1 // Copyright (c) 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 STORAGE_BROWSER_FILEAPI_EXTERNAL_MOUNT_POINTS_H_ 6 #define STORAGE_BROWSER_FILEAPI_EXTERNAL_MOUNT_POINTS_H_ 7 8 #include <map> 9 #include <string> 10 #include <vector> 11 12 #include "base/memory/ref_counted.h" 13 #include "base/synchronization/lock.h" 14 #include "storage/browser/fileapi/mount_points.h" 15 #include "storage/browser/storage_browser_export.h" 16 #include "storage/common/fileapi/file_system_mount_option.h" 17 #include "storage/common/fileapi/file_system_types.h" 18 19 namespace base { 20 class FilePath; 21 } 22 23 namespace storage { 24 25 class FileSystemURL; 26 27 // Manages external filesystem namespaces that are identified by 'mount name' 28 // and are persisted until RevokeFileSystem is called. 29 // Files in an external filesystem are identified by a filesystem URL like: 30 // 31 // filesystem:<origin>/external/<mount_name>/relative/path 32 // 33 class STORAGE_EXPORT ExternalMountPoints 34 : public base::RefCountedThreadSafe<ExternalMountPoints>, 35 public MountPoints { 36 public: 37 static ExternalMountPoints* GetSystemInstance(); 38 static scoped_refptr<ExternalMountPoints> CreateRefCounted(); 39 40 // Registers a new named external filesystem. 41 // The |path| is registered as the root path of the mount point which 42 // is identified by a URL "filesystem:.../external/mount_name". 43 // 44 // For example, if the path "/media/removable" is registered with 45 // the mount_name "removable", a filesystem URL like 46 // "filesystem:.../external/removable/a/b" will be resolved as 47 // "/media/removable/a/b". 48 // 49 // The |mount_name| should NOT contain a path separator '/'. 50 // Returns false if the given name is already registered. 51 // 52 // Overlapping mount points in a single MountPoints instance are not allowed. 53 // Adding mount point whose path overlaps with an existing mount point will 54 // fail except for media galleries, which do not count toward registered 55 // paths for overlap calculation. 56 // 57 // If not empty, |path| must be absolute. It is allowed for the path to be 58 // empty, but |GetVirtualPath| will not work for those mount points. 59 // 60 // An external file system registered by this method can be revoked 61 // by calling RevokeFileSystem with |mount_name|. 62 bool RegisterFileSystem(const std::string& mount_name, 63 FileSystemType type, 64 const FileSystemMountOption& mount_option, 65 const base::FilePath& path); 66 67 // MountPoints overrides. 68 virtual bool HandlesFileSystemMountType(FileSystemType type) const OVERRIDE; 69 virtual bool RevokeFileSystem(const std::string& mount_name) OVERRIDE; 70 virtual bool GetRegisteredPath(const std::string& mount_name, 71 base::FilePath* path) const OVERRIDE; 72 virtual bool CrackVirtualPath( 73 const base::FilePath& virtual_path, 74 std::string* mount_name, 75 FileSystemType* type, 76 std::string* cracked_id, 77 base::FilePath* path, 78 FileSystemMountOption* mount_option) const OVERRIDE; 79 virtual FileSystemURL CrackURL(const GURL& url) const OVERRIDE; 80 virtual FileSystemURL CreateCrackedFileSystemURL( 81 const GURL& origin, 82 FileSystemType type, 83 const base::FilePath& path) const OVERRIDE; 84 85 // Returns a list of registered MountPointInfos (of <mount_name, path>). 86 void AddMountPointInfosTo(std::vector<MountPointInfo>* mount_points) const; 87 88 // Converts a path on a registered file system to virtual path relative to the 89 // file system root. E.g. if 'Downloads' file system is mapped to 90 // '/usr/local/home/Downloads', and |absolute| path is set to 91 // '/usr/local/home/Downloads/foo', the method will set |virtual_path| to 92 // 'Downloads/foo'. 93 // Returns false if the path cannot be resolved (e.g. if the path is not 94 // part of any registered filesystem). 95 // 96 // Media gallery type file systems do not count for this calculation. i.e. 97 // if only a media gallery is registered for the path, false will be returned. 98 // If a media gallery and another file system are registered for related 99 // paths, only the other registration is taken into account. 100 // 101 // Returned virtual_path will have normalized path separators. 102 bool GetVirtualPath(const base::FilePath& absolute_path, 103 base::FilePath* virtual_path) const; 104 105 // Returns the virtual root path that looks like /<mount_name>. 106 base::FilePath CreateVirtualRootPath(const std::string& mount_name) const; 107 108 FileSystemURL CreateExternalFileSystemURL( 109 const GURL& origin, 110 const std::string& mount_name, 111 const base::FilePath& path) const; 112 113 // Revoke all registered filesystems. Used only by testing (for clean-ups). 114 void RevokeAllFileSystems(); 115 116 private: 117 friend class base::RefCountedThreadSafe<ExternalMountPoints>; 118 119 // Represents each file system instance (defined in the .cc). 120 class Instance; 121 122 typedef std::map<std::string, Instance*> NameToInstance; 123 124 // Reverse map from registered path to its corresponding mount name. 125 typedef std::map<base::FilePath, std::string> PathToName; 126 127 // Use |GetSystemInstance| of |CreateRefCounted| to get an instance. 128 ExternalMountPoints(); 129 virtual ~ExternalMountPoints(); 130 131 // MountPoint overrides. 132 virtual FileSystemURL CrackFileSystemURL( 133 const FileSystemURL& url) const OVERRIDE; 134 135 // Performs sanity checks on the new mount point. 136 // Checks the following: 137 // - there is no registered mount point with mount_name 138 // - path does not contain a reference to a parent 139 // - path is absolute 140 // - path does not overlap with an existing mount point path unless it is a 141 // media gallery type. 142 // 143 // |lock_| should be taken before calling this method. 144 bool ValidateNewMountPoint(const std::string& mount_name, 145 FileSystemType type, 146 const base::FilePath& path); 147 148 // This lock needs to be obtained when accessing the instance_map_. 149 mutable base::Lock lock_; 150 151 NameToInstance instance_map_; 152 PathToName path_to_name_map_; 153 154 DISALLOW_COPY_AND_ASSIGN(ExternalMountPoints); 155 }; 156 157 } // namespace storage 158 159 #endif // STORAGE_BROWSER_FILEAPI_EXTERNAL_MOUNT_POINTS_H_ 160