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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 CHROME_BROWSER_CHROMEOS_FILEAPI_FILE_SYSTEM_BACKEND_H_
6 #define CHROME_BROWSER_CHROMEOS_FILEAPI_FILE_SYSTEM_BACKEND_H_
7 
8 #include <map>
9 #include <string>
10 #include <vector>
11 
12 #include "base/compiler_specific.h"
13 #include "base/files/file_path.h"
14 #include "base/memory/scoped_ptr.h"
15 #include "base/synchronization/lock.h"
16 #include "webkit/browser/fileapi/file_system_backend.h"
17 #include "webkit/browser/quota/special_storage_policy.h"
18 #include "webkit/browser/webkit_storage_browser_export.h"
19 #include "webkit/common/fileapi/file_system_types.h"
20 
21 namespace fileapi {
22 class CopyOrMoveFileValidatorFactory;
23 class ExternalMountPoints;
24 class FileSystemFileUtil;
25 class FileSystemURL;
26 class IsolatedContext;
27 }
28 
29 namespace chromeos {
30 
31 class FileSystemBackendDelegate;
32 class FileAccessPermissions;
33 
34 // FileSystemBackend is a Chrome OS specific implementation of
35 // ExternalFileSystemBackend. This class is responsible for a
36 // number of things, including:
37 //
38 // - Add system mount points
39 // - Grant/revoke/check file access permissions
40 // - Create FileSystemOperation per file system type
41 // - Create FileStreamReader/Writer per file system type
42 //
43 // Chrome OS specific mount points:
44 //
45 // "Downloads" is a mount point for user's Downloads directory on the local
46 // disk, where downloaded files are stored by default.
47 //
48 // "archive" is a mount point for an archive file, such as a zip file. This
49 // mount point exposes contents of an archive file via cros_disks and AVFS
50 // <http://avf.sourceforge.net/>.
51 //
52 // "removable" is a mount point for removable media such as an SD card.
53 // Insertion and removal of removable media are handled by cros_disks.
54 //
55 // "oem" is a read-only mount point for a directory containing OEM data.
56 //
57 // "drive" is a mount point for Google Drive. Drive is integrated with the
58 // FileSystem API layer via drive::FileSystemProxy. This mount point is added
59 // by drive::DriveIntegrationService.
60 //
61 // These mount points are placed under the "external" namespace, and file
62 // system URLs for these mount points look like:
63 //
64 //   filesystem:<origin>/external/<mount_name>/...
65 //
66 class FileSystemBackend : public fileapi::ExternalFileSystemBackend {
67  public:
68   using fileapi::FileSystemBackend::OpenFileSystemCallback;
69 
70   // FileSystemBackend will take an ownership of a |mount_points|
71   // reference. On the other hand, |system_mount_points| will be kept as a raw
72   // pointer and it should outlive FileSystemBackend instance.
73   // The ownership of |drive_delegate| is also taken.
74   FileSystemBackend(
75       FileSystemBackendDelegate* drive_delegate,
76       scoped_refptr<quota::SpecialStoragePolicy> special_storage_policy,
77       scoped_refptr<fileapi::ExternalMountPoints> mount_points,
78       fileapi::ExternalMountPoints* system_mount_points);
79   virtual ~FileSystemBackend();
80 
81   // Adds system mount points, such as "archive", and "removable". This
82   // function is no-op if these mount points are already present.
83   void AddSystemMountPoints();
84 
85   // Returns true if CrosMountpointProvider can handle |url|, i.e. its
86   // file system type matches with what this provider supports.
87   // This could be called on any threads.
88   static bool CanHandleURL(const fileapi::FileSystemURL& url);
89 
90   // fileapi::FileSystemBackend overrides.
91   virtual bool CanHandleType(fileapi::FileSystemType type) const OVERRIDE;
92   virtual void Initialize(fileapi::FileSystemContext* context) OVERRIDE;
93   virtual void OpenFileSystem(
94       const GURL& origin_url,
95       fileapi::FileSystemType type,
96       fileapi::OpenFileSystemMode mode,
97       const OpenFileSystemCallback& callback) OVERRIDE;
98   virtual fileapi::AsyncFileUtil* GetAsyncFileUtil(
99       fileapi::FileSystemType type) OVERRIDE;
100   virtual fileapi::CopyOrMoveFileValidatorFactory*
101       GetCopyOrMoveFileValidatorFactory(
102           fileapi::FileSystemType type,
103           base::PlatformFileError* error_code) OVERRIDE;
104   virtual fileapi::FileSystemOperation* CreateFileSystemOperation(
105       const fileapi::FileSystemURL& url,
106       fileapi::FileSystemContext* context,
107       base::PlatformFileError* error_code) const OVERRIDE;
108   virtual scoped_ptr<webkit_blob::FileStreamReader> CreateFileStreamReader(
109       const fileapi::FileSystemURL& path,
110       int64 offset,
111       const base::Time& expected_modification_time,
112       fileapi::FileSystemContext* context) const OVERRIDE;
113   virtual scoped_ptr<fileapi::FileStreamWriter> CreateFileStreamWriter(
114       const fileapi::FileSystemURL& url,
115       int64 offset,
116       fileapi::FileSystemContext* context) const OVERRIDE;
117   virtual fileapi::FileSystemQuotaUtil* GetQuotaUtil() OVERRIDE;
118 
119   // fileapi::ExternalFileSystemBackend overrides.
120   virtual bool IsAccessAllowed(const fileapi::FileSystemURL& url)
121       const OVERRIDE;
122   virtual std::vector<base::FilePath> GetRootDirectories() const OVERRIDE;
123   virtual void GrantFullAccessToExtension(
124       const std::string& extension_id) OVERRIDE;
125   virtual void GrantFileAccessToExtension(
126       const std::string& extension_id,
127       const base::FilePath& virtual_path) OVERRIDE;
128   virtual void RevokeAccessForExtension(
129       const std::string& extension_id) OVERRIDE;
130   virtual bool GetVirtualPath(const base::FilePath& filesystem_path,
131                               base::FilePath* virtual_path) OVERRIDE;
132 
133  private:
134   scoped_refptr<quota::SpecialStoragePolicy> special_storage_policy_;
135   scoped_ptr<FileAccessPermissions> file_access_permissions_;
136   scoped_ptr<fileapi::AsyncFileUtil> local_file_util_;
137 
138   // The Delegate instance for the drive file system related operation.
139   scoped_ptr<FileSystemBackendDelegate> drive_delegate_;
140 
141   // Mount points specific to the owning context (i.e. per-profile mount
142   // points).
143   //
144   // It is legal to have mount points with the same name as in
145   // system_mount_points_. Also, mount point paths may overlap with mount point
146   // paths in system_mount_points_. In both cases mount points in
147   // |mount_points_| will have a priority.
148   // E.g. if |mount_points_| map 'foo1' to '/foo/foo1' and
149   // |file_system_mount_points_| map 'xxx' to '/foo/foo1/xxx', |GetVirtualPaths|
150   // will resolve '/foo/foo1/xxx/yyy' as 'foo1/xxx/yyy' (i.e. the mapping from
151   // |mount_points_| will be used).
152   scoped_refptr<fileapi::ExternalMountPoints> mount_points_;
153 
154   // Globally visible mount points. System MountPonts instance should outlive
155   // all FileSystemBackend instances, so raw pointer is safe.
156   fileapi::ExternalMountPoints* system_mount_points_;
157 
158   DISALLOW_COPY_AND_ASSIGN(FileSystemBackend);
159 };
160 
161 }  // namespace chromeos
162 
163 #endif  // CHROME_BROWSER_CHROMEOS_FILEAPI_FILE_SYSTEM_BACKEND_H_
164