Merge changes I4c2acb80,Ib4ccd1be

* changes:
  Use AtomicFile
  Assert there is only one data folder created during test (1/n)

services/core/java/com/android/server/rollback/RollbackStore.java

@@ -25,6 +25,7 @@ import android.content.rollback.PackageRollbackInfo;
 import android.content.rollback.PackageRollbackInfo.RestoreInfo;
 import android.content.rollback.RollbackInfo;
 import android.os.UserHandle;
+import android.util.AtomicFile;
 import android.util.Slog;
 import android.util.SparseIntArray;
 
@@ -37,6 +38,7 @@ import org.json.JSONException;
 import org.json.JSONObject;
 
 import java.io.File;
+import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.PrintWriter;
 import java.nio.file.Files;
@@ -66,8 +68,6 @@ class RollbackStore {
     //
     // * XXX, YYY are the rollbackIds for the corresponding rollbacks.
     // * rollback.json contains all relevant metadata for the rollback.
-    //
-    // TODO: Use AtomicFile for all the .json files?
     private final File mRollbackDataDir;
 
     RollbackStore(File rollbackDataDir) {
@@ -259,6 +259,8 @@ class RollbackStore {
      * Saves the given rollback to persistent storage.
      */
     static void saveRollback(Rollback rollback) {
+        FileOutputStream fos = null;
+        AtomicFile file = new AtomicFile(new File(rollback.getBackupDir(), "rollback.json"));
         try {
             JSONObject dataJson = new JSONObject();
             dataJson.put("info", rollbackInfoToJson(rollback.info));
@@ -272,11 +274,16 @@ class RollbackStore {
             dataJson.putOpt(
                     "extensionVersions", extensionVersionsToJson(rollback.getExtensionVersions()));
 
-            PrintWriter pw = new PrintWriter(new File(rollback.getBackupDir(), "rollback.json"));
+            fos = file.startWrite();
+            PrintWriter pw = new PrintWriter(fos);
             pw.println(dataJson.toString());
             pw.close();
+            file.finishWrite(fos);
         } catch (JSONException | IOException e) {
             Slog.e(TAG, "Unable to save rollback for: " + rollback.info.getRollbackId(), e);
+            if (fos != null) {
+                file.failWrite(fos);
+            }
         }
     }
 

tests/RollbackTest/StagedRollbackTest/src/com/android/tests/rollback/host/StagedRollbackTest.java

@@ -18,6 +18,8 @@ package com.android.tests.rollback.host;
 
 import static com.android.tests.rollback.host.WatchdogEventLogger.watchdogEventOccurred;
 
+import static com.google.common.truth.Truth.assertThat;
+
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
@@ -272,6 +274,8 @@ public class StagedRollbackTest extends BaseHostJUnit4Test {
         List<String> after = getSnapshotDirectories("/data/misc_ce/0/rollback");
         // Only check directories newly created during the test
         after.removeAll(before);
+        // There should be only one /data/misc_ce/0/rollback/<rollbackId> created during test
+        assertThat(after).hasSize(1);
         after.forEach(dir -> assertDirectoryIsEmpty(dir));
     }
 
@@ -358,6 +362,8 @@ public class StagedRollbackTest extends BaseHostJUnit4Test {
         List<String> after = getSnapshotDirectories("/data/misc/apexrollback");
         // Only check directories newly created during the test
         after.removeAll(before);
+        // There should be only one /data/misc/apexrollback/<rollbackId> created during test
+        assertThat(after).hasSize(1);
         after.forEach(dir -> assertDirectoryIsEmpty(dir));
     }
 
@@ -405,6 +411,8 @@ public class StagedRollbackTest extends BaseHostJUnit4Test {
         List<String> after = getSnapshotDirectories("/data/misc_de/0/apexrollback");
         // Only check directories newly created during the test
         after.removeAll(before);
+        // There should be only one /data/misc_de/0/apexrollback/<rollbackId> created during test
+        assertThat(after).hasSize(1);
         after.forEach(dir -> assertDirectoryIsEmpty(dir));
     }
 
@@ -450,6 +458,8 @@ public class StagedRollbackTest extends BaseHostJUnit4Test {
         List<String> after = getSnapshotDirectories("/data/misc_ce/0/apexrollback");
         // Only check directories newly created during the test
         after.removeAll(before);
+        // There should be only one /data/misc_ce/0/apexrollback/<rollbackId> created during test
+        assertThat(after).hasSize(1);
         after.forEach(dir -> assertDirectoryIsEmpty(dir));
     }
 
@@ -509,6 +519,8 @@ public class StagedRollbackTest extends BaseHostJUnit4Test {
         List<String> after = getSnapshotDirectories("/data/misc_ce/0/apexrollback");
         // Only check directories newly created during the test
         after.removeAll(before);
+        // There should be only one /data/misc_ce/0/apexrollback/<rollbackId> created during test
+        assertThat(after).hasSize(1);
         // Expire all rollbacks and check CE snapshot directories are deleted
         runPhase("testCleanUp");
         for (String dir : after) {