sync/sessions/ordered_commit_set.h

   1 // Copyright 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 SYNC_SESSIONS_ORDERED_COMMIT_SET_H_
   6 #define SYNC_SESSIONS_ORDERED_COMMIT_SET_H_
   7
   8 #include <map>
   9 #include <set>
  10 #include <vector>
  11
  12 #include "sync/base/sync_export.h"
  13 #include "sync/internal_api/public/base/model_type.h"
  14 #include "sync/internal_api/public/engine/model_safe_worker.h"
  15 #include "sync/syncable/syncable_id.h"
  16
  17 namespace syncer {
  18 namespace 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.
  23 class SYNC_EXPORT_PRIVATE 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 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                      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   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(
  68       ModelSafeGroup group) const;
  69
  70   size_t Size() const {
  71     return commit_ids_.size();
  72   }
  73
  74   bool Empty() const {
  75     return Size() == 0;
  76   }
  77
  78   // Returns true iff any of the commit ids added to this set have model type
  79   // BOOKMARKS.
  80   bool HasBookmarkCommitId() const;
  81
  82   void Append(const OrderedCommitSet& other);
  83   void AppendReverse(const OrderedCommitSet& other);
  84   void Truncate(size_t max_size);
  85
  86   // Removes all entries from this set.
  87   void Clear();
  88
  89   void operator=(const OrderedCommitSet& other);
  90  private:
  91   // A set of CommitIdProjections associated with particular ModelSafeGroups.
  92   typedef std::map<ModelSafeGroup, Projection> Projections;
  93
  94   // Helper container for return value of GetCommitItemAt.
  95   struct CommitItem {
  96     int64 meta;
  97     syncable::Id id;
  98     ModelType group;
  99   };
 100
 101   CommitItem GetCommitItemAt(const size_t position) const;
 102
 103   // These lists are different views of the same items; e.g they are
 104   // isomorphic.
 105   std::set<int64> inserted_metahandles_;
 106   std::vector<syncable::Id> commit_ids_;
 107   std::vector<int64> metahandle_order_;
 108   Projections projections_;
 109
 110   // We need this because of operations like AppendReverse that take ids from
 111   // one OrderedCommitSet and insert into another -- we need to know the
 112   // group for each ID so that the insertion can update the appropriate
 113   // projection.  We could store it in commit_ids_, but sometimes we want
 114   // to just return the vector of Ids, so this is more straightforward
 115   // and shouldn't take up too much extra space since commit lists are small.
 116   std::vector<ModelType> types_;
 117
 118   ModelSafeRoutingInfo routes_;
 119 };
 120
 121 }  // namespace sessions
 122 }  // namespace syncer
 123
 124 #endif  // SYNC_SESSIONS_ORDERED_COMMIT_SET_H_
 125