sync/syncable/parent_child_index.h

   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 SYNC_SYNCABLE_PARENT_CHILD_INDEX
   6 #define SYNC_SYNCABLE_PARENT_CHILD_INDEX
   7
   8 #include <map>
   9 #include <set>
  10
  11 #include "base/basictypes.h"
  12 #include "sync/base/sync_export.h"
  13
  14 namespace syncer {
  15 namespace syncable {
  16
  17 struct EntryKernel;
  18 class Id;
  19 class ParentChildIndex;
  20
  21 // A node ordering function.
  22 struct SYNC_EXPORT_PRIVATE ChildComparator {
  23   bool operator() (const EntryKernel* a, const EntryKernel* b) const;
  24 };
  25
  26 // An ordered set of nodes.
  27 typedef std::set<EntryKernel*, ChildComparator> OrderedChildSet;
  28
  29 // Container that tracks parent-child relationships.
  30 // Provides fast lookup of all items under a given parent.
  31 class SYNC_EXPORT_PRIVATE ParentChildIndex {
  32  public:
  33   ParentChildIndex();
  34   ~ParentChildIndex();
  35
  36   // Returns whether or not this entry belongs in the index.
  37   // True for all non-deleted, non-root entries.
  38   static bool ShouldInclude(const EntryKernel* e);
  39
  40   // Inserts a given child into the index.
  41   bool Insert(EntryKernel* e);
  42
  43   // Removes a given child from the index.
  44   void Remove(EntryKernel* e);
  45
  46   // Returns true if this item is in the index as a child.
  47   bool Contains(EntryKernel* e) const;
  48
  49   // Returns all children of the entry with the given Id.  Returns NULL if the
  50   // node has no children or the Id does not identify a valid directory node.
  51   const OrderedChildSet* GetChildren(const Id& id);
  52
  53  private:
  54   typedef std::map<syncable::Id, OrderedChildSet*> ParentChildrenMap;
  55
  56   // A map of parent IDs to children.
  57   // Parents with no children are not included in this map.
  58   ParentChildrenMap parent_children_map_;
  59
  60   DISALLOW_COPY_AND_ASSIGN(ParentChildIndex);
  61 };
  62
  63 }  // namespace syncable
  64 }  // namespace syncer
  65
  66 #endif  // SYNC_SYNCABLE_PARENT_CHILD_INDEX