Cargo.lock

@@ -92,6 +92,7 @@ dependencies = [
  "notify 6.1.1",
  "serde",
  "systemfd",
+ "thiserror",
  "tokio",
  "tower-http",
  "tower-livereload",
@@ -1066,6 +1067,7 @@ dependencies = [
  "http",
  "tauri",
  "tauri-build",
+ "thiserror",
  "tokio",
  "tower",
 ]
@@ -3915,8 +3917,10 @@ dependencies = [
 name = "sesam-vitale"
 version = "0.1.0"
 dependencies = [
+ "anyhow",
  "dotenv",
  "libc",
+ "thiserror",
 ]
 
 [[package]]

crates/app/Cargo.toml

@@ -10,6 +10,7 @@ axum = "0.7.5"
 listenfd = "1.0.1"
 notify = "6.1.1"
 serde = { version = "1.0.204", features = ["derive"] }
+thiserror = "1.0.63"
 tokio = { version = "1.39.1", features = ["macros", "rt-multi-thread"] }
 tower-http = { version = "0.5.2", features = ["fs"] }
 tower-livereload = "0.9.3"

crates/app/src/main.rs

@@ -3,12 +3,23 @@ use axum::body::Body;
 use axum::http::Request;
 use listenfd::ListenFd;
 use notify::Watcher;
-use std::env;
 use std::path::Path;
+use std::{env, io};
+use thiserror::Error;
 use tokio::net::TcpListener;
 use tower_livereload::predicate::Predicate;
 use tower_livereload::LiveReloadLayer;
 
+#[derive(Error, Debug)]
+pub enum AppError {
+    #[error("Unable to bind to TCP listener")]
+    TCPListener(#[from] std::io::Error),
+    #[error("Error with the notify watcher")]
+    NotifyWatcher(#[from] notify::Error),
+    #[error("Missing environment variable {var}")]
+    MissingEnvVar { var: &'static str },
+}
+
 /// Nous filtrons les requêtes de `htmx` pour ne pas inclure le script _JS_ qui gère le rechargement
 /// Voir https://github.com/leotaku/tower-livereload/pull/3
 #[derive(Copy, Clone)]
@@ -20,44 +31,47 @@ impl<T> Predicate<Request<T>> for NotHtmxPredicate {
 }
 
 const DEFAULT_LISTENER: &str = "localhost:3000";
-async fn get_tcp_listener() -> TcpListener {
+async fn get_tcp_listener() -> Result<TcpListener, io::Error> {
     let mut listenfd = ListenFd::from_env();
 
-    match listenfd.take_tcp_listener(0).unwrap() {
+    match listenfd.take_tcp_listener(0)? {
         // if we are given a tcp listener on listen fd 0, we use that one
         Some(listener) => {
-            listener.set_nonblocking(true).unwrap();
+            listener.set_nonblocking(true)?;
-            TcpListener::from_std(listener).unwrap()
+            Ok(TcpListener::from_std(listener)?)
         }
         // otherwise fall back to local listening
-        None => TcpListener::bind(DEFAULT_LISTENER).await.unwrap(),
+        None => Ok(TcpListener::bind(DEFAULT_LISTENER).await?),
     }
 }
 
-fn get_livereload_layer(templates_path: &Path) -> LiveReloadLayer<NotHtmxPredicate> {
+fn get_livereload_layer(
+    templates_path: &Path,
+) -> Result<LiveReloadLayer<NotHtmxPredicate>, notify::Error> {
     let livereload = LiveReloadLayer::new();
     let reloader = livereload.reloader();
-    let mut watcher = notify::recommended_watcher(move |_| reloader.reload()).unwrap();
+    let mut watcher = notify::recommended_watcher(move |_| reloader.reload())?;
-    watcher
+    watcher.watch(templates_path, notify::RecursiveMode::Recursive)?;
-        .watch(templates_path, notify::RecursiveMode::Recursive)
+    Ok(livereload.request_predicate::<Body, NotHtmxPredicate>(NotHtmxPredicate))
-        .unwrap();
-    livereload.request_predicate::<Body, NotHtmxPredicate>(NotHtmxPredicate)
 }
 
 #[tokio::main]
-async fn main() {
+async fn main() -> Result<(), AppError> {
-    let manifest_dir = env::var("CARGO_MANIFEST_DIR").unwrap();
+    let manifest_dir = env::var("CARGO_MANIFEST_DIR").map_err(|_| AppError::MissingEnvVar {
+        var: "CARGO_MANIFEST_DIR",
+    })?;
     let assets_path = Path::new(&manifest_dir).join("assets");
     let templates_path = Path::new(&manifest_dir).join("templates");
 
-    let livereload_layer = get_livereload_layer(&templates_path);
+    let livereload_layer =
+        get_livereload_layer(&templates_path).map_err(AppError::NotifyWatcher)?;
     let router = get_router(assets_path.as_path()).layer(livereload_layer);
 
-    let listener: TcpListener = get_tcp_listener().await;
+    let listener: TcpListener = get_tcp_listener().await.map_err(AppError::TCPListener)?;
-    println!("Listening on: http://{}", listener.local_addr().unwrap());
+    let local_addr = listener.local_addr().map_err(AppError::TCPListener)?;
+    println!("Listening on: http://{}", local_addr);
 
     // Run the server with the router
-    axum::serve(listener, router.into_make_service())
+    axum::serve(listener, router.into_make_service()).await?;
-        .await
+    Ok(())
-        .unwrap();
 }

crates/desktop/Cargo.toml

@@ -21,4 +21,5 @@ tokio = "1.39.1"
 app = { path = "../app" }
 http = "1.1.0"
 bytes = "1.6.1"
+thiserror = "1.0.63"
 

crates/desktop/src/lib.rs

@@ -1,21 +1,30 @@
+use axum::body::{to_bytes, Body};
+use axum::Router;
 use bytes::Bytes;
 use http::{request, response, Request, Response};
 use std::path::PathBuf;
 use std::sync::Arc;
-
-use axum::body::{to_bytes, Body};
-
-use axum::Router;
-
 use tauri::path::BaseDirectory;
 use tauri::Manager;
+use thiserror::Error;
 use tokio::sync::{Mutex, MutexGuard};
 use tower::{Service, ServiceExt};
 
+#[derive(Error, Debug)]
+pub enum DesktopError {
+    #[error("Axum error:\n{0}")]
+    Axum(#[from] axum::Error),
+    #[error("Infallible error")]
+    Infallible(#[from] std::convert::Infallible),
+}
+
+/// Process requests sent to Tauri (with the `axum://` protocol) and handle them with Axum
+/// When an error occurs, this function is expected to panic, which should result in a 500 error
+/// being sent to the client, so we let the client handle the error recovering
 async fn process_tauri_request(
     tauri_request: Request<Vec<u8>>,
     mut router: MutexGuard<'_, Router>,
-) -> Response<Vec<u8>> {
+) -> Result<Response<Vec<u8>>, DesktopError> {
     let (parts, body): (request::Parts, Vec<u8>) = tauri_request.into_parts();
     let axum_request: Request<Body> = Request::from_parts(parts, body.into());
 
@@ -23,17 +32,16 @@ async fn process_tauri_request(
         .as_service()
         .ready()
         .await
-        .expect("Failed to get ready service from router")
+        .map_err(DesktopError::Infallible)?
         .call(axum_request)
         .await
-        .expect("Could not get response from router");
+        .map_err(DesktopError::Infallible)?;
 
     let (parts, body): (response::Parts, Body) = axum_response.into_parts();
-    let body: Bytes = to_bytes(body, usize::MAX).await.unwrap_or_default();
+    let body: Bytes = to_bytes(body, usize::MAX).await?;
 
     let tauri_response: Response<Vec<u8>> = Response::from_parts(parts, body.into());
-
+    Ok(tauri_response)
-    tauri_response
 }
 
 #[cfg_attr(mobile, tauri::mobile_entry_point)]
@@ -43,7 +51,7 @@ pub fn run() {
             let assets_path: PathBuf = app
                 .path()
                 .resolve("assets", BaseDirectory::Resource)
-                .expect("Path should be resolvable");
+                .expect("Assets path should be resolvable");
 
             // Adds Axum router to application state
             // This makes it so we can retrieve it from any app instance (see bellow)
@@ -60,8 +68,19 @@ pub fn run() {
             // Spawn a new async task to process the request
             tauri::async_runtime::spawn(async move {
                 let router = router.lock().await;
-                let response = process_tauri_request(request, router).await;
+                match process_tauri_request(request, router).await {
-                responder.respond(response);
+                    Ok(response) => responder.respond(response),
+                    Err(err) => {
+                        let body = format!("Failed to process an axum:// request:\n{}", err);
+                        responder.respond(
+                            http::Response::builder()
+                                .status(http::StatusCode::BAD_REQUEST)
+                                .header(http::header::CONTENT_TYPE, "text/plain")
+                                .body::<Vec<u8>>(body.into())
+                                .expect("BAD_REQUEST response should be valid"),
+                        )
+                    }
+                }
             });
         })
         .run(tauri::generate_context!())

crates/sesam-vitale/Cargo.toml

@@ -4,8 +4,10 @@ version = "0.1.0"
 edition = "2021"
 
 [dependencies]
+anyhow = "1.0.86"
 dotenv = "0.15"
 libc = "0.2"
+thiserror = "1.0.63"
 
 [build-dependencies]
 dotenv = "0.15"

crates/sesam-vitale/build.rs

@@ -5,7 +5,7 @@ use std::path::PathBuf;
 
 fn main() {
     // Load the .env.build file for build-time environment variables
-    let manifest_dir = env::var("CARGO_MANIFEST_DIR").unwrap();
+    let manifest_dir = env::var("CARGO_MANIFEST_DIR").expect("CARGO_MANIFEST_DIR must be set");
     let manifest_path = PathBuf::from(manifest_dir);
     dotenv::from_path(manifest_path.join(".env.build")).ok();
 
@@ -22,12 +22,13 @@ fn main() {
     );
 
     // Add the SESAM_FSV_LIB_PATH to the linker search path
-    let fsv_lib_path = PathBuf::from(env::var("SESAM_FSV_LIB_PATH").unwrap());
+    let fsv_lib_path =
+        PathBuf::from(env::var("SESAM_FSV_LIB_PATH").expect("SESAM_FSV_LIB_PATH must be set"));
     println!("cargo::rustc-link-search=native={}", fsv_lib_path.display());
 
     // Add the SESAM_FSV_LIB_PATH to the PATH environment variable
     if cfg!(target_os = "windows") {
-        let path = env::var("PATH").unwrap_or(String::new());
+        let path = env::var("PATH").unwrap_or_default();
         println!("cargo:rustc-env=PATH={};{}", fsv_lib_path.display(), path);
     } else if cfg!(target_os = "linux") {
         println!("cargo:rustc-env=LD_LIBRARY_PATH={}", fsv_lib_path.display());
@@ -36,7 +37,7 @@ fn main() {
     // Link the SESAM_FSV_SSVLIB dynamic library
     println!(
         "cargo::rustc-link-lib=dylib={}",
-        env::var("SESAM_FSV_SSVLIB").unwrap()
+        env::var("SESAM_FSV_SSVLIB").expect("SESAM_FSV_SSVLIB must be set")
     );
     // TODO : try `raw-dylib` instead of `dylib` on Windows to avoid the need of the `lib` headers compiled from the `def`
 }

crates/sesam-vitale/src/cps.rs

@@ -1,9 +1,24 @@
 use libc::{c_void, size_t};
 use std::ffi::CString;
 use std::ptr;
+use thiserror::Error;
 
-use crate::libssv::SSV_LireCartePS;
+use crate::libssv::{self, SSV_LireCartePS};
-use crate::ssv_memory::{decode_ssv_memory, Block};
+use crate::ssv_memory::{decode_ssv_memory, Block, SSVMemoryError};
+
+#[derive(Error, Debug)]
+pub enum CartePSError {
+    #[error("Unknown (group, field) pair: ({group}, {field})")]
+    UnknownGroupFieldPair { group: u16, field: u16 },
+    #[error("CString creation error: {0}")]
+    CString(#[from] std::ffi::NulError),
+    #[error("Unable to get the last situation while parsing a CartePS")]
+    InvalidLastSituation,
+    #[error(transparent)]
+    SSVMemory(#[from] SSVMemoryError),
+    #[error(transparent)]
+    SSVLibErrorCode(#[from] libssv::LibSSVError),
+}
 
 #[derive(Debug, Default)]
 pub struct CartePS {
@@ -52,10 +67,10 @@ struct SituationPS {
     habilitation_à_signer_un_lot: String,
 }
 
-pub fn lire_carte(code_pin: &str, lecteur: &str) -> Result<CartePS, String> {
+pub fn lire_carte(code_pin: &str, lecteur: &str) -> Result<CartePS, CartePSError> {
-    let resource_ps = CString::new(lecteur).expect("CString::new failed");
+    let resource_ps = CString::new(lecteur)?;
-    let resource_reader = CString::new("").expect("CString::new failed");
+    let resource_reader = CString::new("")?;
-    let card_number = CString::new(code_pin).expect("CString::new failed");
+    let card_number = CString::new(code_pin)?;
 
     let mut buffer: *mut c_void = ptr::null_mut();
     let mut size: size_t = 0;
@@ -69,17 +84,32 @@ pub fn lire_carte(code_pin: &str, lecteur: &str) -> Result<CartePS, String> {
             &mut size,
         );
         println!("SSV_LireCartePS result: {}", result);
+        if result != 0 {
+            return Err(libssv::LibSSVError::StandardErrorCode {
+                code: result,
+                function: "SSV_LireCartePS",
+            }
+            .into());
+        }
 
         if !buffer.is_null() {
             hex_values = std::slice::from_raw_parts(buffer as *const u8, size);
             libc::free(buffer);
         }
     }
-    let groups = decode_ssv_memory(hex_values, hex_values.len());
+    let groups =
+        decode_ssv_memory(hex_values, hex_values.len()).map_err(CartePSError::SSVMemory)?;
     decode_carte_ps(groups)
 }
 
-fn decode_carte_ps(groups: Vec<Block>) -> Result<CartePS, String> {
+fn get_last_mut_situation(carte_ps: &mut CartePS) -> Result<&mut SituationPS, CartePSError> {
+    carte_ps
+        .situations
+        .last_mut()
+        .ok_or(CartePSError::InvalidLastSituation)
+}
+
+fn decode_carte_ps(groups: Vec<Block>) -> Result<CartePS, CartePSError> {
     let mut carte_ps = CartePS::default();
     for group in groups {
         for field in group.content {
@@ -118,137 +148,99 @@ fn decode_carte_ps(groups: Vec<Block>) -> Result<CartePS, String> {
                 }
                 (2..=16, 1) => {
                     carte_ps.situations.push(SituationPS::default());
-                    carte_ps
+                    get_last_mut_situation(&mut carte_ps)?
-                        .situations
-                        .last_mut()
-                        .unwrap()
                         .numero_logique_de_la_situation_de_facturation_du_ps = field.content[0];
                 }
                 (2..=16, 2) => {
-                    carte_ps.situations.last_mut().unwrap().mode_d_exercice =
+                    get_last_mut_situation(&mut carte_ps)?.mode_d_exercice =
                         String::from_utf8_lossy(field.content).to_string();
                 }
                 (2..=16, 3) => {
-                    carte_ps.situations.last_mut().unwrap().statut_d_exercice =
+                    get_last_mut_situation(&mut carte_ps)?.statut_d_exercice =
                         String::from_utf8_lossy(field.content).to_string();
                 }
                 (2..=16, 4) => {
-                    carte_ps.situations.last_mut().unwrap().secteur_d_activite =
+                    get_last_mut_situation(&mut carte_ps)?.secteur_d_activite =
                         String::from_utf8_lossy(field.content).to_string();
                 }
                 (2..=16, 5) => {
-                    carte_ps
+                    get_last_mut_situation(&mut carte_ps)?.type_d_identification_structure =
-                        .situations
-                        .last_mut()
-                        .unwrap()
-                        .type_d_identification_structure =
                         String::from_utf8_lossy(field.content).to_string();
                 }
                 (2..=16, 6) => {
-                    carte_ps
+                    get_last_mut_situation(&mut carte_ps)?.numero_d_identification_structure =
-                        .situations
-                        .last_mut()
-                        .unwrap()
-                        .numero_d_identification_structure =
                         String::from_utf8_lossy(field.content).to_string();
                 }
                 (2..=16, 7) => {
-                    carte_ps
+                    get_last_mut_situation(&mut carte_ps)?
-                        .situations
-                        .last_mut()
-                        .unwrap()
                         .cle_du_numero_d_identification_structure =
                         String::from_utf8_lossy(field.content).to_string();
                 }
                 (2..=16, 8) => {
-                    carte_ps
+                    get_last_mut_situation(&mut carte_ps)?.raison_sociale_structure =
-                        .situations
-                        .last_mut()
-                        .unwrap()
-                        .raison_sociale_structure =
                         String::from_utf8_lossy(field.content).to_string();
                 }
                 (2..=16, 9) => {
-                    carte_ps
+                    get_last_mut_situation(&mut carte_ps)?
-                        .situations
-                        .last_mut()
-                        .unwrap()
                         .numero_d_identification_de_facturation_du_ps =
                         String::from_utf8_lossy(field.content).to_string();
                 }
                 (2..=16, 10) => {
-                    carte_ps
+                    get_last_mut_situation(&mut carte_ps)?
-                        .situations
-                        .last_mut()
-                        .unwrap()
                         .cle_du_numero_d_identification_de_facturation_du_ps =
                         String::from_utf8_lossy(field.content).to_string();
                 }
                 (2..=16, 11) => {
-                    carte_ps
+                    get_last_mut_situation(&mut carte_ps)?
-                        .situations
-                        .last_mut()
-                        .unwrap()
                         .numero_d_identification_du_ps_remplaçant =
                         String::from_utf8_lossy(field.content).to_string();
                 }
                 (2..=16, 12) => {
-                    carte_ps
+                    get_last_mut_situation(&mut carte_ps)?
-                        .situations
-                        .last_mut()
-                        .unwrap()
                         .cle_du_numero_d_identification_du_ps_remplaçant =
                         String::from_utf8_lossy(field.content).to_string();
                 }
                 (2..=16, 13) => {
-                    carte_ps.situations.last_mut().unwrap().code_conventionnel =
+                    get_last_mut_situation(&mut carte_ps)?.code_conventionnel =
                         String::from_utf8_lossy(field.content).to_string();
                 }
                 (2..=16, 14) => {
-                    carte_ps.situations.last_mut().unwrap().code_specialite =
+                    get_last_mut_situation(&mut carte_ps)?.code_specialite =
                         String::from_utf8_lossy(field.content).to_string();
                 }
                 (2..=16, 15) => {
-                    carte_ps.situations.last_mut().unwrap().code_zone_tarifaire =
+                    get_last_mut_situation(&mut carte_ps)?.code_zone_tarifaire =
                         String::from_utf8_lossy(field.content).to_string();
                 }
                 (2..=16, 16) => {
-                    carte_ps.situations.last_mut().unwrap().code_zone_ik =
+                    get_last_mut_situation(&mut carte_ps)?.code_zone_ik =
                         String::from_utf8_lossy(field.content).to_string();
                 }
                 (2..=16, 17) => {
-                    carte_ps.situations.last_mut().unwrap().code_agrement_1 =
+                    get_last_mut_situation(&mut carte_ps)?.code_agrement_1 =
                         String::from_utf8_lossy(field.content).to_string();
                 }
                 (2..=16, 18) => {
-                    carte_ps.situations.last_mut().unwrap().code_agrement_2 =
+                    get_last_mut_situation(&mut carte_ps)?.code_agrement_2 =
                         String::from_utf8_lossy(field.content).to_string();
                 }
                 (2..=16, 19) => {
-                    carte_ps.situations.last_mut().unwrap().code_agrement_3 =
+                    get_last_mut_situation(&mut carte_ps)?.code_agrement_3 =
                         String::from_utf8_lossy(field.content).to_string();
                 }
                 (2..=16, 20) => {
-                    carte_ps
+                    get_last_mut_situation(&mut carte_ps)?.habilitation_à_signer_une_facture =
-                        .situations
-                        .last_mut()
-                        .unwrap()
-                        .habilitation_à_signer_une_facture =
                         String::from_utf8_lossy(field.content).to_string();
                 }
                 (2..=16, 21) => {
-                    carte_ps
+                    get_last_mut_situation(&mut carte_ps)?.habilitation_à_signer_un_lot =
-                        .situations
-                        .last_mut()
-                        .unwrap()
-                        .habilitation_à_signer_un_lot =
                         String::from_utf8_lossy(field.content).to_string();
                 }
                 _ => {
-                    return Err(format!(
+                    return Err(CartePSError::UnknownGroupFieldPair {
-                        "Unknown (group, field) pair: ({}, {})",
+                        group: group.id,
-                        group.id, field.id
+                        field: field.id,
-                    ))
+                    });
                 }
             }
         }
@@ -279,7 +271,7 @@ mod test_decode_carte_ps {
             57, 53, 8, 48, 48, 50, 48, 50, 52, 49, 57, 1, 56, 0, 1, 48, 1, 49, 2, 53, 48, 2, 49,
             48, 2, 48, 48, 1, 48, 1, 48, 1, 48, 1, 49, 1, 49,
         ];
-        let blocks = decode_ssv_memory(bytes, bytes.len());
+        let blocks = decode_ssv_memory(bytes, bytes.len()).unwrap();
         let carte_ps = decode_carte_ps(blocks).unwrap();
 
         assert_eq!(carte_ps.titulaire.type_de_carte_ps, "0");
@@ -370,7 +362,7 @@ mod test_decode_carte_ps {
             57, 53, 8, 48, 48, 50, 48, 50, 52, 49, 57, 1, 56, 0, 1, 48, 1, 49, 2, 53, 48, 2, 49,
             48, 2, 48, 48, 1, 48, 1, 48, 1, 48, 1, 49, 1, 49,
         ];
-        let blocks = decode_ssv_memory(bytes, bytes.len());
+        let blocks = decode_ssv_memory(bytes, bytes.len()).unwrap();
         let carte_ps = decode_carte_ps(blocks).unwrap();
 
         assert_eq!(carte_ps.situations.len(), 3);

crates/sesam-vitale/src/libssv.rs

@@ -3,6 +3,13 @@
 /// Low level bindings to the SSVLIB dynamic library.
 // TODO : look for creating a dedicated *-sys crate : https://kornel.ski/rust-sys-crate
 use libc::{c_char, c_ushort, c_void, size_t};
+use thiserror::Error;
+
+#[derive(Debug, Error)]
+pub enum LibSSVError {
+    #[error("SSV library error in {function}: {code}")]
+    StandardErrorCode { code: u16, function: &'static str },
+}
 
 #[cfg_attr(target_os = "linux", link(name = "ssvlux64"))]
 #[cfg_attr(target_os = "windows", link(name = "ssvw64"))]

crates/sesam-vitale/src/main.rs

@@ -3,6 +3,8 @@ mod libssv;
 mod ssv_memory;
 mod ssvlib_demo;
 
-fn main() {
+use anyhow::{Context, Result};
-    ssvlib_demo::demo();
+
+fn main() -> Result<()> {
+    ssvlib_demo::demo().context("Error while running the SSV library demo")
 }

crates/sesam-vitale/src/ssv_memory.rs

@@ -1,6 +1,33 @@
 /// # SSV Memory
 /// Provide functions to manipulate raw memory from SSV library.
 use std::convert::TryFrom;
+use thiserror::Error;
+
+#[derive(Debug, Error)]
+pub enum BytesReadingError {
+    #[error("Empty bytes input")]
+    EmptyBytes,
+    #[error("Invalid memory: not enough bytes ({actual}) to read the expected size ({expected})")]
+    InvalidSize { expected: usize, actual: usize },
+    #[error("Invalid memory: size ({actual}) is expected to be less than {expected} bytes")]
+    SizeTooBig { expected: usize, actual: usize },
+    #[error("Invalid memory: not enough bytes to read the block id")]
+    InvalidBlockId(#[from] std::array::TryFromSliceError),
+    #[error("Error while reading field at offset {offset}")]
+    InvalidField {
+        source: Box<BytesReadingError>,
+        offset: usize,
+    },
+}
+
+#[derive(Debug, Error)]
+pub enum SSVMemoryError {
+    #[error("Error while parsing block at offset {offset}")]
+    BlockParsing {
+        source: BytesReadingError,
+        offset: usize,
+    },
+}
 
 #[derive(PartialEq, Debug)]
 struct ElementSize {
@@ -9,13 +36,12 @@ struct ElementSize {
 }
 
 // TODO : Est-ce qu'on pourrait/devrait définir un type custom pour représenter les tableaux de bytes ?
-
 impl TryFrom<&[u8]> for ElementSize {
-    type Error = &'static str;
+    type Error = BytesReadingError;
 
     fn try_from(bytes: &[u8]) -> Result<Self, Self::Error> {
         if bytes.is_empty() {
-            return Err("Empty bytes input");
+            return Err(BytesReadingError::EmptyBytes);
         }
 
         let mut element_size = ElementSize { size: 0, pad: 1 };
@@ -30,9 +56,15 @@ impl TryFrom<&[u8]> for ElementSize {
             // N are the 7 lower bits of the first byte
             let size_bytes_len = (bytes[0] & 0b0111_1111) as usize;
             if size_bytes_len > bytes.len() - 1 {
-                return Err("Invalid memory: not enough bytes to read the size");
+                return Err(BytesReadingError::InvalidSize {
+                    expected: size_bytes_len,
+                    actual: bytes.len() - 1,
+                });
             } else if size_bytes_len > 4 {
-                return Err("Invalid memory: size is too big");
+                return Err(BytesReadingError::SizeTooBig {
+                    expected: 4,
+                    actual: size_bytes_len,
+                });
             }
             let size_bytes = &bytes[1..1 + size_bytes_len];
 
@@ -54,15 +86,21 @@ pub struct Block<'a> {
     pub content: Vec<Field<'a>>,
 }
 
-impl<'a> From<&'a [u8]> for Block<'a> {
+impl<'a> TryFrom<&'a [u8]> for Block<'a> {
-    fn from(bytes: &'a [u8]) -> Self {
+    type Error = BytesReadingError;
+
+    fn try_from(bytes: &'a [u8]) -> Result<Self, Self::Error> {
         let mut offset = 0;
-        let id = u16::from_be_bytes(bytes[..2].try_into().unwrap());
+        let id = u16::from_be_bytes(
+            bytes[..2]
+                .try_into()
+                .map_err(BytesReadingError::InvalidBlockId)?,
+        );
         offset += 2;
         let ElementSize {
             size: block_size,
             pad,
-        } = bytes[2..].try_into().unwrap();
+        } = bytes[2..].try_into()?;
         offset += pad;
         let raw_content = &bytes[offset..];
         let mut field_offset = 0;
@@ -70,17 +108,22 @@ impl<'a> From<&'a [u8]> for Block<'a> {
         let mut content = Vec::new();
         let mut field_id = 1;
         while field_offset < block_size {
-            let mut field: Field<'a> = raw_content[field_offset..].into();
+            let mut field: Field<'a> = raw_content[field_offset..].try_into().map_err(|err| {
+                BytesReadingError::InvalidField {
+                    source: Box::new(err),
+                    offset: field_offset,
+                }
+            })?;
             field.id = field_id;
             field_offset += field.size;
             field_id += 1;
             content.push(field);
         }
-        Block {
+        Ok(Block {
             id,
             size: offset + block_size,
             content,
-        }
+        })
     }
 }
 
@@ -91,31 +134,41 @@ pub struct Field<'a> {
     pub content: &'a [u8],
 }
 
-impl<'a> From<&'a [u8]> for Field<'a> {
+impl<'a> TryFrom<&'a [u8]> for Field<'a> {
-    fn from(bytes: &'a [u8]) -> Self {
+    type Error = BytesReadingError;
-        let ElementSize { size, pad } = bytes.try_into().unwrap();
+
+    fn try_from(bytes: &'a [u8]) -> Result<Self, Self::Error> {
+        let ElementSize { size, pad } = bytes.try_into()?;
         let contenu = &bytes[pad..pad + size];
-        Field {
+        Ok(Field {
             id: 0,
             size: pad + size,
             content: contenu,
-        }
+        })
     }
 }
 
-pub fn decode_ssv_memory(bytes: &[u8], size: usize) -> Vec<Block> {
+pub fn decode_ssv_memory(bytes: &[u8], size: usize) -> Result<Vec<Block>, SSVMemoryError> {
     let mut blocks: Vec<Block> = Vec::new();
     let mut offset = 0;
     while offset < size {
-        let block: Block = bytes[offset..].into();
+        let block: Block =
+            bytes[offset..]
+                .try_into()
+                .map_err(|err| SSVMemoryError::BlockParsing {
+                    source: err,
+                    offset,
+                })?;
         offset += block.size;
         blocks.push(block);
     }
-    blocks
+    Ok(blocks)
 }
 
 #[cfg(test)]
 mod test_element_size {
+    use std::any::Any;
+
     use super::*;
 
     #[test]
@@ -142,29 +195,51 @@ mod test_element_size {
     #[test]
     fn null_size() {
         let bytes: &[u8] = &[];
-        let result: Result<ElementSize, &str> = bytes.try_into();
+        let result: Result<ElementSize, BytesReadingError> = bytes.try_into();
-        assert_eq!(result, Err("Empty bytes input"),);
+        assert!(result.is_err());
+        assert_eq!(
+            result.unwrap_err().type_id(),
+            BytesReadingError::EmptyBytes.type_id()
+        );
     }
 
     #[test]
     fn invalid_memory() {
         let bytes: &[u8] = &[0b_1000_0001_u8];
-        let result: Result<ElementSize, &str> = bytes.try_into();
+        let result: Result<ElementSize, BytesReadingError> = bytes.try_into();
+        assert!(result.is_err());
         assert_eq!(
-            result,
+            result.unwrap_err().to_string(),
-            Err("Invalid memory: not enough bytes to read the size"),
+            BytesReadingError::InvalidSize {
+                expected: 1,
+                actual: 0
+            }
+            .to_string()
         );
 
         let bytes: &[u8] = &[0b_1000_0010_u8, 1];
-        let result: Result<ElementSize, &str> = bytes.try_into();
+        let result: Result<ElementSize, BytesReadingError> = bytes.try_into();
+        assert!(result.is_err());
         assert_eq!(
-            result,
+            result.unwrap_err().to_string(),
-            Err("Invalid memory: not enough bytes to read the size"),
+            BytesReadingError::InvalidSize {
+                expected: 2,
+                actual: 1
+            }
+            .to_string()
         );
 
         let bytes: &[u8] = &[0b_1000_0101_u8, 1, 1, 1, 1, 1];
-        let result: Result<ElementSize, &str> = bytes.try_into();
+        let result: Result<ElementSize, BytesReadingError> = bytes.try_into();
-        assert_eq!(result, Err("Invalid memory: size is too big"),);
+        assert!(result.is_err());
+        assert_eq!(
+            result.unwrap_err().to_string(),
+            BytesReadingError::SizeTooBig {
+                expected: 4,
+                actual: 5
+            }
+            .to_string()
+        );
     }
 }
 
@@ -179,7 +254,7 @@ mod test_field {
             80, 72, 65, 82, 77, 65, 67, 73, 69, 78, 48, 48, 53, 50, 52, 49, 57, 9, 70, 82, 65, 78,
             67, 79, 73, 83, 69, 1, 84,
         ];
-        let element: Field = bytes.into();
+        let element: Field = bytes.try_into().unwrap();
         assert_eq!(element.size, 52);
         assert_eq!(element.content[..5], [1, 48, 1, 56, 11]);
     }
@@ -194,7 +269,7 @@ mod test_field {
         // Add 256 bytes to the content
         bytes_vec.append(&mut vec![1; 256]);
         let bytes: &[u8] = &bytes_vec;
-        let element: Field = bytes.into();
+        let element: Field = bytes.try_into().unwrap();
         assert_eq!(element.size, 259);
         assert_eq!(element.content.len(), 256);
     }
@@ -208,15 +283,15 @@ mod test_block {
     fn test_francoise_pharmacien0052419_partial_block_1() {
         let bytes: &[u8] = &[1, 48, 1, 56, 11, 57, 57, 55, 48, 48, 53, 50, 52, 49, 57, 52];
 
-        let field1: Field = bytes.into();
+        let field1: Field = bytes.try_into().unwrap();
         assert_eq!(field1.size, 2);
         assert_eq!(field1.content, &[48]);
 
-        let field2: Field = bytes[field1.size..].into();
+        let field2: Field = bytes[field1.size..].try_into().unwrap();
         assert_eq!(field2.size, 2);
         assert_eq!(field2.content, &[56]);
 
-        let field3: Field = bytes[field1.size + field2.size..].into();
+        let field3: Field = bytes[field1.size + field2.size..].try_into().unwrap();
         assert_eq!(field3.size, 12);
         assert_eq!(
             field3.content,
@@ -243,12 +318,12 @@ mod test_block {
             48, 2, 49, 48, 2, 48, 48, 1, 48, 1, 48, 1, 48, 1, 49, 1, 49,
         ];
 
-        let first_block: Block = bytes.into();
+        let first_block: Block = bytes.try_into().unwrap();
         assert_eq!(first_block.id, 1);
         assert_eq!(first_block.size, 54);
         assert_eq!(first_block.content.len(), 8);
 
-        let second_block: Block = bytes[first_block.size..].into();
+        let second_block: Block = bytes[first_block.size..].try_into().unwrap();
         assert_eq!(second_block.id, 2);
         assert_eq!(second_block.size, 86);
         assert_eq!(second_block.content.len(), 21);
@@ -277,7 +352,7 @@ mod test_decode_ssv_memory {
             50, 50, 49, 57, 53, 8, 48, 48, 50, 48, 50, 52, 49, 57, 1, 56, 0, 1, 48, 1, 49, 2, 53,
             48, 2, 49, 48, 2, 48, 48, 1, 48, 1, 48, 1, 48, 1, 49, 1, 49,
         ];
-        let blocks = decode_ssv_memory(bytes, bytes.len());
+        let blocks = decode_ssv_memory(bytes, bytes.len()).unwrap();
         assert_eq!(blocks.len(), 2);
     }
 }

crates/sesam-vitale/src/ssvlib_demo.rs

@@ -6,25 +6,49 @@ use std::env;
 use std::ffi::CString;
 use std::path::PathBuf;
 use std::ptr;
+use thiserror::Error;
 
 use crate::cps::lire_carte;
 use crate::libssv::{SSV_InitLIB2, SSV_LireConfig};
 
-fn ssv_init_lib_2() {
+#[derive(Error, Debug)]
+pub enum SSVDemoError {
+    #[error(transparent)]
+    CartePSReading(#[from] crate::cps::CartePSError),
+    #[error(transparent)]
+    SSVLibErrorCode(#[from] crate::libssv::LibSSVError),
+}
+
+fn ssv_init_lib_2() -> Result<(), SSVDemoError> {
     let ini_str = env::var("SESAM_INI_PATH").expect("SESAM_INI_PATH must be set");
     let ini = CString::new(ini_str).expect("CString::new failed");
     unsafe {
         let result = SSV_InitLIB2(ini.as_ptr());
         println!("SSV_InitLIB2 result: {}", result);
+        if result != 0 {
+            return Err(crate::libssv::LibSSVError::StandardErrorCode {
+                code: result,
+                function: "SSV_InitLIB2",
             }
+            .into());
+        }
+    }
+    Ok(())
 }
 
-fn ssv_lire_config() {
+fn ssv_lire_config() -> Result<(), SSVDemoError> {
     let mut buffer: *mut c_void = ptr::null_mut();
     let mut size: size_t = 0;
     unsafe {
         let result = SSV_LireConfig(&mut buffer, &mut size);
         println!("SSV_LireConfig result: {}", result);
+        if result != 0 {
+            return Err(crate::libssv::LibSSVError::StandardErrorCode {
+                code: result,
+                function: "SSV_LireConfig",
+            }
+            .into());
+        }
 
         if !buffer.is_null() {
             let hex_values = std::slice::from_raw_parts(buffer as *const u8, size);
@@ -36,25 +60,27 @@ fn ssv_lire_config() {
             libc::free(buffer);
         }
     }
+    Ok(())
 }
 
-pub fn demo() {
+pub fn demo() -> Result<(), SSVDemoError> {
     // TODO : this is probably not working on release, because I'm not sure it exists a CARGO_MANIFEST_DIR and so it can find the `.env`
     // Maybe we could use a system standard config path to store a config file
-    let manifest_dir = env::var("CARGO_MANIFEST_DIR").unwrap();
+    let manifest_dir = env::var("CARGO_MANIFEST_DIR").expect("CARGO_MANIFEST_DIR must be set");
     let manifest_path = PathBuf::from(manifest_dir);
     dotenv::from_path(manifest_path.join(".env")).ok();
 
     println!("------- Demo for the SSV library --------");
 
-    ssv_init_lib_2();
+    ssv_init_lib_2()?;
 
     let code_pin = "1234";
     let lecteur = "HID Global OMNIKEY 3x21 Smart Card Reader 0";
-    let carte_ps = lire_carte(code_pin, lecteur).unwrap();
+    let carte_ps = lire_carte(code_pin, lecteur)?;
     println!("CartePS: {:#?}", carte_ps);
 
-    ssv_lire_config();
+    ssv_lire_config()?;
 
     println!("-----------------------------------------");
+    Ok(())
 }

docs/errors.md

@@ -0,0 +1,85 @@
+# Gestion des erreurs
+
+Ce document décrit comment les erreurs sont gérées dans le projet.
+
+## Gestion native
+
+Par principe, en Rust, on évite au maximum la gestion par exception, ne la réservant qu'aux situations où un crash du programme est la meilleure solution.
+En temps normal, on renvoie des `Result<Valeur, Erreur>` (pour les situations réussite/erreur) ou des `Option<Valeur>` (pour les situations valeur non-nulle/nulle).
+
+Quand on fait face à une situation d'erreur, on cherchera à la gérer de manière explicite (voir [Récupération des erreurs](#récupération-des-erreurs)) ou à la remonter à un niveau supérieur, généralement à l'aide de l'opérateur `?`.
+
+On évitera, par contre, au maximum de générer des exceptions (appelées "panics" en Rust), que ce soit par l'usage de `panic!` ou par des appels à des fonctions qui paniquent en cas d'erreur (comme `unwrap` ou `expect`).
+
+De nombreux exemples des idiomes natifs de gestion des erreurs en Rust sont disponibles dans la documentation [Rust by example](https://doc.rust-lang.org/rust-by-example/error.html).
+
+## Librairies de gestion des erreurs
+
+Deux librairies sont utilisées pour gérer les erreurs dans le projet :
+- [`anyhow`](https://docs.rs/anyhow/latest/anyhow/) : qui permet de renvoyer des erreurs faiblement typées, mais très facile à enrichir avec des messages d'explication. On l'utilise pour communiquer facilement des erreurs de haut niveau avec un utilisateur final.
+    ```rust
+    use anyhow::{anyhow, Result};
+
+    fn get_cluster_info() -> Result<ClusterInfo> {
+        let data = fs::read_to_string("cluster.json")
+            .with_context(|| "failed to read cluster config")?;
+        let info: ClusterInfo = serde_json::from_str(&data)
+            .with_context(|| "failed to parse cluster config")?;
+        Ok(info)
+    }
+    ```
+- [`thiserror`](https://docs.rs/thiserror/latest/thiserror/) : qui fournit des macros pour définir des erreurs fortement typées. On l'utilise pour définir des erreurs spécifiques à une partie du code, contextualisées avec des données structurées plutôt que de simples messages d'erreurs, afin de favoriser la "récupération" face aux erreurs.
+    ```rust
+    use thiserror::Error;
+
+    #[derive(Error, Debug)]
+    pub enum DataStoreError {
+        #[error("data store disconnected")]
+        Disconnect(#[from] io::Error),
+        #[error("the data for key `{0}` is not available")]
+        Redaction(String),
+        #[error("invalid header (expected {expected:?}, found {found:?})")]
+        InvalidHeader {
+            expected: String,
+            found: String,
+        },
+        #[error("unknown data store error")]
+        Unknown,
+    }
+    ```
+
+## Récupération des erreurs
+
+Dans la mesure du possible, on essaie de privilégier la "récupération" face à une erreur plutôt que le "crash". Les stratégies de récupération sont :
+- Réessayer l'opération, tel quel ou avec des paramètres différents
+- Contourner l'opération, en la remplaçant par une autre
+- À défaut, informer l'utilisateur de l'erreur et :
+    - arrêter / annuler l'opération en cours
+    - ignorer l'erreur et continuer l'exécution
+
+Quand on ne peut pas récupérer une erreur, on la remonte à un niveau supérieur, si besoin en la convertissant dans un type d'erreur plus générique et approprié au niveau considéré.
+
+## Conversion des erreurs
+
+Quand on remonte une erreur à un niveau supérieur, on peut être amené à la convertir dans un type d'erreur plus générique et approprié au niveau considéré. Pour faciliter cette conversion, on implémente le trait `From`. Avec `thiserror`, on peut utiliser l'attribut `#[from]` ou le paramètre `source` pour automatiser l'implémentation de telles conversions.
+
+On peut ensuite, lors de la gestion d'une erreur, on pourra :
+- soit directement renvoyer l'erreur à l'aide de l'opérateur `?`, qui se chargera de la conversion ;
+- soit convertir l'erreur explicitement, par exemple en utilisant la méthode `map_err` sur un `Result`, en particulier quand on veut enrichir l'erreur avec des informations supplémentaires.
+
+## Usages exceptionnels de `unwrap` et `expect`
+
+Provoquant des "panics" en cas d'erreur, les fonctions `unwrap` et `expect` ne doivent être utilisées que dans des cas exceptionnels :
+- Dans les tests, pour signaler une erreur de test
+- Au plus haut niveau de l'application, pour signaler une erreur fatale qui ne peut pas être récupérée
+- Dans des situations où l'erreur ne peut pas se produire, par exemple après une vérification de préconditions
+
+Dans l'idéal, on préférera l'usage de `expect` à `unwrap`, car il permet de donner un message d'erreur explicite.
+
+## Ressources
+
+- [The Rust Programming Language - Ch. 9: Error Handling](https://doc.rust-lang.org/book/ch09-00-error-handling.html)
+- [The NRC Book - Error Handling in Rust](https://nrc.github.io/error-docs/intro.html)
+- [The Error Design Patterns Book - by Project Error Handling WG](https://github.com/rust-lang/project-error-handling/blob/master/error-design-patterns-book/src/SUMMARY.md)
+- [The Rust Cookbook - Error Handling](https://rust-lang-nursery.github.io/rust-cookbook/error-handling.html)
+- [Le ticket initial de l'intégration de la gestion des erreurs dans le projet](https://forge.p4pillon.org/P4Pillon/Krys4lide/issues/34)