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.

6 files changed, 46 insertions, 6 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index cebe8cb..419a942 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -18,6 +18,8 @@ SPDX-License-Identifier: CC0-1.0
 - Add the `get_status` function to the `Device` trait.
 - Rename `Status::get_status` to `get_storage_status`.
 - Add the `get_sd_card_usage` function to the `Storage` struct.
+- Add the `OperationStatus` enum and the `get_operation_status` function for
+  the `Storage` struct.
 
 # v0.4.0 (2020-01-02)
 - Remove the `test-pro` and `test-storage` features.
diff --git a/TODO.md b/TODO.md
index 79a68e4..8f9b898 100644
--- a/TODO.md
+++ b/TODO.md
@@ -5,7 +5,6 @@ SPDX-License-Identifier: CC0-1.0
 
 - Add support for the currently unsupported commands:
     - `NK_fill_SD_card_with_random_data`
-    - `NK_get_progress_bar_value`
 - Clear passwords from memory.
 - Lock password safe in `PasswordSafe::drop()` (see [nitrokey-storage-firmware
   issue 65][]).
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
diff --git a/src/lib.rs b/src/lib.rs
index 41c99c5..c6c3ff5 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -126,7 +126,7 @@ use nitrokey_sys;
 pub use crate::auth::{Admin, Authenticate, User};
 pub use crate::config::Config;
 pub use crate::device::{
-    Device, DeviceInfo, DeviceWrapper, Model, Pro, SdCardData, Status, Storage,
+    Device, DeviceInfo, DeviceWrapper, Model, OperationStatus, Pro, SdCardData, Status, Storage,
     StorageProductionInfo, StorageStatus, VolumeMode, VolumeStatus,
 };
 pub use crate::error::{CommandError, CommunicationError, Error, LibraryError};
diff --git a/tests/device.rs b/tests/device.rs
index 070f3c1..7296372 100644
--- a/tests/device.rs
+++ b/tests/device.rs
@@ -9,8 +9,8 @@ use std::{thread, time};
 
 use nitrokey::{
     Authenticate, CommandError, CommunicationError, Config, ConfigureOtp, Device, DeviceInfo,
-    Error, GenerateOtp, GetPasswordSafe, LibraryError, OtpMode, OtpSlotData, Storage, VolumeMode,
-    DEFAULT_ADMIN_PIN, DEFAULT_USER_PIN,
+    Error, GenerateOtp, GetPasswordSafe, LibraryError, OperationStatus, OtpMode, OtpSlotData,
+    Storage, VolumeMode, DEFAULT_ADMIN_PIN, DEFAULT_USER_PIN,
 };
 use nitrokey_test::test as test_device;
 
@@ -648,6 +648,11 @@ fn get_sd_card_usage(device: Storage) {
 }
 
 #[test_device]
+fn get_operation_status(device: Storage) {
+    assert_ok!(OperationStatus::Idle, device.get_operation_status());
+}
+
+#[test_device]
 fn export_firmware(device: Storage) {
     let mut device = device;
     assert_cmd_err!(