Make an attempt to store/retrieve backups from removable storage

Fixes #7521

src/org/thoughtcrime/securesms/RegistrationActivity.java

@@ -314,7 +314,7 @@ public class RegistrationActivity extends BaseActionBarActivity implements Verif
       @Override
       protected @Nullable BackupUtil.BackupInfo doInBackground(Void... voids) {
         try {
-          return BackupUtil.getLatestBackup();
+          return BackupUtil.getLatestBackup(RegistrationActivity.this);
         } catch (NoExternalStorageException e) {
           Log.w(TAG, e);
           return null;

src/org/thoughtcrime/securesms/backup/BackupDialog.java

@@ -77,7 +77,7 @@ public class BackupDialog {
                    .setPositiveButton(R.string.BackupDialog_delete_backups_statement, (dialog, which) -> {
                      TextSecurePreferences.setBackupPassphrase(context, null);
                      TextSecurePreferences.setBackupEnabled(context, false);
-                     BackupUtil.deleteAllBackups();
+                     BackupUtil.deleteAllBackups(context);
                      preference.setChecked(false);
                    })
                    .create()

src/org/thoughtcrime/securesms/jobs/LocalBackupJob.java

@@ -50,7 +50,7 @@ public class LocalBackupJob extends ContextJob {
 
     try {
       String backupPassword  = TextSecurePreferences.getBackupPassphrase(context);
-      File   backupDirectory = StorageUtil.getBackupDirectory();
+      File   backupDirectory = StorageUtil.getBackupDirectory(context);
       String timestamp       = new SimpleDateFormat("yyyy-MM-dd-HH-mm-ss", Locale.US).format(new Date());
       String fileName        = String.format("signal-%s.backup", timestamp);
       File   backupFile      = new File(backupDirectory, fileName);
@@ -76,7 +76,7 @@ public class LocalBackupJob extends ContextJob {
         throw new IOException("Renaming temporary backup file failed!");
       }
 
-      BackupUtil.deleteOldBackups();
+      BackupUtil.deleteOldBackups(context);
     } finally {
       GenericForegroundService.stopForegroundTask(context);
     }

src/org/thoughtcrime/securesms/util/BackupUtil.java

@@ -22,7 +22,7 @@ public class BackupUtil {
 
   public static @NonNull String getLastBackupTime(@NonNull Context context, @NonNull Locale locale) {
     try {
-      BackupInfo backup = getLatestBackup();
+      BackupInfo backup = getLatestBackup(context);
 
       if (backup == null) return context.getString(R.string.BackupUtil_never);
       else                return DateUtils.getExtendedRelativeTimeSpanString(context, locale, backup.getTimestamp());
@@ -32,8 +32,8 @@ public class BackupUtil {
     }
   }
 
-  public static @Nullable BackupInfo getLatestBackup() throws NoExternalStorageException {
+  public static @Nullable BackupInfo getLatestBackup(@NonNull Context context) throws NoExternalStorageException {
-    File       backupDirectory = StorageUtil.getBackupDirectory();
+    File       backupDirectory = StorageUtil.getBackupDirectory(context);
     File[]     backups         = backupDirectory.listFiles();
     BackupInfo latestBackup    = null;
 
@@ -49,9 +49,9 @@ public class BackupUtil {
   }
 
   @SuppressWarnings("ResultOfMethodCallIgnored")
-  public static void deleteAllBackups() {
+  public static void deleteAllBackups(@NonNull Context context) {
     try {
-      File   backupDirectory = StorageUtil.getBackupDirectory();
+      File   backupDirectory = StorageUtil.getBackupDirectory(context);
       File[] backups         = backupDirectory.listFiles();
 
       for (File backup : backups) {
@@ -62,9 +62,9 @@ public class BackupUtil {
     }
   }
 
-  public static void deleteOldBackups() {
+  public static void deleteOldBackups(@NonNull Context context) {
     try {
-      File   backupDirectory = StorageUtil.getBackupDirectory();
+      File   backupDirectory = StorageUtil.getBackupDirectory(context);
       File[] backups         = backupDirectory.listFiles();
 
       if (backups != null && backups.length > 5) {

src/org/thoughtcrime/securesms/util/StorageUtil.java

@@ -1,8 +1,13 @@
 package org.thoughtcrime.securesms.util;
 
+import android.content.Context;
+import android.os.Build;
 import android.os.Environment;
 import android.support.annotation.Nullable;
 
+import com.annimon.stream.Objects;
+import com.annimon.stream.Stream;
+
 import org.thoughtcrime.securesms.database.NoExternalStorageException;
 
 import java.io.File;
@@ -10,8 +15,25 @@ import java.io.File;
 public class StorageUtil
 {
 
-  public static File getBackupDirectory() throws NoExternalStorageException {
+  public static File getBackupDirectory(Context context) throws NoExternalStorageException {
-    File storage = Environment.getExternalStorageDirectory();
+    File storage = null;
+
+    if (Build.VERSION.SDK_INT >= 19) {
+      File[] directories = context.getExternalFilesDirs(null);
+
+      if (directories != null) {
+        storage = Stream.of(directories)
+                        .withoutNulls()
+                        .filterNot(f -> f.getAbsolutePath().contains("emulated"))
+                        .limit(1)
+                        .findSingle()
+                        .orElse(null);
+      }
+    }
+
+    if (storage == null) {
+      storage = Environment.getExternalStorageDirectory();
+    }
 
     if (!storage.canWrite()) {
       throw new NoExternalStorageException();