diff options
| -rw-r--r-- | chrome/browser/chromeos/drive/change_list_processor.cc | 35 |
1 files changed, 30 insertions, 5 deletions
diff --git a/chrome/browser/chromeos/drive/change_list_processor.cc b/chrome/browser/chromeos/drive/change_list_processor.cc index 2e44dea..a2b8d2b 100644 --- a/chrome/browser/chromeos/drive/change_list_processor.cc +++ b/chrome/browser/chromeos/drive/change_list_processor.cc @@ -157,12 +157,37 @@ void ChangeListProcessor::ApplyEntryMap( continue; } - // Start from entry_map_.begin() and traverse ancestors. + // Start from entry_map_.begin() and traverse ancestors using the + // parent-child relashonships in the result (after this apply) tree. + // Then apply the topmost change first. + // + // By doing this, assuming the result tree does not contain any cycles, we + // can guarantee that no cycle is made during this apply (i.e. no entry gets + // moved under any of its descendants) because the following conditions are + // always satisfied in any move: + // - The new parent entry is not a descendant of the moved entry. + // - The new parent and its ancestors will no longer move during this apply. std::vector<ResourceEntryMap::iterator> entries; - for (; it != entry_map_.end(); - it = entry_map_.find(it->second.parent_resource_id())) { - DCHECK_EQ(it->first, it->second.resource_id()); - entries.push_back(it); + entries.push_back(entry_map_.begin()); + for (std::string parent_id = entries.back()->second.parent_resource_id(); + !parent_id.empty();) { + ResourceEntryMap::iterator it_parent = entry_map_.find(parent_id); + if (it_parent != entry_map_.end()) { + // This entry is going to be updated, get the parent from the new data. + entries.push_back(it_parent); + parent_id = it_parent->second.parent_resource_id(); + } else { + // This entry is already updated or not going to be updated, get the + // parent from the current tree. + ResourceEntry parent_entry; + FileError error = + resource_metadata_->GetResourceEntryById(parent_id, &parent_entry); + if (error != FILE_ERROR_OK) { + LOG(ERROR) << "Cannot get the parent: " << FileErrorToString(error); + break; + } + parent_id = parent_entry.parent_resource_id(); + } } // Apply the parent first. |