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

webkit/fileapi/recursive_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/recursive_operation_delegate.h"
+
+#include "base/bind.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 {
+
+RecursiveOperationDelegate::RecursiveOperationDelegate(
+    LocalFileSystemOperation* original_operation)
+    : original_operation_(original_operation),
+      inflight_operations_(0) {
+}
+
+RecursiveOperationDelegate::~RecursiveOperationDelegate() {}
+
+void RecursiveOperationDelegate::StartRecursiveOperation(
+    const FileSystemURL& root,
+    const StatusCallback& callback) {
+  callback_ = callback;
+  pending_directories_.push(root);
+  ProcessNextDirectory(base::PLATFORM_FILE_OK);
+}
+
+LocalFileSystemOperation* RecursiveOperationDelegate::NewOperation(
+    const FileSystemURL& url,
+    base::PlatformFileError* error_out) {
+  base::PlatformFileError error = base::PLATFORM_FILE_OK;
+  FileSystemOperation* operation = original_operation_->file_system_context()->
+      CreateFileSystemOperation(url, &error);
+  if (error != base::PLATFORM_FILE_OK) {
+    if (error_out)
+      *error_out = error;
+    return NULL;
+  }
+  LocalFileSystemOperation* local_operation =
+      operation->AsLocalFileSystemOperation();
+  DCHECK(local_operation);
+
+  // Let the new operation inherit from the original operation.
+  local_operation->set_overriding_operation_context(
+      original_operation_->operation_context());
+  if (error_out)
+    *error_out = base::PLATFORM_FILE_OK;
+  return local_operation;
+}
+
+FileSystemContext* RecursiveOperationDelegate::file_system_context() {
+  return original_operation_->file_system_context();
+}
+
+void RecursiveOperationDelegate::ProcessNextDirectory(
+    base::PlatformFileError error) {
+  if (error != base::PLATFORM_FILE_OK) {
+    callback_.Run(error);
+    return;
+  }
+  if (inflight_operations_ > 0)
+    return;
+  if (pending_directories_.empty()) {
+    callback_.Run(error);
+    return;
+  }
+  FileSystemURL url = pending_directories_.front();
+  pending_directories_.pop();
+  LocalFileSystemOperation* operation = NewOperation(url, &error);
+  if (!operation) {
+    callback_.Run(error);
+    return;
+  }
+  inflight_operations_++;
+  ProcessDirectory(
+      url, base::Bind(&RecursiveOperationDelegate::DidProcessDirectory,
+                      AsWeakPtr(), url));
+}
+
+void RecursiveOperationDelegate::DidProcessFile(base::PlatformFileError error) {
+  inflight_operations_--;
+  DCHECK_GE(inflight_operations_, 0);
+  ProcessNextDirectory(error);
+}
+
+void RecursiveOperationDelegate::DidProcessDirectory(
+    const FileSystemURL& url,
+    base::PlatformFileError error) {
+  if (error != base::PLATFORM_FILE_OK) {
+    callback_.Run(error);
+    return;
+  }
+  LocalFileSystemOperation* operation = NewOperation(url, &error);
+  if (!operation) {
+    callback_.Run(error);
+    return;
+  }
+  operation->ReadDirectory(
+      url, base::Bind(&RecursiveOperationDelegate::DidReadDirectory,
+                      AsWeakPtr(), url));
+}
+
+void RecursiveOperationDelegate::DidReadDirectory(
+    const FileSystemURL& parent,
+    base::PlatformFileError error,
+    const FileEntryList& entries,
+    bool has_more) {
+  if (error != base::PLATFORM_FILE_OK) {
+    if (error == base::PLATFORM_FILE_ERROR_NOT_A_DIRECTORY) {
+      // The given path may have been a file, so try RemoveFile now.
+      ProcessFile(parent,
+                  base::Bind(&RecursiveOperationDelegate::DidTryProcessFile,
+                             AsWeakPtr(), error));
+      return;
+    }
+    callback_.Run(error);
+    return;
+  }
+  for (size_t i = 0; i < entries.size(); i++) {
+    FileSystemURL url = parent.WithPath(parent.path().Append(entries[i].name));
+    if (entries[i].is_directory) {
+      pending_directories_.push(url);
+      continue;
+    }
+    inflight_operations_++;
+    ProcessFile(url, base::Bind(&RecursiveOperationDelegate::DidProcessFile,
+                                AsWeakPtr()));
+  }
+  if (has_more)
+    return;
+
+  inflight_operations_--;
+  DCHECK_GE(inflight_operations_, 0);
+  ProcessNextDirectory(base::PLATFORM_FILE_OK);
+}
+
+void RecursiveOperationDelegate::DidTryProcessFile(
+    base::PlatformFileError previous_error,
+    base::PlatformFileError error) {
+  if (error == base::PLATFORM_FILE_ERROR_NOT_A_FILE) {
+    // It wasn't a file either; returns with the previous error.
+    callback_.Run(previous_error);
+    return;
+  }
+  DidProcessFile(error);
+}
+
+}  // namespace fileapi