Restructure guest/host error handling

Justfile

@@ -355,7 +355,7 @@ build-fuzzer fuzz-target:
 ###################
 
 gen-all-fbs-rust-code:
-    for fbs in `find src -name "*.fbs"`; do flatc -r --rust-module-root-file --gen-all -o ./src/hyperlight_common/src/flatbuffers/ $fbs; done
+    flatc --rust --rust-module-root-file --gen-all -o ./src/hyperlight_common/src/flatbuffers/ ./src/schema/all.fbs
     just fmt-apply
 
 install-vcpkg:

docs/how-to-use-flatbuffers.md

@@ -19,9 +19,3 @@ We recommend building `flatc` from source. To generate rust code, use
 ```console
 just gen-all-fbs-rust-code
 ```
-
-### Note about generated code
-
-Because we invoke `flatc` multiple times when generating the Rust code, the `mod.rs` generated in `./src/hyperlight_common/src/flatbuffers` is overwritten multiple times and will likely be incorrect. Make sure to manually inspect and if necessary update this file before continuing with your changes as certain modules might be missing. After fixing `mod.rs`, you might need to re-run `just fmt`, since it might not have applied to all generated files if your `mod.rs` was invalid.
-
->`flatc` does support passing multiple schema files (e.g. it is possible to pass `.\src\schema\*.fbs`), so we could regenerate all the files each time a change was made, however that generates incorrect code (see [here](https://github.com/google/flatbuffers/issues/6800) for details).

src/hyperlight_common/src/flatbuffer_wrappers/guest_error.rs

@@ -17,16 +17,11 @@ limitations under the License.
 extern crate flatbuffers;
 
 use alloc::string::{String, ToString};
-use alloc::vec::Vec;
 
-use anyhow::{Error, Result};
-use flatbuffers::size_prefixed_root;
 #[cfg(feature = "tracing")]
 use tracing::{Span, instrument};
 
-use crate::flatbuffers::hyperlight::generated::{
-    ErrorCode as FbErrorCode, GuestError as FbGuestError, GuestErrorArgs,
-};
+use crate::flatbuffers::hyperlight::generated::ErrorCode as FbErrorCode;
 
 #[derive(Debug, Clone, Copy, Eq, PartialEq)]
 #[repr(C)]
@@ -48,6 +43,7 @@ pub enum ErrorCode {
     GuestFunctionParameterTypeMismatch = 14,
     GuestError = 15,
     ArrayLengthParamIsMissing = 16,
+    HostFunctionError = 17,
 }
 
 impl From<ErrorCode> for FbErrorCode {
@@ -73,6 +69,7 @@ impl From<ErrorCode> for FbErrorCode {
             }
             ErrorCode::GuestError => Self::GuestError,
             ErrorCode::ArrayLengthParamIsMissing => Self::ArrayLengthParamIsMissing,
+            ErrorCode::HostFunctionError => Self::HostError,
         }
     }
 }
@@ -99,6 +96,7 @@ impl From<FbErrorCode> for ErrorCode {
             }
             FbErrorCode::GuestError => Self::GuestError,
             FbErrorCode::ArrayLengthParamIsMissing => Self::ArrayLengthParamIsMissing,
+            FbErrorCode::HostError => Self::HostFunctionError,
             _ => Self::UnknownError,
         }
     }
@@ -123,6 +121,7 @@ impl From<u64> for ErrorCode {
             14 => Self::GuestFunctionParameterTypeMismatch,
             15 => Self::GuestError,
             16 => Self::ArrayLengthParamIsMissing,
+            17 => Self::HostFunctionError,
             _ => Self::UnknownError,
         }
     }
@@ -147,6 +146,7 @@ impl From<ErrorCode> for u64 {
             ErrorCode::GuestFunctionParameterTypeMismatch => 14,
             ErrorCode::GuestError => 15,
             ErrorCode::ArrayLengthParamIsMissing => 16,
+            ErrorCode::HostFunctionError => 17,
         }
     }
 }
@@ -174,6 +174,7 @@ impl From<ErrorCode> for String {
             }
             ErrorCode::GuestError => "GuestError".to_string(),
             ErrorCode::ArrayLengthParamIsMissing => "ArrayLengthParamIsMissing".to_string(),
+            ErrorCode::HostFunctionError => "HostFunctionError".to_string(),
         }
     }
 }
@@ -194,44 +195,6 @@ impl GuestError {
     }
 }
 
-impl TryFrom<&[u8]> for GuestError {
-    type Error = Error;
-    fn try_from(value: &[u8]) -> Result<Self> {
-        let guest_error_fb = size_prefixed_root::<FbGuestError>(value)
-            .map_err(|e| anyhow::anyhow!("Error while reading GuestError: {:?}", e))?;
-        let code = guest_error_fb.code();
-        let message = match guest_error_fb.message() {
-            Some(message) => message.to_string(),
-            None => String::new(),
-        };
-        Ok(Self {
-            code: code.into(),
-            message,
-        })
-    }
-}
-
-impl TryFrom<&GuestError> for Vec<u8> {
-    type Error = Error;
-    #[cfg_attr(feature = "tracing", instrument(err(Debug), skip_all, parent = Span::current(), level= "Trace"))]
-    fn try_from(value: &GuestError) -> Result<Vec<u8>> {
-        let mut builder = flatbuffers::FlatBufferBuilder::new();
-        let message = builder.create_string(&value.message);
-
-        let guest_error_fb = FbGuestError::create(
-            &mut builder,
-            &GuestErrorArgs {
-                code: value.code.into(),
-                message: Some(message),
-            },
-        );
-        builder.finish_size_prefixed(guest_error_fb, None);
-        let res = builder.finished_data().to_vec();
-
-        Ok(res)
-    }
-}
-
 impl Default for GuestError {
     #[cfg_attr(feature = "tracing", instrument(parent = Span::current(), level= "Trace"))]
     fn default() -> Self {