blob: b704ffb0a234977a6ea2fd612d5095de41e70c3e (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
|
// Copyright 2017 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.
#ifndef COMPONENTS_OFFLINE_ITEMS_COLLETION_CORE_THROTTLED_OFFLINE_CONTENT_PROVIDER_H_
#define COMPONENTS_OFFLINE_ITEMS_COLLETION_CORE_THROTTLED_OFFLINE_CONTENT_PROVIDER_H_
#include <map>
#include "base/memory/weak_ptr.h"
#include "base/observer_list.h"
#include "components/offline_items_collection/core/offline_content_provider.h"
namespace base {
class TimeDelta;
} // namespace base
namespace offline_items_collection {
// A simple wrapper around an OfflineContentProvider that throttles
// OfflineContentProvider::Observer::OnItemUpdated() calls to all registered
// observers. This class will coalesce updates to an item with an equal
// ContentId.
class ThrottledOfflineContentProvider
: public OfflineContentProvider,
public OfflineContentProvider::Observer {
public:
explicit ThrottledOfflineContentProvider(OfflineContentProvider* provider);
ThrottledOfflineContentProvider(const base::TimeDelta& delay_between_updates,
OfflineContentProvider* provider);
~ThrottledOfflineContentProvider() override;
// OfflineContentProvider implementation.
bool AreItemsAvailable() override;
void OpenItem(const ContentId& id) override;
void RemoveItem(const ContentId& id) override;
void CancelDownload(const ContentId& id) override;
void PauseDownload(const ContentId& id) override;
void ResumeDownload(const ContentId& id) override;
// Because this class queues updates, a call to Observer::OnItemUpdated might
// get triggered with the same contents as returned by these getter methods in
// the future.
const OfflineItem* GetItemById(const ContentId& id) override;
OfflineItemList GetAllItems() override;
void AddObserver(OfflineContentProvider::Observer* observer) override;
void RemoveObserver(OfflineContentProvider::Observer* observer) override;
private:
// OfflineContentProvider::Observer implementation.
void OnItemsAvailable(OfflineContentProvider* provider) override;
void OnItemsAdded(const OfflineItemList& items) override;
void OnItemRemoved(const ContentId& id) override;
void OnItemUpdated(const OfflineItem& item) override;
// Used to notify |observer| that the underying OfflineContentProvider has
// called OfflineContentProvider::Observer::OnItemsAvailable().
void NotifyItemsAvailable(OfflineContentProvider::Observer* observer);
// Checks if |item| already has an update pending. If so, replaces the
// content of the update with |item|.
void UpdateItemIfPresent(const OfflineItem& item);
// Flushes all pending updates to the observers.
void FlushUpdates();
const base::TimeDelta delay_between_updates_;
bool update_queued_;
OfflineContentProvider* const wrapped_provider_;
base::ObserverList<OfflineContentProvider::Observer> observers_;
typedef std::map<ContentId, OfflineItem> OfflineItemMap;
OfflineItemMap updates_;
base::WeakPtrFactory<ThrottledOfflineContentProvider> weak_ptr_factory_;
DISALLOW_COPY_AND_ASSIGN(ThrottledOfflineContentProvider);
};
} // namespace offline_items_collection
#endif // COMPONENTS_OFFLINE_ITEMS_COLLETION_CORE_THROTTLED_OFFLINE_CONTENT_PROVIDER_H_
|
