Add ScopedFile class which supports scope-out deletion and/or callbacks

webkit/blob/scoped_file.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/blob/scoped_file.h"
+
+#include "base/bind.h"
+#include "base/callback.h"
+#include "base/files/file_util_proxy.h"
+#include "base/location.h"
+#include "base/message_loop/message_loop_proxy.h"
+#include "base/task_runner.h"
+
+namespace webkit_blob {
+
+ScopedFile::ScopedFile() {
+}
+
+ScopedFile::ScopedFile(
+    const base::FilePath& path, ScopeOutPolicy policy,
+    base::TaskRunner* file_task_runner)
+    : path_(path),
+      scope_out_policy_(policy),
+      file_task_runner_(file_task_runner) {
+}
+
+ScopedFile::ScopedFile(RValue other) {
+  Swap(*other.object);
+}
+
+ScopedFile::~ScopedFile() {
+  ScopeOut();
+}
+
+void ScopedFile::AddScopeOutCallback(
+    const ScopeOutCallback& callback,
+    base::TaskRunner* callback_runner) {
+  if (!callback_runner)
+    callback_runner = base::MessageLoopProxy::current();
+  scope_out_callbacks_.push_back(std::make_pair(callback, callback_runner));
+}
+
+base::FilePath ScopedFile::Release() {
+  base::FilePath path = path_;
+  path_.clear();
+  return path;
+}
+
+void ScopedFile::Swap(ScopedFile& other) {
+  path_ = other.Release();
+  scope_out_policy_ = other.scope_out_policy_;
+  scope_out_callbacks_.swap(other.scope_out_callbacks_);
+  file_task_runner_ = other.file_task_runner_;
+}
+
+void ScopedFile::ScopeOut() {
+  if (path_.empty())
+    return;
+
+  for (ScopeOutCallbackList::iterator iter = scope_out_callbacks_.begin();
+       iter != scope_out_callbacks_.end(); ++iter) {
+    iter->second->PostTask(FROM_HERE, base::Bind(iter->first, path_));

[michaeln, 2013/04/22 21:07:03]

There's a subtle behavior change here (not sure it matters, just pointing it
out), the finalreleasecallbacks are now deferred where as before they happened
prior to return from ~ShareableFileRef().

[kinuko, 2013/04/23 06:31:29]

Right... hope this has no regression (otherwise we'll fix!)

+  }
+
+  if (scope_out_policy_ == DELETE_ON_SCOPE_OUT) {
+    base::FileUtilProxy::Delete(
+        file_task_runner_, path_, false /* recursive */,
+        base::FileUtilProxy::StatusCallback());
+  }
+}
+
+}  // namespace webkit_blob