Require mutable reference if method changes device state

Previously, all methods that access a Nitrokey device took a reference
to the device as input.  This method changes methods that change the
device state to require a mutable reference instead.  In most case,
this is straightforward as the method writes data to the device (for
example write_config or change_user_pin).  But there are two edge cases:
- Authenticating with a PIN changes the device state as it may decrease
  the PIN retry counter if the authentication fails.
- Generating an HOTP code changes the device state as it increases the
  HOTP counter.

1 files changed, 7 insertions, 7 deletions

diff --git a/src/auth.rs b/src/auth.rs
index 8cec49c..f9f50fa 100644
--- a/src/auth.rs
+++ b/src/auth.rs
@@ -226,7 +226,7 @@ impl<T: Device> ops::DerefMut for User<T> {
 }
 
 impl<T: Device> GenerateOtp for User<T> {
-    fn get_hotp_code(&self, slot: u8) -> Result<String, Error> {
+    fn get_hotp_code(&mut self, slot: u8) -> Result<String, Error> {
         result_from_string(unsafe {
             nitrokey_sys::NK_get_hotp_code_PIN(slot, self.temp_password_ptr())
         })
@@ -290,7 +290,7 @@ impl<T: Device> Admin<T> {
     /// let device = nitrokey::connect()?;
     /// let config = Config::new(None, None, None, false);
     /// match device.authenticate_admin("12345678") {
-    ///     Ok(admin) => {
+    ///     Ok(mut admin) => {
     ///         admin.write_config(config);
     ///         ()
     ///     },
@@ -301,7 +301,7 @@ impl<T: Device> Admin<T> {
     /// ```
     ///
     /// [`InvalidSlot`]: enum.LibraryError.html#variant.InvalidSlot
-    pub fn write_config(&self, config: Config) -> Result<(), Error> {
+    pub fn write_config(&mut self, config: Config) -> Result<(), Error> {
         let raw_config = RawConfig::try_from(config)?;
         get_command_result(unsafe {
             nitrokey_sys::NK_write_config(
@@ -317,7 +317,7 @@ impl<T: Device> Admin<T> {
 }
 
 impl<T: Device> ConfigureOtp for Admin<T> {
-    fn write_hotp_slot(&self, data: OtpSlotData, counter: u64) -> Result<(), Error> {
+    fn write_hotp_slot(&mut self, data: OtpSlotData, counter: u64) -> Result<(), Error> {
         let raw_data = RawOtpSlotData::new(data)?;
         get_command_result(unsafe {
             nitrokey_sys::NK_write_hotp_slot(
@@ -334,7 +334,7 @@ impl<T: Device> ConfigureOtp for Admin<T> {
         })
     }
 
-    fn write_totp_slot(&self, data: OtpSlotData, time_window: u16) -> Result<(), Error> {
+    fn write_totp_slot(&mut self, data: OtpSlotData, time_window: u16) -> Result<(), Error> {
         let raw_data = RawOtpSlotData::new(data)?;
         get_command_result(unsafe {
             nitrokey_sys::NK_write_totp_slot(
@@ -351,13 +351,13 @@ impl<T: Device> ConfigureOtp for Admin<T> {
         })
     }
 
-    fn erase_hotp_slot(&self, slot: u8) -> Result<(), Error> {
+    fn erase_hotp_slot(&mut self, slot: u8) -> Result<(), Error> {
         get_command_result(unsafe {
             nitrokey_sys::NK_erase_hotp_slot(slot, self.temp_password_ptr())
         })
     }
 
-    fn erase_totp_slot(&self, slot: u8) -> Result<(), Error> {
+    fn erase_totp_slot(&mut self, slot: u8) -> Result<(), Error> {
         get_command_result(unsafe {
             nitrokey_sys::NK_erase_totp_slot(slot, self.temp_password_ptr())
         })