Implement async verision of FileSystemFileUtil and in-memory file system for testing purposes.

webkit/chromeos/fileapi/file_util_async.cc

+// 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.
+
+#include "webkit/chromeos/fileapi/file_util_async.h"
+
+#include "base/bind.h"
+#include "base/memory/weak_ptr.h"
+#include "base/message_loop.h"
+
+namespace fileapi {
+
+FileUtilAsync::FileUtilAsync() {
+}
+
+// Depending on the flags value the flow of file opening will be one of
+// the following:
+//
+// PLATFORM_FILE_OPEN:
+// GetFileInfo
+// DidGetFileInfoForOpen
+// OpenVerifiedFile
+//
+// PLATFORM_FILE_CREATE:
+// Create
+// DidCreateOrTruncateForOpen
+// OpenVerifiedFile
+//
+// PLATFORM_FILE_OPEN_ALWAYS:
+// GetFileInfo
+// DidGetFileInfoForOpen
+// OpenVerifiedFile   OR   Create
+//                         DidCreateOrTruncateForOpen
+//                         OpenVerifiedFile
+//
+// PLATFORM_FILE_CREATE_ALWAYS:
+// Truncate
+// OpenTruncatedFileOrCreate
+// OpenVerifiedFile   OR   Create
+//                         DidCreateOrTruncateForOpen
+//                         OpenVerifiedFile
+//
+// PLATFORM_FILE_OPEN_TRUNCATED:
+// Truncate
+// DidCreateOrTruncateForOpen
+// OpenVerifiedFile
+//
+void FileUtilAsync::Open(

[satorux1, 2011/12/14 08:42:29]

She was doubtful of having the default implementation here. I think she's right.
The implementation assumes that the logic is reusable for file system
implementations but the assumption doesn't seem to be sound.

[satorux1, 2011/12/14 08:55:32]

Moved to MemoryFileUtil.

[Oleg Eterevsky, 2011/12/14 15:20:59]

To be honest, I'm not sure about this. Having the Open() code in the base class
guarantees that different implementations will behave in the same way with
regard to open modes.

Also much the same code should be present in almost any implementation of
FileUtilAsync, so moving it to just one instance looks wasteful to me.

On the other hand, it's never too late to move this code back once it proves to
be useful in another FU implementation. Plainly, I'm too anxious to commit this
code ASAP to argue about about the best place for this code. :)

+    const FilePath& file_path,
+    int flags,
+    const OpenCallback& callback) {
+  int create_flag = flags & (base::PLATFORM_FILE_OPEN |
+                             base::PLATFORM_FILE_CREATE |
+                             base::PLATFORM_FILE_OPEN_ALWAYS |
+                             base::PLATFORM_FILE_CREATE_ALWAYS |
+                             base::PLATFORM_FILE_OPEN_TRUNCATED);
+  switch (create_flag) {
+    case base::PLATFORM_FILE_OPEN:
+    case base::PLATFORM_FILE_OPEN_ALWAYS:
+      GetFileInfo(
+          file_path,
+          base::Bind(&FileUtilAsync::DidGetFileInfoForOpen,
+                     base::Unretained(this), file_path, flags, callback));
+
+      break;
+
+    case base::PLATFORM_FILE_CREATE:
+      Create(
+          file_path,
+          base::Bind(&FileUtilAsync::DidCreateOrTruncateForOpen,
+                     base::Unretained(this), file_path, flags, 0, callback));
+      break;
+
+    case base::PLATFORM_FILE_CREATE_ALWAYS:
+      Truncate(
+          file_path,
+          0,
+          base::Bind(&FileUtilAsync::OpenTruncatedFileOrCreate,
+                     base::Unretained(this), file_path, flags, callback));
+
+    case base::PLATFORM_FILE_OPEN_TRUNCATED:
+      Truncate(
+          file_path,
+          0,
+          base::Bind(&FileUtilAsync::DidCreateOrTruncateForOpen,
+                     base::Unretained(this), file_path, flags, 0, callback));
+      break;
+
+    default:
+      MessageLoop::current()->PostTask(
+          FROM_HERE,
+          base::Bind(callback,
+                     base::PLATFORM_FILE_ERROR_INVALID_OPERATION,
+                     static_cast<AsyncFileStream*>(NULL)));
+  }
+}
+
+void FileUtilAsync::DidGetFileInfoForOpen(
+    const FilePath& file_path,
+    int flags,
+    const OpenCallback& callback,
+    PlatformFileError get_info_result,
+    const base::PlatformFileInfo& file_info) {
+  if (get_info_result == base::PLATFORM_FILE_OK && file_info.is_directory) {
+    callback.Run(base::PLATFORM_FILE_ERROR_NOT_A_FILE, NULL);
+    return;
+  }
+
+  if (get_info_result == base::PLATFORM_FILE_OK) {
+    OpenVerifiedFile(file_path, flags, callback);
+    return;
+  }
+
+  if (get_info_result == base::PLATFORM_FILE_ERROR_NOT_FOUND &&
+      flags & base::PLATFORM_FILE_CREATE_ALWAYS) {
+    Create(file_path,
+           base::Bind(&FileUtilAsync::DidCreateOrTruncateForOpen,
+                      base::Unretained(this), file_path, flags, 0, callback));
+    return;
+  }
+
+  callback.Run(get_info_result, NULL);
+}
+
+void FileUtilAsync::OpenTruncatedFileOrCreate(
+    const FilePath& file_path,
+    int flags,
+    const OpenCallback& callback,
+    PlatformFileError result) {
+  if (result == base::PLATFORM_FILE_OK) {
+    OpenVerifiedFile(file_path, flags, callback);
+    return;
+  }
+
+  if (result == base::PLATFORM_FILE_ERROR_NOT_FOUND) {
+    Create(
+        file_path,
+        base::Bind(&FileUtilAsync::DidCreateOrTruncateForOpen,
+                   base::Unretained(this), file_path, flags, 0, callback));
+    return;
+  }
+
+  callback.Run(result, NULL);
+}
+
+void FileUtilAsync::DidCreateOrTruncateForOpen(
+    const FilePath& file_path,
+    int flags,
+    int64 size,
+    const OpenCallback& callback,
+    PlatformFileError result) {
+  if (result != base::PLATFORM_FILE_OK) {
+    callback.Run(result, NULL);
+    return;
+  }
+
+  OpenVerifiedFile(file_path, flags, callback);
+}
+
+}  // namespace fileapi