Add the get_operation_status function to the Storage struct

This patch adds support for the NK_get_progress_bar_value function:  It
adds the OperationStatus enum that stores the return value of this
command and adds the get_operation_status function to the Storage struct
that executes the command.

2 files changed, 36 insertions, 2 deletions

diff --git a/src/device/mod.rs b/src/device/mod.rs
index 8b7f1c6..16d6b11 100644
--- a/src/device/mod.rs
+++ b/src/device/mod.rs
@@ -25,7 +25,8 @@ use crate::util::{
 
 pub use pro::Pro;
 pub use storage::{
-    SdCardData, Storage, StorageProductionInfo, StorageStatus, VolumeMode, VolumeStatus,
+    OperationStatus, SdCardData, Storage, StorageProductionInfo, StorageStatus, VolumeMode,
+    VolumeStatus,
 };
 pub use wrapper::DeviceWrapper;
 
diff --git a/src/device/storage.rs b/src/device/storage.rs
index a2c598b..8d45763 100644
--- a/src/device/storage.rs
+++ b/src/device/storage.rs
@@ -1,6 +1,7 @@
 // Copyright (C) 2019-2020 Robin Krahl <robin.krahl@ireas.org>
 // SPDX-License-Identifier: MIT
 
+use std::convert::TryFrom as _;
 use std::fmt;
 use std::ops;
 
@@ -9,7 +10,7 @@ use nitrokey_sys;
 use crate::device::{Device, FirmwareVersion, Model, Status};
 use crate::error::Error;
 use crate::otp::GenerateOtp;
-use crate::util::{get_command_result, get_cstring};
+use crate::util::{get_command_result, get_cstring, get_last_error};
 
 /// A Nitrokey Storage device without user or admin authentication.
 ///
@@ -142,6 +143,20 @@ pub struct StorageStatus {
     pub stick_initialized: bool,
 }
 
+/// The progress of a background operation on the Nitrokey.
+///
+/// Some commands may start a background operation during which no other commands can be executed.
+/// This enum stores the status of a background operation:  Ongoing with a relative progress (up to
+/// 100), or idle, i. e. no background operation has been started or the last one has been
+/// finished.
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub enum OperationStatus {
+    /// A background operation with its progress value (less than or equal to 100).
+    Ongoing(u8),
+    /// No backgrund operation.
+    Idle,
+}
+
 impl<'a> Storage<'a> {
     pub(crate) fn new(manager: &'a mut crate::Manager) -> Storage<'a> {
         Storage {
@@ -680,6 +695,24 @@ impl<'a> Storage<'a> {
         get_command_result(unsafe { nitrokey_sys::NK_wink() })
     }
 
+    /// Returns the status of an ongoing background operation on the Nitrokey Storage.
+    ///
+    /// Some commands may start a background operation during which no other commands can be
+    /// executed.  This method can be used to check whether such an operation is ongoing.
+    ///
+    /// Currently, this is only used by the `fill_sd_card` method.
+    pub fn get_operation_status(&self) -> Result<OperationStatus, Error> {
+        let status = unsafe { nitrokey_sys::NK_get_progress_bar_value() };
+        match status {
+            0..=100 => u8::try_from(status)
+                .map(OperationStatus::Ongoing)
+                .map_err(|_| Error::UnexpectedError),
+            -1 => Ok(OperationStatus::Idle),
+            -2 => Err(get_last_error()),
+            _ => Err(Error::UnexpectedError),
+        }
+    }
+
     /// Exports the firmware to the unencrypted volume.
     ///
     /// This command requires the admin PIN.  The unencrypted volume must be in read-write mode