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      1 /*
      2  * Copyright (C) 2016 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 package com.android.compatibility.common.util;
     17 
     18 import android.util.JsonWriter;
     19 
     20 import java.io.BufferedReader;
     21 import java.io.BufferedWriter;
     22 import java.io.File;
     23 import java.io.FileReader;
     24 import java.io.FileWriter;
     25 import java.io.IOException;
     26 
     27 public class ReportLogDeviceInfoStore extends DeviceInfoStore {
     28 
     29     private final String mStreamName;
     30     private File tempJsonFile;
     31 
     32     public ReportLogDeviceInfoStore(File jsonFile, String streamName) throws Exception {
     33         mJsonFile = jsonFile;
     34         mStreamName = streamName;
     35     }
     36 
     37     /**
     38      * Creates the writer and starts the JSON Object for the metric stream.
     39      */
     40     @Override
     41     public void open() throws IOException {
     42         // Write new metrics to a temp file to avoid invalid JSON files due to failed tests.
     43         BufferedWriter formatWriter;
     44         tempJsonFile = File.createTempFile(mStreamName, "-temp-report-log");
     45         formatWriter = new BufferedWriter(new FileWriter(tempJsonFile));
     46         if (mJsonFile.exists()) {
     47             BufferedReader jsonReader = new BufferedReader(new FileReader(mJsonFile));
     48             String currentLine;
     49             String nextLine = jsonReader.readLine();
     50             while ((currentLine = nextLine) != null) {
     51                 nextLine = jsonReader.readLine();
     52                 if (nextLine == null && currentLine.charAt(currentLine.length() - 1) == '}') {
     53                     // Reopen overall JSON object to write new metrics.
     54                     currentLine = currentLine.substring(0, currentLine.length() - 1) + ",";
     55                 }
     56                 // Copy to temp file directly to avoid large metrics string in memory.
     57                 formatWriter.write(currentLine, 0, currentLine.length());
     58             }
     59             jsonReader.close();
     60         } else {
     61             formatWriter.write("{", 0 , 1);
     62         }
     63         // Start new JSON object for new metrics.
     64         formatWriter.write("\"" + mStreamName + "\":", 0, mStreamName.length() + 3);
     65         formatWriter.flush();
     66         formatWriter.close();
     67         mJsonWriter = new JsonWriter(new FileWriter(tempJsonFile, true));
     68         mJsonWriter.beginObject();
     69     }
     70 
     71     /**
     72      * Closes the writer.
     73      */
     74     @Override
     75     public void close() throws IOException {
     76         // Close JSON Writer.
     77         mJsonWriter.endObject();
     78         mJsonWriter.close();
     79         // Close overall JSON Object.
     80         try (BufferedWriter formatWriter = new BufferedWriter(new FileWriter(tempJsonFile, true))) {
     81             formatWriter.write("}", 0, 1);
     82         }
     83         // Copy metrics from temp file and delete temp file.
     84         mJsonFile.createNewFile();
     85         try (
     86                 BufferedReader jsonReader = new BufferedReader(new FileReader(tempJsonFile));
     87                 BufferedWriter metricsWriter = new BufferedWriter(new FileWriter(mJsonFile))
     88         ) {
     89             String line;
     90             while ((line = jsonReader.readLine()) != null) {
     91                 // Copy from temp file directly to avoid large metrics string in memory.
     92                 metricsWriter.write(line, 0, line.length());
     93             }
     94         }
     95     }
     96 }
     97