solana-program-library/feature-proposal/program/src/borsh_utils.rs

56 lines
2.1 KiB
Rust

//! Borsh utils
use borsh::schema::{BorshSchema, Declaration, Definition, Fields};
use std::collections::HashMap;
/// Get packed length for the given BorchSchema Declaration
fn get_declaration_packed_len(
declaration: &str,
definitions: &HashMap<Declaration, Definition>,
) -> usize {
match definitions.get(declaration) {
Some(Definition::Array { length, elements }) => {
*length as usize * get_declaration_packed_len(elements, definitions)
}
Some(Definition::Enum { variants }) => {
1 + variants
.iter()
.map(|(_, declaration)| get_declaration_packed_len(declaration, definitions))
.max()
.unwrap_or(0)
}
Some(Definition::Struct { fields }) => match fields {
Fields::NamedFields(named_fields) => named_fields
.iter()
.map(|(_, declaration)| get_declaration_packed_len(declaration, definitions))
.sum(),
Fields::UnnamedFields(declarations) => declarations
.iter()
.map(|declaration| get_declaration_packed_len(declaration, definitions))
.sum(),
Fields::Empty => 0,
},
Some(Definition::Sequence {
elements: _elements,
}) => panic!("Missing support for Definition::Sequence"),
Some(Definition::Tuple { elements }) => elements
.iter()
.map(|element| get_declaration_packed_len(element, definitions))
.sum(),
None => match declaration {
"u8" | "i8" => 1,
"u16" | "i16" => 2,
"u32" | "i32" => 2,
"u64" | "i64" => 8,
"u128" | "i128" => 16,
"nil" => 0,
_ => panic!("Missing primitive type: {}", declaration),
},
}
}
/// Get the worst-case packed length for the given BorshSchema
pub fn get_packed_len<S: BorshSchema>() -> usize {
let schema_container = S::schema_container();
get_declaration_packed_len(&schema_container.declaration, &schema_container.definitions)
}