1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
use crate::{directoryservice::DirectoryService, Error, Node, Path};
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, path), fields(%path))]
pub async fn descend_to<DS>(
    directory_service: DS,
    root_node: Node,
    path: impl AsRef<Path> + std::fmt::Display,
) -> Result<Option<Node>, Error>
where
    DS: AsRef<dyn DirectoryService>,
{
    let mut parent_node = root_node;
    for component in path.as_ref().components_bytes() {
        match parent_node {
            Node::File { .. } | Node::Symlink { .. } => {
                // There's still some path left, but the parent node is no directory.
                // This means the path doesn't exist, as we can't reach it.
                return Ok(None);
            }
            Node::Directory { digest, .. } => {
                // fetch the linked node from the directory_service.
                let directory =
                    directory_service
                        .as_ref()
                        .get(&digest)
                        .await?
                        .ok_or_else(|| {
                            // If we didn't get the directory node that's linked, that's a store inconsistency, bail out!
                            warn!("directory {} does not exist", digest);

                            Error::StorageError(format!("directory {} does not exist", digest))
                        })?;

                // look for the component in the [Directory].
                if let Some((_child_name, child_node)) = directory
                    .into_nodes()
                    .find(|(name, _node)| name.as_ref() == component)
                {
                    // child node found, update prev_node to that and continue.
                    parent_node = child_node.clone();
                } else {
                    // child node not found means there's no such element inside the directory.
                    return Ok(None);
                };
            }
        }
    }

    // We traversed the entire path, so this must be the node.
    Ok(Some(parent_node))
}

#[cfg(test)]
mod tests {
    use crate::{
        directoryservice,
        fixtures::{DIRECTORY_COMPLICATED, DIRECTORY_WITH_KEEP, EMPTY_BLOB_DIGEST},
        Node, PathBuf,
    };

    use super::descend_to;

    #[tokio::test]
    async fn test_descend_to() {
        let directory_service = directoryservice::from_addr("memory://").await.unwrap();

        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");

        handle.close().await.expect("must upload");

        // construct the node for DIRECTORY_COMPLICATED
        let node_directory_complicated = Node::Directory {
            digest: DIRECTORY_COMPLICATED.digest(),
            size: DIRECTORY_COMPLICATED.size(),
        };

        // construct the node for DIRECTORY_COMPLICATED
        let node_directory_with_keep = Node::Directory {
            digest: DIRECTORY_WITH_KEEP.digest(),
            size: DIRECTORY_WITH_KEEP.size(),
        };

        // construct the node for the .keep file
        let node_file_keep = Node::File {
            digest: EMPTY_BLOB_DIGEST.clone(),
            size: 0,
            executable: false,
        };

        // traversal to an empty subpath should return the root node.
        {
            let resp = descend_to(
                &directory_service,
                node_directory_complicated.clone(),
                "".parse::<PathBuf>().unwrap(),
            )
            .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(),
                "keep".parse::<PathBuf>().unwrap(),
            )
            .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(),
                "keep/.keep".parse::<PathBuf>().unwrap(),
            )
            .await
            .expect("must succeed");

            assert_eq!(Some(node_file_keep.clone()), resp);
        }

        // traversal to `void` should return None (doesn't exist)
        {
            let resp = descend_to(
                &directory_service,
                node_directory_complicated.clone(),
                "void".parse::<PathBuf>().unwrap(),
            )
            .await
            .expect("must succeed");

            assert_eq!(None, resp);
        }

        // traversal to `v/oid` should return None (doesn't exist)
        {
            let resp = descend_to(
                &directory_service,
                node_directory_complicated.clone(),
                "v/oid".parse::<PathBuf>().unwrap(),
            )
            .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(),
                "keep/.keep/foo".parse::<PathBuf>().unwrap(),
            )
            .await
            .expect("must succeed");

            assert_eq!(None, resp);
        }
    }
}