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      1 // Copyright (c) 2012 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 CHROME_BROWSER_STORAGE_MONITOR_STORAGE_MONITOR_H_
      6 #define CHROME_BROWSER_STORAGE_MONITOR_STORAGE_MONITOR_H_
      7 
      8 #include <map>
      9 #include <string>
     10 #include <vector>
     11 
     12 #include "base/callback.h"
     13 #include "base/files/file_path.h"
     14 #include "base/observer_list_threadsafe.h"
     15 #include "base/strings/string16.h"
     16 #include "base/synchronization/lock.h"
     17 #include "base/threading/thread_checker.h"
     18 #include "chrome/browser/storage_monitor/storage_info.h"
     19 
     20 class MediaFileSystemRegistryTest;
     21 class MediaGalleriesPlatformAppBrowserTest;
     22 class MediaGalleriesPrivateApiTest;
     23 class RemovableStorageObserver;
     24 class SystemStorageApiTest;
     25 class SystemStorageEjectApiTest;
     26 class TransientDeviceIds;
     27 
     28 namespace device {
     29 class MediaTransferProtocolManager;
     30 }
     31 
     32 // Base class for platform-specific instances watching for removable storage
     33 // attachments/detachments.
     34 // Lifecycle contracts: This class is created in the browser process
     35 // before the profile is initialized, so listeners can be
     36 // created during profile construction. The platform-specific initialization,
     37 // which can lead to calling registered listeners with notifications of
     38 // attached volumes, are done lazily at first use through the async
     39 // |EnsureInitialized()| method. That must be done before any of the registered
     40 // listeners will receive updates or calls to other API methods return
     41 // meaningful results.
     42 // A post-initialization |GetAttachedStorage()| call coupled with a
     43 // registered listener will receive a complete set, albeit potentially with
     44 // duplicates. This is because there's no tracking between when listeners were
     45 // registered and the state of initialization, and the fact that platforms
     46 // behave differently in how these notifications are provided.
     47 class StorageMonitor {
     48  public:
     49   // This interface is provided to generators of storage notifications.
     50   class Receiver {
     51    public:
     52     virtual ~Receiver();
     53 
     54     virtual void ProcessAttach(const StorageInfo& info) = 0;
     55     virtual void ProcessDetach(const std::string& id) = 0;
     56     virtual void MarkInitialized() = 0;
     57   };
     58 
     59   // Status codes for the result of an EjectDevice() call.
     60   enum EjectStatus {
     61     EJECT_OK,
     62     EJECT_IN_USE,
     63     EJECT_NO_SUCH_DEVICE,
     64     EJECT_FAILURE
     65   };
     66 
     67   // Returns a pointer to a newly created per-platform object with the
     68   // StorageMonitor interface.
     69   static StorageMonitor* Create();
     70 
     71   // Returns a pointer to an object owned by BrowserProcess, with lifetime
     72   // starting before main message loop start, and ending after main message loop
     73   // shutdown. Called outside it's lifetime (or with no browser process),
     74   // returns NULL.
     75   static StorageMonitor* GetInstance();
     76 
     77   virtual ~StorageMonitor();
     78 
     79   // Ensures that the storage monitor is initialized. The provided callback, if
     80   // non-null, will be called when initialization is complete. If initialization
     81   // has already completed, this callback will be invoked within the calling
     82   // stack. Before the callback is run, calls to |GetAllAvailableStorages| and
     83   // |GetStorageInfoForPath| may not return the correct results. In addition,
     84   // registered observers will not be notified on device attachment/detachment.
     85   // Should be invoked on the UI thread; callbacks will be run on the UI thread.
     86   void EnsureInitialized(base::Closure callback);
     87 
     88   // Return true if the storage monitor has already been initialized.
     89   bool IsInitialized() const;
     90 
     91   // Finds the device that contains |path| and populates |device_info|.
     92   // Should be able to handle any path on the local system, not just removable
     93   // storage. Returns false if unable to find the device.
     94   virtual bool GetStorageInfoForPath(
     95       const base::FilePath& path,
     96       StorageInfo* device_info) const = 0;
     97 
     98 // TODO(gbillock): make this either unnecessary (implementation-specific) or
     99 // platform-independent.
    100 #if defined(OS_WIN)
    101   // Gets the MTP device storage information specified by |storage_device_id|.
    102   // On success, returns true and fills in |device_location| with device
    103   // interface details and |storage_object_id| with the string ID that
    104   // uniquely identifies the object on the device. This ID need not be
    105   // persistent across sessions.
    106   virtual bool GetMTPStorageInfoFromDeviceId(
    107       const std::string& storage_device_id,
    108       base::string16* device_location,
    109       base::string16* storage_object_id) const = 0;
    110 #endif
    111 
    112 #if defined(OS_LINUX)
    113   virtual device::MediaTransferProtocolManager*
    114       media_transfer_protocol_manager() = 0;
    115 #endif
    116 
    117   // Returns information for all known storages on the system,
    118   // including fixed and removable storages.
    119   std::vector<StorageInfo> GetAllAvailableStorages() const;
    120 
    121   void AddObserver(RemovableStorageObserver* obs);
    122   void RemoveObserver(RemovableStorageObserver* obs);
    123 
    124   std::string GetTransientIdForDeviceId(const std::string& device_id);
    125   std::string GetDeviceIdForTransientId(const std::string& transient_id) const;
    126 
    127   virtual void EjectDevice(
    128       const std::string& device_id,
    129       base::Callback<void(EjectStatus)> callback);
    130 
    131  protected:
    132   friend class ::MediaFileSystemRegistryTest;
    133   friend class ::MediaGalleriesPlatformAppBrowserTest;
    134   friend class ::MediaGalleriesPrivateApiTest;
    135   friend class ::SystemStorageApiTest;
    136   friend class ::SystemStorageEjectApiTest;
    137 
    138   StorageMonitor();
    139 
    140   virtual Receiver* receiver() const;
    141 
    142   // Called to initialize the storage monitor.
    143   virtual void Init() = 0;
    144 
    145   // Called by subclasses to mark the storage monitor as
    146   // fully initialized. Must be called on the UI thread.
    147   void MarkInitialized();
    148 
    149  private:
    150   class ReceiverImpl;
    151   friend class ReceiverImpl;
    152 
    153   // Key: device id.
    154   typedef std::map<std::string, StorageInfo> StorageMap;
    155 
    156   void ProcessAttach(const StorageInfo& storage);
    157   void ProcessDetach(const std::string& id);
    158 
    159   scoped_ptr<Receiver> receiver_;
    160 
    161   scoped_refptr<ObserverListThreadSafe<RemovableStorageObserver> >
    162       observer_list_;
    163 
    164   // Used to make sure we call initialize from the same thread as creation.
    165   base::ThreadChecker thread_checker_;
    166 
    167   bool initializing_;
    168   bool initialized_;
    169   std::vector<base::Closure> on_initialize_callbacks_;
    170 
    171   // For manipulating storage_map_ structure.
    172   mutable base::Lock storage_lock_;
    173 
    174   // Map of all known storage devices,including fixed and removable storages.
    175   StorageMap storage_map_;
    176 
    177   scoped_ptr<TransientDeviceIds> transient_device_ids_;
    178 };
    179 
    180 #endif  // CHROME_BROWSER_STORAGE_MONITOR_STORAGE_MONITOR_H_
    181