more SAF implementation

* full support for Directory API (Android Lollipop or later)
* best effort to handle any kind errors (missing file, revoked permissions, etc) and recover the download
* implemented directory choosing
* fix download database version upgrading
* misc. cleanup
* do not release permission on the old save path (if the user change the download directory) under SAF api

app/src/main/java/org/schabi/newpipe/streams/DataReader.java

@@ -16,6 +16,8 @@ public class DataReader {
     public final static int INTEGER_SIZE = 4;
     public final static int FLOAT_SIZE = 4;
 
+    private final static int BUFFER_SIZE = 128 * 1024;// 128 KiB
+
     private long position = 0;
     private final SharpStream stream;
 
@@ -229,7 +231,7 @@ public class DataReader {
         }
     }
 
-    private final byte[] readBuffer = new byte[8 * 1024];
+    private final byte[] readBuffer = new byte[BUFFER_SIZE];
     private int readOffset;
     private int readCount;
 

app/src/main/java/org/schabi/newpipe/streams/Mp4FromDashWriter.java

@@ -12,7 +12,6 @@ import java.io.IOException;
 import java.nio.ByteBuffer;
 
 /**
- *
  * @author kapodamy
  */
 public class Mp4FromDashWriter {
@@ -262,12 +261,12 @@ public class Mp4FromDashWriter {
         final int ftyp_size = make_ftyp();
 
         // reserve moov space in the output stream
-        if (outStream.canSetLength()) {
+        /*if (outStream.canSetLength()) {
             long length = writeOffset + auxSize;
             outStream.setLength(length);
             outSeek(length);
-        } else {
-            // hard way
+        } else {*/
+        if (auxSize > 0) {
             int length = auxSize;
             byte[] buffer = new byte[8 * 1024];// 8 KiB
             while (length > 0) {
@@ -276,6 +275,7 @@ public class Mp4FromDashWriter {
                 length -= count;
             }
         }
+
         if (auxBuffer == null) {
             outSeek(ftyp_size);
         }