From 4e9117b94ba48140e142fdc136e91d48cad2bd89 Mon Sep 17 00:00:00 2001
From: Tobias Breitwieser <tobias@breitwieser.biz>
Date: Sun, 24 Dec 2023 16:05:12 +0100
Subject: [PATCH] change to TryFrom for State

---
 src/asynch/runner.rs | 16 ++++++++--------
 src/asynch/state.rs  | 19 ++++++++++---------
 2 files changed, 18 insertions(+), 17 deletions(-)

diff --git a/src/asynch/runner.rs b/src/asynch/runner.rs
index 1f4dfc5..eec1b37 100644
--- a/src/asynch/runner.rs
+++ b/src/asynch/runner.rs
@@ -313,9 +313,9 @@ impl<'d, AT: AtatClient, C: CellularConfig, const URC_CAPACITY: usize>
                     let steps = desired_state as isize - start_state;
                     for step in 0..steps {
                         let next_state = start_state + step;
-                        match OperationState::from(next_state) {
-                            Some(OperationState::PowerDown) => {}
-                            Some(OperationState::PowerUp) => match self.power_up().await {
+                        match OperationState::try_from(next_state) {
+                            Ok(OperationState::PowerDown) => {}
+                            Ok(OperationState::PowerUp) => match self.power_up().await {
                                 Ok(_) => {
                                     self.ch.set_power_state(OperationState::PowerUp);
                                 }
@@ -324,7 +324,7 @@ impl<'d, AT: AtatClient, C: CellularConfig, const URC_CAPACITY: usize>
                                     break;
                                 }
                             },
-                            Some(OperationState::Alive) => match self.is_alive().await {
+                            Ok(OperationState::Alive) => match self.is_alive().await {
                                 Ok(_) => {
                                     self.ch.set_power_state(OperationState::Alive);
                                 }
@@ -333,7 +333,7 @@ impl<'d, AT: AtatClient, C: CellularConfig, const URC_CAPACITY: usize>
                                     break;
                                 }
                             },
-                            Some(OperationState::Initialized) => match self.init_at().await {
+                            Ok(OperationState::Initialized) => match self.init_at().await {
                                 Ok(_) => {
                                     self.ch.set_power_state(OperationState::Initialized);
                                 }
@@ -342,13 +342,13 @@ impl<'d, AT: AtatClient, C: CellularConfig, const URC_CAPACITY: usize>
                                     break;
                                 }
                             },
-                            Some(OperationState::Connected) => {
+                            Ok(OperationState::Connected) => {
                                 todo!()
                             }
-                            Some(OperationState::DataEstablished) => {
+                            Ok(OperationState::DataEstablished) => {
                                 todo!()
                             }
-                            None => {
+                            Err(_) => {
                                 error!("State transition next_state not valid: start_state={}, next_state={}, steps={} ", start_state, next_state, steps);
                                 break;
                             }
diff --git a/src/asynch/state.rs b/src/asynch/state.rs
index f46aa4d..9feae6e 100644
--- a/src/asynch/state.rs
+++ b/src/asynch/state.rs
@@ -36,18 +36,19 @@ pub enum OperationState {
     DataEstablished,
 }
 
-impl OperationState {
-    pub fn from(state: isize) -> Option<Self> {
+impl TryFrom<isize> for OperationState {
+    fn try_from(state: isize) -> Result<Self, ()> {
         match state {
-            0 => Some(OperationState::PowerDown),
-            1 => Some(OperationState::PowerUp),
-            2 => Some(OperationState::Alive),
-            3 => Some(OperationState::Initialized),
-            4 => Some(OperationState::Connected),
-            5 => Some(OperationState::DataEstablished),
-            _ => None,
+            0 => Ok(OperationState::PowerDown),
+            1 => Ok(OperationState::PowerUp),
+            2 => Ok(OperationState::Alive),
+            3 => Ok(OperationState::Initialized),
+            4 => Ok(OperationState::Connected),
+            5 => Ok(OperationState::DataEstablished),
+            _ => Err(()),
         }
     }
+    type Error = ();
 }
 
 use crate::command::Urc;