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Diffstat (limited to 'tvix/castore/src/directoryservice/traverse.rs')
| -rw-r--r-- | tvix/castore/src/directoryservice/traverse.rs | 231 |
1 files changed, 231 insertions, 0 deletions
diff --git a/tvix/castore/src/directoryservice/traverse.rs b/tvix/castore/src/directoryservice/traverse.rs new file mode 100644 index 000000000000..528cef757432 --- /dev/null +++ b/tvix/castore/src/directoryservice/traverse.rs @@ -0,0 +1,231 @@ +use super::DirectoryService; +use crate::{proto::NamedNode, B3Digest, Error}; +use std::os::unix::ffi::OsStrExt; +use tracing::{instrument, warn}; + +/// This descends from a (root) node to the given (sub)path, returning the Node +/// at that path, or none, if there's nothing at that path. +#[instrument(skip(directory_service))] +pub async fn descend_to<DS>( + directory_service: DS, + root_node: crate::proto::node::Node, + path: &std::path::Path, +) -> Result<Option<crate::proto::node::Node>, Error> +where + DS: AsRef<dyn DirectoryService>, +{ + // strip a possible `/` prefix from the path. + let path = { + if path.starts_with("/") { + path.strip_prefix("/").unwrap() + } else { + path + } + }; + + let mut cur_node = root_node; + let mut it = path.components(); + + loop { + match it.next() { + None => { + // the (remaining) path is empty, return the node we're current at. + return Ok(Some(cur_node)); + } + Some(first_component) => { + match cur_node { + crate::proto::node::Node::File(_) | crate::proto::node::Node::Symlink(_) => { + // There's still some path left, but the current node is no directory. + // This means the path doesn't exist, as we can't reach it. + return Ok(None); + } + crate::proto::node::Node::Directory(directory_node) => { + let digest: B3Digest = directory_node.digest.try_into().map_err(|_e| { + Error::StorageError("invalid digest length".to_string()) + })?; + + // fetch the linked node from the directory_service + match directory_service.as_ref().get(&digest).await? { + // If we didn't get the directory node that's linked, that's a store inconsistency, bail out! + None => { + warn!("directory {} does not exist", digest); + + return Err(Error::StorageError(format!( + "directory {} does not exist", + digest + ))); + } + Some(directory) => { + // look for first_component in the [Directory]. + // FUTUREWORK: as the nodes() iterator returns in a sorted fashion, we + // could stop as soon as e.name is larger than the search string. + let child_node = directory.nodes().find(|n| { + n.get_name() == first_component.as_os_str().as_bytes() + }); + + match child_node { + // child node not found means there's no such element inside the directory. + None => { + return Ok(None); + } + // child node found, return to top-of loop to find the next + // node in the path. + Some(child_node) => { + cur_node = child_node; + } + } + } + } + } + } + } + } + } +} + +#[cfg(test)] +mod tests { + use std::path::PathBuf; + + use crate::fixtures::{DIRECTORY_COMPLICATED, DIRECTORY_WITH_KEEP}; + use crate::utils::gen_directory_service; + + use super::descend_to; + + #[tokio::test] + async fn test_descend_to() { + let directory_service = gen_directory_service(); + + let mut handle = directory_service.put_multiple_start(); + handle + .put(DIRECTORY_WITH_KEEP.clone()) + .await + .expect("must succeed"); + handle + .put(DIRECTORY_COMPLICATED.clone()) + .await + .expect("must succeed"); + + // construct the node for DIRECTORY_COMPLICATED + let node_directory_complicated = + crate::proto::node::Node::Directory(crate::proto::DirectoryNode { + name: "doesntmatter".into(), + digest: DIRECTORY_COMPLICATED.digest().into(), + size: DIRECTORY_COMPLICATED.size(), + }); + + // construct the node for DIRECTORY_COMPLICATED + let node_directory_with_keep = crate::proto::node::Node::Directory( + DIRECTORY_COMPLICATED.directories.first().unwrap().clone(), + ); + + // construct the node for the .keep file + let node_file_keep = + crate::proto::node::Node::File(DIRECTORY_WITH_KEEP.files.first().unwrap().clone()); + + // traversal to an empty subpath should return the root node. + { + let resp = descend_to( + &directory_service, + node_directory_complicated.clone(), + &PathBuf::from(""), + ) + .await + .expect("must succeed"); + + assert_eq!(Some(node_directory_complicated.clone()), resp); + } + + // traversal to `keep` should return the node for DIRECTORY_WITH_KEEP + { + let resp = descend_to( + &directory_service, + node_directory_complicated.clone(), + &PathBuf::from("keep"), + ) + .await + .expect("must succeed"); + + assert_eq!(Some(node_directory_with_keep), resp); + } + + // traversal to `keep/.keep` should return the node for the .keep file + { + let resp = descend_to( + &directory_service, + node_directory_complicated.clone(), + &PathBuf::from("keep/.keep"), + ) + .await + .expect("must succeed"); + + assert_eq!(Some(node_file_keep.clone()), resp); + } + + // traversal to `keep/.keep` should return the node for the .keep file + { + let resp = descend_to( + &directory_service, + node_directory_complicated.clone(), + &PathBuf::from("/keep/.keep"), + ) + .await + .expect("must succeed"); + + assert_eq!(Some(node_file_keep), resp); + } + + // traversal to `void` should return None (doesn't exist) + { + let resp = descend_to( + &directory_service, + node_directory_complicated.clone(), + &PathBuf::from("void"), + ) + .await + .expect("must succeed"); + + assert_eq!(None, resp); + } + + // traversal to `void` should return None (doesn't exist) + { + let resp = descend_to( + &directory_service, + node_directory_complicated.clone(), + &PathBuf::from("//v/oid"), + ) + .await + .expect("must succeed"); + + assert_eq!(None, resp); + } + + // traversal to `keep/.keep/404` should return None (the path can't be + // reached, as keep/.keep already is a file) + { + let resp = descend_to( + &directory_service, + node_directory_complicated.clone(), + &PathBuf::from("keep/.keep/foo"), + ) + .await + .expect("must succeed"); + + assert_eq!(None, resp); + } + + // traversal to a subpath of '/' should return the root node. + { + let resp = descend_to( + &directory_service, + node_directory_complicated.clone(), + &PathBuf::from("/"), + ) + .await + .expect("must succeed"); + + assert_eq!(Some(node_directory_complicated), resp); + } + } +} |