Improve Wasm module linking facilities

src/error.rs

@@ -1,3 +1,4 @@
+use crate::linking::LinkingError;
 use core::fmt;
 
 pub enum Error {
@@ -14,6 +15,8 @@ pub enum Error {
     AuthorIDMismatch,
     AppIDMismatch,
 
+    Linking(LinkingError),
+
     DecodeMeta(postcard::Error),
     DecodeStats(postcard::Error),
     SerialEncode(postcard::Error),
@@ -64,6 +67,7 @@ impl fmt::Display for Error {
             Self::ReadFile(name, err) => write!(f, "cannot read {name}: {err}"),
             Self::AuthorIDMismatch => write!(f, "author ID in meta and in path don't match"),
             Self::AppIDMismatch => write!(f, "app ID in meta and in path don't match"),
+            Self::Linking(err) => write!(f, "linking: {err}"),
             Self::DecodeMeta(err) => write!(f, "cannot decode _meta: {err}"),
             Self::DecodeStats(err) => write!(f, "cannot decode stats: {err}"),
             Self::SerialEncode(err) => write!(f, "cannot encode response for serial: {err}"),
@@ -83,6 +87,12 @@ impl From<wasmi::Error> for Error {
     }
 }
 
+impl From<LinkingError> for Error {
+    fn from(value: LinkingError) -> Self {
+        Self::Linking(value)
+    }
+}
+
 /// Runtime stats provided on guest failure that should help to debug the failure cause.
 pub struct RuntimeStats {
     pub(crate) last_called: &'static str,

src/frame_buffer.rs

@@ -188,6 +188,7 @@ impl DrawTarget for FrameBuffer {
         for y in top_y..bottom_y {
             let start_i = y * WIDTH / 2 + start_x / 2;
             let end_i = start_i + width / 2;
+            // TODO: IT PANICS (end_i overflows)
             self.data[start_i..end_i].fill(new_byte);
         }