Merge pull request #143 from lvgl/infallible-raw

`<T as NativeObject>::raw()` infallible, `Obj` store `NonNull` pointers

Author: nia-e

examples/sdl.rs

@@ -28,11 +28,11 @@ fn main() -> LvResult<()> {
 
     let mut screen_style = Style::default();
     screen_style.set_bg_color(Color::from_rgb((0, 0, 0)));
-    screen.add_style(Part::Main, &mut screen_style)?;
+    screen.add_style(Part::Main, &mut screen_style);
     // Create the button
     let mut button = Btn::create(&mut screen)?;
-    button.set_align(Align::LeftMid, 30, 0)?;
-    button.set_size(180, 80)?;
+    button.set_align(Align::LeftMid, 30, 0);
+    button.set_size(180, 80);
     let mut btn_lbl = Label::create(&mut button)?;
     btn_lbl.set_text(CString::new("Click me!").unwrap().as_c_str())?;
 

lvgl-codegen/src/lib.rs

@@ -110,7 +110,7 @@ impl Rusty for LvFunc {
                 pub fn create(parent: &mut impl crate::NativeObject) -> crate::LvResult<Self> {
                     unsafe {
                         let ptr = lvgl_sys::#original_func_name(
-                            parent.raw()?.as_mut(),
+                            parent.raw().as_mut(),
                         );
                         if let Some(raw) = core::ptr::NonNull::new(ptr) {
                             let core = <crate::Obj as crate::Widget>::from_raw(raw).unwrap();
@@ -196,7 +196,7 @@ impl Rusty for LvFunc {
             .fold(quote!(), |args, (i, arg)| {
                 // if first arg is `const`, then it should be immutable
                 let next_arg = if i == 0 {
-                    quote!(self.core.raw()?.as_mut())
+                    quote!(self.core.raw().as_mut())
                 } else {
                     let var = arg.get_value_usage();
                     quote!(#var)
@@ -557,7 +557,7 @@ mod test {
         let expected_code = quote! {
             pub fn set_bg_end_angle(&mut self, end: u16) -> crate::LvResult<()> {
                 unsafe {
-                    lvgl_sys::lv_arc_set_bg_end_angle(self.core.raw()?.as_mut(), end);
+                    lvgl_sys::lv_arc_set_bg_end_angle(self.core.raw().as_mut(), end);
                 }
                 Ok(())
             }
@@ -590,7 +590,7 @@ mod test {
             pub fn set_text(&mut self, text: &cstr_core::CStr) -> crate::LvResult<()> {
                 unsafe {
                     lvgl_sys::lv_label_set_text(
-                        self.core.raw()?.as_mut(),
+                        self.core.raw().as_mut(),
                         text.as_ptr()
                     );
                 }
@@ -649,7 +649,7 @@ mod test {
                 pub fn create(parent: &mut impl crate::NativeObject) -> crate::LvResult<Self> {
                     unsafe {
                         let ptr = lvgl_sys::lv_arc_create(
-                            parent.raw()?.as_mut(),
+                            parent.raw().as_mut(),
                         );
                         if let Some(raw) = core::ptr::NonNull::new(ptr) {
                             let core = <crate::Obj as crate::Widget>::from_raw(raw).unwrap();

lvgl/src/display.rs

@@ -1,6 +1,6 @@
 use crate::functions::CoreError;
 use crate::Screen;
-use crate::{disp_drv_register, disp_get_default, get_str_act, LvResult, NativeObject};
+use crate::{disp_drv_register, disp_get_default, get_str_act, NativeObject};
 use crate::{Box, Color};
 use core::convert::TryInto;
 #[cfg(feature = "nightly")]
@@ -77,10 +77,9 @@ impl<'a> Display {
     }
 
     /// Sets a `Screen` as currently active.
-    pub fn set_scr_act(&'a self, screen: &'a mut Screen) -> LvResult<()> {
-        let scr_ptr = unsafe { screen.raw()?.as_mut() };
+    pub fn set_scr_act(&'a self, screen: &'a mut Screen) {
+        let scr_ptr = unsafe { screen.raw().as_mut() };
         unsafe { lvgl_sys::lv_disp_load_scr(scr_ptr) }
-        Ok(())
     }
 
     /// Registers a display from raw functions and values.
@@ -89,6 +88,7 @@ impl<'a> Display {
     ///
     /// `hor_res` and `ver_res` must be nonzero, and the provided functions
     /// must not themselves cause undefined behavior.
+    #[allow(clippy::too_many_arguments)]
     pub unsafe fn register_raw<const N: usize>(
         draw_buffer: DrawBuffer<N>,
         hor_res: u32,
@@ -230,6 +230,7 @@ impl<'a, const N: usize> DisplayDriver<N> {
         }))
     }
 
+    #[allow(clippy::too_many_arguments)]
     pub unsafe fn new_raw(
         mut draw_buffer: DrawBuffer<N>,
         flush_cb: Option<

lvgl/src/functions.rs

@@ -72,11 +72,10 @@ pub fn task_handler() {
 pub fn event_send<W: for<'a> Widget<'a>>(
     obj: &mut W,
     event: Event<<W as Widget<'_>>::SpecialEvent>,
-) -> LvResult<()> {
+) {
     unsafe {
-        lvgl_sys::lv_event_send(obj.raw()?.as_mut(), event.into(), ptr::null_mut());
+        lvgl_sys::lv_event_send(obj.raw().as_mut(), event.into(), ptr::null_mut());
     };
-    Ok(())
 }
 
 /// Register an input device driver to LVGL.

lvgl/src/lv_core/group.rs

@@ -27,7 +27,7 @@ impl Group {
 
     /// Adds an object to the group.
     pub fn add_obj(&mut self, obj: &impl NativeObject) -> LvResult<()> {
-        unsafe { lvgl_sys::lv_group_add_obj(self.raw()?.as_mut(), obj.raw()?.as_mut()) }
+        unsafe { lvgl_sys::lv_group_add_obj(self.raw()?.as_mut(), obj.raw().as_mut()) }
         Ok(())
     }
 

lvgl/src/lv_core/obj.rs

@@ -9,23 +9,24 @@ use crate::lv_core::style::Style;
 use crate::{Align, LvError, LvResult};
 use core::fmt::{self, Debug};
 use core::marker::PhantomData;
-use core::ptr;
+use core::ptr::{self, NonNull};
 
 /// Represents a native LVGL object.
 pub trait NativeObject {
     /// Provide common way to access to the underlying native object pointer.
-    fn raw(&self) -> LvResult<ptr::NonNull<lvgl_sys::lv_obj_t>>;
+    fn raw(&self) -> NonNull<lvgl_sys::lv_obj_t>;
 }
 
 /// Generic LVGL object.
 ///
-/// This is the parent object of all widget types. It stores the native LVGL raw pointer.
+/// This is the parent object of all widget types. It stores the native LVGL
+/// raw pointer.
 pub struct Obj<'a> {
-    // We use a raw pointer here because we do not control this memory address, it is controlled
-    // by LVGL's global state.
-    raw: *mut lvgl_sys::lv_obj_t,
-    // This is to ensure safety for style memory; it has no runtime impact
-    styles_used: PhantomData<&'a lvgl_sys::lv_style_t>,
+    // We use a raw pointer here because we do not control this memory address,
+    // it is controlled by LVGL's global state.
+    raw: NonNull<lvgl_sys::lv_obj_t>,
+    // This is to ensure safety for children memory; it has no runtime impact
+    dependents: PhantomData<&'a isize>,
 }
 
 impl Debug for Obj<'_> {
@@ -38,15 +39,15 @@ impl Debug for Obj<'_> {
 
 // We need to manually impl methods on Obj since widget codegen is defined in
 // terms of Obj
-impl Obj<'_> {
-    pub fn create(parent: &mut impl NativeObject) -> LvResult<Self> {
+impl<'a> Obj<'a> {
+    pub fn create(parent: &'a mut impl NativeObject) -> LvResult<Self> {
         unsafe {
-            let ptr = lvgl_sys::lv_obj_create(parent.raw()?.as_mut());
-            if ptr::NonNull::new(ptr).is_some() {
+            let ptr = lvgl_sys::lv_obj_create(parent.raw().as_mut());
+            if let Some(nn_ptr) = ptr::NonNull::new(ptr) {
                 //(*ptr).user_data = Box::new(UserDataObj::empty()).into_raw() as *mut _;
                 Ok(Self {
-                    raw: ptr,
-                    styles_used: PhantomData,
+                    raw: nn_ptr,
+                    dependents: PhantomData::<&'a _>,
                 })
             } else {
                 Err(LvError::InvalidReference)
@@ -56,17 +57,23 @@ impl Obj<'_> {
 
     pub fn new() -> crate::LvResult<Self> {
         let mut parent = crate::display::get_scr_act()?;
-        Self::create(&mut parent)
+        Self::create(unsafe { &mut *(&mut parent as *mut _) })
+    }
+
+    pub fn blank() -> LvResult<Self> {
+        match NonNull::new(unsafe { lvgl_sys::lv_obj_create(ptr::null_mut()) }) {
+            Some(raw) => Ok(Self {
+                raw,
+                dependents: PhantomData,
+            }),
+            None => Err(LvError::LvOOMemory),
+        }
     }
 }
 
 impl NativeObject for Obj<'_> {
-    fn raw(&self) -> LvResult<ptr::NonNull<lvgl_sys::lv_obj_t>> {
-        if let Some(non_null_ptr) = ptr::NonNull::new(self.raw) {
-            Ok(non_null_ptr)
-        } else {
-            Err(LvError::InvalidReference)
-        }
+    fn raw(&self) -> ptr::NonNull<lvgl_sys::lv_obj_t> {
+        self.raw
     }
 }
 
@@ -85,92 +92,77 @@ pub trait Widget<'a>: NativeObject + Sized + 'a {
     unsafe fn from_raw(raw_pointer: ptr::NonNull<lvgl_sys::lv_obj_t>) -> Option<Self>;
 
     /// Adds a `Style` to a given widget.
-    fn add_style(&mut self, part: Self::Part, style: &'a mut Style) -> LvResult<()> {
+    fn add_style(&mut self, part: Self::Part, style: &'a mut Style) {
         unsafe {
             lvgl_sys::lv_obj_add_style(
-                self.raw()?.as_mut(),
+                self.raw().as_mut(),
                 style.raw.as_mut() as *mut _,
                 part.into(),
             );
         };
-        Ok(())
     }
 
     /// Sets a widget's position relative to its parent.
-    fn set_pos(&mut self, x: i16, y: i16) -> LvResult<()> {
+    fn set_pos(&mut self, x: i16, y: i16) {
         unsafe {
             lvgl_sys::lv_obj_set_pos(
-                self.raw()?.as_mut(),
+                self.raw().as_mut(),
                 x as lvgl_sys::lv_coord_t,
                 y as lvgl_sys::lv_coord_t,
             );
         }
-        Ok(())
     }
 
     /// Sets a widget's size. Alternatively, use `set_width()` and `set_height()`.
-    fn set_size(&mut self, w: i16, h: i16) -> LvResult<()> {
+    fn set_size(&mut self, w: i16, h: i16) {
         unsafe {
             lvgl_sys::lv_obj_set_size(
-                self.raw()?.as_mut(),
+                self.raw().as_mut(),
                 w as lvgl_sys::lv_coord_t,
                 h as lvgl_sys::lv_coord_t,
             );
         }
-        Ok(())
     }
 
     /// Sets a widget's width. Alternatively, use `set_size()`.
-    fn set_width(&mut self, w: u32) -> LvResult<()> {
+    fn set_width(&mut self, w: u32) {
         unsafe {
-            lvgl_sys::lv_obj_set_width(self.raw()?.as_mut(), w as lvgl_sys::lv_coord_t);
+            lvgl_sys::lv_obj_set_width(self.raw().as_mut(), w as lvgl_sys::lv_coord_t);
         }
-        Ok(())
     }
 
     /// Sets a widget's height. Alternatively, use `set_size()`.
-    fn set_height(&mut self, h: u32) -> LvResult<()> {
+    fn set_height(&mut self, h: u32) {
         unsafe {
-            lvgl_sys::lv_obj_set_height(self.raw()?.as_mut(), h as lvgl_sys::lv_coord_t);
+            lvgl_sys::lv_obj_set_height(self.raw().as_mut(), h as lvgl_sys::lv_coord_t);
         }
-        Ok(())
     }
 
     /// Sets a widget's align relative to its parent along with an offset.
-    fn set_align(&mut self, align: Align, x_mod: i32, y_mod: i32) -> LvResult<()> {
+    fn set_align(&mut self, align: Align, x_mod: i32, y_mod: i32) {
         unsafe {
             lvgl_sys::lv_obj_align(
-                self.raw()?.as_mut(),
+                self.raw().as_mut(),
                 align.into(),
                 x_mod as lvgl_sys::lv_coord_t,
                 y_mod as lvgl_sys::lv_coord_t,
             );
         }
-        Ok(())
     }
 }
 
 impl<'a> Widget<'a> for Obj<'a> {
     type SpecialEvent = u32;
     type Part = Part;
 
-    unsafe fn from_raw(raw: ptr::NonNull<lvgl_sys::lv_obj_t>) -> Option<Self> {
+    unsafe fn from_raw(raw: NonNull<lvgl_sys::lv_obj_t>) -> Option<Self> {
         Some(Self {
-            raw: raw.as_ptr(),
-            styles_used: PhantomData,
+            raw,
+            dependents: PhantomData,
         })
     }
 }
 
-impl Default for Obj<'_> {
-    fn default() -> Self {
-        Self {
-            raw: unsafe { lvgl_sys::lv_obj_create(ptr::null_mut()) },
-            styles_used: PhantomData,
-        }
-    }
-}
-
 macro_rules! define_object {
     ($item:ident) => {
         define_object!($item, event = (), part = $crate::Part);
@@ -197,7 +189,7 @@ macro_rules! define_object {
             {
                 use $crate::NativeObject;
                 unsafe {
-                    let obj = self.raw()?.as_mut();
+                    let obj = self.raw().as_mut();
                     obj.user_data = $crate::Box::into_raw($crate::Box::new(f)) as *mut _;
                     lvgl_sys::lv_obj_add_event_cb(
                         obj,
@@ -213,7 +205,7 @@ macro_rules! define_object {
         }
 
         impl $crate::NativeObject for $item<'_> {
-            fn raw(&self) -> $crate::LvResult<core::ptr::NonNull<lvgl_sys::lv_obj_t>> {
+            fn raw(&self) -> core::ptr::NonNull<lvgl_sys::lv_obj_t> {
                 self.core.raw()
             }
         }

lvgl/src/lv_core/screen.rs

@@ -1,13 +1,19 @@
-use crate::{LvError, NativeObject, Obj, Part, Widget};
+use crate::{LvError, LvResult, NativeObject, Obj, Part, Widget};
 
 /// An LVGL screen.
-#[derive(Debug, Default)]
+#[derive(Debug)]
 pub struct Screen<'a> {
     raw: Obj<'a>,
 }
 
+impl Screen<'_> {
+    pub fn blank() -> LvResult<Self> {
+        Ok(Self { raw: Obj::blank()? })
+    }
+}
+
 impl NativeObject for Screen<'_> {
-    fn raw(&self) -> crate::LvResult<core::ptr::NonNull<lvgl_sys::lv_obj_t>> {
+    fn raw(&self) -> core::ptr::NonNull<lvgl_sys::lv_obj_t> {
         self.raw.raw()
     }
 }
@@ -28,13 +34,14 @@ impl<'a> TryFrom<Obj<'a>> for Screen<'a> {
     type Error = LvError;
 
     fn try_from(value: Obj<'a>) -> Result<Self, Self::Error> {
-        match unsafe { value.raw()?.as_mut().parent } as usize {
+        match unsafe { value.raw().as_mut().parent } as usize {
             0 => Ok(Self { raw: value }),
             _ => Err(LvError::InvalidReference),
         }
     }
 }
 
+#[allow(clippy::from_over_into)]
 impl<'a> Into<Obj<'a>> for Screen<'a> {
     fn into(self) -> Obj<'a> {
         self.raw
@@ -66,8 +73,8 @@ mod test {
         let buffer = DrawBuffer::<{ (HOR_RES * VER_RES) as usize }>::default();
         let display = Display::register(buffer, HOR_RES, VER_RES, |_| {}).unwrap();
         let mut screen_old = display.get_scr_act().unwrap();
-        let mut screen_new = Screen::default();
-        display.set_scr_act(&mut screen_new).unwrap();
-        display.set_scr_act(&mut screen_old).unwrap();
+        let mut screen_new = Screen::blank().unwrap();
+        display.set_scr_act(&mut screen_new);
+        display.set_scr_act(&mut screen_old);
     }
 }

lvgl/src/misc/anim.rs

@@ -113,7 +113,7 @@ where
         let anim =
             NonNull::new(lvgl_sys::lv_anim_get(obj, None) as *mut lvgl_sys::lv_anim_t).unwrap();
         // yes, we have to do it this way. Casting `obj` directly to `&mut Obj` segfaults
-        let obj = (*(obj as *mut T)).raw().unwrap();
+        let obj = (*(obj as *mut T)).raw();
         if !anim.as_ref().user_data.is_null() {
             let callback = &mut *(obj.as_ref().user_data as *mut F);
             let mut obj_nondrop = Obj::from_raw(obj).unwrap();