From f604574713038d3ba2edc22b396e6fd718e0dfc6 Mon Sep 17 00:00:00 2001
From: debris <marek.kotewicz@gmail.com>
Date: Mon, 31 Oct 2016 15:28:28 +0100
Subject: [PATCH] make import::open_blk_dir prettier

---
 import/src/blk.rs | 39 +++++++++++----------------------------
 1 file changed, 11 insertions(+), 28 deletions(-)

diff --git a/import/src/blk.rs b/import/src/blk.rs
index 6bc2e53f..b78fac7d 100644
--- a/import/src/blk.rs
+++ b/import/src/blk.rs
@@ -1,7 +1,7 @@
 use std::{io, fs, path};
 use ser::{ReadIterator, deserialize_iterator, Error as ReaderError};
 use block::Block;
-use fs::{read_blk_dir, ReadBlkDir};
+use fs::read_blk_dir;
 
 pub fn open_blk_file<P>(path: P) -> Result<BlkFile, io::Error> where P: AsRef<path::Path> {
 	let file = try!(fs::File::open(path));
@@ -24,45 +24,28 @@ impl Iterator for BlkFile {
 }
 
 pub fn open_blk_dir<P>(path: P) -> Result<BlkDir, io::Error> where P: AsRef<path::Path> {
-	let dir_iter = try!(read_blk_dir(path));
+	let iter = try!(read_blk_dir(path))
+		// flatten results...
+		.flat_map(|entry| entry.and_then(|file| open_blk_file(file.path)))
+		// flat iterators over each block in each file
+		.flat_map(|file| file);
+
 	let blk_dir = BlkDir {
-		dir_iter: dir_iter,
-		current_file: None,
+		iter: Box::new(iter),
 	};
+
 	Ok(blk_dir)
 }
 
 pub struct BlkDir {
-	dir_iter: ReadBlkDir,
-	current_file: Option<BlkFile>,
+	iter: Box<Iterator<Item = Result<Block, ReaderError>>>,
 }
 
 impl Iterator for BlkDir {
 	type Item = Result<Block, ReaderError>;
 
 	fn next(&mut self) -> Option<Self::Item> {
-		// TODO: use chained iterators instead
-		let next_file = match self.current_file {
-			Some(ref mut file) => match file.next() {
-				Some(block) => return Some(block),
-				None => self.dir_iter.next(),
-			},
-			None => self.dir_iter.next(),
-		};
-
-		match next_file {
-			Some(Ok(next_file)) => {
-				self.current_file = match open_blk_file(next_file.path) {
-					Err(_) => return Some(Err(ReaderError::MalformedData)),
-					Ok(file) => Some(file),
-				};
-				self.next()
-			},
-			Some(Err(_)) => {
-				Some(Err(ReaderError::MalformedData))
-			},
-			None => None,
-		}
+		self.iter.next()
 	}
 }