Support for full backup/restore to sdcard

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

@@ -0,0 +1,160 @@
+package org.thoughtcrime.securesms.util;
+
+
+import android.content.Context;
+import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
+import android.util.Log;
+
+import org.thoughtcrime.securesms.R;
+import org.thoughtcrime.securesms.database.NoExternalStorageException;
+import org.whispersystems.libsignal.util.ByteUtil;
+
+import java.io.File;
+import java.security.SecureRandom;
+import java.util.Arrays;
+import java.util.Calendar;
+import java.util.Locale;
+
+public class BackupUtil {
+
+  private static final String TAG = BackupUtil.class.getSimpleName();
+
+  public static @NonNull String getLastBackupTime(@NonNull Context context, @NonNull Locale locale) {
+    try {
+      BackupInfo backup = getLatestBackup();
+
+      if (backup == null) return context.getString(R.string.BackupUtil_never);
+      else                return DateUtils.getExtendedRelativeTimeSpanString(context, locale, backup.getTimestamp());
+    } catch (NoExternalStorageException e) {
+      Log.w(TAG, e);
+      return context.getString(R.string.BackupUtil_unknown);
+    }
+  }
+
+  public static @Nullable BackupInfo getLatestBackup() throws NoExternalStorageException {
+    File       backupDirectory = StorageUtil.getBackupDirectory();
+    File[]     backups         = backupDirectory.listFiles();
+    BackupInfo latestBackup    = null;
+
+    for (File backup : backups) {
+      long backupTimestamp = getBackupTimestamp(backup);
+
+      if (latestBackup == null || (backupTimestamp != -1 && backupTimestamp > latestBackup.getTimestamp())) {
+        latestBackup = new BackupInfo(backupTimestamp, backup.length(), backup);
+      }
+    }
+
+    return latestBackup;
+  }
+
+  @SuppressWarnings("ResultOfMethodCallIgnored")
+  public static void deleteAllBackups() {
+    try {
+      File   backupDirectory = StorageUtil.getBackupDirectory();
+      File[] backups         = backupDirectory.listFiles();
+
+      for (File backup : backups) {
+        if (backup.isFile()) backup.delete();
+      }
+    } catch (NoExternalStorageException e) {
+      Log.w(TAG, e);
+    }
+  }
+
+  public static void deleteOldBackups() {
+    try {
+      File   backupDirectory = StorageUtil.getBackupDirectory();
+      File[] backups         = backupDirectory.listFiles();
+
+      if (backups != null && backups.length > 5) {
+        Arrays.sort(backups, (left, right) -> {
+          long leftTimestamp  = getBackupTimestamp(left);
+          long rightTimestamp = getBackupTimestamp(right);
+
+          if      (leftTimestamp == -1 && rightTimestamp == -1) return 0;
+          else if (leftTimestamp == -1)                         return 1;
+          else if (rightTimestamp == -1)                        return -1;
+
+          return (int)(rightTimestamp - leftTimestamp);
+        });
+
+        for (int i=5;i<backups.length;i++) {
+          Log.w(TAG, "Deleting: " + backups[i].getAbsolutePath());
+
+          if (!backups[i].delete()) {
+            Log.w(TAG, "Delete failed: " + backups[i].getAbsolutePath());
+          }
+        }
+      }
+    } catch (NoExternalStorageException e) {
+      Log.w(TAG, e);
+    }
+  }
+
+  public static @NonNull String[] generateBackupPassphrase() {
+    String[] result = new String[6];
+    byte[]   random = new byte[30];
+
+    new SecureRandom().nextBytes(random);
+
+    for (int i=0;i<30;i+=5) {
+      result[i/5] = String.format("%05d", ByteUtil.byteArray5ToLong(random, i) % 100000);
+    }
+
+    return result;
+  }
+
+  private static long getBackupTimestamp(File backup) {
+    String   name  = backup.getName();
+    String[] prefixSuffix = name.split("[.]");
+
+    if (prefixSuffix.length == 2) {
+      String[] parts = prefixSuffix[0].split("\\-");
+
+      if (parts.length == 7) {
+        try {
+          Calendar calendar = Calendar.getInstance();
+          calendar.set(Calendar.YEAR, Integer.parseInt(parts[1]));
+          calendar.set(Calendar.MONTH, Integer.parseInt(parts[2]) - 1);
+          calendar.set(Calendar.DAY_OF_MONTH, Integer.parseInt(parts[3]));
+          calendar.set(Calendar.HOUR_OF_DAY, Integer.parseInt(parts[4]));
+          calendar.set(Calendar.MINUTE, Integer.parseInt(parts[5]));
+          calendar.set(Calendar.SECOND, Integer.parseInt(parts[6]));
+          calendar.set(Calendar.MILLISECOND, 0);
+
+          return calendar.getTimeInMillis();
+        } catch (NumberFormatException e) {
+          Log.w(TAG, e);
+        }
+      }
+    }
+
+    return -1;
+  }
+
+  public static class BackupInfo {
+
+    private final long timestamp;
+    private final long size;
+    private final File file;
+
+    BackupInfo(long timestamp, long size, File file) {
+      this.timestamp = timestamp;
+      this.size      = size;
+      this.file      = file;
+    }
+
+    public long getTimestamp() {
+      return timestamp;
+    }
+
+    public long getSize() {
+      return size;
+    }
+
+    public File getFile() {
+      return file;
+    }
+  }
+}