From 70b9a1f0287f2aeda9677110106f43d1048306f3 Mon Sep 17 00:00:00 2001
From: Robin Krahl <robin.krahl@ireas.org>
Date: Wed, 9 Sep 2020 21:24:59 +0200
Subject: Refactor find_device into find_devices

This patch refactors the find_device function that finds a Nitrokey
device that matches the given filter or returns an error if there are
no or multiple matching Nitrokey devices into the find_devices function
that returns a vector with all matching Nitrokey devices.  The check for
exactly one matching device is now performed in the connect function.
---
 src/commands.rs | 47 +++++++++++++++++++++++------------------------
 1 file changed, 23 insertions(+), 24 deletions(-)

diff --git a/src/commands.rs b/src/commands.rs
index 23f43f3..597fcd8 100644
--- a/src/commands.rs
+++ b/src/commands.rs
@@ -65,11 +65,11 @@ fn format_filter(config: &config::Config) -> String {
   }
 }
 
-/// Find a Nitrokey device that matches the given requirements
-fn find_device(config: &config::Config) -> anyhow::Result<nitrokey::DeviceInfo> {
+/// Find all Nitrokey devices that match the given requirements
+fn find_devices(config: &config::Config) -> anyhow::Result<Vec<nitrokey::DeviceInfo>> {
   let devices = nitrokey::list_devices().context("Failed to enumerate Nitrokey devices")?;
   let nkmodel = config.model.map(nitrokey::Model::from);
-  let mut iter = devices
+  let matching_devices = devices
     .into_iter()
     .filter(|device| nkmodel.is_none() || device.model == nkmodel)
     .filter(|device| {
@@ -79,35 +79,34 @@ fn find_device(config: &config::Config) -> anyhow::Result<nitrokey::DeviceInfo>
           .map(|sn| config.serial_numbers.contains(&sn))
           .unwrap_or_default()
     })
-    .filter(|device| config.usb_path.is_none() || config.usb_path.as_ref() == Some(&device.path));
+    .filter(|device| config.usb_path.is_none() || config.usb_path.as_ref() == Some(&device.path))
+    .collect();
+  Ok(matching_devices)
+}
 
-  let device = iter
-    .next()
-    .with_context(|| format!("Nitrokey device not found{}", format_filter(config)))?;
+/// Connect to a Nitrokey device that matches the given requirements
+fn connect<'mgr>(
+  manager: &'mgr mut nitrokey::Manager,
+  config: &config::Config,
+) -> anyhow::Result<nitrokey::DeviceWrapper<'mgr>> {
+  let device_infos = find_devices(config)?;
 
   anyhow::ensure!(
-    iter.next().is_none(),
+    device_infos.len() < 2,
     "Multiple Nitrokey devices found{}.  Use the --model, --serial-number, and --usb-path options \
     to select one",
     format_filter(config)
   );
-  Ok(device)
-}
 
-/// Connect to a Nitrokey device that matches the given requirements
-fn connect<'mgr>(
-  manager: &'mgr mut nitrokey::Manager,
-  config: &config::Config,
-) -> anyhow::Result<nitrokey::DeviceWrapper<'mgr>> {
-  let device_info = find_device(config)?;
-  manager
-    .connect_path(device_info.path.deref())
-    .with_context(|| {
-      format!(
-        "Failed to connect to Nitrokey device at path {}",
-        device_info.path
-      )
-    })
+  let device = device_infos
+    .first()
+    .with_context(|| format!("Nitrokey device not found{}", format_filter(config)))?;
+  manager.connect_path(device.path.deref()).with_context(|| {
+    format!(
+      "Failed to connect to Nitrokey device at path {}",
+      device.path
+    )
+  })
 }
 
 /// Connect to any Nitrokey device and do something with it.
-- 
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