[Offline Pages] Updated clearing logic in storage manager.

components/offline_pages/offline_page_storage_manager.h

Index: components/offline_pages/offline_page_storage_manager.h
diff --git a/components/offline_pages/offline_page_storage_manager.h b/components/offline_pages/offline_page_storage_manager.h
index eebcff6c4538c66f0200b30d4008f80df6eceeb5..288873431ebba42fc4625c4a8883eba085842f68 100644
--- a/components/offline_pages/offline_page_storage_manager.h
+++ b/components/offline_pages/offline_page_storage_manager.h
@@ -12,8 +12,10 @@
 #include "base/callback.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
+#include "base/time/time.h"
 #include "components/offline_pages/offline_page_types.h"
 
+class PrefService;
 namespace base {
 class Clock;
 }
@@ -22,6 +24,15 @@ namespace offline_pages {
 
 class ClientPolicyController;
 
+// Limit of the total storage space occupied by offline pages should be minimal
+// of (50 MB, 10% of available storage space).

[fgorski, 2016/05/17 05:33:29]

where did the second number come from?

[romax, 2016/05/18 02:36:19]

it's from the Offline Page Cache prd. second point under 'Manager Storage'

+static const int64_t kOfflinePageStorageLimit = 50 * (1 << 20);
+static const double kOfflinePageStorageLimitPercentage = 0.1;
+static const base::TimeDelta kClearStorageTimeGap =

[fgorski, 2016/05/17 05:33:29]

kClearStorageInterval

[romax, 2016/05/18 02:36:19]

Done.

+    base::TimeDelta::FromHours(6);
+static const char kOfflinePageStorageLastClearedTime[] =

[fgorski, 2016/05/17 05:33:29]

isn't this defined already?
If unaccessible, this can stay of course.

[romax, 2016/05/18 02:36:20]

yes it was unaccessible. removing since we no longer use it.

+    "offline_page.storage.last_cleared_time";
+
 // This class is used for storage management of offline pages. It provides
 // a ClearPagesIfNeeded method which is used to clear expired offline pages
 // based on last_access_time and lifetime policy of its namespace.
@@ -46,13 +57,20 @@ class OfflinePageStorageManager {
                                         const DeletePageCallback& callback) = 0;
   };
 
+  enum class StorageClearResult {
+    SUCCESS,      // Cleared successfully.
+    UNNECESSARY,  // No expired pages.
+    DELETE_FAIL,  // Deletion failed.

[fgorski, 2016/05/17 05:33:29]

FAILURE?

[romax, 2016/05/18 02:36:20]

Done.

+  };
+
   // Callback used when calling ClearPagesIfNeeded.
   // int: the number of deleted pages.
   // DeletePageResult: result of deleting pages.
-  typedef base::Callback<void(int, DeletePageResult)> ClearPageCallback;
+  typedef base::Callback<void(int, StorageClearResult)> ClearPageCallback;
 
   explicit OfflinePageStorageManager(Client* client,
-                                     ClientPolicyController* policy_controller);
+                                     ClientPolicyController* policy_controller,
+                                     PrefService* prefs);
 
   ~OfflinePageStorageManager();
 
@@ -64,6 +82,13 @@ class OfflinePageStorageManager {
   void SetClockForTesting(std::unique_ptr<base::Clock> clock);
 
  private:
+  // Enum indicating how to clear the pages.
+  enum class ClearMode {
+    DEFAULT,    // Using normal expiration logic.
+    CLEAR_ALL,  // Remove all offline pages.
+    NO_NEED,    // No need to remove any page.

[fgorski, 2016/05/17 05:33:29]

Please explain that a bit better.

[romax, 2016/05/18 02:36:20]

Done.

+  };
+
   // Selects and removes pages that need to be expired. Triggered as a callback
   // to |GetAllPages|.
   void ClearExpiredPages(const ClearPageCallback& callback,
@@ -79,7 +104,7 @@ class OfflinePageStorageManager {
                              DeletePageResult result);
 
   // Determine if manager should clear pages.
-  bool ShouldClearPages();
+  ClearMode ShouldClearPages(const MultipleOfflinePageItemResult& pages);
 
   // Return true if |page| is expired comparing to |now|.
   bool ShouldBeExpired(const base::Time& now, const OfflinePageItem& page);
@@ -90,6 +115,9 @@ class OfflinePageStorageManager {
   // Not owned.
   ClientPolicyController* policy_controller_;
 
+  // Not owned, PrefService which is used to store last clear time.
+  PrefService* prefs_;
+
   bool in_progress_;
 
   // Clock for getting time.