Clean up a few Option/Result patterns that fit an std combinator

(cherry picked from commit f731019c83)

quinn-proto/src/connection/assembler.rs

@@ -51,10 +51,7 @@ impl Assembler {
     /// Get the the next chunk
     pub(crate) fn read(&mut self, max_length: usize, ordered: bool) -> Option<Chunk> {
         loop {
-            let mut chunk = match self.data.peek_mut() {
-                Some(chunk) => chunk,
-                None => return None,
-            };
+            let mut chunk = self.data.peek_mut()?;
 
             if ordered {
                 if chunk.offset > self.bytes_read {

quinn-proto/src/connection/streams/mod.rs

@@ -254,10 +254,11 @@ impl<'a> SendStream<'a> {
     /// # Panics
     /// - when applied to a receive stream
     pub fn reset(&mut self, error_code: VarInt) -> Result<(), UnknownStream> {
-        let stream = match self.state.send.get_mut(&self.id) {
-            Some(ss) => ss,
-            None => return Err(UnknownStream { _private: () }),
-        };
+        let stream = self
+            .state
+            .send
+            .get_mut(&self.id)
+            .ok_or(UnknownStream { _private: () })?;
 
         if matches!(stream.state, SendState::ResetSent) {
             // Redundant reset call
@@ -280,10 +281,11 @@ impl<'a> SendStream<'a> {
     /// # Panics
     /// - when applied to a receive stream
     pub fn set_priority(&mut self, priority: i32) -> Result<(), UnknownStream> {
-        let stream = match self.state.send.get_mut(&self.id) {
-            Some(ss) => ss,
-            None => return Err(UnknownStream { _private: () }),
-        };
+        let stream = self
+            .state
+            .send
+            .get_mut(&self.id)
+            .ok_or(UnknownStream { _private: () })?;
 
         stream.priority = priority;
         Ok(())
@@ -294,10 +296,11 @@ impl<'a> SendStream<'a> {
     /// # Panics
     /// - when applied to a receive stream
     pub fn priority(&self) -> Result<i32, UnknownStream> {
-        let stream = match self.state.send.get(&self.id) {
-            Some(ss) => ss,
-            None => return Err(UnknownStream { _private: () }),
-        };
+        let stream = self
+            .state
+            .send
+            .get(&self.id)
+            .ok_or(UnknownStream { _private: () })?;
 
         Ok(stream.priority)
     }

quinn/examples/server.rs

@@ -243,7 +243,7 @@ fn process_get(root: &Path, x: &[u8]) -> Result<Vec<u8>> {
         bail!("missing \\r\\n");
     }
     let x = &x[4..x.len() - 2];
-    let end = x.iter().position(|&c| c == b' ').unwrap_or_else(|| x.len());
+    let end = x.iter().position(|&c| c == b' ').unwrap_or(x.len());
     let path = str::from_utf8(&x[..end]).context("path is malformed UTF-8")?;
     let path = Path::new(&path);
     let mut real_path = PathBuf::from(root);