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 CHROME_BROWSER_DOWNLOAD_DOWNLOAD_HISTORY_H_
6#define CHROME_BROWSER_DOWNLOAD_DOWNLOAD_HISTORY_H_
7
8#include <set>
9#include <vector>
10
11#include "base/basictypes.h"
12#include "base/callback.h"
13#include "base/memory/weak_ptr.h"
14#include "base/observer_list.h"
15#include "chrome/browser/download/all_download_item_notifier.h"
16#include "chrome/browser/history/history_service.h"
17#include "content/public/browser/download_item.h"
18#include "content/public/browser/download_manager.h"
19
20namespace history {
21struct DownloadRow;
22}  // namespace history
23
24// Observes a single DownloadManager and all its DownloadItems, keeping the
25// DownloadDatabase up to date.
26class DownloadHistory : public AllDownloadItemNotifier::Observer {
27 public:
28  typedef std::set<uint32> IdSet;
29
30  // Caller must guarantee that HistoryService outlives HistoryAdapter.
31  class HistoryAdapter {
32   public:
33    explicit HistoryAdapter(HistoryService* history);
34    virtual ~HistoryAdapter();
35
36    virtual void QueryDownloads(
37        const HistoryService::DownloadQueryCallback& callback);
38
39    virtual void CreateDownload(
40        const history::DownloadRow& info,
41        const HistoryService::DownloadCreateCallback& callback);
42
43    virtual void UpdateDownload(const history::DownloadRow& data);
44
45    virtual void RemoveDownloads(const std::set<uint32>& ids);
46
47   private:
48    HistoryService* history_;
49    DISALLOW_COPY_AND_ASSIGN(HistoryAdapter);
50  };
51
52  class Observer {
53   public:
54    Observer();
55    virtual ~Observer();
56
57    // Fires when a download is added to or updated in the database, just after
58    // the task is posted to the history thread.
59    virtual void OnDownloadStored(content::DownloadItem* item,
60                                  const history::DownloadRow& info) {}
61
62    // Fires when RemoveDownloads messages are sent to the DB thread.
63    virtual void OnDownloadsRemoved(const IdSet& ids) {}
64
65    // Fires when the DownloadHistory is being destroyed so that implementors
66    // can RemoveObserver() and nullify their DownloadHistory*s.
67    virtual void OnDownloadHistoryDestroyed() {}
68  };
69
70  // Returns true if the item is persisted.
71  static bool IsPersisted(content::DownloadItem* item);
72
73  // Neither |manager| nor |history| may be NULL.
74  // DownloadService creates DownloadHistory some time after DownloadManager is
75  // created and destroys DownloadHistory as DownloadManager is shutting down.
76  DownloadHistory(
77      content::DownloadManager* manager,
78      scoped_ptr<HistoryAdapter> history);
79
80  virtual ~DownloadHistory();
81
82  void AddObserver(Observer* observer);
83  void RemoveObserver(Observer* observer);
84
85 private:
86  typedef std::set<content::DownloadItem*> ItemSet;
87
88  // Callback from |history_| containing all entries in the downloads database
89  // table.
90  void QueryCallback(
91      scoped_ptr<std::vector<history::DownloadRow> > infos);
92
93  // May add |item| to |history_|.
94  void MaybeAddToHistory(content::DownloadItem* item);
95
96  // Callback from |history_| when an item was successfully inserted into the
97  // database.
98  void ItemAdded(uint32 id, bool success);
99
100  // AllDownloadItemNotifier::Observer
101  virtual void OnDownloadCreated(
102      content::DownloadManager* manager, content::DownloadItem* item) OVERRIDE;
103  virtual void OnDownloadUpdated(
104      content::DownloadManager* manager, content::DownloadItem* item) OVERRIDE;
105  virtual void OnDownloadOpened(
106      content::DownloadManager* manager, content::DownloadItem* item) OVERRIDE;
107  virtual void OnDownloadRemoved(
108      content::DownloadManager* manager, content::DownloadItem* item) OVERRIDE;
109
110  // Schedule a record to be removed from |history_| the next time
111  // RemoveDownloadsBatch() runs. Schedule RemoveDownloadsBatch() to be run soon
112  // if it isn't already scheduled.
113  void ScheduleRemoveDownload(uint32 download_id);
114
115  // Removes all |removing_ids_| from |history_|.
116  void RemoveDownloadsBatch();
117
118  AllDownloadItemNotifier notifier_;
119
120  scoped_ptr<HistoryAdapter> history_;
121
122  // Identifier of the item being created in QueryCallback(), matched up with
123  // created items in OnDownloadCreated() so that the item is not re-added to
124  // the database.
125  uint32 loading_id_;
126
127  // Identifiers of items that are scheduled for removal from history, to
128  // facilitate batching removals together for database efficiency.
129  IdSet removing_ids_;
130
131  // |GetId()|s of items that were removed while they were being added, so that
132  // they can be removed when the database finishes adding them.
133  // TODO(benjhayden) Can this be removed now that it doesn't need to wait for
134  // the db_handle, and can rely on PostTask sequentiality?
135  IdSet removed_while_adding_;
136
137  // Count the number of items in the history for UMA.
138  int64 history_size_;
139
140  ObserverList<Observer> observers_;
141
142  base::WeakPtrFactory<DownloadHistory> weak_ptr_factory_;
143
144  DISALLOW_COPY_AND_ASSIGN(DownloadHistory);
145};
146
147#endif  // CHROME_BROWSER_DOWNLOAD_DOWNLOAD_HISTORY_H_
148