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

webkit/fileapi/cross_operation_delegate.cc

+// Copyright (c) 2013 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/cross_operation_delegate.h"
+
+#include "base/bind.h"
+#include "webkit/blob/shareable_file_reference.h"
+#include "webkit/fileapi/file_system_context.h"
+#include "webkit/fileapi/file_system_operation_context.h"
+#include "webkit/fileapi/local_file_system_operation.h"
+
+namespace fileapi {
+
+CrossOperationDelegate::CrossOperationDelegate(
+    LocalFileSystemOperation* original_operation,
+    const FileSystemURL& src_root,
+    const FileSystemURL& dest_root,
+    OperationType operation_type,
+    const StatusCallback& callback)
+    : RecursiveOperationDelegate(original_operation),
+      src_root_(src_root),
+      dest_root_(dest_root),
+      operation_type_(operation_type),
+      callback_(callback),
+      src_root_operation_(NULL) {
+  same_file_system_ =
+      src_root_.origin() == dest_root_.origin() &&
+      src_root_.type() == dest_root_.type();
+}
+
+CrossOperationDelegate::~CrossOperationDelegate() {
+  if (src_root_operation_)
+    delete src_root_operation_;
+}
+
+void CrossOperationDelegate::Run() {
+  // Not supported; this should never be called.
+  NOTREACHED();
+}
+
+void CrossOperationDelegate::RunRecursively() {
+  // Perform light-weight checks first.
+
+  // It is an error to try to copy/move an entry into its child.
+  if (same_file_system_ && src_root_.path().IsParent(dest_root_.path())) {
+    callback_.Run(base::PLATFORM_FILE_ERROR_INVALID_OPERATION);
+    return;
+  }
+
+  // It is an error to copy/move an entry into the same path.
+  if (same_file_system_ && src_root_.path() == dest_root_.path()) {
+    callback_.Run(base::PLATFORM_FILE_ERROR_EXISTS);
+    return;
+  }
+
+  // Initialize the src_root_operation_ for the src root URL.
+  DCHECK(!src_root_operation_);
+  if (!same_file_system_) {
+    base::PlatformFileError error = base::PLATFORM_FILE_OK;
+    FileSystemOperation* operation = file_system_context()->
+        CreateFileSystemOperation(src_root_, &error);
+    if (error != base::PLATFORM_FILE_OK) {
+      DCHECK(!operation);
+      callback_.Run(error);
+      return;
+    }
+    src_root_operation_ = operation->AsLocalFileSystemOperation();
+    DCHECK(src_root_operation_);
+  }
+
+  // First try to copy/move it as a file.
+  CopyOrMoveFile(src_root_, dest_root_,
+                 base::Bind(&CrossOperationDelegate::DidTryCopyOrMoveFile,
+                            AsWeakPtr()));
+}
+
+void CrossOperationDelegate::ProcessFile(const FileSystemURL& src_url,
+                                         const StatusCallback& callback) {
+  CopyOrMoveFile(src_url, CreateDestURL(src_url), callback);
+}
+
+void CrossOperationDelegate::ProcessDirectory(const FileSystemURL& src_url,
+                                              const StatusCallback& callback) {
+  FileSystemURL dest_url = CreateDestURL(src_url);
+  LocalFileSystemOperation* dest_operation = NewDestOperation(dest_url);
+  if (!dest_operation) {
+    return;
+  }
+
+  // If operation_type == Move we may need to record directories and
+  // restore directory timestamps in the end, though it may have
+  // negative performance impact.
+  // See http://crbug.com/171284 for more details.
+  dest_operation->CreateDirectory(
+      dest_url, false /* exclusive */, false /* recursive */, callback);
+}
+
+void CrossOperationDelegate::DidTryCopyOrMoveFile(
+    base::PlatformFileError error) {
+  if (error == base::PLATFORM_FILE_OK ||
+      error != base::PLATFORM_FILE_ERROR_NOT_A_FILE) {
+    callback_.Run(error);
+    return;
+  }
+
+  // The src_root_ looks to be a directory.
+  // Try removing the dest_root_ to see if it exists and/or it is an
+  // empty directory.
+  LocalFileSystemOperation* dest_operation = NewDestOperation(dest_root_);
+  if (!dest_operation)
+    return;
+  dest_operation->RemoveDirectory(
+      dest_root_, base::Bind(&CrossOperationDelegate::DidTryRemoveDestRoot,
+                             AsWeakPtr()));
+}
+
+void CrossOperationDelegate::DidTryRemoveDestRoot(
+    base::PlatformFileError error) {
+  if (error == base::PLATFORM_FILE_ERROR_NOT_A_DIRECTORY) {
+    callback_.Run(base::PLATFORM_FILE_ERROR_INVALID_OPERATION);
+    return;
+  }
+  if (error != base::PLATFORM_FILE_OK &&
+      error != base::PLATFORM_FILE_ERROR_NOT_FOUND) {
+    callback_.Run(error);
+    return;
+  }
+
+  // Start to process the source directory recursively.
+  StartRecursiveOperation(
+      src_root_, base::Bind(&CrossOperationDelegate::DidFinishCopy,
+                            AsWeakPtr(), src_root_, callback_));
+}
+
+void CrossOperationDelegate::CopyOrMoveFile(
+    const FileSystemURL& src,
+    const FileSystemURL& dest,
+    const StatusCallback& callback) {
+  LocalFileSystemOperation* src_operation = NewSourceOperation(src);
+  if (!src_operation)
+    return;
+
+  // Same filesystem case.
+  if (same_file_system_) {

[ericu, 2013/01/23 19:27:23]

I'm getting a bit lost in all the redirection.  If we're doing a move of a local
directory, to the same filesystem, possibly overwriting an empty directory, will
we still do a fast local move, or will we recursively copy and then remove the
original?

+    if (operation_type_ == OPERATION_MOVE)
+      src_operation->MoveLocalFile(src, dest, callback);
+    else
+      src_operation->CopyLocalFile(src, dest, callback);
+    return;
+  }
+
+  // Cross filesystem case.
+  // Performs CreateSnapshotFile, CopyInForeignFile and then calls
+  // copy_callback which removes the source file if operation_type == MOVE.
+  StatusCallback copy_callback =
+      base::Bind(&CrossOperationDelegate::DidFinishCopy, AsWeakPtr(),
+                 src, callback);
+  src_operation->CreateSnapshotFile(
+      src, base::Bind(&CrossOperationDelegate::DidCreateSnapshot, AsWeakPtr(),
+                      dest, copy_callback));
+}
+
+void CrossOperationDelegate::DidCreateSnapshot(
+    const FileSystemURL& dest,
+    const StatusCallback& callback,
+    base::PlatformFileError error,
+    const base::PlatformFileInfo& file_info,
+    const FilePath& platform_path,
+    const scoped_refptr<webkit_blob::ShareableFileReference>& file_ref) {
+  if (error != base::PLATFORM_FILE_OK) {
+    callback.Run(error);
+    return;
+  }
+  current_file_ref_ = file_ref;
+
+  // For now we assume CreateSnapshotFile always return a valid local file path.
+  // TODO(kinuko): Otherwise create a FileStreamReader to perform a copy/move.
+  DCHECK(!platform_path.empty());
+
+  LocalFileSystemOperation* dest_operation = NewDestOperation(dest);
+  if (!dest_operation)
+    return;
+  dest_operation->CopyInForeignFile(platform_path, dest, callback);
+}
+
+void CrossOperationDelegate::DidFinishCopy(
+    const FileSystemURL& src,
+    const StatusCallback& callback,
+    base::PlatformFileError error) {
+  if (error != base::PLATFORM_FILE_OK ||
+      operation_type_ == OPERATION_COPY) {
+    callback.Run(error);
+    return;
+  }
+
+  DCHECK_EQ(OPERATION_MOVE, operation_type_);
+
+  // Remove the source for finalizing move oepration.

[ericu, 2013/01/23 19:27:23]

typo: operation

+  LocalFileSystemOperation* src_operation = NewSourceOperation(src);
+  if (!src_operation)
+    return;
+  src_operation->Remove(
+      src_root_, true /* recursive */,
+      base::Bind(&CrossOperationDelegate::DidRemoveSourceForMove,
+                 AsWeakPtr(), callback));
+}
+
+void CrossOperationDelegate::DidRemoveSourceForMove(
+    const StatusCallback& callback,
+    base::PlatformFileError error) {
+  if (error == base::PLATFORM_FILE_ERROR_NOT_FOUND)
+    error = base::PLATFORM_FILE_OK;
+  callback.Run(error);
+}
+
+FileSystemURL CrossOperationDelegate::CreateDestURL(
+    const FileSystemURL& src_url) const {
+  DCHECK_EQ(src_root_.type(), src_url.type());
+  DCHECK_EQ(src_root_.origin(), src_url.origin());
+
+  FilePath path = dest_root_.path();
+  src_root_.path().AppendRelativePath(src_url.path(), &path);
+  return dest_root_.WithPath(path);
+}
+
+LocalFileSystemOperation* CrossOperationDelegate::NewDestOperation(
+    const FileSystemURL& url) {
+  base::PlatformFileError error = base::PLATFORM_FILE_OK;
+  LocalFileSystemOperation* operation =
+      RecursiveOperationDelegate::NewOperation(url, &error);
+  if (!operation) {
+    DCHECK_NE(base::PLATFORM_FILE_OK, error);
+    callback_.Run(error);
+    return NULL;
+  }
+  return operation;
+}
+
+LocalFileSystemOperation* CrossOperationDelegate::NewSourceOperation(
+    const FileSystemURL& url) {
+  if (same_file_system_)
+    return NewDestOperation(url);
+
+  base::PlatformFileError error = base::PLATFORM_FILE_OK;
+  FileSystemOperation* operation = file_system_context()->
+      CreateFileSystemOperation(url, &error);
+  if (!operation) {
+    DCHECK_NE(base::PLATFORM_FILE_OK, error);
+    callback_.Run(error);
+    return NULL;
+  }
+  LocalFileSystemOperation* local_operation =
+      operation->AsLocalFileSystemOperation();
+  DCHECK(local_operation);
+  DCHECK(src_root_operation_);
+
+  // Let the new operation inherit from the root operation.
+  local_operation->set_overriding_operation_context(
+      src_root_operation_->operation_context());
+  return local_operation;
+}
+
+}  // namespace fileapi