ServiceWorker: Migrate the script cache backend from BlockFile to Simple

content/browser/service_worker/service_worker_database.h

 // Copyright 2014 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 CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_DATABASE_H_
 #define CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_DATABASE_H_
 
 #include <map>
 #include <set>
 #include <string>
@@ skipping 74 matching lines @@
   };
 
   // Reads next available ids from the database. Returns OK if they are
   // successfully read. Fills the arguments with an initial value and returns
   // OK if they are not found in the database. Otherwise, returns an error.
   Status GetNextAvailableIds(
       int64* next_avail_registration_id,
       int64* next_avail_version_id,
       int64* next_avail_resource_id);
 
+  enum DiskCacheMigrationState {
+    // A diskcache has not been used yet.
+    DISKCACHE_NOT_USED,
+
+    // A diskcache needs to be migrated.
+    DISKCACHE_NEEDS_TO_MIGRATE,
+
+    // A diskcache was migrated but an old diskcache still exists.
+    DISKCACHE_NEEDS_TO_DELETE_OLD,
+
+    // A diskcache was migrated and an old diskcache was deleted.
+    DISKCACHE_MIGRATED,

[michaeln, 2015/06/12 01:55:45]

Can MIGRATED and NOT_USED be merged into MIGRATION_NOT_NEEDED?

+
+    DISKCACHE_UNKNOWN_STATE,
+  };
+
+  // Reads a diskcache migration state from the database.
+  Status ReadDiskCacheMigrationState(DiskCacheMigrationState* state);
+
+  // Writes a diskcache migration state in the database. |state| should be
+  // DISKCACHE_MIGRATED or DISKCACHE_NEEDS_TO_DELETE_OLD.
+  Status WriteDiskCacheMigrationState(DiskCacheMigrationState state);
+
   // Reads origins that have one or more than one registration from the
   // database. Returns OK if they are successfully read or not found.
   // Otherwise, returns an error.
   Status GetOriginsWithRegistrations(std::set<GURL>* origins);
 
   // Reads registrations for |origin| from the database. Returns OK if they are
   // successfully read or not found. Otherwise, returns an error.
   Status GetRegistrationsForOrigin(
       const GURL& origin,
       std::vector<RegistrationData>* registrations,
@@ skipping 259 matching lines @@
     INITIALIZED,
     DISABLED,
   };
   State state_;
 
   base::SequenceChecker sequence_checker_;
 
   FRIEND_TEST_ALL_PREFIXES(ServiceWorkerDatabaseTest, OpenDatabase);
   FRIEND_TEST_ALL_PREFIXES(ServiceWorkerDatabaseTest, OpenDatabase_InMemory);
   FRIEND_TEST_ALL_PREFIXES(ServiceWorkerDatabaseTest, DatabaseVersion);
+  FRIEND_TEST_ALL_PREFIXES(ServiceWorkerDatabaseTest, DiskCacheMigrationState);
   FRIEND_TEST_ALL_PREFIXES(ServiceWorkerDatabaseTest, GetNextAvailableIds);
   FRIEND_TEST_ALL_PREFIXES(ServiceWorkerDatabaseTest,
                            Registration_UninitializedDatabase);
   FRIEND_TEST_ALL_PREFIXES(ServiceWorkerDatabaseTest,
                            UserData_UninitializedDatabase);
   FRIEND_TEST_ALL_PREFIXES(ServiceWorkerDatabaseTest, DestroyDatabase);
   FRIEND_TEST_ALL_PREFIXES(ServiceWorkerDatabaseTest, UpgradeSchemaToVersion2);
 
   DISALLOW_COPY_AND_ASSIGN(ServiceWorkerDatabase);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_DATABASE_H_