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|
use std::io::{self, BufReader};
use crate::{
blobservice::BlobService,
directoryservice::DirectoryService,
proto::{self, NamedNode},
B3Digest,
};
use data_encoding::BASE64;
use nix_compat::nar;
use super::RenderError;
/// A NAR renderer, using a blob_service, chunk_service and directory_service
/// to render a NAR to a writer.
#[derive(Clone)]
pub struct NARRenderer<BS: BlobService, DS: DirectoryService> {
blob_service: BS,
directory_service: DS,
}
impl<BS: BlobService, DS: DirectoryService> NARRenderer<BS, DS> {
pub fn new(blob_service: BS, directory_service: DS) -> Self {
Self {
blob_service,
directory_service,
}
}
/// Consumes a [proto::node::Node] pointing to the root of a (store) path,
/// and writes the contents in NAR serialization to the passed
/// [std::io::Write].
///
/// It uses the different clients in the struct to perform the necessary
/// lookups as it traverses the structure.
pub fn write_nar<W: std::io::Write>(
&self,
w: &mut W,
proto_root_node: &proto::node::Node,
) -> Result<(), RenderError> {
// Initialize NAR writer
let nar_root_node = nar::writer::open(w).map_err(RenderError::NARWriterError)?;
self.walk_node(nar_root_node, proto_root_node)
}
/// Process an intermediate node in the structure.
/// This consumes the node.
fn walk_node(
&self,
nar_node: nar::writer::Node,
proto_node: &proto::node::Node,
) -> Result<(), RenderError> {
match proto_node {
proto::node::Node::Symlink(proto_symlink_node) => {
nar_node
.symlink(&proto_symlink_node.target)
.map_err(RenderError::NARWriterError)?;
}
proto::node::Node::File(proto_file_node) => {
let digest: [u8; 32] =
proto_file_node.digest.to_owned().try_into().map_err(|_e| {
RenderError::StoreError(crate::Error::StorageError(
"invalid digest len in file node".to_string(),
))
})?;
// TODO: handle error
let mut blob_reader = match self.blob_service.open_read(&digest).unwrap() {
Some(blob_reader) => Ok(BufReader::new(blob_reader)),
None => Err(RenderError::NARWriterError(io::Error::new(
io::ErrorKind::NotFound,
format!("blob with digest {} not found", BASE64.encode(&digest)),
))),
}?;
nar_node
.file(
proto_file_node.executable,
proto_file_node.size.into(),
&mut blob_reader,
)
.map_err(RenderError::NARWriterError)?;
}
proto::node::Node::Directory(proto_directory_node) => {
let digest =
B3Digest::from_vec(proto_directory_node.digest.to_vec()).map_err(|_e| {
RenderError::StoreError(crate::Error::StorageError(
"invalid digest len in directory node".to_string(),
))
})?;
// look it up with the directory service
let resp = self
.directory_service
.get(&digest)
.map_err(RenderError::StoreError)?;
match resp {
// if it's None, that's an error!
None => {
return Err(RenderError::DirectoryNotFound(
digest,
proto_directory_node.name.to_owned(),
))
}
Some(proto_directory) => {
// start a directory node
let mut nar_node_directory =
nar_node.directory().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())
.map_err(RenderError::NARWriterError)?;
self.walk_node(child_node, &proto_node)?;
}
// close the directory
nar_node_directory
.close()
.map_err(RenderError::NARWriterError)?;
}
}
}
}
Ok(())
}
}
|
