sync/syncable/parent_child_index.cc

   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 #include "sync/syncable/parent_child_index.h"
   6
   7 #include "base/stl_util.h"
   8
   9 #include "sync/syncable/entry_kernel.h"
  10 #include "sync/syncable/syncable_id.h"
  11
  12 namespace syncer {
  13 namespace syncable {
  14
  15 bool ChildComparator::operator()(const EntryKernel* a,
  16                                  const EntryKernel* b) const {
  17   const UniquePosition& a_pos = a->ref(UNIQUE_POSITION);
  18   const UniquePosition& b_pos = b->ref(UNIQUE_POSITION);
  19
  20   if (a_pos.IsValid() && b_pos.IsValid()) {
  21     // Position is important to this type.
  22     return a_pos.LessThan(b_pos);
  23   } else if (a_pos.IsValid() && !b_pos.IsValid()) {
  24     // TODO(rlarocque): Remove this case.
  25     // An item with valid position as sibling of one with invalid position.
  26     // We should not support this, but the tests rely on it.  For now, just
  27     // move all invalid position items to the right.
  28     return true;
  29   } else if (!a_pos.IsValid() && b_pos.IsValid()) {
  30     // TODO(rlarocque): Remove this case.
  31     // Mirror of the above case.
  32     return false;
  33   } else {
  34     // Position doesn't matter.
  35     DCHECK(!a->ref(UNIQUE_POSITION).IsValid());
  36     DCHECK(!b->ref(UNIQUE_POSITION).IsValid());
  37     // Sort by META_HANDLE to ensure consistent order for testing.
  38     return a->ref(META_HANDLE) < b->ref(META_HANDLE);
  39   }
  40 }
  41
  42 ParentChildIndex::ParentChildIndex() {
  43 }
  44
  45 ParentChildIndex::~ParentChildIndex() {
  46   STLDeleteContainerPairSecondPointers(
  47       parent_children_map_.begin(), parent_children_map_.end());
  48 }
  49
  50 bool ParentChildIndex::ShouldInclude(const EntryKernel* entry) {
  51   // This index excludes deleted items and the root item.  The root
  52   // item is excluded so that it doesn't show up as a child of itself.
  53   return !entry->ref(IS_DEL) && !entry->ref(ID).IsRoot();
  54 }
  55
  56 bool ParentChildIndex::Insert(EntryKernel* entry) {
  57   DCHECK(ShouldInclude(entry));
  58
  59   const Id& parent_id = GetParentId(entry);
  60   // Store type root ID when inserting a type root entry.
  61   if (parent_id.IsRoot()) {
  62     ModelType model_type = GetModelType(entry);
  63     // TODO(stanisc): there are some unit tests that create entries
  64     // at the root and don't bother initializing specifics which
  65     // produces TOP_LEVEL_FOLDER type here.
  66     if (syncer::IsRealDataType(model_type)) {
  67       model_type_root_ids_[model_type] = entry->ref(ID);
  68     }
  69   }
  70
  71   OrderedChildSet* children = NULL;
  72   ParentChildrenMap::iterator i = parent_children_map_.find(parent_id);
  73   if (i != parent_children_map_.end()) {
  74     children = i->second;
  75   } else {
  76     children = new OrderedChildSet();
  77     parent_children_map_.insert(std::make_pair(parent_id, children));
  78   }
  79
  80   return children->insert(entry).second;
  81 }
  82
  83 // Like the other containers used to help support the syncable::Directory, this
  84 // one does not own any EntryKernels.  This function removes references to the
  85 // given EntryKernel but does not delete it.
  86 void ParentChildIndex::Remove(EntryKernel* e) {
  87   const Id& parent_id = GetParentId(e);
  88
  89   ParentChildrenMap::iterator parent = parent_children_map_.find(parent_id);
  90   DCHECK(parent != parent_children_map_.end());
  91
  92   OrderedChildSet* children = parent->second;
  93   OrderedChildSet::iterator j = children->find(e);
  94   DCHECK(j != children->end());
  95
  96   children->erase(j);
  97   if (children->empty()) {
  98     delete children;
  99     parent_children_map_.erase(parent);
 100   }
 101 }
 102
 103 bool ParentChildIndex::Contains(EntryKernel *e) const {
 104   const Id& parent_id = GetParentId(e);
 105   ParentChildrenMap::const_iterator parent =
 106       parent_children_map_.find(parent_id);
 107   if (parent == parent_children_map_.end()) {
 108     return false;
 109   }
 110   const OrderedChildSet* children = parent->second;
 111   DCHECK(children && !children->empty());
 112   return children->count(e) > 0;
 113 }
 114
 115 const OrderedChildSet* ParentChildIndex::GetChildren(const Id& id) const {
 116   DCHECK(!id.IsNull());
 117
 118   ParentChildrenMap::const_iterator parent = parent_children_map_.find(id);
 119   if (parent == parent_children_map_.end()) {
 120     return nullptr;
 121   }
 122
 123   // A successful lookup implies at least some children exist.
 124   DCHECK(!parent->second->empty());
 125   return parent->second;
 126 }
 127
 128 const OrderedChildSet* ParentChildIndex::GetChildren(EntryKernel* e) const {
 129   return GetChildren(e->ref(ID));
 130 }
 131
 132 const OrderedChildSet* ParentChildIndex::GetSiblings(EntryKernel* e) const {
 133   DCHECK(Contains(e));
 134   const OrderedChildSet* siblings = GetChildren(GetParentId(e));
 135   DCHECK(siblings && !siblings->empty());
 136   return siblings;
 137 }
 138
 139 const Id& ParentChildIndex::GetParentId(EntryKernel* e) const {
 140   const Id& parent_id = e->ref(PARENT_ID);
 141   if (!parent_id.IsNull()) {
 142     return parent_id;
 143   }
 144   return GetModelTypeRootId(GetModelType(e));
 145 }
 146
 147 ModelType ParentChildIndex::GetModelType(EntryKernel* e) {
 148   // TODO(stanisc): is there a more effective way to find out model type?
 149   ModelType model_type = e->GetModelType();
 150   if (!syncer::IsRealDataType(model_type)) {
 151     model_type = e->GetServerModelType();
 152   }
 153   return model_type;
 154 }
 155
 156 const Id& ParentChildIndex::GetModelTypeRootId(ModelType model_type) const {
 157   // TODO(stanisc): Review whether this approach is reliable enough.
 158   // Should this method simply enumerate children of root node ("r") instead?
 159   return model_type_root_ids_[model_type];
 160 }
 161
 162 }  // namespace syncable
 163 }  // namespace syncer