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      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 APPS_SAVED_FILES_SERVICE_H_
      6 #define APPS_SAVED_FILES_SERVICE_H_
      7 
      8 #include <map>
      9 #include <set>
     10 #include <string>
     11 #include <vector>
     12 
     13 #include "base/files/file_path.h"
     14 #include "base/gtest_prod_util.h"
     15 #include "base/stl_util.h"
     16 #include "components/keyed_service/core/keyed_service.h"
     17 #include "content/public/browser/notification_observer.h"
     18 #include "content/public/browser/notification_registrar.h"
     19 
     20 class Profile;
     21 class SavedFilesServiceUnitTest;
     22 FORWARD_DECLARE_TEST(SavedFilesServiceUnitTest, RetainTwoFilesTest);
     23 FORWARD_DECLARE_TEST(SavedFilesServiceUnitTest, EvictionTest);
     24 FORWARD_DECLARE_TEST(SavedFilesServiceUnitTest, SequenceNumberCompactionTest);
     25 
     26 namespace extensions {
     27 class Extension;
     28 }
     29 
     30 namespace apps {
     31 
     32 // Represents a file entry that a user has given an app permission to
     33 // access. Will be persisted to disk (in the Preferences file), so should remain
     34 // serializable.
     35 struct SavedFileEntry {
     36   SavedFileEntry();
     37 
     38   SavedFileEntry(const std::string& id,
     39                  const base::FilePath& path,
     40                  bool is_directory,
     41                  int sequence_number);
     42 
     43   // The opaque id of this file entry.
     44   std::string id;
     45 
     46   // The path to a file entry that the app had permission to access.
     47   base::FilePath path;
     48 
     49   // Whether or not the entry refers to a directory.
     50   bool is_directory;
     51 
     52   // The sequence number in the LRU of the file entry. The value 0 indicates
     53   // that the entry is not in the LRU.
     54   int sequence_number;
     55 };
     56 
     57 // Tracks the files that apps have retained access to both while running and
     58 // when suspended.
     59 class SavedFilesService : public KeyedService,
     60                           public content::NotificationObserver {
     61  public:
     62   explicit SavedFilesService(Profile* profile);
     63   virtual ~SavedFilesService();
     64 
     65   static SavedFilesService* Get(Profile* profile);
     66 
     67   // Registers a file entry with the saved files service, making it eligible to
     68   // be put into the queue. File entries that are in the retained files queue at
     69   // object construction are automatically registered.
     70   void RegisterFileEntry(const std::string& extension_id,
     71                          const std::string& id,
     72                          const base::FilePath& file_path,
     73                          bool is_directory);
     74 
     75   // If the file with |id| is not in the queue of files to be retained
     76   // permanently, adds the file to the back of the queue, evicting the least
     77   // recently used entry at the front of the queue if it is full. If it is
     78   // already present, moves it to the back of the queue. The |id| must have been
     79   // registered.
     80   void EnqueueFileEntry(const std::string& extension_id, const std::string& id);
     81 
     82   // Returns whether the file entry with the given |id| has been registered.
     83   bool IsRegistered(const std::string& extension_id, const std::string& id);
     84 
     85   // Gets a borrowed pointer to the file entry with the specified |id|. Returns
     86   // NULL if the file entry has not been registered.
     87   const SavedFileEntry* GetFileEntry(const std::string& extension_id,
     88                                      const std::string& id);
     89 
     90   // Returns all registered file entries.
     91   std::vector<SavedFileEntry> GetAllFileEntries(
     92       const std::string& extension_id);
     93 
     94   // Clears all retained files if the app does not have the
     95   // fileSystem.retainEntries permission.
     96   void ClearQueueIfNoRetainPermission(const extensions::Extension* extension);
     97 
     98   // Clears all retained files.
     99   void ClearQueue(const extensions::Extension* extension);
    100 
    101  private:
    102   FRIEND_TEST_ALL_PREFIXES(::SavedFilesServiceUnitTest, RetainTwoFilesTest);
    103   FRIEND_TEST_ALL_PREFIXES(::SavedFilesServiceUnitTest, EvictionTest);
    104   FRIEND_TEST_ALL_PREFIXES(::SavedFilesServiceUnitTest,
    105                            SequenceNumberCompactionTest);
    106   friend class ::SavedFilesServiceUnitTest;
    107 
    108   // A container for the registered files for an app.
    109   class SavedFiles;
    110 
    111   // content::NotificationObserver.
    112   virtual void Observe(int type,
    113                        const content::NotificationSource& source,
    114                        const content::NotificationDetails& details) OVERRIDE;
    115 
    116   // Returns the SavedFiles for |extension_id| or NULL if one does not exist.
    117   SavedFiles* Get(const std::string& extension_id) const;
    118 
    119   // Returns the SavedFiles for |extension_id|, creating it if necessary.
    120   SavedFiles* GetOrInsert(const std::string& extension_id);
    121 
    122   // Clears the SavedFiles for |extension_id|.
    123   void Clear(const std::string& extension_id);
    124 
    125   static void SetMaxSequenceNumberForTest(int max_value);
    126   static void ClearMaxSequenceNumberForTest();
    127   static void SetLruSizeForTest(int size);
    128   static void ClearLruSizeForTest();
    129 
    130   std::map<std::string, SavedFiles*> extension_id_to_saved_files_;
    131   STLValueDeleter<std::map<std::string, SavedFiles*> >
    132       extension_id_to_saved_files_deleter_;
    133   content::NotificationRegistrar registrar_;
    134   Profile* profile_;
    135 
    136   DISALLOW_COPY_AND_ASSIGN(SavedFilesService);
    137 };
    138 
    139 }  // namespace apps
    140 
    141 #endif  // APPS_SAVED_FILES_SERVICE_H_
    142