1 /* 2 * Copyright (C) 2018 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef SRC_TRACE_PROCESSOR_QUERY_CONSTRAINTS_H_ 18 #define SRC_TRACE_PROCESSOR_QUERY_CONSTRAINTS_H_ 19 20 #include <sqlite3.h> 21 22 #include <vector> 23 24 #include "perfetto/base/scoped_file.h" 25 26 namespace perfetto { 27 namespace trace_processor { 28 29 // This class stores the constraints (including the order-by information) for 30 // a query on a sqlite3 virtual table and handles their de/serialization into 31 // strings. 32 // This is because the constraint columns and the order-by clauses are passed 33 // to the xBestIndex method but the constraint values are available only in the 34 // xFilter method. Unfortunately sqlite vtable API don't give any hint about 35 // the validity of the constraints (i.e. constraints passed to xBestIndex can 36 // be used by future xFilter calls in the far future). The only mechanism 37 // offered by sqlite is the idxStr string which is returned by the vtable 38 // in the xBestIndex call and passed to each corresponding xFilter call. 39 class QueryConstraints { 40 public: 41 using Constraint = sqlite3_index_info::sqlite3_index_constraint; 42 using OrderBy = sqlite3_index_info::sqlite3_index_orderby; 43 44 static int FreeSqliteString(char* resource); 45 46 using SqliteString = base::ScopedResource<char*, FreeSqliteString, nullptr>; 47 48 QueryConstraints(); 49 ~QueryConstraints(); 50 QueryConstraints(QueryConstraints&&) noexcept; 51 QueryConstraints& operator=(QueryConstraints&&); 52 53 // Two QueryConstraints with the same constraint and orderby vectors 54 // are equal. 55 bool operator==(const QueryConstraints& other) const; 56 57 void AddConstraint(int column, unsigned char op); 58 59 void AddOrderBy(int column, unsigned char desc); 60 61 void ClearOrderBy() { order_by_.clear(); } 62 63 // Converts the constraints and order by information to a string for 64 // use by sqlite. 65 SqliteString ToNewSqlite3String() const; 66 67 // Deserializes the string into QueryConstraints. String given is in the form 68 // C{# of constraints},col1,op1,col2,op2...,O{# of order by},col1,desc1... 69 // For example C1,0,3,O2,1,0,4,1 70 static QueryConstraints FromString(const char* idxStr); 71 72 const std::vector<OrderBy>& order_by() const { return order_by_; } 73 74 const std::vector<Constraint>& constraints() const { return constraints_; } 75 76 private: 77 QueryConstraints(const QueryConstraints&) = delete; 78 QueryConstraints& operator=(const QueryConstraints&) = delete; 79 80 std::vector<OrderBy> order_by_; 81 std::vector<Constraint> constraints_; 82 }; 83 84 } // namespace trace_processor 85 } // namespace perfetto 86 87 #endif // SRC_TRACE_PROCESSOR_QUERY_CONSTRAINTS_H_ 88
