1// Copyright (c) 2012 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef STORAGE_COMMON_BLOB_SHAREABLE_FILE_REFERENCE_H_
6#define STORAGE_COMMON_BLOB_SHAREABLE_FILE_REFERENCE_H_
7
8#include <vector>
9
10#include "storage/common/blob/scoped_file.h"
11
12namespace storage {
13
14// ShareableFileReference allows consumers to share FileReference for the
15// same path if it already exists in its internal map.
16// This class is non-thread-safe and all methods must be called on a single
17// thread.
18class STORAGE_COMMON_EXPORT ShareableFileReference
19    : public base::RefCounted<ShareableFileReference> {
20 public:
21  typedef ScopedFile::ScopeOutCallback FinalReleaseCallback;
22
23  enum FinalReleasePolicy {
24    DELETE_ON_FINAL_RELEASE = ScopedFile::DELETE_ON_SCOPE_OUT,
25    DONT_DELETE_ON_FINAL_RELEASE = ScopedFile::DONT_DELETE_ON_SCOPE_OUT,
26  };
27
28  // Returns a ShareableFileReference for the given path, if no reference
29  // for this path exists returns NULL.
30  static scoped_refptr<ShareableFileReference> Get(const base::FilePath& path);
31
32  // Returns a ShareableFileReference for the given path, creating a new
33  // reference if none yet exists. If there's a pre-existing reference for
34  // the path, the policy parameter of this method is ignored.
35  static scoped_refptr<ShareableFileReference> GetOrCreate(
36      const base::FilePath& path,
37      FinalReleasePolicy policy,
38      base::TaskRunner* file_task_runner);
39
40  // Returns a ShareableFileReference for the given path of the |scoped_file|,
41  // creating a new reference if none yet exists. The ownership of |scoped_file|
42  // is passed to this reference.
43  // If there's a pre-existing reference for the path, the scope out policy
44  // and scope-out-callbacks of the given |scoped_file| is ignored.
45  // If the given scoped_file has an empty path (e.g. maybe already
46  // released) this returns NULL reference.
47  //
48  // TODO(kinuko): Make sure if this behavior is ok, we could alternatively
49  // merge callbacks to the existing one.
50  static scoped_refptr<ShareableFileReference> GetOrCreate(
51      ScopedFile scoped_file);
52
53  // The full file path.
54  const base::FilePath& path() const { return scoped_file_.path(); }
55
56  // The |callback| is fired when the final reference of this instance
57  // is released. If release policy is DELETE_ON_FINAL_RELEASE the
58  // callback task(s) is/are posted before the deletion is scheduled.
59  void AddFinalReleaseCallback(const FinalReleaseCallback& callback);
60
61 private:
62  friend class base::RefCounted<ShareableFileReference>;
63
64  ShareableFileReference(ScopedFile scoped_file);
65  ~ShareableFileReference();
66
67  ScopedFile scoped_file_;
68
69  DISALLOW_COPY_AND_ASSIGN(ShareableFileReference);
70};
71
72}  // namespace storage
73
74#endif  // STORAGE_COMMON_BLOB_SHAREABLE_FILE_REFERENCE_H_
75