Make ListView friendlier to ? syntax (#166)

* PodSliceError ergonomics change

* Review updates

Author: grod220

Cargo.lock

@@ -18,6 +18,7 @@ bytemuck_derive = { version = "1.10.1" }
 num-derive = "0.4"
 num_enum = "0.7"
 num-traits = "0.2"
+pinocchio = "0.9.2"
 serde = { version = "1.0.228", optional = true }
 solana-program-error = "3.0.0"
 solana-program-option = "3.0.0"

pod/Cargo.toml

@@ -1,6 +1,6 @@
 //! wrappers for `bytemuck` functions
 
-use {bytemuck::Pod, solana_program_error::ProgramError};
+use {crate::error::SplPodError, bytemuck::Pod};
 
 /// On-chain size of a `Pod` type
 pub const fn pod_get_packed_len<T: Pod>() -> usize {
@@ -13,38 +13,36 @@ pub fn pod_bytes_of<T: Pod>(t: &T) -> &[u8] {
 }
 
 /// Convert a slice of bytes into a `Pod` (zero copy)
-pub fn pod_from_bytes<T: Pod>(bytes: &[u8]) -> Result<&T, ProgramError> {
-    bytemuck::try_from_bytes(bytes).map_err(|_| ProgramError::InvalidArgument)
+pub fn pod_from_bytes<T: Pod>(bytes: &[u8]) -> Result<&T, SplPodError> {
+    Ok(bytemuck::try_from_bytes(bytes)?)
 }
 
 /// Maybe convert a slice of bytes into a `Pod` (zero copy)
 ///
 /// Returns `None` if the slice is empty, or else `Err` if input length is not
 /// equal to `pod_get_packed_len::<T>()`.
 /// This function exists primarily because `Option<T>` is not a `Pod`.
-pub fn pod_maybe_from_bytes<T: Pod>(bytes: &[u8]) -> Result<Option<&T>, ProgramError> {
+pub fn pod_maybe_from_bytes<T: Pod>(bytes: &[u8]) -> Result<Option<&T>, SplPodError> {
     if bytes.is_empty() {
         Ok(None)
     } else {
-        bytemuck::try_from_bytes(bytes)
-            .map(Some)
-            .map_err(|_| ProgramError::InvalidArgument)
+        Ok(bytemuck::try_from_bytes(bytes).map(Some)?)
     }
 }
 
 /// Convert a slice of bytes into a mutable `Pod` (zero copy)
-pub fn pod_from_bytes_mut<T: Pod>(bytes: &mut [u8]) -> Result<&mut T, ProgramError> {
-    bytemuck::try_from_bytes_mut(bytes).map_err(|_| ProgramError::InvalidArgument)
+pub fn pod_from_bytes_mut<T: Pod>(bytes: &mut [u8]) -> Result<&mut T, SplPodError> {
+    Ok(bytemuck::try_from_bytes_mut(bytes)?)
 }
 
 /// Convert a slice of bytes into a `Pod` slice (zero copy)
-pub fn pod_slice_from_bytes<T: Pod>(bytes: &[u8]) -> Result<&[T], ProgramError> {
-    bytemuck::try_cast_slice(bytes).map_err(|_| ProgramError::InvalidArgument)
+pub fn pod_slice_from_bytes<T: Pod>(bytes: &[u8]) -> Result<&[T], SplPodError> {
+    Ok(bytemuck::try_cast_slice(bytes)?)
 }
 
 /// Convert a slice of bytes into a mutable `Pod` slice (zero copy)
-pub fn pod_slice_from_bytes_mut<T: Pod>(bytes: &mut [u8]) -> Result<&mut [T], ProgramError> {
-    bytemuck::try_cast_slice_mut(bytes).map_err(|_| ProgramError::InvalidArgument)
+pub fn pod_slice_from_bytes_mut<T: Pod>(bytes: &mut [u8]) -> Result<&mut [T], SplPodError> {
+    Ok(bytemuck::try_cast_slice_mut(bytes)?)
 }
 
 /// Convert a `Pod` slice into a single slice of bytes

pod/src/bytemuck.rs

@@ -1,5 +1,7 @@
 //! Error types
+use pinocchio::program_error::ProgramError as PinocchioProgramError;
 use {
+    bytemuck::PodCastError,
     solana_program_error::{ProgramError, ToStr},
     std::num::TryFromIntError,
 };
@@ -15,7 +17,7 @@ use {
     num_enum::TryFromPrimitive,
     num_derive::FromPrimitive,
 )]
-pub enum PodSliceError {
+pub enum SplPodError {
     /// Error in checked math operation
     #[error("Error in checked math operation")]
     CalculationFailure,
@@ -25,30 +27,90 @@ pub enum PodSliceError {
     /// Provided byte buffer too large for expected type
     #[error("Provided byte buffer too large for expected type")]
     BufferTooLarge,
+    /// Index out of range for list operation
+    #[error("Index out of range for list operation")]
+    IndexOutOfRange,
+    /// Type used as a length prefix has invalid alignment
+    #[error("Type used as a length prefix has invalid alignment")]
+    InvalidLengthTypeAlignment,
+    /// A `PodCast` operation from `bytemuck` failed
+    #[error("A `PodCast` operation from `bytemuck` failed")]
+    PodCast,
     /// An integer conversion failed because the value was out of range for the target type
     #[error("An integer conversion failed because the value was out of range for the target type")]
     ValueOutOfRange,
 }
 
-impl From<PodSliceError> for ProgramError {
-    fn from(e: PodSliceError) -> Self {
+impl From<SplPodError> for ProgramError {
+    fn from(e: SplPodError) -> Self {
         ProgramError::Custom(e as u32)
     }
 }
 
-impl ToStr for PodSliceError {
+impl ToStr for SplPodError {
     fn to_str(&self) -> &'static str {
         match self {
-            PodSliceError::CalculationFailure => "Error in checked math operation",
-            PodSliceError::BufferTooSmall => "Provided byte buffer too small for expected type",
-            PodSliceError::BufferTooLarge => "Provided byte buffer too large for expected type",
-            PodSliceError::ValueOutOfRange => "An integer conversion failed because the value was out of range for the target type"
+            SplPodError::CalculationFailure => "Error in checked math operation",
+            SplPodError::BufferTooSmall => "Provided byte buffer too small for expected type",
+            SplPodError::BufferTooLarge => "Provided byte buffer too large for expected type",
+            SplPodError::IndexOutOfRange => "Index out of range for list operation",
+            SplPodError::InvalidLengthTypeAlignment => "Type used as a length prefix has invalid alignment",
+            SplPodError::PodCast => "A `PodCast` operation from `bytemuck` failed",
+            SplPodError::ValueOutOfRange => "An integer conversion failed because the value was out of range for the target type",
         }
     }
 }
 
-impl From<TryFromIntError> for PodSliceError {
+impl From<PodCastError> for SplPodError {
+    fn from(_: PodCastError) -> Self {
+        SplPodError::PodCast
+    }
+}
+
+impl From<TryFromIntError> for SplPodError {
     fn from(_: TryFromIntError) -> Self {
-        PodSliceError::ValueOutOfRange
+        SplPodError::ValueOutOfRange
+    }
+}
+
+impl From<SplPodError> for PinocchioProgramError {
+    fn from(e: SplPodError) -> Self {
+        PinocchioProgramError::Custom(e as u32)
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    use crate::list::ListView;
+    use pinocchio::program_error::ProgramError as PinocchioProgramError;
+
+    fn raises_solana_err() -> Result<(), ProgramError> {
+        ListView::<u8>::size_of(usize::MAX)?; // raises err
+        Ok(())
+    }
+
+    fn raises_pino_err() -> Result<(), PinocchioProgramError> {
+        ListView::<u8>::size_of(usize::MAX)?; // raises err
+        Ok(())
+    }
+
+    #[test]
+    fn test_from_pod_slice_error_for_solana_program_error() {
+        let result = raises_solana_err();
+        assert!(result.is_err());
+        let solana_err = result.unwrap_err();
+        let expected_err: ProgramError = SplPodError::CalculationFailure.into();
+        assert_eq!(solana_err, expected_err);
+    }
+
+    #[test]
+    fn test_from_pod_slice_error_for_pinocchio_program_error() {
+        let result = raises_pino_err();
+        assert!(result.is_err());
+        let pinocchio_err = result.unwrap_err();
+        let expected_solana_err: ProgramError = SplPodError::CalculationFailure.into();
+        let expected_pinocchio_err: PinocchioProgramError = u64::from(expected_solana_err).into();
+        assert_eq!(pinocchio_err, expected_pinocchio_err);
     }
 }

pod/src/error.rs

@@ -1,7 +1,6 @@
 use {
-    crate::{list::ListView, pod_length::PodLength},
+    crate::{error::SplPodError, list::ListView, pod_length::PodLength},
     bytemuck::Pod,
-    solana_program_error::ProgramError,
     std::ops::Deref,
 };
 
@@ -17,12 +16,12 @@ pub trait List: Deref<Target = [Self::Item]> {
     fn capacity(&self) -> usize;
 
     /// Returns the number of **bytes currently occupied** by the live elements
-    fn bytes_used(&self) -> Result<usize, ProgramError> {
+    fn bytes_used(&self) -> Result<usize, SplPodError> {
         ListView::<Self::Item, Self::Length>::size_of(self.len())
     }
 
     /// Returns the number of **bytes reserved** by the entire backing buffer.
-    fn bytes_allocated(&self) -> Result<usize, ProgramError> {
+    fn bytes_allocated(&self) -> Result<usize, SplPodError> {
         ListView::<Self::Item, Self::Length>::size_of(self.capacity())
     }
 }