refactor(core): move c string conversion out of UI code

[no changelog]

core/embed/rust/src/lib.rs

@@ -44,6 +44,9 @@ mod trezorhal;
 #[cfg(feature = "ui")]
 pub mod ui;
 
+
+pub mod util;
+
 #[cfg(feature = "debug")]
 #[cfg(not(test))]
 #[panic_handler]

core/embed/rust/src/ui/api/bootloader_c.rs

@@ -7,9 +7,9 @@ use crate::{
     },
     ui::{
         ui_bootloader::{BootloaderLayoutType as _, BootloaderUI},
-        util::{from_c_array, from_c_str},
         ModelUI,
     },
+    util::{from_c_array, from_c_str},
 };
 
 #[no_mangle]

core/embed/rust/src/ui/api/common_c.rs

@@ -3,9 +3,7 @@
 
 use crate::ui::{CommonUI, ModelUI};
 
-use crate::ui::shape;
+use crate::{ui::shape, util::from_c_str};
-
-use crate::ui::util::from_c_str;
 
 #[no_mangle]
 extern "C" fn display_rsod_rust(

core/embed/rust/src/ui/api/prodtest_c.rs

@@ -5,9 +5,9 @@ use crate::{
     },
     ui::{
         ui_prodtest::{ProdtestLayoutType, ProdtestUI},
-        util::from_c_array,
         ModelUI,
     },
+    util::from_c_array,
 };
 
 #[cfg(feature = "touch")]

core/embed/rust/src/ui/util.rs

@@ -15,50 +15,6 @@ impl<T, E> ResultExt for Result<T, E> {
     }
 }
 
-/// Constructs a string from a C string.
-///
-/// # Safety
-///
-/// The caller is responsible that the pointer is valid, which means that:
-/// (a) it points to a memory containing a valid C string (zero-terminated
-/// sequence of characters), and
-/// (b) that the pointer has appropriate lifetime.
-pub unsafe fn from_c_str<'a>(c_str: *const cty::c_char) -> Option<&'a str> {
-    if c_str.is_null() {
-        return None;
-    }
-    unsafe {
-        let bytes = core::ffi::CStr::from_ptr(c_str as _).to_bytes();
-        if bytes.is_ascii() {
-            Some(core::str::from_utf8_unchecked(bytes))
-        } else {
-            None
-        }
-    }
-}
-
-/// Construct str from a C array.
-///
-/// # Safety
-///
-/// The caller is responsible that the pointer is valid, which means that:
-/// (a) it points to a memory containing array of characters, with length `len`,
-/// and
-/// (b) that the pointer has appropriate lifetime.
-pub unsafe fn from_c_array<'a>(c_str: *const cty::c_char, len: usize) -> Option<&'a str> {
-    if c_str.is_null() {
-        return None;
-    }
-    unsafe {
-        let slice = core::slice::from_raw_parts(c_str as *const u8, len);
-        if slice.is_ascii() {
-            Some(core::str::from_utf8_unchecked(slice))
-        } else {
-            None
-        }
-    }
-}
-
 #[cfg(feature = "ui_debug")]
 static mut DISABLE_ANIMATION: bool = false;
 

core/embed/rust/src/util/mod.rs

@@ -0,0 +1,43 @@
+/// Constructs a string from a C string.
+///
+/// # Safety
+///
+/// The caller is responsible that the pointer is valid, which means that:
+/// (a) it points to a memory containing a valid C string (zero-terminated
+/// sequence of characters), and
+/// (b) that the pointer has appropriate lifetime.
+pub unsafe fn from_c_str<'a>(c_str: *const cty::c_char) -> Option<&'a str> {
+    if c_str.is_null() {
+        return None;
+    }
+    unsafe {
+        let bytes = core::ffi::CStr::from_ptr(c_str as _).to_bytes();
+        if bytes.is_ascii() {
+            Some(core::str::from_utf8_unchecked(bytes))
+        } else {
+            None
+        }
+    }
+}
+
+/// Construct str from a C array.
+///
+/// # Safety
+///
+/// The caller is responsible that the pointer is valid, which means that:
+/// (a) it points to a memory containing array of characters, with length `len`,
+/// and
+/// (b) that the pointer has appropriate lifetime.
+pub unsafe fn from_c_array<'a>(c_str: *const cty::c_char, len: usize) -> Option<&'a str> {
+    if c_str.is_null() {
+        return None;
+    }
+    unsafe {
+        let slice = core::slice::from_raw_parts(c_str as *const u8, len);
+        if slice.is_ascii() {
+            Some(core::str::from_utf8_unchecked(slice))
+        } else {
+            None
+        }
+    }
+}