FileSystem code cleanup 2nd cut - introduce SandboxedFileSystemOperation

webkit/fileapi/sandboxed_file_system_operation.h

+// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef WEBKIT_FILEAPI_SANDBOXED_FILE_SYSTEM_OPERATION_H_
+#define WEBKIT_FILEAPI_SANDBOXED_FILE_SYSTEM_OPERATION_H_
+
+#include "base/scoped_callback_factory.h"
+#include "webkit/fileapi/file_system_operation.h"
+#include "webkit/fileapi/file_system_types.h"
+
+namespace fileapi {
+
+class SandboxedFileSystemContext;
+
+// This class provides a 'sandboxed' access to the underlying file system,
+// that is:
+// 1. provides OpenFileSystem method that returns a (hidden) root path
+//    that is given by |file_system_context|.
+// 2. enforces quota and file names/paths restrictions on each operation
+//    via |file_system_context|.
+class SandboxedFileSystemOperation : public FileSystemOperation {
+ public:
+  // This class doesn't hold a reference or ownership of |file_system_context|.
+  // It is the caller's responsibility to keep the pointer alive *until*
+  // it calls any of the operation methods.  The |file_system_context| won't be
+  // used in the callback path and can be deleted after the operation is
+  // made (e.g. after one of CreateFile, CreateDirectory, Copy, etc is called).
+  SandboxedFileSystemOperation(FileSystemCallbackDispatcher* dispatcher,
+                               scoped_refptr<base::MessageLoopProxy> proxy,
+                               SandboxedFileSystemContext* file_system_context);
+
+  void OpenFileSystem(const GURL& origin_url,
+                      fileapi::FileSystemType type,
+                      bool create);
+
+  // FileSystemOperation's methods.
+  virtual void CreateFile(const FilePath& path,
+                          bool exclusive);
+  virtual void CreateDirectory(const FilePath& path,
+                               bool exclusive,
+                               bool recursive);
+  virtual void Copy(const FilePath& src_path,
+                    const FilePath& dest_path);
+  virtual void Move(const FilePath& src_path,
+                    const FilePath& dest_path);
+  virtual void DirectoryExists(const FilePath& path);
+  virtual void FileExists(const FilePath& path);
+  virtual void GetMetadata(const FilePath& path);
+  virtual void ReadDirectory(const FilePath& path);
+  virtual void Remove(const FilePath& path, bool recursive);
+  virtual void Write(
+      scoped_refptr<URLRequestContext> url_request_context,
+      const FilePath& path, const GURL& blob_url, int64 offset);
+  virtual void Truncate(const FilePath& path, int64 length);
+  virtual void TouchFile(const FilePath& path,
+                 const base::Time& last_access_time,
+                 const base::Time& last_modified_time);
+
+ private:
+  enum SandboxedFileSystemOperationType {
+    kOperationOpenFileSystem = 100,
+  };
+
+  // A callback used for OpenFileSystem.
+  void DidGetRootPath(bool success,
+                      const FilePath& path,
+                      const std::string& name);
+
+  // Checks the validity of a given |path| for reading.
+  // Returns true if the given |path| is a valid FileSystem path.
+  // Otherwise it calls dispatcher's DidFail method with
+  // PLATFORM_FILE_ERROR_SECURITY and returns false.
+  bool VerifyFileSystemPathForRead(const FilePath& path);
+
+  // Checks the validity of a given |path| for writing.
+  // Returns true if the given |path| is a valid FileSystem path, and
+  // its origin embedded in the path has the right to write as much as
+  // the given |growth|.
+  // Otherwise it fires dispatcher's DidFail method with
+  // PLATFORM_FILE_ERROR_SECURITY if the path is not valid for writing,
+  // or with PLATFORM_FILE_ERROR_NO_SPACE if the origin is not allowed to
+  // increase the usage by |growth|.
+  // In either case it returns false after firing DidFail.
+  // If |create| flag is true this also checks if the |path| contains
+  // any restricted names and chars. If it does, the call fires dispatcher's
+  // DidFail with PLATFORM_FILE_ERROR_SECURITY and returns false.
+  bool VerifyFileSystemPathForWrite(const FilePath& path,
+                                    bool create,
+                                    int64 growth);
+
+  // Checks if a given |path| does not contain any restricted names/chars
+  // for new files. Returns true if the given |path| is safe.
+  // Otherwise it fires dispatcher's DidFail method with
+  // PLATFORM_FILE_ERROR_SECURITY and returns false.
+  bool CheckIfFilePathIsSafe(const FilePath& path);
+
+  // Not owned.  See the comment at the constructor.
+  SandboxedFileSystemContext* file_system_context_;
+
+  base::ScopedCallbackFactory<SandboxedFileSystemOperation> callback_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(SandboxedFileSystemOperation);
+};
+
+}  // namespace fileapi
+
+#endif  // WEBKIT_FILEAPI_SANDBOXED_FILE_SYSTEM_OPERATION_H_