Add the connect_model function

This patch adds the global connect_model function that can be used to
connect to a Nitrokey device of a given model.  Contrary to Pro::connect
and Storage::connect, the model does not have to be set at compile time.

4 files changed, 42 insertions, 1 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7394cb0..4e046f2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,8 @@
 - Add support for the hidden volumes on a Nitrokey Storage
   (`enable_hidden_volume`, `disable_hidden_volume` and `create_hidden_volume`
   methods for the `Storage` struct).
+- Add the `connect_model` function to connect to a specific model using an enum
+  variant.
 
 # v0.3.0 (2019-01-04)
 - Add a `force` argument to `ConfigureOtp::set_time`.
diff --git a/src/device.rs b/src/device.rs
index 88be5b5..2eee08e 100644
--- a/src/device.rs
+++ b/src/device.rs
@@ -613,6 +613,35 @@ pub fn connect() -> Result<DeviceWrapper, CommandError> {
     }
 }
 
+/// Connects to a Nitrokey device of the given model.
+///
+/// # Errors
+///
+/// - [`Undefined`][] if no Nitrokey device of the given model is connected
+///
+/// # Example
+///
+/// ```
+/// use nitrokey::DeviceWrapper;
+/// use nitrokey::Model;
+///
+/// fn do_something(device: DeviceWrapper) {}
+///
+/// match nitrokey::connect_model(Model::Pro) {
+///     Ok(device) => do_something(device),
+///     Err(err) => println!("Could not connect to a Nitrokey Pro: {}", err),
+/// }
+/// ```
+///
+/// [`Undefined`]: enum.CommandError.html#variant.Undefined
+pub fn connect_model(model: Model) -> Result<DeviceWrapper, CommandError> {
+    if connect_enum(model) {
+        Ok(create_device_wrapper(model))
+    } else {
+        Err(CommandError::Undefined)
+    }
+}
+
 fn get_connected_model() -> Option<Model> {
     unsafe {
         match nitrokey_sys::NK_get_device_model() {
diff --git a/src/lib.rs b/src/lib.rs
index 9f21518..bb34870 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -98,7 +98,7 @@ use nitrokey_sys;
 pub use crate::auth::{Admin, Authenticate, User};
 pub use crate::config::Config;
 pub use crate::device::{
-    connect, Device, DeviceWrapper, Model, Pro, Storage, StorageStatus, VolumeStatus,
+    connect, connect_model, Device, DeviceWrapper, Model, Pro, Storage, StorageStatus, VolumeStatus,
 };
 pub use crate::otp::{ConfigureOtp, GenerateOtp, OtpMode, OtpSlotData};
 pub use crate::pws::{GetPasswordSafe, PasswordSafe, SLOT_COUNT};
diff --git a/tests/device.rs b/tests/device.rs
index f7d8df3..db8194c 100644
--- a/tests/device.rs
+++ b/tests/device.rs
@@ -31,6 +31,8 @@ fn count_nitrokey_block_devices() -> usize {
 #[test_device]
 fn connect_no_device() {
     assert!(nitrokey::connect().is_err());
+    assert!(nitrokey::connect_model(nitrokey::Model::Pro).is_err());
+    assert!(nitrokey::connect_model(nitrokey::Model::Storage).is_err());
     assert!(nitrokey::Pro::connect().is_err());
     assert!(nitrokey::Storage::connect().is_err());
 }
@@ -41,7 +43,11 @@ fn connect_pro(device: Pro) {
     drop(device);
 
     assert!(nitrokey::connect().is_ok());
+    assert!(nitrokey::connect_model(nitrokey::Model::Pro).is_ok());
     assert!(nitrokey::Pro::connect().is_ok());
+
+    assert!(nitrokey::connect_model(nitrokey::Model::Storage).is_err());
+    assert!(nitrokey::Storage::connect().is_err());
 }
 
 #[test_device]
@@ -50,7 +56,11 @@ fn connect_storage(device: Storage) {
     drop(device);
 
     assert!(nitrokey::connect().is_ok());
+    assert!(nitrokey::connect_model(nitrokey::Model::Storage).is_ok());
     assert!(nitrokey::Storage::connect().is_ok());
+
+    assert!(nitrokey::connect_model(nitrokey::Model::Pro).is_err());
+    assert!(nitrokey::Pro::connect().is_err());
 }
 
 fn assert_empty_serial_number() {