diff options
| -rw-r--r-- | tvix/store/src/nixpath.rs | 30 |
1 files changed, 18 insertions, 12 deletions
diff --git a/tvix/store/src/nixpath.rs b/tvix/store/src/nixpath.rs index b619126868d5..ed0d39864de4 100644 --- a/tvix/store/src/nixpath.rs +++ b/tvix/store/src/nixpath.rs @@ -3,7 +3,10 @@ use data_encoding::DecodeError; use std::fmt; use thiserror::Error; -const PATH_HASH_SIZE: usize = 20; +pub const DIGEST_SIZE: usize = 20; +// lazy_static doesn't allow us to call NIXBASE32.encode_len(), so we ran it +// manually and have an assert in the tests. +pub const ENCODED_DIGEST_SIZE: usize = 32; /// Errors that can occur during the validation of name characters. #[derive(Debug, PartialEq, Eq, Error)] @@ -18,39 +21,36 @@ pub enum ParseNixPathError { #[derive(Debug, PartialEq, Eq)] pub struct NixPath { - pub digest: [u8; PATH_HASH_SIZE], + pub digest: [u8; DIGEST_SIZE], pub name: String, } impl NixPath { pub fn from_string(s: &str) -> Result<NixPath, ParseNixPathError> { - let encoded_path_hash_size = NIXBASE32.encode_len(PATH_HASH_SIZE); - let name_offset = encoded_path_hash_size + 1; - // the whole string needs to be at least: // // - 32 characters (encoded hash) // - 1 dash // - 1 character for the name - if s.len() < name_offset + 1 { + if s.len() < ENCODED_DIGEST_SIZE + 2 { return Err(ParseNixPathError::InvalidName("".to_string())); } - let digest = match NIXBASE32.decode(s[..encoded_path_hash_size].as_bytes()) { + let digest = match NIXBASE32.decode(s[..ENCODED_DIGEST_SIZE].as_bytes()) { Ok(decoded) => decoded, Err(decoder_error) => { return Err(ParseNixPathError::InvalidHashEncoding(decoder_error)) } }; - if s.as_bytes()[encoded_path_hash_size] != b'-' { + if s.as_bytes()[ENCODED_DIGEST_SIZE] != b'-' { return Err(ParseNixPathError::MissingDash()); } - NixPath::validate_characters(&s[name_offset..])?; + NixPath::validate_characters(&s[ENCODED_DIGEST_SIZE + 2..])?; Ok(NixPath { - name: s[name_offset..].to_string(), + name: s[ENCODED_DIGEST_SIZE + 1..].to_string(), digest: digest.try_into().expect("size is known"), }) } @@ -88,18 +88,24 @@ impl fmt::Display for NixPath { #[cfg(test)] mod tests { - use crate::nixpath::PATH_HASH_SIZE; + use crate::nixbase32::NIXBASE32; + use crate::nixpath::{DIGEST_SIZE, ENCODED_DIGEST_SIZE}; use super::NixPath; #[test] + fn encoded_digest_size() { + assert_eq!(ENCODED_DIGEST_SIZE, NIXBASE32.encode_len(DIGEST_SIZE)); + } + + #[test] fn happy_path() { let example_nix_path_str = "00bgd045z0d4icpbc2yyz4gx48ak44la-net-tools-1.60_p20170221182432"; let nixpath = NixPath::from_string(&example_nix_path_str).expect("Error parsing example string"); - let expected_digest: [u8; PATH_HASH_SIZE] = [ + let expected_digest: [u8; DIGEST_SIZE] = [ 0x8a, 0x12, 0x32, 0x15, 0x22, 0xfd, 0x91, 0xef, 0xbd, 0x60, 0xeb, 0xb2, 0x48, 0x1a, 0xf8, 0x85, 0x80, 0xf6, 0x16, 0x00, ]; |