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

webkit/blob/scoped_file.cc

Index: webkit/blob/scoped_file.cc
diff --git a/webkit/blob/scoped_file.cc b/webkit/blob/scoped_file.cc
new file mode 100644
index 0000000000000000000000000000000000000000..7543758babaf9454b828434804f08e85d794b543
--- /dev/null
+++ b/webkit/blob/scoped_file.cc
@@ -0,0 +1,77 @@
+// 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()
+    : scope_out_policy_(DONT_DELETE_ON_SCOPE_OUT) {
+}
+
+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) {
+  DCHECK(path.empty() || policy != DELETE_ON_SCOPE_OUT || file_task_runner)
+      << "path:" << path.value()
+      << " policy:" << policy
+      << " runner:" << file_task_runner;
+}
+
+ScopedFile::ScopedFile(RValue other) {
+  MoveFrom(*other.object);
+}
+
+ScopedFile::~ScopedFile() {
+  Reset();
+}
+
+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();
+  scope_out_callbacks_.clear();
+  return path;
+}
+
+void ScopedFile::Reset() {
+  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_));
+  }
+
+  if (scope_out_policy_ == DELETE_ON_SCOPE_OUT) {
+    base::FileUtilProxy::Delete(file_task_runner_, path_, false /* recursive */,
+                                base::FileUtilProxy::StatusCallback());
+  }

[michaeln, 2013/04/24 19:18:04]

maybe clear path_ and callbacks_ here too after doing the work

[kinuko, 2013/04/25 02:42:00]

Done.

+}
+
+void ScopedFile::MoveFrom(ScopedFile& other) {

[michaeln, 2013/04/24 19:18:04]

What if 'this' instance is populated with a policy, path, and callbacks? When
swapping callbacks below the 'other' will assume ownership of them and run them
when it scopes out.

might want to clear this.scope_out_callbacks_ first, or would this.Reset() first
be more semantically correct?

[kinuko, 2013/04/25 02:42:00]

Ah... sounds correct. Added Reset() at the beginning.

+  scope_out_policy_ = other.scope_out_policy_;
+  scope_out_callbacks_.swap(other.scope_out_callbacks_);
+  file_task_runner_ = other.file_task_runner_;
+  path_ = other.Release();
+}
+
+}  // namespace webkit_blob