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.
5 #ifndef WEBKIT_BROWSER_FILEAPI_ISOLATED_CONTEXT_H_
6 #define WEBKIT_BROWSER_FILEAPI_ISOLATED_CONTEXT_H_
13 #include "base/basictypes.h"
14 #include "base/files/file_path.h"
15 #include "base/lazy_instance.h"
16 #include "base/memory/singleton.h"
17 #include "base/synchronization/lock.h"
18 #include "webkit/browser/fileapi/mount_points.h"
19 #include "webkit/browser/webkit_storage_browser_export.h"
20 #include "webkit/common/fileapi/file_system_types.h"
28 // Manages isolated filesystem mount points which have no well-known names
29 // and are identified by a string 'filesystem ID', which usually just looks
31 // This type of filesystem can be created on the fly and may go away when it has
32 // no references from renderers.
33 // Files in an isolated filesystem are registered with corresponding names and
34 // identified by a filesystem URL like:
36 // filesystem:<origin>/isolated/<filesystem_id>/<name>/relative/path
38 // Some methods of this class are virtual just for mocking.
40 class WEBKIT_STORAGE_BROWSER_EXPORT IsolatedContext : public MountPoints {
42 class WEBKIT_STORAGE_BROWSER_EXPORT FileInfoSet {
47 // Add the given |path| to the set and populates |registered_name| with
48 // the registered name assigned for the path. |path| needs to be
49 // absolute and should not contain parent references.
50 // Return false if the |path| is not valid and could not be added.
51 bool AddPath(const base::FilePath& path, std::string* registered_name);
53 // Add the given |path| with the |name|.
54 // Return false if the |name| is already registered in the set or
55 // is not valid and could not be added.
56 bool AddPathWithName(const base::FilePath& path, const std::string& name);
58 const std::set<MountPointInfo>& fileset() const { return fileset_; }
61 std::set<MountPointInfo> fileset_;
64 // The instance is lazily created per browser process.
65 static IsolatedContext* GetInstance();
67 // Returns true if the given filesystem type is managed by IsolatedContext
68 // (i.e. if the given |type| is Isolated or External).
69 // TODO(kinuko): needs a better function name.
70 static bool IsIsolatedType(FileSystemType type);
72 // Registers a new isolated filesystem with the given FileInfoSet |files|
73 // and returns the new filesystem_id. The files are registered with their
74 // register_name as their keys so that later we can resolve the full paths
75 // for the given name. We only expose the name and the ID for the
76 // newly created filesystem to the renderer for the sake of security.
78 // The renderer will be sending filesystem requests with a virtual path like
79 // '/<filesystem_id>/<registered_name>/<relative_path_from_the_dropped_path>'
80 // for which we could crack in the browser process by calling
81 // CrackIsolatedPath to get the full path.
83 // For example: if a dropped file has a path like '/a/b/foo' and we register
84 // the path with the name 'foo' in the newly created filesystem.
85 // Later if the context is asked to crack a virtual path like '/<fsid>/foo'
86 // it can properly return the original path '/a/b/foo' by looking up the
87 // internal mapping. Similarly if a dropped entry is a directory and its
88 // path is like '/a/b/dir' a virtual path like '/<fsid>/dir/foo' can be
89 // cracked into '/a/b/dir/foo'.
91 // Note that the path in |fileset| that contains '..' or is not an
92 // absolute path is skipped and is not registered.
93 std::string RegisterDraggedFileSystem(const FileInfoSet& files);
95 // Registers a new isolated filesystem for a given |path| of filesystem
96 // |type| filesystem and returns a new filesystem ID.
97 // |path| must be an absolute path which has no parent references ('..').
98 // If |register_name| is non-null and has non-empty string the path is
99 // registered as the given |register_name|, otherwise it is populated
100 // with the name internally assigned to the path.
101 std::string RegisterFileSystemForPath(FileSystemType type,
102 const base::FilePath& path,
103 std::string* register_name);
105 // Registers a virtual filesystem. This is different from
106 // RegisterFileSystemForPath because register_name is required, and
107 // cracked_path_prefix is allowed to be non-absolute.
108 // |register_name| is required, since we cannot infer one from the path.
109 // |cracked_path_prefix| has no parent references, but can be relative.
110 std::string RegisterFileSystemForVirtualPath(
112 const std::string& register_name,
113 const base::FilePath& cracked_path_prefix);
115 // Revokes all filesystem(s) registered for the given path.
116 // This is assumed to be called when the registered path becomes
117 // globally invalid, e.g. when a device for the path is detached.
119 // Note that this revokes the filesystem no matter how many references it has.
120 // It is ok to call this for the path that has no associated filesystems.
121 // Note that this only works for the filesystems registered by
122 // |RegisterFileSystemForPath|.
123 void RevokeFileSystemByPath(const base::FilePath& path);
125 // Adds a reference to a filesystem specified by the given filesystem_id.
126 void AddReference(const std::string& filesystem_id);
128 // Removes a reference to a filesystem specified by the given filesystem_id.
129 // If the reference count reaches 0 the isolated context gets destroyed.
130 // It is OK to call this on the filesystem that has been already deleted
131 // (e.g. by RevokeFileSystemByPath).
132 void RemoveReference(const std::string& filesystem_id);
134 // Returns a set of dragged MountPointInfos registered for the
136 // The filesystem_id must be pointing to a dragged file system
137 // (i.e. must be the one registered by RegisterDraggedFileSystem).
138 // Returns false if the |filesystem_id| is not valid.
139 bool GetDraggedFileInfo(const std::string& filesystem_id,
140 std::vector<MountPointInfo>* files) const;
142 // MountPoints overrides.
143 virtual bool HandlesFileSystemMountType(FileSystemType type) const OVERRIDE;
144 virtual bool RevokeFileSystem(const std::string& filesystem_id) OVERRIDE;
145 virtual bool GetRegisteredPath(const std::string& filesystem_id,
146 base::FilePath* path) const OVERRIDE;
147 virtual bool CrackVirtualPath(const base::FilePath& virtual_path,
148 std::string* filesystem_id,
149 FileSystemType* type,
150 base::FilePath* path) const OVERRIDE;
151 virtual FileSystemURL CrackURL(const GURL& url) const OVERRIDE;
152 virtual FileSystemURL CreateCrackedFileSystemURL(
155 const base::FilePath& path) const OVERRIDE;
157 // Returns the virtual root path that looks like /<filesystem_id>.
158 base::FilePath CreateVirtualRootPath(const std::string& filesystem_id) const;
161 friend struct base::DefaultLazyInstanceTraits<IsolatedContext>;
163 // Represents each file system instance (defined in the .cc).
166 typedef std::map<std::string, Instance*> IDToInstance;
168 // Reverse map from registered path to IDs.
169 typedef std::map<base::FilePath, std::set<std::string> > PathToID;
171 // Obtain an instance of this class via GetInstance().
173 virtual ~IsolatedContext();
175 // MountPoints overrides.
176 virtual FileSystemURL CrackFileSystemURL(
177 const FileSystemURL& url) const OVERRIDE;
179 // Unregisters a file system of given |filesystem_id|. Must be called with
180 // lock_ held. Returns true if the file system is unregistered.
181 bool UnregisterFileSystem(const std::string& filesystem_id);
183 // Returns a new filesystem_id. Called with lock.
184 std::string GetNewFileSystemId() const;
186 // This lock needs to be obtained when accessing the instance_map_.
187 mutable base::Lock lock_;
189 IDToInstance instance_map_;
190 PathToID path_to_id_map_;
192 DISALLOW_COPY_AND_ASSIGN(IsolatedContext);
195 } // namespace fileapi
197 #endif // WEBKIT_BROWSER_FILEAPI_ISOLATED_CONTEXT_H_