(For-try) Divide recursive Copy/Move into multiple async tasks

webkit/fileapi/file_util_helper.cc

 // Copyright (c) 2012 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/fileapi/file_util_helper.h"
 
 #include <stack>
 #include <utility>
 
 #include "webkit/fileapi/file_system_file_util.h"
@@ skipping 92 matching lines @@
   DCHECK(src_util_);
   DCHECK(dest_util_);
   same_file_system_ =
       src_root_url_.origin() == dest_root_url_.origin() &&
       src_root_url_.type() == dest_root_url_.type();
 }
 
 CrossFileUtilHelper::~CrossFileUtilHelper() {}
 
 base::PlatformFileError CrossFileUtilHelper::DoWork() {
-  base::PlatformFileError error = PerformErrorCheckAndPreparation();
-  if (error != base::PLATFORM_FILE_OK)
-    return error;
-  if (FileUtilHelper::DirectoryExists(context_, src_util_, src_root_url_))
-    return CopyOrMoveDirectory(src_root_url_, dest_root_url_);
-  return CopyOrMoveFile(src_root_url_, dest_root_url_);
-}
-
-PlatformFileError CrossFileUtilHelper::PerformErrorCheckAndPreparation() {
-  FilePath platform_path;
-  base::PlatformFileInfo src_root_info;
-  base::PlatformFileInfo dest_root_info;
-
-  PlatformFileError error = src_util_->GetFileInfo(
-      context_, src_root_url_, &src_root_info, &platform_path);
-
-  if (error != base::PLATFORM_FILE_OK)
-    return error;
-
-  error = dest_util_->GetFileInfo(
-      context_, dest_root_url_, &dest_root_info, &platform_path);
-  bool dest_root_exists = (error == base::PLATFORM_FILE_OK);
-  bool dest_parent_exists = dest_root_exists || IsInRoot(dest_root_url_);
-
-  if (!dest_parent_exists) {
-    base::PlatformFileInfo file_info;
-    FileSystemURL parent_url = dest_root_url_.WithPath(
-        dest_root_url_.path().DirName());
-    error = dest_util_->GetFileInfo(
-        context_, parent_url, &file_info, &platform_path);
-    dest_parent_exists = (error == base::PLATFORM_FILE_OK &&
-                          file_info.is_directory);
-  }
-
-  // The parent of the |dest_root_url_| does not exist.
-  if (!dest_parent_exists)
-    return base::PLATFORM_FILE_ERROR_NOT_FOUND;
-
   // It is an error to try to copy/move an entry into its child.
   if (same_file_system_ && src_root_url_.path().IsParent(dest_root_url_.path()))
     return base::PLATFORM_FILE_ERROR_INVALID_OPERATION;
 
-  // Now it is ok to return if the |dest_root_url_| does not exist.
-  if (!dest_root_exists)
-    return base::PLATFORM_FILE_OK;
-
-  // |src_root_url_| exists and is a directory.
-  // |dest_root_url_| exists and is a file.
-  bool src_is_directory = src_root_info.is_directory;
-  bool dest_is_directory = dest_root_info.is_directory;
-
-  // Either one of |src_root_url_| or |dest_root_url_| is directory,
-  // while the other is not.
-  if (src_is_directory != dest_is_directory)
-    return base::PLATFORM_FILE_ERROR_INVALID_OPERATION;
-
   // It is an error to copy/move an entry into the same path.
   if (same_file_system_ &&
       src_root_url_.path() == dest_root_url_.path())
     return base::PLATFORM_FILE_ERROR_EXISTS;
 
-  if (dest_is_directory) {
-    // It is an error to copy/move an entry to a non-empty directory.
-    // Otherwise the copy/move attempt must overwrite the destination, but
-    // the file_util's Copy or Move method doesn't perform overwrite
-    // on all platforms, so we delete the destination directory here.
-    if (base::PLATFORM_FILE_OK !=
-        dest_util_->DeleteSingleDirectory(context_, dest_root_url_)) {
-      if (!dest_util_->IsDirectoryEmpty(context_, dest_root_url_))
-        return base::PLATFORM_FILE_ERROR_NOT_EMPTY;
-      return base::PLATFORM_FILE_ERROR_FAILED;
-    }
-  }
-  return base::PLATFORM_FILE_OK;
+  // First try to copy/move the file.
+  base::PlatformFileError error = CopyOrMoveFile(src_root_url_, dest_root_url_);
+  if (error == base::PLATFORM_FILE_OK ||
+      error != base::PLATFORM_FILE_ERROR_NOT_A_FILE)
+    return error;
+
+  // Now we should be sure that the source (and destination if exists)
+  // is directory.
+  // Now let's try to remove the destination directory, this must
+  // fail if the directory isn't empty or its parent doesn't exist.
+  error = dest_util_->DeleteDirectory(context_, dest_root_url_);
+  if (error == base::PLATFORM_FILE_ERROR_NOT_A_DIRECTORY)
+    return base::PLATFORM_FILE_ERROR_INVALID_OPERATION;
+  if (error != base::PLATFORM_FILE_OK &&
+      error != base::PLATFORM_FILE_ERROR_NOT_FOUND)
+    return error;
+
+  // Perform the actual work for directory copy/move.
+  return CopyOrMoveDirectory(src_root_url_, dest_root_url_);
 }
 
 PlatformFileError CrossFileUtilHelper::CopyOrMoveDirectory(
     const FileSystemURL& src_url,
     const FileSystemURL& dest_url) {
   // At this point we must have gone through
   // PerformErrorCheckAndPreparationForMoveAndCopy so this must be true.
   DCHECK(!same_file_system_ ||
          !src_url.path().IsParent(dest_url.path()));
 
@@ skipping 80 matching lines @@
   base::PlatformFileInfo file_info;
   FilePath platform_file_path;
   FileSystemFileUtil::SnapshotFilePolicy snapshot_policy;
 
   PlatformFileError error = src_util_->CreateSnapshotFile(
       context_, src_url, &file_info, &platform_file_path, &snapshot_policy);
   if (error != base::PLATFORM_FILE_OK)
     return error;
 
   // For now we don't support non-snapshot file case.
+  // TODO(kinuko): Address this case too.
   DCHECK(!platform_file_path.empty());
 
   scoped_ptr<ScopedFileDeleter> file_deleter;
   if (snapshot_policy == FileSystemFileUtil::kSnapshotFileTemporary)
     file_deleter.reset(new ScopedFileDeleter(platform_file_path));
 
   // Call CopyInForeignFile() on the dest_util_ with the resolved source path
   // to perform limited cross-FileSystemFileUtil copy/move.
   error = dest_util_->CopyInForeignFile(
       context_, platform_file_path, dest_url);
@@ skipping 44 matching lines @@
 }
 
 // static
 base::PlatformFileError FileUtilHelper::Delete(
     FileSystemOperationContext* context,
     FileSystemFileUtil* file_util,
     const FileSystemURL& url,
     bool recursive) {
   if (DirectoryExists(context, file_util, url)) {
     if (!recursive)
-      return file_util->DeleteSingleDirectory(context, url);
+      return file_util->DeleteDirectory(context, url);
     else
       return DeleteDirectoryRecursive(context, file_util, url);
   } else {
     return file_util->DeleteFile(context, url);
   }
 }
 
 // static
 base::PlatformFileError FileUtilHelper::ReadDirectory(
     FileSystemOperationContext* context,
@@ skipping 42 matching lines @@
     } else {
       PlatformFileError error = file_util->DeleteFile(
           context, url.WithPath(file_path_each));
       if (error != base::PLATFORM_FILE_ERROR_NOT_FOUND &&
           error != base::PLATFORM_FILE_OK)
         return error;
     }
   }
 
   while (!directories.empty()) {
-    PlatformFileError error = file_util->DeleteSingleDirectory(
+    PlatformFileError error = file_util->DeleteDirectory(
         context, url.WithPath(directories.top()));
     if (error != base::PLATFORM_FILE_ERROR_NOT_FOUND &&
         error != base::PLATFORM_FILE_OK)
       return error;
     directories.pop();
   }
-  return file_util->DeleteSingleDirectory(context, url);
+  return file_util->DeleteDirectory(context, url);
 }
 
 }  // namespace fileapi