From f3ba9d982fd5d40157180ba7867cb47027cbf8e8 Mon Sep 17 00:00:00 2001
From: Salvatore Ingala <6681844+bigspider@users.noreply.github.com>
Date: Fri, 11 Oct 2024 11:35:27 +0200
Subject: [PATCH] Refactor APDU messages in client

---
 client-sdk/src/apdu.rs            | 32 +++++++++++++++++++++++++
 client-sdk/src/vanadium_client.rs | 40 +++++++++----------------------
 2 files changed, 43 insertions(+), 29 deletions(-)

diff --git a/client-sdk/src/apdu.rs b/client-sdk/src/apdu.rs
index 9b2ca90..fa6b066 100644
--- a/client-sdk/src/apdu.rs
+++ b/client-sdk/src/apdu.rs
@@ -83,3 +83,35 @@ pub fn apdu_continue(data: Vec<u8>) -> APDUCommand {
         data,
     }
 }
+
+pub fn apdu_continue_with_p1(data: Vec<u8>, p1: u8) -> APDUCommand {
+    APDUCommand {
+        cla: 0xE0,
+        ins: 0xff,
+        p1,
+        p2: 0,
+        data,
+    }
+}
+
+pub fn apdu_register_vapp(serialized_manifest: Vec<u8>) -> APDUCommand {
+    APDUCommand {
+        cla: 0xE0,
+        ins: 2,
+        p1: 0,
+        p2: 0,
+        data: serialized_manifest,
+    }
+}
+
+pub fn apdu_run_vapp(serialized_manifest: Vec<u8>, app_hmac: [u8; 32]) -> APDUCommand {
+    let mut data = serialized_manifest;
+    data.extend_from_slice(&app_hmac);
+    APDUCommand {
+        cla: 0xE0,
+        ins: 3,
+        p1: 0,
+        p2: 0,
+        data,
+    }
+}
diff --git a/client-sdk/src/vanadium_client.rs b/client-sdk/src/vanadium_client.rs
index 49a39d9..ca37aae 100644
--- a/client-sdk/src/vanadium_client.rs
+++ b/client-sdk/src/vanadium_client.rs
@@ -17,7 +17,10 @@ use common::constants::{page_start, PAGE_SIZE};
 use common::manifest::Manifest;
 use sha2::{Digest, Sha256};
 
-use crate::apdu::{apdu_continue, APDUCommand, StatusWord};
+use crate::apdu::{
+    apdu_continue, apdu_continue_with_p1, apdu_register_vapp, apdu_run_vapp, APDUCommand,
+    StatusWord,
+};
 use crate::elf::ElfFile;
 use crate::transport::Transport;
 
@@ -137,22 +140,12 @@ struct VAppEngine<E: std::fmt::Debug + Send + Sync + 'static> {
 
 impl<E: std::fmt::Debug + Send + Sync + 'static> VAppEngine<E> {
     pub async fn run(mut self, app_hmac: [u8; 32]) -> Result<(), &'static str> {
-        let mut data =
+        let serialized_manifest =
             postcard::to_allocvec(&self.manifest).map_err(|_| "manifest serialization failed")?;
 
-        data.extend_from_slice(&app_hmac);
-
-        let command = APDUCommand {
-            cla: 0xE0,
-            ins: 3,
-            p1: 0,
-            p2: 0,
-            data,
-        };
-
         let (status, result) = self
             .transport
-            .exchange(&command)
+            .exchange(&apdu_run_vapp(serialized_manifest, app_hmac))
             .await
             .map_err(|_| "exchange failed")?;
 
@@ -206,16 +199,10 @@ impl<E: std::fmt::Debug + Send + Sync + 'static> VAppEngine<E> {
         let (mut data, _) = segment.get_page(page_index)?;
         let p1 = data.pop().unwrap();
 
-        // return the content of the page
+        // return the content of the page (the last byte is in p1)
         Ok(self
             .transport
-            .exchange(&APDUCommand {
-                cla: 0xE0,
-                ins: 0xff,
-                p1,
-                p2: 0,
-                data,
-            })
+            .exchange(&apdu_continue_with_p1(data, p1))
             .await
             .map_err(|_| "exchange failed")?)
     }
@@ -513,16 +500,11 @@ impl GenericVanadiumClient {
         transport: Arc<dyn Transport<Error = E>>,
         manifest: &Manifest,
     ) -> Result<[u8; 32], &'static str> {
-        let command = APDUCommand {
-            cla: 0xE0,
-            ins: 2,
-            p1: 0,
-            p2: 0,
-            data: postcard::to_allocvec(manifest).map_err(|_| "manifest serialization failed")?,
-        };
+        let serialized_manifest =
+            postcard::to_allocvec(manifest).map_err(|_| "manifest serialization failed")?;
 
         let (status, result) = transport
-            .exchange(&command)
+            .exchange(&apdu_register_vapp(serialized_manifest))
             .await
             .map_err(|_| "exchange failed")?;