Amount now as coin string and u64

Author: kingofpayne

Cargo.lock

@@ -12,6 +12,7 @@ include_gif = "1.0.0"
 serde = {version="1.0.192", default_features = false, features = ["derive"]}
 serde-json-core = { git = "https://github.com/rust-embedded-community/serde-json-core"}
 hex = { version = "0.4.3", default-features = false, features = ["serde"] }
+numtoa = "0.2.4"
 
 [profile.release]
 opt-level = 'z'

Cargo.toml

@@ -15,42 +15,60 @@
  *  limitations under the License.
  *****************************************************************************/
 
+use core::str::from_utf8;
+
 use crate::handlers::sign_tx::Tx;
+use crate::utils::concatenate;
 use ledger_device_ui_sdk::bitmaps::{CROSSMARK, EYE, VALIDATE_14};
 use ledger_device_ui_sdk::ui::{Field, MultiFieldReview};
+use numtoa::NumToA;
+
+const MAX_COIN_LENGTH: usize = 10;
 
 pub fn ui_display_tx(tx: &Tx) -> bool {
-    // Generate destination address string in hexadecimal format.
-    let mut to_str = [0u8; 42];
-    to_str[..2].copy_from_slice("0x".as_bytes());
-    hex::encode_to_slice(tx.to, &mut to_str[2..]).unwrap();
-
-    // Define transaction review fields
-    let my_fields = [
-        Field {
-            name: "Amount",
-            value: tx.value,
-        },
-        Field {
-            name: "Destination",
-            value: core::str::from_utf8(&to_str).unwrap(),
-        },
-        Field {
-            name: "Memo",
-            value: tx.memo,
-        },
-    ];
-
-    // Create transaction review
-    let my_review = MultiFieldReview::new(
-        &my_fields,
-        &["Review ", "Transaction"],
-        Some(&EYE),
-        "Approve",
-        Some(&VALIDATE_14),
-        "Reject",
-        Some(&CROSSMARK),
-    );
-
-    my_review.show()
+    // Generate string for amount
+    let mut numtoa_buf = [0u8; 20];
+    let mut value_buf = [0u8; 20 + MAX_COIN_LENGTH + 1];
+
+    if let Ok(value_str) = concatenate(
+        &[tx.coin, &" ", tx.value.numtoa_str(10, &mut numtoa_buf)],
+        &mut value_buf,
+    ) {
+        // Generate destination address string in hexadecimal format.
+        let mut to_str = [0u8; 42];
+        to_str[..2].copy_from_slice("0x".as_bytes());
+        hex::encode_to_slice(tx.to, &mut to_str[2..]).unwrap();
+
+        // Define transaction review fields
+        let my_fields = [
+            Field {
+                name: "Amount",
+                value: value_str,
+            },
+            Field {
+                name: "Destination",
+                value: core::str::from_utf8(&to_str).unwrap(),
+            },
+            Field {
+                name: "Memo",
+                value: tx.memo,
+            },
+        ];
+
+        // Create transaction review
+        let my_review = MultiFieldReview::new(
+            &my_fields,
+            &["Review ", "Transaction"],
+            Some(&EYE),
+            "Approve",
+            Some(&VALIDATE_14),
+            "Reject",
+            Some(&CROSSMARK),
+        );
+
+        my_review.show()
+    } else {
+        // Coin name too long, concatenation buffer was too small.
+        return false;
+    }
 }

src/app_ui/sign.rs

@@ -31,8 +31,9 @@ const MAX_TRANSACTION_LEN: usize = 510;
 #[derive(Deserialize)]
 pub struct Tx<'a> {
     nonce: u64,
-    pub value: &'a str,
-    #[serde(with = "hex::serde")]
+    pub coin: &'a str,
+    pub value: u64,
+    #[serde(with = "hex::serde")] // Allows JSON deserialization from hex string
     pub to: [u8; 20],
     pub memo: &'a str,
 }

src/handlers/sign_tx.rs

@@ -1,5 +1,5 @@
 use crate::AppSW;
-use core::char;
+use core::{char, str::from_utf8};
 
 pub const MAX_ALLOWED_PATH_LEN: usize = 10;
 const MAX_HEX_LEN: usize = 64;
@@ -31,20 +31,19 @@ pub fn read_bip32_path(data: &[u8], path: &mut [u32]) -> Result<usize, AppSW> {
     Ok(idx)
 }
 
-/// Concatenate multiple strings into a fixed-size array
-pub fn concatenate(strings: &[&str], output: &mut [u8]) {
+/// Returns concatenated strings, or an error if the concatenation buffer is too small.
+pub fn concatenate<'a>(strings: &[&str], output: &'a mut [u8]) -> Result<&'a str, ()> {
     let mut offset = 0;
 
     for s in strings {
         let s_len = s.len();
-        let copy_len = core::cmp::min(s_len, output.len() - offset);
-
-        if copy_len > 0 {
-            output[offset..offset + copy_len].copy_from_slice(&s.as_bytes()[..copy_len]);
-            offset += copy_len;
-        } else {
-            // If the output buffer is full, stop concatenating.
-            break;
+        if offset + s_len > output.len() {
+            return Err(());
         }
+
+        output[offset..offset + s_len].copy_from_slice(&s.as_bytes());
+        offset += s_len;
     }
+
+    Ok(from_utf8(&output[..offset]).unwrap())
 }

src/utils.rs

@@ -11,12 +11,14 @@ class TransactionError(Exception):
 class Transaction:
     def __init__(self,
                  nonce: int,
-                 value: float,
+                 coin: str,
+                 value: int,
                  to: str,
                  memo: str,
                  do_check: bool = True) -> None:
         self.nonce: int = nonce
-        self.value: str = "CRAB " + str(value)
+        self.coin: str = coin
+        self.value: str = value
         self.to: str = to 
         self.memo: str = memo
 
@@ -31,6 +33,7 @@ def serialize(self) -> bytes:
         # Serialize the transaction data to a JSON-formatted string
         return json.dumps({
             "nonce": self.nonce,
+            "coin": self.coin,
             "value": self.value,
             "to": self.to,
             "memo": self.memo

tests/application_client/boilerplate_transaction.py

@@ -26,7 +26,8 @@ def test_sign_tx_short_tx(firmware, backend, navigator, test_name):
     # Create the transaction that will be sent to the device for signing
     transaction = Transaction(
         nonce=1,
-        value=0.777,
+        coin="CRAB",
+        value=777,
         to="de0b295669a9fd93d5f28d9ec85e40f4cb697bae",
         memo="For u EthDev"
     ).serialize()
@@ -70,8 +71,9 @@ def test_sign_tx_long_tx(firmware, backend, navigator, test_name):
 
     transaction = Transaction(
         nonce=1,
-        to="de0b295669a9fd93d5f28d9ec85e40f4cb697bae",
+        coin="CRAB",
         value=666,
+        to="de0b295669a9fd93d5f28d9ec85e40f4cb697bae",
         memo=("This is a very long memo. "
               "It will force the app client to send the serialized transaction to be sent in chunk. "
               "As the maximum chunk size is 255 bytes we will make this memo greater than 255 characters. "
@@ -109,8 +111,9 @@ def test_sign_tx_refused(firmware, backend, navigator, test_name):
 
     transaction = Transaction(
         nonce=1,
-        to="de0b295669a9fd93d5f28d9ec85e40f4cb697bae",
+        coin="CRAB",
         value=666,
+        to="de0b295669a9fd93d5f28d9ec85e40f4cb697bae",
         memo="This transaction will be refused by the user"
     ).serialize()