Retrying DFU

dfu/src/main/java/no/nordicsemi/android/dfu/BaseDfuImpl.java

@@ -707,6 +707,10 @@ import no.nordicsemi.android.dfu.internal.scanner.BootloaderScannerFactory;
 
 		if (newAddress != null)
 			intent.putExtra(DfuBaseService.EXTRA_DEVICE_ADDRESS, newAddress);
+
+		// Reset the DFU attempt counter
+		intent.putExtra(DfuBaseService.EXTRA_DFU_ATTEMPT, 0);
+
 		mService.startService(intent);
 	}
 

dfu/src/main/java/no/nordicsemi/android/dfu/DfuBaseService.java

@@ -1347,9 +1347,19 @@ public abstract class DfuBaseService extends IntentService implements DfuProgres
 				mProgressInfo.setProgress(PROGRESS_ABORTED);
 			} catch (final DeviceDisconnectedException e) {
 				sendLogBroadcast(LOG_LEVEL_ERROR, "Device has disconnected");
-				// TODO reconnect n times?
 				loge(e.getMessage());
 				close(gatt);
+
+				final int attempt = intent.getIntExtra(EXTRA_DFU_ATTEMPT, 0);
+				final int limit = intent.getIntExtra(EXTRA_MAX_DFU_ATTEMPTS, 0);
+				if (attempt < limit) {
+					logi("Restarting the service (" + (attempt + 1)  + " /" + limit + ")");
+					final Intent newIntent = new Intent();
+					newIntent.fillIn(intent, Intent.FILL_IN_COMPONENT | Intent.FILL_IN_PACKAGE);
+					newIntent.putExtra(EXTRA_DFU_ATTEMPT, attempt + 1);
+					startService(newIntent);
+					return;
+				}
 				report(ERROR_DEVICE_DISCONNECTED);
 			} catch (final DfuException e) {
 				int error = e.getErrorNumber();

dfu/src/main/java/no/nordicsemi/android/dfu/DfuServiceInitiator.java

@@ -79,6 +79,7 @@ public class DfuServiceInitiator {
 	private boolean forceDfu = false;
 	private boolean enableUnsafeExperimentalButtonlessDfu = false;
 	private boolean disableResume = false;
+	private int numberOfRetries = 0; // 0 to be backwards compatible
 
 	private Boolean packetReceiptNotificationsEnabled;
 	private int numberOfPackets = 12;
@@ -269,6 +270,28 @@ public class DfuServiceInitiator {
 		return this;
 	}
 
+	/**
+	 * Sets the number of retries that the DFU service will use to complete DFU. The default
+	 * value is 0, for backwards compatibility reason.
+	 * <p>
+	 * If the given value is greater than 0, the service will restart itself at most {@code max}
+	 * times in case of an undesired disconnection during DFU operation. This attempt counter
+	 * is independent from another counter, for reconnection attempts, which is equal to 3.
+	 * The latter one will be used when connection will fail with an error (possible packet
+	 * collision or any other reason). After successful connection, the reconnection counter is
+	 * reset, while the retry counter is cleared after a DFU finishes with success.
+	 * <p>
+	 * The service will not try to retry DFU in case of any other error, for instance an error
+	 * sent from the target device.
+	 *
+	 * @param max Maximum number of retires to complete DFU. Usually around 2.
+	 * @return the builder
+	 */
+	public DfuServiceInitiator setNumberOfRetries(@IntRange(from = 0) final int max) {
+		this.numberOfRetries = max;
+		return this;
+	}
+
 	/**
 	 * Sets the Maximum Transfer Unit (MTU) value that the Secure DFU service will try to request
 	 * before performing DFU. By default, value 517 will be used, which is the highest supported
@@ -704,6 +727,7 @@ public class DfuServiceInitiator {
 		intent.putExtra(DfuBaseService.EXTRA_RESTORE_BOND, restoreBond);
 		intent.putExtra(DfuBaseService.EXTRA_FORCE_DFU, forceDfu);
 		intent.putExtra(DfuBaseService.EXTRA_DISABLE_RESUME, disableResume);
+		intent.putExtra(DfuBaseService.EXTRA_MAX_DFU_ATTEMPTS, numberOfRetries);
 		if (mtu > 0)
 			intent.putExtra(DfuBaseService.EXTRA_MTU, mtu);
 		intent.putExtra(DfuBaseService.EXTRA_CURRENT_MTU, currentMtu);

dfu/src/main/java/no/nordicsemi/android/dfu/LegacyDfuImpl.java

@@ -474,7 +474,6 @@ import no.nordicsemi.android.error.LegacyDfuError;
 			} catch (final DeviceDisconnectedException e) {
 				loge("Disconnected while sending data");
 				throw e;
-				// TODO reconnect?
 			}
 			final long endTime = SystemClock.elapsedRealtime();
 

dfu/src/main/java/no/nordicsemi/android/dfu/SecureDfuImpl.java

@@ -391,8 +391,13 @@ class SecureDfuImpl extends BaseCustomDfuImpl {
 					mService.sendLogBroadcast(DfuBaseService.LOG_LEVEL_APPLICATION, "Command object created");
 				}
 				// Write Init data to the Packet Characteristic
-				logi("Sending " + (mInitPacketSizeInBytes - info.offset) + " bytes of init packet...");
+				try {
-				writeInitData(mPacketCharacteristic, crc32);
+					logi("Sending " + (mInitPacketSizeInBytes - info.offset) + " bytes of init packet...");
+					writeInitData(mPacketCharacteristic, crc32);
+				} catch (final DeviceDisconnectedException e) {
+					loge("Disconnected while sending init packet");
+					throw e;
+				}
 				final int crc = (int) (crc32.getValue() & 0xFFFFFFFFL);
 				mService.sendLogBroadcast(DfuBaseService.LOG_LEVEL_APPLICATION, String.format(Locale.US, "Command object sent (CRC = %08X)", crc));