Use the rollback data policy specified in the manifest (2/n)

Now app can specifies the rollback data policy in the manifest.

Note the policy specified in the manifest will take precedence only when
it is not the default (i.e. RESTORE) in order not to break the existing
code. When Play has done migration and stopped using
SessionParams#setEnableRollback(boolean, int), we will remove related
code and manifest will be the single source of truth to specify the
rollback data policy.

Bug: 148098864
Test: atest RollbackTest StagedRollbackTest
Change-Id: Ia8ac9d710b7c36519672b4a90eccea4f6836b5c5

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

@@ -808,6 +808,19 @@ class RollbackManagerServiceImpl extends IRollbackManager.Stub {
         return enableRollbackForPackageSession(newRollback, packageSession);
     }
 
+    @WorkerThread
+    private int computeRollbackDataPolicy(int sessionPolicy, int manifestPolicy) {
+        assertInWorkerThread();
+        // TODO: In order not to break existing code, the policy specified in the manifest will take
+        // precedence only when it is not the default (i.e. RESTORE). We will remove
+        // SessionParams#setEnableRollback(boolean, int) and related code when Play has migrated to
+        // using the manifest to specify the policy.
+        if (manifestPolicy != PackageManager.RollbackDataPolicy.RESTORE) {
+            return manifestPolicy;
+        }
+        return sessionPolicy;
+    }
+
     /**
      * Do code and userdata backups to enable rollback of the given session.
      * In case of multiPackage sessions, <code>session</code> should be one of
@@ -845,9 +858,11 @@ class RollbackManagerServiceImpl extends IRollbackManager.Stub {
         }
 
         String packageName = newPackage.packageName;
+        int rollbackDataPolicy = computeRollbackDataPolicy(
+                session.rollbackDataPolicy, newPackage.rollbackDataPolicy);
         Slog.i(TAG, "Enabling rollback for install of " + packageName
                 + ", session:" + session.sessionId
-                + ", rollbackDataPolicy=" + newPackage.rollbackDataPolicy);
+                + ", rollbackDataPolicy=" + rollbackDataPolicy);
 
         String installerPackageName = session.getInstallerPackageName();
         if (!enableRollbackAllowed(installerPackageName, packageName)) {
@@ -887,7 +902,7 @@ class RollbackManagerServiceImpl extends IRollbackManager.Stub {
                     return false;
                 }
                 if (!rollback.enableForPackageInApex(
-                        apkInApex, apkPkgInfo.getLongVersionCode(), session.rollbackDataPolicy)) {
+                        apkInApex, apkPkgInfo.getLongVersionCode(), rollbackDataPolicy)) {
                     return false;
                 }
             }
@@ -903,7 +918,7 @@ class RollbackManagerServiceImpl extends IRollbackManager.Stub {
         ApplicationInfo appInfo = pkgInfo.applicationInfo;
         return rollback.enableForPackage(packageName, newPackage.versionCode,
                 pkgInfo.getLongVersionCode(), isApex, appInfo.sourceDir,
-                appInfo.splitSourceDirs, session.rollbackDataPolicy);
+                appInfo.splitSourceDirs, rollbackDataPolicy);
     }
 
     @ExtThread