENTS_PRECACHE_CONTENT_PRECACHE_MANAGER_H_
   6 #define COMPONENTS_PRECACHE_CONTENT_PRECACHE_MANAGER_H_
   7
   8 #include <list>
   9 #include <string>
  10 #include <utility>
  11 #include <vector>
  12
  13 #include "base/callback.h"
  14 #include "base/compiler_specific.h"
  15 #include "base/memory/ref_counted.h"
  16 #include "base/memory/scoped_ptr.h"
  17 #include "base/memory/weak_ptr.h"
  18 #include "components/history/core/browser/history_types.h"
  19 #include "components/keyed_service/core/keyed_service.h"
  20 #include "components/precache/core/precache_fetcher.h"
  21 #include "url/gurl.h"
  22
  23 namespace base {
  24 class Time;
  25 }
  26
  27 namespace content {
  28 class BrowserContext;
  29 }
  30
  31 namespace history {
  32 class HistoryService;
  33 }
  34
  35 namespace sync_driver {
  36 class SyncService;
  37 }
  38
  39 namespace precache {
  40
  41 class PrecacheDatabase;
  42
  43 // Visible for test.
  44 int NumTopHosts();
  45
  46 // Class that manages all precaching-related activities. Owned by the
  47 // BrowserContext that it is constructed for. Use
  48 // PrecacheManagerFactory::GetForBrowserContext to get an instance of this
  49 // class. All methods must be called on the UI thread unless indicated
  50 // otherwise.
  51 // TODO(sclittle): Delete precache history when browsing history is deleted.
  52 // http://crbug.com/326549
  53 class PrecacheManager : public KeyedService,
  54                         public PrecacheFetcher::PrecacheDelegate,
  55                         public base::SupportsWeakPtr<PrecacheManager> {
  56  public:
  57   typedef base::Callback<void(bool)> PrecacheCompletionCallback;
  58
  59   PrecacheManager(content::BrowserContext* browser_context,
  60                   const sync_driver::SyncService* const sync_service,
  61                   const history::HistoryService* const history_service);
  62   ~PrecacheManager() override;
  63
  64   // Returns true if precaching is allowed for the browser context based on user
  65   // settings, and enabled as part of a field trial or by commandline flag.
  66   // Virtual for testing.
  67   virtual bool ShouldRun() const;
  68
  69   // Returns true if precaching is allowed for the browser context based on user
  70   // settings. Virtual for testing.
  71   virtual bool WouldRun() const;
  72
  73   // Starts precaching resources that the user is predicted to fetch in the
  74   // future. If precaching is already currently in progress, then this method
  75   // does nothing. The |precache_completion_callback| will be passed true when
  76   // precaching finishes, and passed false when precaching abort due to failed
  77   // preconditions, but will not be run if precaching is canceled.
  78   void StartPrecaching(
  79       const PrecacheCompletionCallback& precache_completion_callback);
  80
  81   // Cancels precaching if it is in progress.
  82   void CancelPrecaching();
  83
  84   // Returns true if precaching is currently in progress, or false otherwise.
  85   bool IsPrecaching() const;
  86
  87   // Update precache-related metrics in response to a URL being fetched.
  88   void RecordStatsForFetch(const GURL& url,
  89                            const base::TimeDelta& latency,
  90                            const base::Time& fetch_time,
  91                            int64 size,
  92                            bool was_cached);
  93
  94   // Posts a task to the DB thread to delete all history entries from the
  95   // database. Does not wait for completion of this task.
  96   void ClearHistory();
  97
  98  private:
  99   enum class AllowedType {
 100     ALLOWED,
 101     DISALLOWED,
 102     PENDING
 103   };
 104
 105   // From KeyedService.
 106   void Shutdown() override;
 107
 108   // From PrecacheFetcher::PrecacheDelegate.
 109   void OnDone() override;
 110
 111   // From history::HistoryService::TopHosts.
 112   void OnHostsReceived(const history::TopHostsList& host_counts);
 113
 114   // Returns true if precaching is enabled as part of a field trial or by the
 115   // command line flag. This has a different meaning from the
 116   // "is_precaching_enabled" pref set in PrecacheServiceLauncher. This method
 117   // can be called on any thread.
 118   static bool IsPrecachingEnabled();
 119
 120   // Returns true if precaching is allowed for the browser context.
 121   AllowedType PrecachingAllowed() const;
 122
 123   // The browser context that owns this PrecacheManager.
 124   content::BrowserContext* const browser_context_;
 125
 126   // The sync service corresponding to the browser context. Used to determine
 127   // whether precache can run. May be null.
 128   const sync_driver::SyncService* const sync_service_;
 129
 130   // The history service corresponding to the browser context. Used to determine
 131   // the list of top hosts. May be null.
 132   const history::HistoryService* const history_service_;
 133
 134   // The PrecacheFetcher used to precache resources. Should only be used on the
 135   // UI thread.
 136   scoped_ptr<PrecacheFetcher> precache_fetcher_;
 137
 138   // The callback that will be run if precaching finishes without being
 139   // canceled.
 140   PrecacheCompletionCallback precache_completion_callback_;
 141
 142   // The PrecacheDatabase for tracking precache metrics. Should only be used on
 143   // the DB thread.
 144   const scoped_refptr<PrecacheDatabase> precache_database_;
 145
 146   // Flag indicating whether or not precaching is currently in progress.
 147   bool is_precaching_;
 148
 149   DISALLOW_COPY_AND_ASSIGN(PrecacheManager);
 150 };
 151
 152 }  // namespace precache
 153
 154 #endif  // COMPONENTS_PRECACHE_CONTENT_PRECACHE_MANAGER_H_