Fix issues reported by clippy

The clippy tool has a couple of suggestions on how to improve the code.
This change applies them to the project's code base.

6 files changed, 72 insertions, 74 deletions

diff --git a/nitrocli/Cargo.lock b/nitrocli/Cargo.lock
index a18c654..8daadf2 100644
--- a/nitrocli/Cargo.lock
+++ b/nitrocli/Cargo.lock
@@ -1,14 +1,3 @@
-[root]
-name = "nitrocli"
-version = "0.1.2"
-dependencies = [
- "cc 1.0.4",
- "hid 0.4.1",
- "hidapi-sys 0.1.4",
- "libc 0.2.36",
- "pkg-config 0.3.9",
-]
-
 [[package]]
 name = "cc"
 version = "1.0.4"
@@ -53,6 +42,17 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 replace = "libc 0.2.36"
 
 [[package]]
+name = "nitrocli"
+version = "0.1.2"
+dependencies = [
+ "cc 1.0.4",
+ "hid 0.4.1",
+ "hidapi-sys 0.1.4",
+ "libc 0.2.36",
+ "pkg-config 0.3.9",
+]
+
+[[package]]
 name = "pkg-config"
 version = "0.3.9"
 
diff --git a/nitrocli/src/crc32.rs b/nitrocli/src/crc32.rs
index 8431db5..8b85b49 100644
--- a/nitrocli/src/crc32.rs
+++ b/nitrocli/src/crc32.rs
@@ -1,7 +1,7 @@
 // crc32.rs
 
 // *************************************************************************
-// * Copyright (C) 2017 Daniel Mueller (deso@posteo.net)                   *
+// * Copyright (C) 2017-2018 Daniel Mueller (deso@posteo.net)              *
 // *                                                                       *
 // * This program is free software: you can redistribute it and/or modify  *
 // * it under the terms of the GNU General Public License as published by  *
@@ -18,20 +18,20 @@
 // *************************************************************************
 
 /// Polynomial used in STM32.
-const CRC32_POLYNOMIAL: u32 = 0x04c11db7;
+const CRC32_POLYNOMIAL: u32 = 0x04c1_1db7;
 
 
 fn crc32(mut crc: u32, data: u32) -> u32 {
-  crc = crc ^ data;
+  crc ^= data;
 
   for _ in 0..32 {
-    if crc & 0x80000000 != 0 {
+    if crc & 0x8000_0000 != 0 {
       crc = (crc << 1) ^ CRC32_POLYNOMIAL;
     } else {
-      crc = crc << 1;
+      crc <<= 1;
     }
   }
-  return crc;
+  crc
 }
 
 
@@ -45,20 +45,20 @@ fn as_slice_u32(data: &[u8]) -> &[u32] {
   unsafe {
     let ptr = data.as_ptr() as *const u32;
     let len = data.len() / ::std::mem::size_of::<u32>();
-    return ::std::slice::from_raw_parts(ptr, len);
+    ::std::slice::from_raw_parts(ptr, len)
   }
 }
 
 
 /// Calculate the CRC of a byte slice.
 pub fn crc(data: &[u8]) -> u32 {
-  let mut crc = 0xffffffff;
+  let mut crc = 0xffff_ffff;
   let data = as_slice_u32(data);
 
-  for i in 0..data.len() {
-    crc = crc32(crc, data[i]);
+  for byte in data {
+    crc = crc32(crc, *byte);
   }
-  return crc;
+  crc
 }
 
 
diff --git a/nitrocli/src/error.rs b/nitrocli/src/error.rs
index a88b5a7..ea9a189 100644
--- a/nitrocli/src/error.rs
+++ b/nitrocli/src/error.rs
@@ -1,7 +1,7 @@
 // error.rs
 
 // *************************************************************************
-// * Copyright (C) 2017 Daniel Mueller (deso@posteo.net)                   *
+// * Copyright (C) 2017-2018 Daniel Mueller (deso@posteo.net)              *
 // *                                                                       *
 // * This program is free software: you can redistribute it and/or modify  *
 // * it under the terms of the GNU General Public License as published by  *
@@ -34,32 +34,32 @@ pub enum Error {
 
 impl From<libhid::Error> for Error {
   fn from(e: libhid::Error) -> Error {
-    return Error::HidError(e);
+    Error::HidError(e)
   }
 }
 
 
 impl From<io::Error> for Error {
   fn from(e: io::Error) -> Error {
-    return Error::IoError(e);
+    Error::IoError(e)
   }
 }
 
 
 impl From<string::FromUtf8Error> for Error {
   fn from(e: string::FromUtf8Error) -> Error {
-    return Error::Utf8Error(e);
+    Error::Utf8Error(e)
   }
 }
 
 
 impl fmt::Display for Error {
   fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-    match *&self {
-      &Error::HidError(ref e) => return write!(f, "hidapi error: {}", e),
-      &Error::Utf8Error(_) => return write!(f, "Encountered UTF-8 conversion error"),
-      &Error::IoError(ref e) => return write!(f, "IO error: {}", e.get_ref().unwrap()),
-      &Error::Error(ref e) => return write!(f, "{}", e),
+    match *self {
+      Error::HidError(ref e) => write!(f, "hidapi error: {}", e),
+      Error::Utf8Error(_) => write!(f, "Encountered UTF-8 conversion error"),
+      Error::IoError(ref e) => write!(f, "IO error: {}", e.get_ref().unwrap()),
+      Error::Error(ref e) => write!(f, "{}", e),
     }
   }
 }
diff --git a/nitrocli/src/main.rs b/nitrocli/src/main.rs
index 5c8856e..3ec3243 100644
--- a/nitrocli/src/main.rs
+++ b/nitrocli/src/main.rs
@@ -1,7 +1,7 @@
 // main.rs
 
 // *************************************************************************
-// * Copyright (C) 2017 Daniel Mueller (deso@posteo.net)                   *
+// * Copyright (C) 2017-2018 Daniel Mueller (deso@posteo.net)              *
 // *                                                                       *
 // * This program is free software: you can redistribute it and/or modify  *
 // * it under the terms of the GNU General Public License as published by  *
@@ -124,13 +124,13 @@ fn transmit<PS, PR>(handle: &mut libhid::Handle,
   where PS: AsRef<[u8]>,
         PR: AsRef<[u8]> + Default,
 {
-  send(handle, &report)?;
+  send(handle, report)?;
 
   // We need to give the stick some time to handle the command. If we
   // don't, we might just receive stale data from before.
   thread::sleep(time::Duration::from_millis(SEND_RECV_DELAY_MS));
 
-  return receive::<PR>(handle);
+  receive::<PR>(handle)
 }
 
 
@@ -144,7 +144,7 @@ fn nitrokey_do(function: &NitroFunc) -> Result<()> {
       return function(&mut device.open()?);
     }
   }
-  return Err(Error::Error("Nitrokey device not found".to_string()));
+  Err(Error::Error("Nitrokey device not found".to_string()))
 }
 
 
@@ -205,7 +205,7 @@ fn print_status(response: &nitrokey::DeviceStatusResponse) {
 fn status() -> Result<()> {
   type Response = nitrokey::Response<nitrokey::DeviceStatusResponse>;
 
-  return nitrokey_do(&|handle| {
+  nitrokey_do(&|handle| {
     let payload = nitrokey::DeviceStatusCommand::new();
     let report = nitrokey::Report::from(payload);
 
@@ -223,8 +223,8 @@ fn status() -> Result<()> {
     }
 
     print_status(response);
-    return Ok(());
-  });
+    Ok(())
+  })
 }
 
 
@@ -251,7 +251,7 @@ fn wait(handle: &mut libhid::Handle) -> Result<nitrokey::StorageStatus> {
 fn open() -> Result<()> {
   type Response = nitrokey::Response<nitrokey::StorageResponse>;
 
-  return nitrokey_do(&|handle| {
+  nitrokey_do(&|handle| {
     let mut retry = 3;
     loop {
       let passphrase = pinentry::inquire_passphrase()?;
@@ -284,7 +284,7 @@ fn open() -> Result<()> {
       }
       return Ok(());
     }
-  });
+  })
 }
 
 
@@ -297,7 +297,7 @@ extern "C" {
 fn close() -> Result<()> {
   type Response = nitrokey::Response<nitrokey::StorageResponse>;
 
-  return nitrokey_do(&|handle| {
+  nitrokey_do(&|handle| {
     // Flush all filesystem caches to disk. We are mostly interested in
     // making sure that the encrypted volume on the nitrokey we are
     // about to close is not closed while not all data was written to
@@ -320,14 +320,14 @@ fn close() -> Result<()> {
       let error = format!("Closing encrypted volume failed: {}", status);
       return Err(Error::Error(error));
     }
-    return Ok(());
-  });
+    Ok(())
+  })
 }
 
 
 /// Clear the PIN stored when opening the nitrokey's encrypted volume.
 fn clear() -> Result<()> {
-  return pinentry::clear_passphrase();
+  pinentry::clear_passphrase()
 }
 
 
diff --git a/nitrocli/src/nitrokey.rs b/nitrocli/src/nitrokey.rs
index f8995eb..83f5d1f 100644
--- a/nitrocli/src/nitrokey.rs
+++ b/nitrocli/src/nitrokey.rs
@@ -1,7 +1,7 @@
 // nitrokey.rs
 
 // *************************************************************************
-// * Copyright (C) 2017 Daniel Mueller (deso@posteo.net)                   *
+// * Copyright (C) 2017-2018 Daniel Mueller (deso@posteo.net)              *
 // *                                                                       *
 // * This program is free software: you can redistribute it and/or modify  *
 // * it under the terms of the GNU General Public License as published by  *
@@ -71,14 +71,14 @@ impl<P> Report<P>
   where P: AsRef<[u8]> + Default,
 {
   pub fn new() -> Report<P> {
-    return Report {
+    Report {
       data: P::default(),
       crc: 0,
-    };
+    }
   }
 
   pub fn is_valid(&self) -> bool {
-    return self.crc == crc(self.data.as_ref());
+    self.crc == crc(self.data.as_ref())
   }
 }
 
@@ -87,7 +87,7 @@ impl<P> AsRef<[u8]> for Report<P>
   where P: AsRef<[u8]>,
 {
   fn as_ref(&self) -> &[u8] {
-    unsafe { return mem::transmute::<&Report<P>, &[u8; 64]>(self) };
+    unsafe { mem::transmute::<&Report<P>, &[u8; 64]>(self) }
   }
 }
 
@@ -97,10 +97,10 @@ impl<P> From<P> for Report<P>
 {
   fn from(payload: P) -> Report<P> {
     let crc = crc(payload.as_ref());
-    return Report {
+    Report {
       data: payload,
       crc: crc,
-    };
+    }
   }
 }
 
@@ -109,7 +109,7 @@ impl<P> AsMut<[u8]> for Report<P>
   where P: AsRef<[u8]>,
 {
   fn as_mut(&mut self) -> &mut [u8] {
-    unsafe { return mem::transmute::<&mut Report<P>, &mut [u8; 64]>(self) };
+    unsafe { mem::transmute::<&mut Report<P>, &mut [u8; 64]>(self) }
   }
 }
 
@@ -120,21 +120,21 @@ pub struct EmptyPayload {
 
 impl Default for EmptyPayload {
   fn default() -> EmptyPayload {
-    return EmptyPayload {
+    EmptyPayload {
       data: [0u8; 60],
-    };
+    }
   }
 }
 
 impl AsRef<[u8]> for EmptyPayload {
   fn as_ref(&self) -> &[u8] {
-    unsafe { return mem::transmute::<&EmptyPayload, &[u8; 60]>(self) };
+    unsafe { mem::transmute::<&EmptyPayload, &[u8; 60]>(self) }
   }
 }
 
 impl<P> AsRef<Response<P>> for EmptyPayload {
   fn as_ref(&self) -> &Response<P> {
-    unsafe { return mem::transmute::<&EmptyPayload, &Response<P>>(self) };
+    unsafe { mem::transmute::<&EmptyPayload, &Response<P>>(self) }
   }
 }
 
@@ -154,10 +154,10 @@ macro_rules! defaultCommandNew {
   ( $name:ident, $command:ident ) => {
     impl $name {
       pub fn new() -> $name {
-        return $name{
+        $name{
           command: Command::$command,
           padding: [0; 59],
-        };
+        }
       }
     }
   }
@@ -167,9 +167,7 @@ macro_rules! defaultPayloadAsRef {
   ( $name:ty ) => {
     impl AsRef<[u8]> for $name {
       fn as_ref(&self) -> &[u8] {
-        unsafe {
-          return mem::transmute::<&$name, &[u8; 60]>(self)
-        };
+        unsafe { mem::transmute::<&$name, &[u8; 60]>(self) }
       }
     }
   }
@@ -198,10 +196,10 @@ pub struct EnableEncryptedVolumeCommand {
 
 
 impl EnableEncryptedVolumeCommand {
-  pub fn new(password: &Vec<u8>) -> EnableEncryptedVolumeCommand {
+  pub fn new(password: &[u8]) -> EnableEncryptedVolumeCommand {
     let mut report = EnableEncryptedVolumeCommand {
       command: Command::EnableEncryptedVolume,
-      kind: 'P' as u8,
+      kind: b'P',
       password: [0; 20],
       padding: [0; 38],
     };
@@ -210,7 +208,7 @@ impl EnableEncryptedVolumeCommand {
 
     let len = cmp::min(report.password.len(), password.len());
     report.password[..len].copy_from_slice(&password[..len]);
-    return report;
+    report
   }
 }
 
@@ -266,7 +264,7 @@ pub struct Response<Payload> {
 
 impl<P> AsRef<[u8]> for Response<P> {
   fn as_ref(&self) -> &[u8] {
-    unsafe { return mem::transmute::<&Response<P>, &[u8; 60]>(self) };
+    unsafe { mem::transmute::<&Response<P>, &[u8; 60]>(self) }
   }
 }
 
diff --git a/nitrocli/src/pinentry.rs b/nitrocli/src/pinentry.rs
index 8de788f..d96d279 100644
--- a/nitrocli/src/pinentry.rs
+++ b/nitrocli/src/pinentry.rs
@@ -1,7 +1,7 @@
 // pinentry.rs
 
 // *************************************************************************
-// * Copyright (C) 2017 Daniel Mueller (deso@posteo.net)                   *
+// * Copyright (C) 2017-2018 Daniel Mueller (deso@posteo.net)              *
 // *                                                                       *
 // * This program is free software: you can redistribute it and/or modify  *
 // * it under the terms of the GNU General Public License as published by  *
@@ -21,7 +21,7 @@ use error::Error;
 use std::process;
 
 
-const CACHE_ID: &'static str = "nitrokey";
+const CACHE_ID: &str = "nitrokey";
 
 
 fn parse_pinentry_passphrase(response: Vec<u8>) -> Result<Vec<u8>, Error> {
@@ -45,14 +45,14 @@ fn parse_pinentry_passphrase(response: Vec<u8>) -> Result<Vec<u8>, Error> {
     let (_, error) = lines[0].split_at(4);
     return Err(Error::Error(error.to_string()));
   }
-  return Err(Error::Error("Unexpected response: ".to_string() + &string));
+  Err(Error::Error("Unexpected response: ".to_string() + &string))
 }
 
 
 pub fn inquire_passphrase() -> Result<Vec<u8>, Error> {
-  const PINENTRY_DESCR: &'static str = "+";
-  const PINENTRY_TITLE: &'static str = "Please+enter+user+PIN";
-  const PINENTRY_PASSWD: &'static str = "PIN";
+  const PINENTRY_DESCR: &str = "+";
+  const PINENTRY_TITLE: &str = "Please+enter+user+PIN";
+  const PINENTRY_PASSWD: &str = "PIN";
 
   let args = vec![CACHE_ID, PINENTRY_DESCR, PINENTRY_PASSWD, PINENTRY_TITLE].join(" ");
   let command = "GET_PASSPHRASE --data ".to_string() + &args;
@@ -65,7 +65,7 @@ pub fn inquire_passphrase() -> Result<Vec<u8>, Error> {
   let output = process::Command::new("gpg-connect-agent").arg(command)
     .arg("/bye")
     .output()?;
-  return parse_pinentry_passphrase(output.stdout);
+  parse_pinentry_passphrase(output.stdout)
 }
 
 
@@ -77,7 +77,7 @@ fn parse_pinentry_response(response: Vec<u8>) -> Result<(), Error> {
     // We got the only valid answer we accept.
     return Ok(());
   }
-  return Err(Error::Error("Unexpected response: ".to_string() + &string));
+  Err(Error::Error("Unexpected response: ".to_string() + &string))
 }
 
 
@@ -88,7 +88,7 @@ pub fn clear_passphrase() -> Result<(), Error> {
     .arg("/bye")
     .output()?;
 
-  return parse_pinentry_response(output.stdout);
+  parse_pinentry_response(output.stdout)
 }