Better support for empty media types.

src/main/java/de/fabianonline/telegram_backup/CommandLineDownloadProgress.java

@@ -16,7 +16,7 @@ class CommandLineDownloadProgress implements DownloadProgressInterface {
 		System.out.println("Checking and downloading media.");
 		System.out.println("Legend:");
 		System.out.println("'V' - Video         'P' - Photo         'D' - Document");
-		System.out.println("'S' - Sticker       'A' - Audio");
+		System.out.println("'S' - Sticker       'A' - Audio         'e' - Empty file");
 		System.out.println("'.' - Previously downloaded file");
 		System.out.println("' ' - Ignored media type (location or website, for example)");
 		System.out.println("" + count + " Files to check / download");    
@@ -28,6 +28,7 @@ class CommandLineDownloadProgress implements DownloadProgressInterface {
 	public void onMediaDownloadedSticker(boolean n) { show(n, 'S'); }
 	public void onMediaDownloadedOther(boolean n) { show(n, ' '); }
 	public void onMediaDownloadedAudio(boolean n) { show(n, 'A'); }
+	public void onMediaDownloadedEmpty(boolean n) { show(true, 'e'); }
 	public void onMediaDownloadFinished() { showNewLine(); System.out.println("Done."); }
 	
 	private void show(boolean n, char letter) { System.out.print(n ? letter : '.'); i++; if (i % 50 == 0) showNewLine();}

src/main/java/de/fabianonline/telegram_backup/DownloadManager.java

@@ -7,6 +7,7 @@ import de.fabianonline.telegram_backup.DownloadProgressInterface;
 
 import com.github.badoualy.telegram.api.TelegramClient;
 import com.github.badoualy.telegram.tl.core.TLIntVector;
+import com.github.badoualy.telegram.tl.core.TLObject;
 import com.github.badoualy.telegram.tl.api.messages.TLAbsMessages;
 import com.github.badoualy.telegram.tl.api.messages.TLAbsDialogs;
 import com.github.badoualy.telegram.tl.api.*;
@@ -134,6 +135,8 @@ class DownloadManager {
 				boolean res = this.downloadPhoto(msg.getId(), (TLFileLocation)size.getLocation(), size.getSize());
 				prog.onMediaDownloadedPhoto(res);
 			}
+		} else if (p.getPhoto() instanceof TLPhotoEmpty) {
+			downloadEmptyObject(p.getPhoto());
 		} else {
 			throw new RuntimeException("Got an unexpected " + p.getPhoto().getClass().getName());
 		}
@@ -180,6 +183,8 @@ class DownloadManager {
 			} else {
 				prog.onMediaDownloadedDocument(res);
 			}
+		} else if (d.getDocument() instanceof TLDocumentEmpty) {
+			downloadEmptyObject(d.getDocument());
 		} else {
 			throw new RuntimeException("Got an unexpected " + d.getDocument().getClass().getName());
 		}
@@ -192,6 +197,10 @@ class DownloadManager {
 			String ext = vid.getMimeType().substring(i+1).toLowerCase();
 			boolean res = this.downloadVideo(this.makeFilename(msg.getId(), ext), vid);
 			prog.onMediaDownloadedVideo(res);
+		} else if (v.getVideo() instanceof TLVideoEmpty) {
+			downloadEmptyObject(v.getVideo());
+		} else {
+			throw new RuntimeException("Got an unexpected " + v.getVideo().getClass().getName());
 		}
 	}
 	
@@ -202,6 +211,10 @@ class DownloadManager {
 			String ext = audio.getMimeType().substring(i+1).toLowerCase();
 			boolean res = this.downloadAudio(this.makeFilename(msg.getId(), ext), audio);
 			prog.onMediaDownloadedAudio(res);
+		} else if (a.getAudio() instanceof TLAudioEmpty) {
+			downloadEmptyObject(a.getAudio());
+		} else {
+			throw new RuntimeException("Got an unexpected " + a.getAudio().getClass().getName());
 		}
 	}
 	
@@ -242,6 +255,10 @@ class DownloadManager {
 		return this.downloadFileFromDc(filename, loc, audio.getDcId(), audio.getSize());
 	}
 	
+	private void downloadEmptyObject(TLObject obj) {
+		prog.onMediaDownloadedEmpty(true);
+	}
+	
 	private String makeFilename(int id, String ext) {
 		String path = this.user.getFileBase() + 
 			Config.FILE_FILES_BASE +

src/main/java/de/fabianonline/telegram_backup/DownloadProgressInterface.java

@@ -12,5 +12,6 @@ interface DownloadProgressInterface {
 	public void onMediaDownloadedSticker(boolean n);
 	public void onMediaDownloadedOther(boolean n);
 	public void onMediaDownloadedAudio(boolean n);
+	public void onMediaDownloadedEmpty(boolean n);
 	public void onMediaDownloadFinished();
 }