[Offline Pages] Removes two-step expiration related.

components/offline_pages/offline_page_storage_manager.h

 // Copyright 2016 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_OFFLINE_PAGES_OFFLINE_PAGE_STORAGE_MANAGER_H_
 #define COMPONENTS_OFFLINE_PAGES_OFFLINE_PAGE_STORAGE_MANAGER_H_
 
 #include <stdint.h>
 
 #include <vector>
 
 #include "base/callback.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/time/time.h"
 #include "components/offline_pages/archive_manager.h"
 #include "components/offline_pages/offline_page_types.h"
 
 namespace base {
 class Clock;
 }  // namespace base
 
 namespace offline_pages {
 
 // Maximum % of total available storage that will be occupied by offline pages
 // before a storage clearup.
 const double kOfflinePageStorageLimit = 0.3;
-// The target % of storage usage we try to reach below when expiring pages.
+// The target % of storage usage we try to reach below when deleting pages.
 const double kOfflinePageStorageClearThreshold = 0.1;
 // The time that the storage cleanup will be triggered again since the last one.
 const base::TimeDelta kClearStorageInterval = base::TimeDelta::FromMinutes(10);
-// The time that the page record will be removed from the store since the page
-// has been expired.
-const base::TimeDelta kRemovePageItemInterval = base::TimeDelta::FromDays(21);
 
 class ClientPolicyController;
 class OfflinePageModel;
 
 // This class is used for storage management of offline pages. It provides
-// a ClearPagesIfNeeded method which is used to clear expired offline pages
+// a ClearPagesIfNeeded method which is used to clear outdated offline pages
 // based on last_access_time and lifetime policy of its namespace.
 // It has its own throttle mechanism so calling the method would not be
 // guaranteed to clear the pages immediately.
 //
 // OfflinePageModel should own and control the lifecycle of this manager.
 // And this manager would use OfflinePageModel to get/remove pages.
 class OfflinePageStorageManager {
  public:
   enum class ClearStorageResult {

[jianli, 2016/11/18 00:15:48]

Do you want to update the histogram for this?

[romax, 2016/11/18 20:50:49]

Yes, I'm following the comment from Filip below to change names. I guess I have
to do the same change in histograms.xml as well.

-    SUCCESS,                     // Cleared successfully.
-    UNNECESSARY,                 // No expired pages.
-    EXPIRE_FAILURE,              // Expiration failed.
-    DELETE_FAILURE,              // Deletion failed.
-    EXPIRE_AND_DELETE_FAILURES,  // Both expiration and deletion failed.
+    SUCCESS,        // Cleared successfully.
+    UNNECESSARY,    // No expired pages.
+    CLEAR_FAILURE,  // Deletion failed.
     // NOTE: always keep this entry at the end. Add new result types only

[fgorski, 2016/11/18 00:13:04]

Read this note before making changes.

Mark the impossible values as DEPRECATED_ but leave them in.
Do the same in histograms.

Keep the name DELETE_FAILURE.

...

Alternatively define a new enum

[romax, 2016/11/18 20:50:49]

Done but not sure, can you please take a close look?

     // immediately above this line. Make sure to update the corresponding
     // histogram enum accordingly.
     RESULT_COUNT,
   };
 
   // Callback used when calling ClearPagesIfNeeded.
-  // size_t: the number of expired pages.
-  // ClearStorageResult: result of expiring pages in storage.
+  // size_t: the number of cleared pages.
+  // ClearStorageResult: result of clearing pages in storage.
   typedef base::Callback<void(size_t, ClearStorageResult)> ClearStorageCallback;
 
   explicit OfflinePageStorageManager(OfflinePageModel* model,
                                      ClientPolicyController* policy_controller,
                                      ArchiveManager* archive_manager);
 
   ~OfflinePageStorageManager();
 
   // The manager would *try* to clear pages when called. It may not delete any
   // pages (if clearing condition wasn't satisfied).
   // It clears the storage (expire pages) when it's using more disk space than a
   // certain limit, or the time elapsed from last time clearing is longer than a
   // certain interval. Both values are defined above.
   void ClearPagesIfNeeded(const ClearStorageCallback& callback);
 
   // Sets the clock for testing.
   void SetClockForTesting(std::unique_ptr<base::Clock> clock);
 
  private:
   // Enum indicating how to clear the pages.
   enum class ClearMode {
-    // Using normal expiration logic to expire pages. Will reduce the storage
+    // Using normal expiration logic to clear pages. Will reduce the storage
     // usage down below the threshold.
     DEFAULT,
-    // No need to expire any page (no pages in the model or no expired
-    // pages and we're not exceeding the storage limit.)
+    // No need to clear any page (no pages in the model or no expired pages and
+    // we're not exceeding the storage limit.)
     NOT_NEEDED,
   };
 
   // Callback called after getting storage stats from archive manager.
   void OnGetStorageStatsDoneForClearingPages(
       const ClearStorageCallback& callback,
       const ArchiveManager::StorageStats& pages);
 
   // Callback called after getting all pages from model.
   void OnGetAllPagesDoneForClearingPages(
       const ClearStorageCallback& callback,
       const ArchiveManager::StorageStats& storage_stats,
       const MultipleOfflinePageItemResult& pages);
 
-  // Callback called after expired pages have been deleted.
-  void OnPagesExpired(const ClearStorageCallback& callback,
-                      size_t pages_to_clear,
-                      const std::vector<int64_t>& page_ids_to_remove,
-                      bool expiration_succeeded);
+  // Callback called after clearing expired pages from model.
+  void OnExpiredPagesCleared(const ClearStorageCallback& callback,

[fgorski, 2016/11/18 00:13:04]

Expired... part should probably go.

[romax, 2016/11/18 20:50:49]

Acknowledged.

+                             size_t pages_cleared,
+                             DeletePageResult result);
 
-  // Callback called after clearing outdated pages from model.
-  void OnOutdatedPagesCleared(const ClearStorageCallback& callback,
-                              size_t pages_cleared,
-                              bool expiration_succeeded,
-                              DeletePageResult result);
-
-  // Gets offline IDs of both pages that should be expired and the ones that
-  // need to be removed from metadata store. |page_ids_to_expire| will have
-  // the pages to be expired, |page_ids_to_remove| will have the pages to be
-  // removed.
+  // Gets offline IDs of pages that should be cleared based on current |stats|
+  // and return the IDs in |page_ids_to_clear|.
   void GetPageIdsToClear(const MultipleOfflinePageItemResult& pages,
                          const ArchiveManager::StorageStats& stats,
-                         std::vector<int64_t>* page_ids_to_expire,
-                         std::vector<int64_t>* page_ids_to_remove);
+                         std::vector<int64_t>* page_ids_to_clear);
 
   // Determines if manager should clear pages.
   ClearMode ShouldClearPages(const ArchiveManager::StorageStats& storage_stats);
 
-  // Returns true if |page| is expired comparing to |clear_time_|.
-  bool ShouldBeExpired(const OfflinePageItem& page) const;
+  // Returns true if |page| is should be cleared based on |clear_time_|.
+  bool IsExpired(const OfflinePageItem& page) const;

[fgorski, 2016/11/18 00:13:04]

Explain why we are still using the concept of expired? Is that for cached pages?

[romax, 2016/11/18 20:50:49]

Yes expiration should still be a valid term for the pages which have been living
longer than the value defined in the expiration_policy. And this mechanism is
only for Offline Page Cache at the moment.

 
   // Returns true if we're currently doing a cleanup.
   bool IsInProgress() const;
 
   // Not owned.
   OfflinePageModel* model_;
 
   // Not owned.
   ClientPolicyController* policy_controller_;
 
@@ skipping 11 matching lines @@
   std::unique_ptr<base::Clock> clock_;
 
   base::WeakPtrFactory<OfflinePageStorageManager> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(OfflinePageStorageManager);
 };
 
 }  // namespace offline_pages
 
 #endif  // COMPONENTS_OFFLINE_PAGES_OFFLINE_PAGE_STORAGE_MANAGER_H_