lance_file/
lib.rs

1// SPDX-License-Identifier: Apache-2.0
2// SPDX-FileCopyrightText: Copyright The Lance Authors
3
4pub mod concat;
5pub mod datatypes;
6pub mod format;
7pub(crate) mod io;
8pub mod reader;
9pub mod testing;
10pub mod version;
11pub mod versions;
12pub mod writer;
13
14#[cfg(test)]
15mod compatibility_tests;
16
17pub use io::LanceEncodingsIo;
18
19use format::MAGIC;
20use lance_core::{Error, Result};
21use lance_io::object_store::ObjectStore;
22use object_store::path::Path;
23use version::ConcreteFileVersion;
24
25pub async fn determine_file_version(
26    store: &ObjectStore,
27    path: &Path,
28    known_size: Option<usize>,
29) -> Result<ConcreteFileVersion> {
30    let size = match known_size {
31        None => usize::try_from(store.size(path).await?).map_err(|_| {
32            Error::invalid_input(format!("file {} is too large for this platform", path))
33        })?,
34        Some(size) => size,
35    };
36    if size < 8 {
37        return Err(Error::invalid_input_source(
38            format!(
39                "the file {} does not appear to be a lance file (too small)",
40                path
41            )
42            .into(),
43        ));
44    }
45    let reader = store.open_with_size(path, size).await?;
46    let footer = reader.get_range((size - 8)..size).await?;
47    if &footer[4..] != MAGIC {
48        return Err(Error::invalid_input_source(
49            format!(
50                "the file {} does not appear to be a lance file (magic mismatch)",
51                path
52            )
53            .into(),
54        ));
55    }
56    let major_version = u16::from_le_bytes([footer[0], footer[1]]);
57    let minor_version = u16::from_le_bytes([footer[2], footer[3]]);
58
59    ConcreteFileVersion::from_footer_numbers(major_version, minor_version)
60}
lance_file/lib.rs

lance_file/
lib.rs
