Improve readability of the code a little

src/adapter.rs

@@ -115,20 +115,18 @@ impl Adapter {
             return Ok(Buffer::new());
         }
 
-        if let Some(sub) = {
-            if let Some(front) = self.deque.front() {
-                if front.get_size() - self.skip >= size {
-                    let new = front.get_buffer().copy_region(self.skip, Some(size)).unwrap();
-                    Some(new)
-                } else {
-                    None
-                }
+        let sub = self.deque.front().and_then(|front| {
+            if front.get_size() - self.skip >= size {
+                let new = front.get_buffer().copy_region(self.skip, Some(size)).unwrap();
+                Some(new)
             } else {
                 None
             }
-        } {
+        });
+
+        if let Some(s) = sub {
             self.flush(size).unwrap();
-            return Ok(sub);
+            return Ok(s);
         }
 
         let mut new = Buffer::new_with_size(size).unwrap();

src/rshttpsrc.rs

@@ -65,13 +65,12 @@ impl HttpSrc {
                   -> Result<StreamingState, ErrorMessage> {
         let mut req = self.client.get(uri.clone());
 
-        if start != 0 || stop.is_some() {
-            req = match stop {
-                None => req.header(Range::Bytes(vec![ByteRangeSpec::AllFrom(start)])),
-                Some(stop) => {
-                    req.header(Range::Bytes(vec![ByteRangeSpec::FromTo(start, stop - 1)]))
-                }
-            };
+        match (start != 0, stop) {
+            (false, None) => (),
+            (true, None) => req = req.header(Range::Bytes(vec![ByteRangeSpec::AllFrom(start)])),
+            (_, Some(stop)) => {
+                req = req.header(Range::Bytes(vec![ByteRangeSpec::FromTo(start, stop - 1)]))
+            }
         }
 
         let response = try!(req.send().or_else(|err| {
@@ -84,11 +83,7 @@ impl HttpSrc {
                                   ["Failed to fetch {}: {}", uri, response.status()]));
         }
 
-        let size = if let Some(&ContentLength(content_length)) = response.headers().get() {
-            Some(content_length + start)
-        } else {
-            None
-        };
+        let size = response.headers().get().map(|&ContentLength(cl)| cl + start);
 
         let accept_byte_ranges = if let Some(&AcceptRanges(ref ranges)) = response.headers()
             .get() {

src/rssource.rs

@@ -122,10 +122,7 @@ impl SourceWrapper {
 
     fn get_size(&self) -> u64 {
         let source = &self.source.lock().unwrap();
-        match source.get_size() {
-            Some(size) => size,
-            None => u64::MAX,
-        }
+        source.get_size().unwrap_or(u64::MAX)
     }
 
     fn start(&self) -> bool {