1 // Copyright (C) 2023 Google LLC 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // http://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 15 #ifndef ICING_JOIN_JOIN_CHILDREN_FETCHER_H_ 16 #define ICING_JOIN_JOIN_CHILDREN_FETCHER_H_ 17 18 #include <unordered_map> 19 #include <vector> 20 21 #include "icing/text_classifier/lib3/utils/base/statusor.h" 22 #include "icing/proto/search.pb.h" 23 #include "icing/scoring/scored-document-hit.h" 24 #include "icing/store/document-id.h" 25 26 namespace icing { 27 namespace lib { 28 29 // A class that provides the GetChildren method for joins to fetch all children 30 // documents given a parent document id. 31 // 32 // Internally, the class maintains a map for each joinable value type that 33 // groups children according to the joinable values. Currently we only support 34 // QUALIFIED_ID joining, in which the joinable value type is document id. 35 class JoinChildrenFetcher { 36 public: JoinChildrenFetcher(const JoinSpecProto & join_spec,std::unordered_map<DocumentId,std::vector<ScoredDocumentHit>> && map_joinable_qualified_id)37 explicit JoinChildrenFetcher( 38 const JoinSpecProto& join_spec, 39 std::unordered_map<DocumentId, std::vector<ScoredDocumentHit>>&& 40 map_joinable_qualified_id) 41 : join_spec_(join_spec), 42 map_joinable_qualified_id_(std::move(map_joinable_qualified_id)) {} 43 44 // Get a vector of children ScoredDocumentHit by parent document id. 45 // 46 // TODO(b/256022027): Implement property value joins with types of string and 47 // int. In these cases, GetChildren should look up joinable cache to fetch 48 // joinable property value of the given parent_doc_id according to 49 // join_spec_.parent_property_expression, and then fetch children by the 50 // corresponding map in this class using the joinable property value. 51 // 52 // Returns: 53 // The vector of results on success. 54 // UNIMPLEMENTED_ERROR if the join type specified by join_spec is not 55 // supported. 56 libtextclassifier3::StatusOr<std::vector<ScoredDocumentHit>> GetChildren( 57 DocumentId parent_doc_id) const; 58 59 private: 60 static constexpr std::string_view kQualifiedIdExpr = "this.qualifiedId()"; 61 62 const JoinSpecProto& join_spec_; // Does not own! 63 64 // The map that groups children by qualified id used to support QualifiedId 65 // joining. The joining type is document id. 66 std::unordered_map<DocumentId, std::vector<ScoredDocumentHit>> 67 map_joinable_qualified_id_; 68 }; 69 70 } // namespace lib 71 } // namespace icing 72 73 #endif // ICING_JOIN_JOIN_CHILDREN_FETCHER_H_ 74