Stackable file_util for FileAPIs. Sample code for discussion. Incomplete. Cannot be compiled.

webkit/fileapi/file_system_file_util_proxy.h

Index: webkit/fileapi/file_system_file_util_proxy.h
diff --git a/webkit/fileapi/file_system_file_util_proxy.h b/webkit/fileapi/file_system_file_util_proxy.h
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+// Copyright (c) 2011 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_FILE_SYSTEM_FILE_UTIL_PROXY_H_
+#define WEBKIT_FILEAPI_FILE_SYSTEM_FILE_UTIL_PROXY_H_
+
+#include <vector>
+
+#include "base/callback.h"
+#include "base/file_path.h"
+#include "base/file_util.h"
+#include "base/file_util_proxy.h"
+#include "base/platform_file.h"
+#include "base/ref_counted.h"
+#include "base/tracked_objects.h"
+#include "webkit/fileapi/file_system_operation_context.h"
+
+namespace base {
+class MessageLoopProxy;
+class Time;
+}
+
+namespace fileapi {
+
+// This class provides asynchronous access to common file routines.
+class FileSystemFileUtilProxy {
+ public:
+  // This callback is used by methods that report only an error code.  It is
+  // valid to pass NULL as the callback parameter to any function that takes a
+  // StatusCallback, in which case the operation will complete silently.
+  typedef Callback1<base::PlatformFileError /* error code */>::Type StatusCallback;
+
+  typedef Callback3<base::PlatformFileError /* error code */,
+                    base::PassPlatformFile,
+                    bool /* created */>::Type CreateOrOpenCallback;
+  typedef Callback3<base::PlatformFileError /* error code */,
+                    base::PassPlatformFile,
+                    FilePath>::Type CreateTemporaryCallback;
+  typedef Callback2<base::PlatformFileError /* error code */,
+                    bool /* created */>::Type EnsureFileExistsCallback;
+  typedef Callback2<base::PlatformFileError /* error code */,
+                    const base::PlatformFileInfo& /* file_info */
+                    >::Type GetFileInfoCallback;
+  typedef Callback2<base::PlatformFileError /* error code */,
+                    const std::vector<base::FileUtilProxy::Entry>&>::Type ReadDirectoryCallback;
+  typedef Callback3<base::PlatformFileError /* error code */,
+                    const char* /* data */,
+                    int /* bytes read/written */>::Type ReadCallback;
+  typedef Callback2<base::PlatformFileError /* error code */,
+                    int /* bytes written */>::Type WriteCallback;
+
+  // Creates or opens a file with the given flags.  It is invalid to pass NULL
+  // for the callback.
+  // If PLATFORM_FILE_CREATE is set in |file_flags| it always tries to create
+  // a new file at the given |file_path| and calls back with
+  // PLATFORM_FILE_ERROR_FILE_EXISTS if the |file_path| already exists.
+  static bool CreateOrOpen(FileSystemOperationContext* fs_context,
+                           scoped_refptr<base::MessageLoopProxy> message_loop_proxy,
+                           const FilePath& file_path,
+                           int file_flags,
+                           CreateOrOpenCallback* callback);
+
+  // Creates a temporary file for writing.  The path and an open file handle
+  // are returned.  It is invalid to pass NULL for the callback.
+  static bool CreateTemporary(
+      FileSystemOperationContext* fs_context,
+      scoped_refptr<base::MessageLoopProxy> message_loop_proxy,
+      CreateTemporaryCallback* callback);
+
+  // Close the given file handle.
+  static bool Close(FileSystemOperationContext* fs_context,
+                    scoped_refptr<base::MessageLoopProxy> message_loop_proxy,
+                    base::PlatformFile,
+                    StatusCallback* callback);
+
+  // Ensures that the given |file_path| exist.  This creates a empty new file
+  // at |file_path| if the |file_path| does not exist.
+  // If a new file han not existed and is created at the |file_path|,
+  // |created| of the callback argument is set true and |error code|
+  // is set PLATFORM_FILE_OK.
+  // If the file already exists, |created| is set false and |error code|
+  // is set PLATFORM_FILE_OK.
+  // If the file hasn't existed but it couldn't be created for some other
+  // reasons, |created| is set false and |error code| indicates the error.
+  static bool EnsureFileExists(
+      FileSystemOperationContext* fs_context,
+      scoped_refptr<base::MessageLoopProxy> message_loop_proxy,
+      const FilePath& file_path,
+      EnsureFileExistsCallback* callback);
+
+  // Retrieves the information about a file. It is invalid to pass NULL for the
+  // callback.
+  static bool GetFileInfo(
+      FileSystemOperationContext* fs_context,
+      scoped_refptr<base::MessageLoopProxy> message_loop_proxy,
+      const FilePath& file_path,
+      GetFileInfoCallback* callback);
+
+  static bool GetFileInfoFromPlatformFile(
+      FileSystemOperationContext* fs_context,
+      scoped_refptr<base::MessageLoopProxy> message_loop_proxy,
+      base::PlatformFile file,
+      GetFileInfoCallback* callback);
+
+  static bool ReadDirectory(FileSystemOperationContext* fs_context,
+                            scoped_refptr<base::MessageLoopProxy> message_loop_proxy,
+                            const FilePath& file_path,
+                            ReadDirectoryCallback* callback);
+
+  // Creates directory at given path. It's an error to create
+  // if |exclusive| is true and dir already exists.
+  static bool CreateDirectory(
+      FileSystemOperationContext* fs_context,
+      scoped_refptr<base::MessageLoopProxy> message_loop_proxy,
+      const FilePath& file_path,
+      bool exclusive,
+      bool recursive,
+      StatusCallback* callback);
+
+  // Copies a file or a directory from |src_file_path| to |dest_file_path|
+  // Error cases:
+  // If destination file doesn't exist or destination's parent
+  // doesn't exists.
+  // If source dir exists but destination path is an existing file.
+  // If source file exists but destination path is an existing directory.
+  // If source is a parent of destination.
+  // If source doesn't exists.
+  static bool Copy(FileSystemOperationContext* fs_context,
+                   scoped_refptr<base::MessageLoopProxy> message_loop_proxy,
+                   const FilePath& src_file_path,
+                   const FilePath& dest_file_path,
+                   StatusCallback* callback);
+
+  // Moves a file or a directory from src_file_path to dest_file_path.
+  // Error cases are similar to Copy method's error cases.
+  static bool Move(
+      FileSystemOperationContext* fs_context,
+      scoped_refptr<base::MessageLoopProxy> message_loop_proxy,
+      const FilePath& src_file_path,
+      const FilePath& dest_file_path,
+      StatusCallback* callback);
+
+  // Deletes a file or a directory.
+  // It is an error to delete a non-empty directory with recursive=false.
+  static bool Delete(FileSystemOperationContext* fs_context,
+                     scoped_refptr<base::MessageLoopProxy> message_loop_proxy,
+                     const FilePath& file_path,
+                     bool recursive,
+                     StatusCallback* callback);
+
+  // Deletes a directory and all of its contents.
+  static bool RecursiveDelete(
+      FileSystemOperationContext* fs_context,
+      scoped_refptr<base::MessageLoopProxy> message_loop_proxy,
+      const FilePath& file_path,
+      StatusCallback* callback);
+
+  // Reads from a file. On success, the file pointer is moved to position
+  // |offset + bytes_to_read| in the file. The callback can be NULL.
+  static bool Read(
+      FileSystemOperationContext* fs_context,
+      scoped_refptr<base::MessageLoopProxy> message_loop_proxy,
+      base::PlatformFile file,
+      int64 offset,
+      int bytes_to_read,
+      ReadCallback* callback);
+
+  // Writes to a file. If |offset| is greater than the length of the file,
+  // |false| is returned. On success, the file pointer is moved to position
+  // |offset + bytes_to_write| in the file. The callback can be NULL.
+  static bool Write(
+      FileSystemOperationContext* fs_context,
+      scoped_refptr<base::MessageLoopProxy> message_loop_proxy,
+      base::PlatformFile file,
+      int64 offset,
+      const char* buffer,
+      int bytes_to_write,
+      WriteCallback* callback);
+
+  // Touches a file. The callback can be NULL.
+  static bool Touch(
+      FileSystemOperationContext* fs_context,
+      scoped_refptr<base::MessageLoopProxy> message_loop_proxy,
+      base::PlatformFile file,
+      const base::Time& last_access_time,
+      const base::Time& last_modified_time,
+      StatusCallback* callback);
+
+  // Touches a file. The callback can be NULL.
+  static bool Touch(
+      FileSystemOperationContext* fs_context,
+      scoped_refptr<base::MessageLoopProxy> message_loop_proxy,
+      const FilePath& file_path,
+      const base::Time& last_access_time,
+      const base::Time& last_modified_time,
+      StatusCallback* callback);
+
+  // Truncates a file to the given length. If |length| is greater than the
+  // current length of the file, the file will be extended with zeroes.
+  // The callback can be NULL.
+  static bool Truncate(
+      FileSystemOperationContext* fs_context,
+      scoped_refptr<base::MessageLoopProxy> message_loop_proxy,
+      base::PlatformFile file,
+      int64 length,
+      StatusCallback* callback);
+
+  // Truncates a file to the given length. If |length| is greater than the
+  // current length of the file, the file will be extended with zeroes.
+  // The callback can be NULL.
+  static bool Truncate(
+      FileSystemOperationContext* fs_context,
+      scoped_refptr<base::MessageLoopProxy> message_loop_proxy,
+      const FilePath& path,
+      int64 length,
+      StatusCallback* callback);
+
+  // Flushes a file. The callback can be NULL.
+  static bool Flush(
+      FileSystemOperationContext* fs_context,
+      scoped_refptr<base::MessageLoopProxy> message_loop_proxy,
+      base::PlatformFile file,
+      StatusCallback* callback);
+
+ private:
+  DISALLOW_IMPLICIT_CONSTRUCTORS(FileSystemFileUtilProxy);
+};
+
+}  // namespace fileapi
+
+#endif  // WEBKIT_FILEAPI_FILE_SYSTEM_FILE_UTIL_PROXY_H_