Add "choice" use case to NBGL lib.

ledger_device_sdk/examples/nbgl_choice.rs

@@ -0,0 +1,51 @@
+#![no_std]
+#![no_main]
+
+// Force boot section to be embedded in
+use ledger_device_sdk as _;
+
+use include_gif::include_gif;
+use ledger_device_sdk::io::*;
+use ledger_device_sdk::nbgl::{init_comm, NbglChoice, NbglGlyph};
+use ledger_secure_sdk_sys::*;
+
+#[panic_handler]
+fn panic(_: &core::panic::PanicInfo) -> ! {
+    exit_app(1);
+}
+
+#[no_mangle]
+extern "C" fn sample_main() {
+    unsafe {
+        nbgl_refreshReset();
+    }
+
+    let mut comm = Comm::new();
+    // Initialize reference to Comm instance for NBGL
+    // API calls.
+    init_comm(&mut comm);
+
+    // Load glyph from 64x64 4bpp gif file with include_gif macro. Creates an NBGL compatible glyph.
+    const WARNING: NbglGlyph =
+        NbglGlyph::from_include(include_gif!("icons/Warning_64px.gif", NBGL));
+
+    let back_to_safety = NbglChoice::new().glyph(&WARNING)
+    .status_text(Some("Transaction rejected"),None)
+    .show(
+        "Security risk detected",
+        "It may not be safe to sign this transaction. To continue, you'll need to review the risk.",
+        "Back to safety",
+        "Review risk",
+    );
+
+    if !back_to_safety {
+        NbglChoice::new()
+        .status_text(Some("Transaction confirmed"), Some("Transaction rejected"))
+        .show(
+                "The transaction cannot be trusted",
+                "Your Ledger cannot decode this transaction. If you sign it, you could be authorizing malicious actions that can drain your wallet.\n\nLearn more: ledger.com/e8",
+                "I accept the risk",
+                "Reject transaction"
+            );
+    }
+}

ledger_device_sdk/src/nbgl.rs

@@ -1079,6 +1079,92 @@ impl<'a> NbglAddressReview<'a> {
     }
 }
 
+/// A wrapper around the synchronous NBGL ux_sync_status C API binding. 
+/// Draws a generic choice page, described in a centered info (with configurable icon),
+/// thanks to a button and a footer at the bottom of the page.
+pub struct NbglChoice<'a> {
+    glyph: Option<&'a NbglGlyph<'a>>,
+    confirmed_text: Option<CString>,
+    cancelled_text: Option<CString>,
+}
+
+impl<'a> NbglChoice<'a> {
+    pub fn new() -> NbglChoice<'a> {
+        NbglChoice {
+            glyph: None,
+            confirmed_text: None,
+            cancelled_text: None,
+        }
+    }
+
+    pub fn glyph(self, glyph: &'a NbglGlyph) -> NbglChoice<'a> {
+        NbglChoice {
+            glyph: Some(glyph),
+            ..self
+        }
+    }
+
+    pub fn status_text(
+        self,
+        confirmed: Option<&'a str>,
+        cancelled: Option<&'a str>,
+    ) -> NbglChoice<'a> {
+        let confirmed_text = confirmed.map(|s| CString::new(s).unwrap());
+        let cancelled_text = cancelled.map(|s| CString::new(s).unwrap());
+        NbglChoice {
+            confirmed_text,
+            cancelled_text,
+            ..self
+        }
+    }
+
+    pub fn show(
+        self,
+        message: &str,
+        sub_message: &str,
+        confirm_text: &str,
+        cancel_text: &str,
+    ) -> bool {
+        unsafe {
+            let icon: nbgl_icon_details_t = match self.glyph {
+                Some(g) => g.into(),
+                None => nbgl_icon_details_t::default(),
+            };
+            let message = CString::new(message).unwrap();
+            let sub_message = CString::new(sub_message).unwrap();
+            let confirm_text = CString::new(confirm_text).unwrap();
+            let cancel_text = CString::new(cancel_text).unwrap();
+
+            let sync_ret = ux_sync_choice(
+                &icon as *const nbgl_icon_details_t,
+                message.as_ptr() as *const c_char,
+                sub_message.as_ptr() as *const c_char,
+                confirm_text.as_ptr() as *const c_char,
+                cancel_text.as_ptr() as *const c_char,
+            );
+
+            // Return true if the user approved the transaction, false otherwise.
+            match sync_ret {
+                ledger_secure_sdk_sys::UX_SYNC_RET_APPROVED => {
+                    if let Some(text) = self.confirmed_text {
+                        ledger_secure_sdk_sys::ux_sync_status(text.as_ptr() as *const c_char, true);
+                    }
+                    return true;
+                }
+                _ => {
+                    if let Some(text) = self.cancelled_text {
+                        ledger_secure_sdk_sys::ux_sync_status(
+                            text.as_ptr() as *const c_char,
+                            false,
+                        );
+                    }
+                    return false;
+                }
+            }
+        }
+    }
+}
+
 #[derive(Copy, Clone)]
 pub enum TuneIndex {
     Reserved,