use anyhow::Result;
use std::collections::HashSet;
use thiserror::Error;
use prost::Message;
tonic::include_proto!("tvix.store.v1");
/// Errors that can occur during the validation of Directory messages.
#[derive(Debug, Error, PartialEq)]
pub enum ValidateDirectoryError {
/// Elements are not in sorted order
#[error("{0} is not sorted")]
WrongSorting(String),
/// Multiple elements with the same name encountered
#[error("{0} is a duplicate name")]
DuplicateName(String),
/// Invalid name encountered
#[error("Invalid name in {0}")]
InvalidName(String),
/// Invalid digest length encountered
#[error("Ivalid Digest length: {0}")]
InvalidDigestLen(usize),
}
/// Checks a name for validity.
/// We disallow slashes, null bytes, '.', '..' and the empty string.
/// Depending on the context, a [DirectoryNode], [FileNode] or [SymlinkNode]
/// message with an empty string as name is allowed, but they don't occur
/// inside a Directory message.
fn validate_node_name(name: &str) -> Result<(), ValidateDirectoryError> {
if name == "" || name == ".." || name == "." || name.contains("\x00") || name.contains("/") {
return Err(ValidateDirectoryError::InvalidName(
name.to_string().clone(),
));
}
Ok(())
}
/// Checks a digest for validity.
/// Digests are 32 bytes long, as we store blake3 digests.
fn validate_digest(digest: &Vec<u8>) -> Result<(), ValidateDirectoryError> {
if digest.len() != 32 {
return Err(ValidateDirectoryError::InvalidDigestLen(digest.len()));
}
Ok(())
}
/// Accepts a name, and a mutable reference to the previous name.
/// If the passed name is larger than the previous one, the reference is updated.
/// If it's not, an error is returned.
fn update_if_lt_prev<'set, 'n>(
prev_name: &'set mut &'n str,
name: &'n str,
) -> Result<(), ValidateDirectoryError> {
if *name < **prev_name {
return Err(ValidateDirectoryError::WrongSorting(
name.to_string().clone(),
));
}
*prev_name = name;
Ok(())
}
/// Inserts the given name into a HashSet if it's not already in there.
/// If it is, an error is returned.
fn insert_once<'n>(
seen_names: &mut HashSet<&'n str>,
name: &'n str,
) -> Result<(), ValidateDirectoryError> {
if seen_names.get(name).is_some() {
return Err(ValidateDirectoryError::DuplicateName(
name.to_string().clone(),
));
}
seen_names.insert(name);
Ok(())
}
impl Directory {
// The size of a directory is the number of all regular and symlink elements,
// the number of directory elements, and their size fields.
pub fn size(&self) -> u32 {
self.files.len() as u32
+ self.symlinks.len() as u32
+ self
.directories
.iter()
.fold(0, |acc: u32, e| (acc + 1 + e.size) as u32)
}
pub fn digest(&self) -> Vec<u8> {
let mut hasher = blake3::Hasher::new();
hasher.update(&self.encode_to_vec()).finalize().as_bytes()[..].to_vec()
}
/// validate checks the directory for invalid data, such as:
/// - violations of name restrictions
/// - invalid digest lengths
/// - not properly sorted lists
/// - duplicate names in the three lists
pub fn validate(&self) -> Result<(), ValidateDirectoryError> {
let mut seen_names: HashSet<&str> = HashSet::new();
let mut last_directory_name: &str = "";
let mut last_file_name: &str = "";
let mut last_symlink_name: &str = "";
// check directories
for directory_node in &self.directories {
validate_node_name(&directory_node.name)?;
validate_digest(&directory_node.digest)?;
update_if_lt_prev(&mut last_directory_name, &mut directory_node.name.as_str())?;
insert_once(&mut seen_names, &directory_node.name.as_str())?;
}
// check files
for file_node in &self.files {
validate_node_name(&file_node.name)?;
validate_digest(&file_node.digest)?;
update_if_lt_prev(&mut last_file_name, &mut file_node.name.as_str())?;
insert_once(&mut seen_names, &file_node.name.as_str())?;
}
// check symlinks
for symlink_node in &self.symlinks {
validate_node_name(&symlink_node.name)?;
update_if_lt_prev(&mut last_symlink_name, &mut symlink_node.name.as_str())?;
insert_once(&mut seen_names, &symlink_node.name.as_str())?;
}
Ok(())
}
}