Fixed block import (#368)

* Fixed decoding from file

* Increased progress frequency

substrate/polkadot/cli/src/lib.rs

@@ -430,8 +430,8 @@ fn import_blocks<E>(matches: &clap::ArgMatches, exit: E) -> error::Result<()>
 		None => Box::new(stdin()),
 	};
 
-	info!("Importing blocks");
 	let count: u32 = Decode::decode(&mut file).ok_or("Error reading file")?;
+	info!("Importing {} blocks", count);
 	let mut block = 0;
 	for _ in 0 .. count {
 		if exit_recv.try_recv().is_ok() {
@@ -448,7 +448,7 @@ fn import_blocks<E>(matches: &clap::ArgMatches, exit: E) -> error::Result<()>
 			}
 		}
 		block += 1;
-		if block % 10000 == 0 {
+		if block % 1000 == 0 {
 			info!("#{}", block);
 		}
 	}

substrate/substrate/codec/src/codec.rs

@@ -49,7 +49,10 @@ impl<'a> Input for &'a [u8] {
 #[cfg(feature = "std")]
 impl<R: ::std::io::Read> Input for R {
 	fn read(&mut self, into: &mut [u8]) -> usize {
-		(self as &mut ::std::io::Read).read(into).unwrap_or(0)
+		match (self as &mut ::std::io::Read).read_exact(into) {
+			Ok(()) => into.len(),
+			Err(_) => 0,
+		}
 	}
 }