content/public/browser/session_storage_namespace.h

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