Retool the backup process to use a new 'BackupAgent' class

Backups will be handled by launching the application in a special
mode under which no activities or services will be started, only
the BackupAgent subclass named in the app's android:backupAgent
manifest property.  This takes the place of the BackupService class
used earlier during development.

In the cases of *full* backup or restore, an application that does
not supply its own BackupAgent will be launched in a restricted
manner; in particular, it will be using the default Application
class rather than any manifest-declared one.  This ensures that the
app is not running any code that may try to manipulate its data
while the backup system reads/writes its data set.

2 files changed, 36 insertions, 2 deletions

diff --git a/core/java/android/content/pm/ApplicationInfo.java b/core/java/android/content/pm/ApplicationInfo.java
index ad022e7..f16eb74 100644
--- a/core/java/android/content/pm/ApplicationInfo.java
+++ b/core/java/android/content/pm/ApplicationInfo.java
@@ -58,11 +58,22 @@ public class ApplicationInfo extends PackageItemInfo implements Parcelable {
      * Class implementing the Application's manage space
      * functionality.  From the "manageSpaceActivity"
      * attribute. This is an optional attribute and will be null if
-     * application's dont specify it in their manifest
+     * applications don't specify it in their manifest
      */
     public String manageSpaceActivityName;    
     
     /**
+     * Class implementing the Application's backup functionality.  From
+     * the "backupAgent" attribute.  This is an optional attribute and
+     * will be null if the application does not specify it in its manifest.
+     * 
+     * <p>If android:allowBackup is set to false, this attribute is ignored.
+     * 
+     * {@hide}
+     */
+    public String backupAgentName;
+    
+    /**
      * Value for {@link #flags}: if set, this application is installed in the
      * device's system image.
      */
@@ -93,7 +104,7 @@ public class ApplicationInfo extends PackageItemInfo implements Parcelable {
     public static final int FLAG_PERSISTENT = 1<<3;
 
     /**
-     * Value for {@link #flags}: set to true iif this application holds the
+     * Value for {@link #flags}: set to true if this application holds the
      * {@link android.Manifest.permission#FACTORY_TEST} permission and the
      * device is running in factory test mode.
      */
@@ -126,6 +137,14 @@ public class ApplicationInfo extends PackageItemInfo implements Parcelable {
     public static final int FLAG_TEST_ONLY = 1<<8;
 
     /**
+     * Value for {@link #flags}: this is false if the application has set
+     * its android:allowBackup to false, true otherwise.
+     * 
+     * {@hide}
+     */
+    public static final int FLAG_ALLOW_BACKUP = 1<<10;
+    
+    /**
      * Flags associated with the application.  Any combination of
      * {@link #FLAG_SYSTEM}, {@link #FLAG_DEBUGGABLE}, {@link #FLAG_HAS_CODE},
      * {@link #FLAG_PERSISTENT}, {@link #FLAG_FACTORY_TEST}, and
@@ -285,6 +304,7 @@ public class ApplicationInfo extends PackageItemInfo implements Parcelable {
         dest.writeInt(targetSdkVersion);
         dest.writeInt(enabled ? 1 : 0);
         dest.writeString(manageSpaceActivityName);
+        dest.writeString(backupAgentName);
         dest.writeInt(descriptionRes);
         dest.writeIntArray(supportsDensities);
     }
@@ -315,6 +335,7 @@ public class ApplicationInfo extends PackageItemInfo implements Parcelable {
         targetSdkVersion = source.readInt();
         enabled = source.readInt() != 0;
         manageSpaceActivityName = source.readString();
+        backupAgentName = source.readString();
         descriptionRes = source.readInt();
         supportsDensities = source.createIntArray();
     }
diff --git a/core/java/android/content/pm/PackageParser.java b/core/java/android/content/pm/PackageParser.java
index ee20aee..36d154e 100644
--- a/core/java/android/content/pm/PackageParser.java
+++ b/core/java/android/content/pm/PackageParser.java
@@ -1176,6 +1176,19 @@ public class PackageParser {
                     outError);
         }
 
+        boolean allowBackup = sa.getBoolean(
+                com.android.internal.R.styleable.AndroidManifestApplication_allowBackup, true);
+        if (allowBackup) {
+            ai.flags |= ApplicationInfo.FLAG_ALLOW_BACKUP;
+            String backupAgent = sa.getNonResourceString(
+                    com.android.internal.R.styleable.AndroidManifestApplication_backupAgent);
+            if (backupAgent != null) {
+                ai.backupAgentName = buildClassName(pkgName, backupAgent, outError);
+                Log.v(TAG, "android:backupAgent = " + ai.backupAgentName
+                        + " from " + pkgName + "+" + backupAgent);
+            }
+        }
+        
         TypedValue v = sa.peekValue(
                 com.android.internal.R.styleable.AndroidManifestApplication_label);
         if (v != null && (ai.labelRes=v.resourceId) == 0) {