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 CONTENT_PUBLIC_BROWSER_SESSION_STORAGE_NAMESPACE_H_
6#define CONTENT_PUBLIC_BROWSER_SESSION_STORAGE_NAMESPACE_H_
7
8#include <map>
9#include <string>
10
11#include "base/basictypes.h"
12#include "base/callback.h"
13#include "base/memory/ref_counted.h"
14
15namespace content {
16
17// This is a ref-counted class that represents a SessionStorageNamespace.
18// On destruction it ensures that the storage namespace is destroyed.
19class SessionStorageNamespace
20    : public base::RefCountedThreadSafe<SessionStorageNamespace> {
21 public:
22  // Returns the ID of the |SessionStorageNamespace|. The ID is unique among all
23  // SessionStorageNamespace objects, but not unique across browser runs.
24  virtual int64 id() const = 0;
25
26  // Returns the persistent ID for the |SessionStorageNamespace|. The ID is
27  // unique across browser runs.
28  virtual const std::string& persistent_id() const = 0;
29
30  // For marking that the sessionStorage will be needed or won't be needed by
31  // session restore.
32  virtual void SetShouldPersist(bool should_persist) = 0;
33
34  virtual bool should_persist() const = 0;
35
36  // SessionStorageNamespaces can be merged. These merges happen based on
37  // a transaction log of operations on the session storage namespace since
38  // this function has been called. Transaction logging will be restricted
39  // to the processes indicated.
40  virtual void AddTransactionLogProcessId(int process_id) = 0;
41
42  // When transaction logging for a process is no longer required, the log
43  // can be removed to save space.
44  virtual void RemoveTransactionLogProcessId(int process_id) = 0;
45
46  // Creates a new session storage namespace which is an alias of the current
47  // instance.
48  virtual SessionStorageNamespace* CreateAlias() = 0;
49
50  enum MergeResult {
51    MERGE_RESULT_NAMESPACE_NOT_FOUND,
52    MERGE_RESULT_NAMESPACE_NOT_ALIAS,
53    MERGE_RESULT_NOT_LOGGING,
54    MERGE_RESULT_NO_TRANSACTIONS,
55    MERGE_RESULT_TOO_MANY_TRANSACTIONS,
56    MERGE_RESULT_NOT_MERGEABLE,
57    MERGE_RESULT_MERGEABLE,
58    MERGE_RESULT_MAX_VALUE
59  };
60
61  typedef base::Callback<void(MergeResult)> MergeResultCallback;
62
63  // Determines whether the transaction log for the process specified can
64  // be merged into the other session storage namespace supplied.
65  // If actually_merge is set to true, the merge will actually be performed,
66  // if possible, and the result of the merge will be returned.
67  // If actually_merge is set to false, the result of whether a merge would be
68  // possible is returned.
69  virtual void Merge(bool actually_merge,
70                     int process_id,
71                     SessionStorageNamespace* other,
72                     const MergeResultCallback& callback) = 0;
73
74  // Indicates whether this SessionStorageNamespace is an alias of |other|,
75  // i.e. whether they point to the same underlying data.
76  virtual bool IsAliasOf(SessionStorageNamespace* other) = 0;
77
78 protected:
79  friend class base::RefCountedThreadSafe<SessionStorageNamespace>;
80  virtual ~SessionStorageNamespace() {}
81};
82
83// Used to store mappings of StoragePartition id to SessionStorageNamespace.
84typedef std::map<std::string, scoped_refptr<SessionStorageNamespace> >
85    SessionStorageNamespaceMap;
86
87}  // namespace content
88
89#endif  // CONTENT_PUBLIC_BROWSER_SESSION_STORAGE_NAMESPACE_H_
90