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1 // Copyright 2014 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_CHROMEOS_FILE_SYSTEM_PROVIDER_SERVICE_H_
6 #define CHROME_BROWSER_CHROMEOS_FILE_SYSTEM_PROVIDER_SERVICE_H_
7 
8 #include <map>
9 #include <string>
10 #include <utility>
11 #include <vector>
12 
13 #include "base/files/file.h"
14 #include "base/files/file_path.h"
15 #include "base/memory/scoped_ptr.h"
16 #include "base/memory/weak_ptr.h"
17 #include "base/observer_list.h"
18 #include "base/threading/thread_checker.h"
19 #include "base/values.h"
20 #include "chrome/browser/chromeos/file_system_provider/observer.h"
21 #include "chrome/browser/profiles/profile.h"
22 #include "chrome/common/extensions/api/file_system_provider.h"
23 #include "components/keyed_service/core/keyed_service.h"
24 #include "content/public/browser/browser_context.h"
25 #include "extensions/browser/extension_registry_observer.h"
26 #include "extensions/common/extension.h"
27 
28 namespace extensions {
29 class ExtensionRegistry;
30 }  // namespace extensions
31 
32 namespace user_prefs {
33 class PrefRegistrySyncable;
34 }  // namespace user_prefs
35 
36 namespace chromeos {
37 namespace file_system_provider {
38 
39 // Key names for preferences.
40 extern const char kPrefKeyFileSystemId[];
41 extern const char kPrefKeyDisplayName[];
42 extern const char kPrefKeyWritable[];
43 
44 class ProvidedFileSystemFactoryInterface;
45 class ProvidedFileSystemInfo;
46 class ProvidedFileSystemInterface;
47 class ServiceFactory;
48 
49 // Registers preferences to remember registered file systems between reboots.
50 void RegisterProfilePrefs(user_prefs::PrefRegistrySyncable* registry);
51 
52 // Manages and registers the file system provider service. Maintains provided
53 // file systems.
54 class Service : public KeyedService,
55                 public extensions::ExtensionRegistryObserver {
56  public:
57   typedef base::Callback<ProvidedFileSystemInterface*(
58       Profile* profile,
59       const ProvidedFileSystemInfo& file_system_info)>
60       FileSystemFactoryCallback;
61 
62   // Reason for unmounting. In case of UNMOUNT_REASON_SHUTDOWN, the file system
63   // will be remounted automatically after a reboot. In case of
64   // UNMOUNT_REASON_USER it will be permanently unmounted.
65   enum UnmountReason { UNMOUNT_REASON_USER, UNMOUNT_REASON_SHUTDOWN };
66 
67   Service(Profile* profile, extensions::ExtensionRegistry* extension_registry);
68   virtual ~Service();
69 
70   // Sets a custom ProvidedFileSystemInterface factory. Used by unit tests,
71   // where an event router is not available.
72   void SetFileSystemFactoryForTesting(
73       const FileSystemFactoryCallback& factory_callback);
74 
75   // Mounts a file system provided by an extension with the |extension_id|. If
76   // |writable| is set to true, then the file system is mounted in a R/W mode.
77   // Otherwise, only read-only operations are supported. For success, returns
78   // true, otherwise false.
79   bool MountFileSystem(const std::string& extension_id,
80                        const std::string& file_system_id,
81                        const std::string& display_name,
82                        bool writable);
83 
84   // Unmounts a file system with the specified |file_system_id| for the
85   // |extension_id|. For success returns true, otherwise false.
86   bool UnmountFileSystem(const std::string& extension_id,
87                          const std::string& file_system_id,
88                          UnmountReason reason);
89 
90   // Requests unmounting of the file system. The callback is called when the
91   // request is accepted or rejected, with an error code. Returns false if the
92   // request could not been created, true otherwise.
93   bool RequestUnmount(const std::string& extension_id,
94                       const std::string& file_system_id);
95 
96   // Returns a list of information of all currently provided file systems. All
97   // items are copied.
98   std::vector<ProvidedFileSystemInfo> GetProvidedFileSystemInfoList();
99 
100   // Returns a provided file system with |file_system_id|, handled by
101   // the extension with |extension_id|. If not found, then returns NULL.
102   ProvidedFileSystemInterface* GetProvidedFileSystem(
103       const std::string& extension_id,
104       const std::string& file_system_id);
105 
106   // Returns a provided file system attached to the the passed
107   // |mount_point_name|. If not found, then returns NULL.
108   ProvidedFileSystemInterface* GetProvidedFileSystem(
109       const std::string& mount_point_name);
110 
111   // Adds and removes observers.
112   void AddObserver(Observer* observer);
113   void RemoveObserver(Observer* observer);
114 
115   // Gets the singleton instance for the |context|.
116   static Service* Get(content::BrowserContext* context);
117 
118   // extensions::ExtensionRegistryObserver overrides.
119   virtual void OnExtensionUnloaded(
120       content::BrowserContext* browser_context,
121       const extensions::Extension* extension,
122       extensions::UnloadedExtensionInfo::Reason reason) OVERRIDE;
123   virtual void OnExtensionLoaded(
124       content::BrowserContext* browser_context,
125       const extensions::Extension* extension) OVERRIDE;
126 
127  private:
128   // Key is a pair of an extension id and file system id, which makes it
129   // unique among the entire service instance.
130   typedef std::pair<std::string, std::string> FileSystemKey;
131 
132   typedef std::map<FileSystemKey, ProvidedFileSystemInterface*>
133       ProvidedFileSystemMap;
134   typedef std::map<std::string, FileSystemKey> MountPointNameToKeyMap;
135 
136   // Called when the providing extension accepts or refuses a unmount request.
137   // If |error| is equal to FILE_OK, then the request is accepted.
138   void OnRequestUnmountStatus(const ProvidedFileSystemInfo& file_system_info,
139                               base::File::Error error);
140 
141   // Remembers the file system in preferences, in order to remount after a
142   // reboot.
143   void RememberFileSystem(const ProvidedFileSystemInfo& file_system_info);
144 
145   // Removes the file system from preferences, so it is not remounmted anymore
146   // after a reboot.
147   void ForgetFileSystem(const std::string& extension_id,
148                         const std::string& file_system_id);
149 
150   // Restores from preferences file systems mounted previously by the
151   // |extension_id| providing extension.
152   void RestoreFileSystems(const std::string& extension_id);
153 
154   Profile* profile_;
155   extensions::ExtensionRegistry* extension_registry_;  // Not owned.
156   FileSystemFactoryCallback file_system_factory_;
157   ObserverList<Observer> observers_;
158   ProvidedFileSystemMap file_system_map_;  // Owns pointers.
159   MountPointNameToKeyMap mount_point_name_to_key_map_;
160   base::ThreadChecker thread_checker_;
161   base::WeakPtrFactory<Service> weak_ptr_factory_;
162 
163   DISALLOW_COPY_AND_ASSIGN(Service);
164 };
165 
166 }  // namespace file_system_provider
167 }  // namespace chromeos
168 
169 #endif  // CHROME_BROWSER_CHROMEOS_FILE_SYSTEM_PROVIDER_SERVICE_H_
170