Move Pod types to separate library (#5119)

* Move Pod types to separate library - just move code

* Move Pod types to separate library - add/modify logic and tests

* Move Pod types to separate library - small test changes

* Move Pod types to separate library - small test changes

* Move Pod types to separate library - small test changes

---------

Co-authored-by: Serban <@>

Author: serbangv

Cargo.lock

@@ -26,6 +26,7 @@ members = [
   "libraries/concurrent-merkle-tree",
   "libraries/math",
   "libraries/merkle-tree-reference",
+  "libraries/pod",
   "libraries/program-error",
   "libraries/tlv-account-resolution",
   "libraries/type-length-value",

Cargo.toml

@@ -0,0 +1,30 @@
+[package]
+name = "spl-pod"
+version = "0.1.0"
+description = "Solana Program Library Plain Old Data (Pod)"
+authors = ["Solana Labs Maintainers <[email protected]>"]
+repository = "https://github.com/solana-labs/solana-program-library"
+license = "Apache-2.0"
+edition = "2021"
+
+[features]
+serde-traits = ["serde", "base64"]
+borsh = ["dep:borsh"]
+
+[dependencies]
+base64 = { version = "0.21.2", optional = true }
+borsh = { version = "0.10", optional = true }
+bytemuck = { version = "1.13.1" }
+serde = { version = "1.0.183", optional = true }
+solana-program = "1.16.3"
+solana-zk-token-sdk = "1.16.3"
+spl-program-error = { version = "0.2.0", path = "../program-error" }
+
+[dev-dependencies]
+serde_json = "1.0.105"
+
+[lib]
+crate-type = ["cdylib", "lib"]
+
+[package.metadata.docs.rs]
+targets = ["x86_64-unknown-linux-gnu"]

libraries/pod/Cargo.toml

@@ -0,0 +1,3 @@
+# Pod
+
+This library contains types shared by SPL libraries that implement the `Pod` trait from `bytemuck` and utils for working with these types.

libraries/pod/README.md

@@ -0,0 +1,52 @@
+//! wrappers for bytemuck functions
+
+use {bytemuck::Pod, solana_program::program_error::ProgramError};
+
+/// On-chain size of a `Pod` type
+pub const fn pod_get_packed_len<T: Pod>() -> usize {
+    std::mem::size_of::<T>()
+}
+
+/// Convert a `Pod` into a slice (zero copy)
+pub fn pod_bytes_of<T: Pod>(t: &T) -> &[u8] {
+    bytemuck::bytes_of(t)
+}
+
+/// Convert a slice 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)
+}
+
+/// Maybe convert a slice into a `Pod` (zero copy)
+///
+/// Returns `None` if the slice is empty, but `Err` if all other lengths but `get_packed_len()`
+/// 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> {
+    if bytes.is_empty() {
+        Ok(None)
+    } else {
+        bytemuck::try_from_bytes(bytes)
+            .map(Some)
+            .map_err(|_| ProgramError::InvalidArgument)
+    }
+}
+
+/// Convert a slice 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)
+}
+
+/// Convert a slice into a mutable `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)
+}
+
+/// Convert a slice 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)
+}
+
+/// Convert a pod slice into its raw bytes
+pub fn pod_slice_to_bytes<T: Pod>(slice: &[T]) -> &[u8] {
+    bytemuck::cast_slice(slice)
+}

libraries/pod/src/bytemuck.rs

@@ -0,0 +1,16 @@
+//! Error types
+use spl_program_error::*;
+
+/// Errors that may be returned by the spl-pod library.
+#[spl_program_error]
+pub enum PodSliceError {
+    /// Error in checked math operation
+    #[error("Error in checked math operation")]
+    CalculationFailure,
+    /// Provided byte buffer too small for expected type
+    #[error("Provided byte buffer too small for expected type")]
+    BufferTooSmall,
+    /// Provided byte buffer too large for expected type
+    #[error("Provided byte buffer too large for expected type")]
+    BufferTooLarge,
+}

libraries/pod/src/error.rs

@@ -0,0 +1,11 @@
+//! Crate containing `Pod` types and `bytemuck` utils used in SPL
+
+pub mod bytemuck;
+pub mod error;
+pub mod optional_keys;
+pub mod primitives;
+pub mod slice;
+
+// Export current sdk types for downstream users building with a different sdk
+// version
+pub use solana_program;