1// Copyright (c) 2010 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_SYNC_SESSIONS_ORDERED_COMMIT_SET_H_
6#define CHROME_BROWSER_SYNC_SESSIONS_ORDERED_COMMIT_SET_H_
7#pragma once
8
9#include <map>
10#include <set>
11#include <vector>
12
13#include "chrome/browser/sync/engine/model_safe_worker.h"
14#include "chrome/browser/sync/syncable/model_type.h"
15#include "chrome/browser/sync/syncable/syncable_id.h"
16
17namespace browser_sync {
18namespace sessions {
19
20// TODO(ncarter): This code is more generic than just Commit and can
21// be reused elsewhere (e.g. ChangeReorderBuffer do similar things).  Merge
22// all these implementations.
23class OrderedCommitSet {
24 public:
25  // A list of indices into the full list of commit ids such that:
26  // 1 - each element is an index belonging to a particular ModelSafeGroup.
27  // 2 - the vector is in sorted (smallest to largest) order.
28  // 3 - each element is a valid index for GetCommitItemAt.
29  // See GetCommitIdProjection for usage.
30  typedef std::vector<size_t> Projection;
31
32  // TODO(chron): Reserve space according to batch size?
33  explicit OrderedCommitSet(const browser_sync::ModelSafeRoutingInfo& routes);
34  ~OrderedCommitSet();
35
36  bool HaveCommitItem(const int64 metahandle) const {
37    return inserted_metahandles_.count(metahandle) > 0;
38  }
39
40  void AddCommitItem(const int64 metahandle, const syncable::Id& commit_id,
41                     syncable::ModelType type);
42
43  const std::vector<syncable::Id>& GetAllCommitIds() const {
44    return commit_ids_;
45  }
46
47  // Return the Id at index |position| in this OrderedCommitSet.  Note that
48  // the index uniquely identifies the same logical item in each of:
49  // 1) this OrderedCommitSet
50  // 2) the CommitRequest sent to the server
51  // 3) the list of EntryResponse objects in the CommitResponse.
52  // These together allow re-association of the pre-commit Id with the
53  // actual committed entry.
54  const syncable::Id& GetCommitIdAt(const size_t position) const {
55    return commit_ids_[position];
56  }
57
58  // Same as above, but for ModelType of the item.
59  syncable::ModelType GetModelTypeAt(const size_t position) const {
60    return types_[position];
61  }
62
63  // Get the projection of commit ids onto the space of commit ids
64  // belonging to |group|.  This is useful when you need to process a commit
65  // response one ModelSafeGroup at a time. See GetCommitIdAt for how the
66  // indices contained in the returned Projection can be used.
67  const Projection& GetCommitIdProjection(browser_sync::ModelSafeGroup group) {
68    return projections_[group];
69  }
70
71  int Size() const {
72    return commit_ids_.size();
73  }
74
75  // Returns true iff any of the commit ids added to this set have model type
76  // BOOKMARKS.
77  bool HasBookmarkCommitId() const;
78
79  void AppendReverse(const OrderedCommitSet& other);
80  void Truncate(size_t max_size);
81
82  void operator=(const OrderedCommitSet& other);
83 private:
84  // A set of CommitIdProjections associated with particular ModelSafeGroups.
85  typedef std::map<browser_sync::ModelSafeGroup, Projection> Projections;
86
87  // Helper container for return value of GetCommitItemAt.
88  struct CommitItem {
89    int64 meta;
90    syncable::Id id;
91    syncable::ModelType group;
92  };
93
94  CommitItem GetCommitItemAt(const int position) const;
95
96  // These lists are different views of the same items; e.g they are
97  // isomorphic.
98  std::set<int64> inserted_metahandles_;
99  std::vector<syncable::Id> commit_ids_;
100  std::vector<int64> metahandle_order_;
101  Projections projections_;
102
103  // We need this because of operations like AppendReverse that take ids from
104  // one OrderedCommitSet and insert into another -- we need to know the
105  // group for each ID so that the insertion can update the appropriate
106  // projection.  We could store it in commit_ids_, but sometimes we want
107  // to just return the vector of Ids, so this is more straightforward
108  // and shouldn't take up too much extra space since commit lists are small.
109  std::vector<syncable::ModelType> types_;
110
111  browser_sync::ModelSafeRoutingInfo routes_;
112};
113
114}  // namespace sessions
115}  // namespace browser_sync
116
117#endif  // CHROME_BROWSER_SYNC_SESSIONS_ORDERED_COMMIT_SET_H_
118
119