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|
use super::RenderError;
use async_recursion::async_recursion;
use count_write::CountWrite;
use nix_compat::nar::writer::r#async as nar_writer;
use sha2::{Digest, Sha256};
use std::{
pin::Pin,
sync::Arc,
task::{self, Poll},
};
use tokio::io::{self, AsyncWrite, BufReader};
use tokio_util::compat::{TokioAsyncReadCompatExt, TokioAsyncWriteCompatExt};
use tvix_castore::{
blobservice::BlobService,
directoryservice::DirectoryService,
proto::{self as castorepb, NamedNode},
};
/// Invoke [write_nar], and return the size and sha256 digest of the produced
/// NAR output.
pub async fn calculate_size_and_sha256(
root_node: &castorepb::node::Node,
blob_service: Arc<dyn BlobService>,
directory_service: Arc<dyn DirectoryService>,
) -> Result<(u64, [u8; 32]), RenderError> {
let mut h = Sha256::new();
let mut cw = CountWrite::from(&mut h);
write_nar(
// The hasher doesn't speak async. It doesn't
// actually do any I/O, so it's fine to wrap.
AsyncIoBridge(&mut cw),
root_node,
blob_service,
directory_service,
)
.await?;
Ok((cw.count(), h.finalize().into()))
}
/// The inverse of [tokio_util::io::SyncIoBridge].
/// Don't use this with anything that actually does blocking I/O.
struct AsyncIoBridge<T>(T);
impl<W: std::io::Write + Unpin> AsyncWrite for AsyncIoBridge<W> {
fn poll_write(
self: Pin<&mut Self>,
_cx: &mut task::Context<'_>,
buf: &[u8],
) -> Poll<io::Result<usize>> {
Poll::Ready(self.get_mut().0.write(buf))
}
fn poll_flush(self: Pin<&mut Self>, _cx: &mut task::Context<'_>) -> Poll<io::Result<()>> {
Poll::Ready(self.get_mut().0.flush())
}
fn poll_shutdown(
self: Pin<&mut Self>,
_cx: &mut task::Context<'_>,
) -> Poll<Result<(), io::Error>> {
Poll::Ready(Ok(()))
}
}
/// Accepts a [castorepb::node::Node] pointing to the root of a (store) path,
/// and uses the passed blob_service and directory_service to perform the
/// necessary lookups as it traverses the structure.
/// The contents in NAR serialization are writen to the passed [AsyncWrite].
pub async fn write_nar<W: AsyncWrite + Unpin + Send>(
w: W,
proto_root_node: &castorepb::node::Node,
blob_service: Arc<dyn BlobService>,
directory_service: Arc<dyn DirectoryService>,
) -> Result<(), RenderError> {
// Initialize NAR writer
let mut w = w.compat_write();
let nar_root_node = nar_writer::open(&mut w)
.await
.map_err(RenderError::NARWriterError)?;
walk_node(
nar_root_node,
proto_root_node,
blob_service,
directory_service,
)
.await?;
Ok(())
}
/// Process an intermediate node in the structure.
/// This consumes the node.
#[async_recursion]
async fn walk_node(
nar_node: nar_writer::Node<'async_recursion, '_>,
proto_node: &castorepb::node::Node,
blob_service: Arc<dyn BlobService>,
directory_service: Arc<dyn DirectoryService>,
) -> Result<(), RenderError> {
match proto_node {
castorepb::node::Node::Symlink(proto_symlink_node) => {
nar_node
.symlink(&proto_symlink_node.target)
.await
.map_err(RenderError::NARWriterError)?;
}
castorepb::node::Node::File(proto_file_node) => {
let digest_len = proto_file_node.digest.len();
let digest = proto_file_node.digest.clone().try_into().map_err(|_| {
RenderError::StoreError(io::Error::new(
io::ErrorKind::Other,
format!("invalid digest len {} in file node", digest_len),
))
})?;
let blob_reader = match blob_service
.open_read(&digest)
.await
.map_err(RenderError::StoreError)?
{
Some(blob_reader) => Ok(BufReader::new(blob_reader)),
None => Err(RenderError::NARWriterError(io::Error::new(
io::ErrorKind::NotFound,
format!("blob with digest {} not found", &digest),
))),
}?;
nar_node
.file(
proto_file_node.executable,
proto_file_node.size,
&mut blob_reader.compat(),
)
.await
.map_err(RenderError::NARWriterError)?;
}
castorepb::node::Node::Directory(proto_directory_node) => {
let digest_len = proto_directory_node.digest.len();
let digest = proto_directory_node
.digest
.clone()
.try_into()
.map_err(|_| {
RenderError::StoreError(io::Error::new(
io::ErrorKind::InvalidData,
format!("invalid digest len {} in directory node", digest_len),
))
})?;
// look it up with the directory service
match directory_service
.get(&digest)
.await
.map_err(|e| RenderError::StoreError(e.into()))?
{
// if it's None, that's an error!
None => {
return Err(RenderError::DirectoryNotFound(
digest,
proto_directory_node.name.clone(),
))
}
Some(proto_directory) => {
// start a directory node
let mut nar_node_directory = nar_node
.directory()
.await
.map_err(RenderError::NARWriterError)?;
// for each node in the directory, create a new entry with its name,
// and then invoke walk_node on that entry.
for proto_node in proto_directory.nodes() {
let child_node = nar_node_directory
.entry(proto_node.get_name())
.await
.map_err(RenderError::NARWriterError)?;
walk_node(
child_node,
&proto_node,
blob_service.clone(),
directory_service.clone(),
)
.await?;
}
// close the directory
nar_node_directory
.close()
.await
.map_err(RenderError::NARWriterError)?;
}
}
}
}
Ok(())
}
|
