diff options
Diffstat (limited to 'storage/importexport/src')
| -rw-r--r-- | storage/importexport/src/main/java/de/danoeh/antennapod/storage/importexport/OpmlBackupAgent.java | 185 |
1 files changed, 185 insertions, 0 deletions
diff --git a/storage/importexport/src/main/java/de/danoeh/antennapod/storage/importexport/OpmlBackupAgent.java b/storage/importexport/src/main/java/de/danoeh/antennapod/storage/importexport/OpmlBackupAgent.java new file mode 100644 index 000000000..4c9256fdc --- /dev/null +++ b/storage/importexport/src/main/java/de/danoeh/antennapod/storage/importexport/OpmlBackupAgent.java @@ -0,0 +1,185 @@ +package de.danoeh.antennapod.storage.importexport; + +import android.app.backup.BackupAgentHelper; +import android.app.backup.BackupDataInputStream; +import android.app.backup.BackupDataOutput; +import android.app.backup.BackupHelper; +import android.content.Context; +import android.os.ParcelFileDescriptor; +import android.util.Log; + +import de.danoeh.antennapod.net.download.serviceinterface.FeedUpdateManager; +import de.danoeh.antennapod.storage.database.FeedDatabaseWriter; +import org.apache.commons.io.IOUtils; +import org.xmlpull.v1.XmlPullParserException; + +import java.io.ByteArrayOutputStream; +import java.io.FileInputStream; +import java.io.FileOutputStream; +import java.io.IOException; +import java.io.InputStreamReader; +import java.io.OutputStreamWriter; +import java.io.Reader; +import java.io.Writer; +import java.math.BigInteger; +import java.nio.charset.Charset; +import java.security.DigestInputStream; +import java.security.DigestOutputStream; +import java.security.MessageDigest; +import java.security.NoSuchAlgorithmException; +import java.util.ArrayList; +import java.util.Arrays; +import java.util.Collections; + +import de.danoeh.antennapod.model.feed.Feed; +import de.danoeh.antennapod.storage.database.DBReader; + +public class OpmlBackupAgent extends BackupAgentHelper { + private static final String OPML_BACKUP_KEY = "opml"; + + @Override + public void onCreate() { + addHelper(OPML_BACKUP_KEY, new OpmlBackupHelper(this)); + } + + /** + * Class for backing up and restoring the OPML file. + */ + private static class OpmlBackupHelper implements BackupHelper { + private static final String TAG = "OpmlBackupHelper"; + + private static final String OPML_ENTITY_KEY = "antennapod-feeds.opml"; + + private final Context mContext; + + /** + * Checksum of restored OPML file + */ + private byte[] mChecksum; + + public OpmlBackupHelper(Context context) { + mContext = context; + } + + @Override + public void performBackup(ParcelFileDescriptor oldState, BackupDataOutput data, ParcelFileDescriptor newState) { + Log.d(TAG, "Performing backup"); + ByteArrayOutputStream byteStream = new ByteArrayOutputStream(); + MessageDigest digester = null; + Writer writer; + + try { + digester = MessageDigest.getInstance("MD5"); + writer = new OutputStreamWriter(new DigestOutputStream(byteStream, digester), + Charset.forName("UTF-8")); + } catch (NoSuchAlgorithmException e) { + writer = new OutputStreamWriter(byteStream, Charset.forName("UTF-8")); + } + + try { + // Write OPML + OpmlWriter.writeDocument(DBReader.getFeedList(), writer); + + // Compare checksum of new and old file to see if we need to perform a backup at all + if (digester != null) { + byte[] newChecksum = digester.digest(); + Log.d(TAG, "New checksum: " + new BigInteger(1, newChecksum).toString(16)); + + // Get the old checksum + if (oldState != null) { + try (final FileInputStream inState = new FileInputStream(oldState.getFileDescriptor())) { + int len = inState.read(); + + if (len != -1) { + byte[] oldChecksum = new byte[len]; + IOUtils.read(inState, oldChecksum, 0, len); + Log.d(TAG, "Old checksum: " + new BigInteger(1, oldChecksum).toString(16)); + + if (Arrays.equals(oldChecksum, newChecksum)) { + Log.d(TAG, "Checksums are the same; won't backup"); + return; + } + } + } + } + + writeNewStateDescription(newState, newChecksum); + } + + Log.d(TAG, "Backing up OPML"); + byte[] bytes = byteStream.toByteArray(); + data.writeEntityHeader(OPML_ENTITY_KEY, bytes.length); + data.writeEntityData(bytes, bytes.length); + } catch (IOException e) { + Log.e(TAG, "Error during backup", e); + } finally { + IOUtils.closeQuietly(writer); + } + } + + @Override + public void restoreEntity(BackupDataInputStream data) { + Log.d(TAG, "Backup restore"); + + if (!OPML_ENTITY_KEY.equals(data.getKey())) { + Log.d(TAG, "Unknown entity key: " + data.getKey()); + return; + } + + MessageDigest digester = null; + Reader reader; + + try { + digester = MessageDigest.getInstance("MD5"); + reader = new InputStreamReader(new DigestInputStream(data, digester), + Charset.forName("UTF-8")); + } catch (NoSuchAlgorithmException e) { + reader = new InputStreamReader(data, Charset.forName("UTF-8")); + } + + try { + ArrayList<OpmlElement> opmlElements = new OpmlReader().readDocument(reader); + mChecksum = digester == null ? null : digester.digest(); + for (OpmlElement opmlElem : opmlElements) { + Feed feed = new Feed(opmlElem.getXmlUrl(), null, opmlElem.getText()); + feed.setItems(Collections.emptyList()); + FeedDatabaseWriter.updateFeed(mContext, feed, false); + } + FeedUpdateManager.getInstance().runOnce(mContext); + } catch (XmlPullParserException e) { + Log.e(TAG, "Error while parsing the OPML file", e); + } catch (IOException e) { + Log.e(TAG, "Failed to restore OPML backup", e); + } finally { + IOUtils.closeQuietly(reader); + } + } + + @Override + public void writeNewStateDescription(ParcelFileDescriptor newState) { + writeNewStateDescription(newState, mChecksum); + } + + /** + * Writes the new state description, which is the checksum of the OPML file. + * + * @param newState + * @param checksum + */ + private void writeNewStateDescription(ParcelFileDescriptor newState, byte[] checksum) { + if (checksum == null) { + return; + } + + try { + FileOutputStream outState = new FileOutputStream(newState.getFileDescriptor()); + outState.write(checksum.length); + outState.write(checksum); + outState.flush(); + outState.close(); + } catch (IOException e) { + Log.e(TAG, "Failed to write new state description", e); + } + } + } +} |