1// Copyright (C) 2024 The Android Open Source Project 2// 3// Licensed under the Apache License, Version 2.0 (the "License"); 4// you may not use size 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 15import {Engine} from '../trace_processor/engine'; 16 17export class FlamegraphCache { 18 private cache: Map<string, string>; 19 private prefix: string; 20 private tableId: number; 21 private cacheSizeLimit: number; 22 23 constructor(prefix: string) { 24 this.cache = new Map<string, string>(); 25 this.prefix = prefix; 26 this.tableId = 0; 27 this.cacheSizeLimit = 10; 28 } 29 30 async getTableName(engine: Engine, query: string): Promise<string> { 31 let tableName = this.cache.get(query); 32 if (tableName === undefined) { 33 // TODO(hjd): This should be LRU. 34 if (this.cache.size > this.cacheSizeLimit) { 35 for (const name of this.cache.values()) { 36 await engine.query(`drop table ${name}`); 37 } 38 this.cache.clear(); 39 } 40 tableName = `${this.prefix}_${this.tableId++}`; 41 await engine.query( 42 `create temp table if not exists ${tableName} as ${query}`, 43 ); 44 this.cache.set(query, tableName); 45 } 46 return tableName; 47 } 48 49 hasQuery(query: string): boolean { 50 return this.cache.get(query) !== undefined; 51 } 52} 53