lance_file/
lib.rs

1// SPDX-License-Identifier: Apache-2.0
2// SPDX-FileCopyrightText: Copyright The Lance Authors
3
4pub mod datatypes;
5pub mod format;
6pub mod page_table;
7pub mod reader;
8pub mod v2;
9pub mod writer;
10
11use format::MAGIC;
12pub use lance_encoding::version;
13
14use lance_core::{Error, Result};
15use lance_encoding::version::LanceFileVersion;
16use lance_io::object_store::ObjectStore;
17use object_store::path::Path;
18use snafu::location;
19
20pub async fn determine_file_version(
21    store: &ObjectStore,
22    path: &Path,
23    known_size: Option<usize>,
24) -> Result<LanceFileVersion> {
25    let size = match known_size {
26        None => store.size(path).await.unwrap(),
27        Some(size) => size,
28    };
29    if size < 8 {
30        return Err(Error::InvalidInput {
31            source: format!(
32                "the file {} does not appear to be a lance file (too small)",
33                path
34            )
35            .into(),
36            location: location!(),
37        });
38    }
39    let reader = store.open_with_size(path, size).await?;
40    let footer = reader.get_range((size - 8)..size).await?;
41    if &footer[4..] != MAGIC {
42        return Err(Error::InvalidInput {
43            source: format!(
44                "the file {} does not appear to be a lance file (magic mismatch)",
45                path
46            )
47            .into(),
48            location: location!(),
49        });
50    }
51    let major_version = u16::from_le_bytes([footer[0], footer[1]]);
52    let minor_version = u16::from_le_bytes([footer[2], footer[3]]);
53
54    LanceFileVersion::try_from_major_minor(major_version as u32, minor_version as u32)
55}
lance_file/lib.rs

lance_file/
lib.rs
