From 5f135563ccf40de41e011f9bfcc1ace28b532f29 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?dj8yf0=CE=BCl?= <feepdake27@gmail.com>
Date: Wed, 20 Mar 2024 19:39:45 +0200
Subject: [PATCH] feat: transform undisplayable characters for `FmtBuffer<N>`

---
 fmt_buffer/src/lib.rs                         | 20 ++++++++++++++++++-
 .../common/action/function_call_permission.rs |  2 +-
 src/utils/types/elipsis_fields.rs             |  2 +-
 3 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/fmt_buffer/src/lib.rs b/fmt_buffer/src/lib.rs
index 4177e24..b1439fb 100644
--- a/fmt_buffer/src/lib.rs
+++ b/fmt_buffer/src/lib.rs
@@ -16,7 +16,14 @@ impl<const N: usize> Buffer<N> {
         }
     }
 
-    pub fn as_str(&self) -> &str {
+    pub fn as_str(&mut self) -> &str {
+        // NOTE: this workaround is needed until https://github.com/LedgerHQ/ledger-device-rust-sdk/issues/146
+        // is handled at sdk level
+        for byte in self.buffer[..self.used].iter_mut() {
+            if *byte < 0x20 {
+                *byte = 0x7f;
+            }
+        }
         debug_assert!(self.used <= self.buffer.len());
         // .unwrap() is ok, as only bytes, comprising a sequence of valid utf8 chars
         // are going to be written to `self.buffer` on `self.write_str` calls
@@ -135,4 +142,15 @@ mod tests {
         assert_eq!("toooooo long:    400000 - 0x61", buffer.as_str());
         assert_eq!(true, buffer.truncated());
     }
+
+    #[test]
+    pub fn test_rewrite_undisplayable_chars() {
+        let mut buffer = Buffer::<30>::new();
+
+        buffer.write_str("Prefix: ");
+
+        buffer.write_str("\x0A\x0D");
+        assert_eq!("Prefix: \x7F\x7F", buffer.as_str());
+        assert_eq!(false, buffer.truncated());
+    }
 }
diff --git a/src/app_ui/sign/common/action/function_call_permission.rs b/src/app_ui/sign/common/action/function_call_permission.rs
index afe6507..d006bd4 100644
--- a/src/app_ui/sign/common/action/function_call_permission.rs
+++ b/src/app_ui/sign/common/action/function_call_permission.rs
@@ -58,7 +58,7 @@ pub fn format<'b, 'a: 'b>(
     }));
 
     let methods_names_fields = ElipsisFields::from_fmt_buffer(
-        &function_call_perm.method_names,
+        &mut function_call_perm.method_names,
         "Method Names",
         &mut field_context.method_names_display_buf,
     );
diff --git a/src/utils/types/elipsis_fields.rs b/src/utils/types/elipsis_fields.rs
index a899878..dab72ed 100644
--- a/src/utils/types/elipsis_fields.rs
+++ b/src/utils/types/elipsis_fields.rs
@@ -20,7 +20,7 @@ impl<'a> ElipsisFields<'a> {
     }
 
     pub fn from_fmt_buffer<const N: usize>(
-        source: &'a Buffer<N>,
+        source: &'a mut Buffer<N>,
         title: &'a str,
         display_buf: &'a mut [u8; 20],
     ) -> Self {