sync: Loop committing items without downloading updates

sync/sessions/ordered_commit_set.h

 // Copyright (c) 2012 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 SYNC_SESSIONS_ORDERED_COMMIT_SET_H_
 #define SYNC_SESSIONS_ORDERED_COMMIT_SET_H_
 #pragma once
 
 #include <map>
 #include <set>
@@ skipping 46 matching lines @@
 
   // Same as above, but for ModelType of the item.
   syncable::ModelType GetModelTypeAt(const size_t position) const {
     return types_[position];
   }
 
   // Get the projection of commit ids onto the space of commit ids
   // belonging to |group|.  This is useful when you need to process a commit
   // response one ModelSafeGroup at a time. See GetCommitIdAt for how the
   // indices contained in the returned Projection can be used.
-  const Projection& GetCommitIdProjection(browser_sync::ModelSafeGroup group) {
-    return projections_[group];
+  const Projection& GetCommitIdProjection(
+      browser_sync::ModelSafeGroup group) const {
+    Projections::const_iterator i = projections_.find(group);

[rlarocque, 2012/04/13 02:02:22]

Because operator[]() is non-const.

+    DCHECK(i != projections_.end());
+    return i->second;
   }
 
-  int Size() const {
+  size_t Size() const {
     return commit_ids_.size();
   }
 
+  bool Empty() const {
+    return Size() == 0;
+  }
+
   // Returns true iff any of the commit ids added to this set have model type
   // BOOKMARKS.
   bool HasBookmarkCommitId() const;
 
   void Append(const OrderedCommitSet& other);
   void AppendReverse(const OrderedCommitSet& other);
   void Truncate(size_t max_size);
 
   void operator=(const OrderedCommitSet& other);
  private:
   // A set of CommitIdProjections associated with particular ModelSafeGroups.
   typedef std::map<browser_sync::ModelSafeGroup, Projection> Projections;
 
   // Helper container for return value of GetCommitItemAt.
   struct CommitItem {
     int64 meta;
     syncable::Id id;
     syncable::ModelType group;
   };
 
-  CommitItem GetCommitItemAt(const int position) const;
+  CommitItem GetCommitItemAt(const size_t position) const;
 
   // These lists are different views of the same items; e.g they are
   // isomorphic.
   std::set<int64> inserted_metahandles_;
   std::vector<syncable::Id> commit_ids_;
   std::vector<int64> metahandle_order_;
   Projections projections_;
 
   // We need this because of operations like AppendReverse that take ids from
   // one OrderedCommitSet and insert into another -- we need to know the
   // group for each ID so that the insertion can update the appropriate
   // projection.  We could store it in commit_ids_, but sometimes we want
   // to just return the vector of Ids, so this is more straightforward
   // and shouldn't take up too much extra space since commit lists are small.
   std::vector<syncable::ModelType> types_;
 
   browser_sync::ModelSafeRoutingInfo routes_;
 };
 
 }  // namespace sessions
 }  // namespace browser_sync
 
 #endif  // SYNC_SESSIONS_ORDERED_COMMIT_SET_H_