Update NBGL spinner: previous and new strings shall be stored to enab…

ledger_device_sdk/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "ledger_device_sdk"
-version = "1.19.6"
+version = "1.20.0"
 authors = ["yhql", "yogh333", "agrojean-ledger", "kingofpayne"]
 edition = "2021"
 license.workspace = true

ledger_device_sdk/examples/nbgl_spinner.rs

@@ -49,7 +49,7 @@ extern "C" fn sample_main() {
         .glyph(&FERRIS)
         .show(&my_field);
 
-    NbglSpinner::new().text("Please wait...").show();
+    NbglSpinner::new().show("Please wait...");
 
     // Simulate an idle state of the app where it just
     // waits for some event to happen (such as APDU reception), going through

ledger_device_sdk/src/libcall/swap.rs

@@ -217,7 +217,7 @@ pub fn sign_tx_params(arg0: u32) -> CreateTxParams {
     }
 
     #[cfg(any(target_os = "stax", target_os = "flex"))]
-    NbglSpinner::new().text("Signing").show();
+    NbglSpinner::new().show("Signing");
 
     create_tx_params
 }

ledger_device_sdk/src/nbgl/nbgl_spinner.rs

@@ -1,28 +1,34 @@
 use super::*;
+extern crate alloc;
+use alloc::ffi::CString;
 
 /// A wrapper around the asynchronous NBGL nbgl_useCaseSpinner C API binding.
 /// Draws a spinner page with the given parameters. The spinner will "turn" automatically every
 /// 800 ms, provided the IO event loop is running to process TickerEvents.
+#[derive(Debug, Default)]
 pub struct NbglSpinner {
-    text: CString,
+    text: [CString; 2],
+    write_idx: usize,
+    read_idx: usize,
 }
 
 impl NbglSpinner {
     pub fn new() -> NbglSpinner {
         NbglSpinner {
-            text: CString::new("").unwrap(),
+            text: [CString::default(), CString::default()],
+            write_idx: 0,
+            read_idx: 0,
         }
     }
 
-    pub fn text(self, text: &str) -> NbglSpinner {
-        NbglSpinner {
-            text: CString::new(text).unwrap(),
-        }
-    }
-
-    pub fn show(&self) {
+    /// Shows the spinner with the current text.
+    /// Every call make the spinner "turn" to the next text.
+    pub fn show(&mut self, text: &str) {
+        self.text[self.write_idx] = CString::new(text).unwrap();
+        self.read_idx = self.write_idx;
+        self.write_idx = (self.write_idx + 1) % 2;
         unsafe {
-            nbgl_useCaseSpinner(self.text.as_ptr() as *const c_char);
+            nbgl_useCaseSpinner(self.text[self.read_idx].as_ptr() as *const c_char);
         }
     }
 }