dora_core/
metadata.rs

1use dora_message::{
2    arrow_data::ArrayData,
3    arrow_schema::DataType,
4    metadata::{ArrowTypeInfo, BufferOffset},
5};
6use eyre::Context;
7
8pub trait ArrowTypeInfoExt {
9    fn empty() -> Self;
10    fn byte_array(data_len: usize) -> Self;
11
12    /// # Safety
13    ///
14    /// This function assumes that the `ArrayData` is backed by a memory region that starts at `region_start`
15    /// and has a length of `region_len`. It will panic if the `ArrayData` does not conform to this assumption.
16    unsafe fn from_array(
17        array: &ArrayData,
18        region_start: *const u8,
19        region_len: usize,
20    ) -> eyre::Result<Self>
21    where
22        Self: Sized;
23}
24
25impl ArrowTypeInfoExt for ArrowTypeInfo {
26    fn empty() -> Self {
27        Self {
28            data_type: DataType::Null,
29            len: 0,
30            null_count: 0,
31            validity: None,
32            offset: 0,
33            buffer_offsets: Vec::new(),
34            child_data: Vec::new(),
35        }
36    }
37
38    fn byte_array(data_len: usize) -> Self {
39        Self {
40            data_type: DataType::UInt8,
41            len: data_len,
42            null_count: 0,
43            validity: None,
44            offset: 0,
45            buffer_offsets: vec![BufferOffset {
46                offset: 0,
47                len: data_len,
48            }],
49            child_data: Vec::new(),
50        }
51    }
52
53    unsafe fn from_array(
54        array: &ArrayData,
55        region_start: *const u8,
56        region_len: usize,
57    ) -> eyre::Result<Self> {
58        Ok(Self {
59            data_type: array.data_type().clone(),
60            len: array.len(),
61            null_count: array.null_count(),
62            validity: array.nulls().map(|b| b.validity().to_owned()),
63            offset: array.offset(),
64            buffer_offsets: array
65                .buffers()
66                .iter()
67                .map(|b| {
68                    let ptr = b.as_ptr();
69                    if ptr as usize <= region_start as usize {
70                        eyre::bail!("ptr {ptr:p} starts before region {region_start:p}");
71                    }
72                    if ptr as usize >= region_start as usize + region_len {
73                        eyre::bail!("ptr {ptr:p} starts after region {region_start:p}");
74                    }
75                    if ptr as usize + b.len() > region_start as usize + region_len {
76                        eyre::bail!("ptr {ptr:p} ends after region {region_start:p}");
77                    }
78                    let offset = usize::try_from(unsafe { ptr.offset_from(region_start) })
79                        .context("offset_from is negative")?;
80
81                    Result::<_, eyre::Report>::Ok(BufferOffset {
82                        offset,
83                        len: b.len(),
84                    })
85                })
86                .collect::<Result<_, _>>()?,
87            child_data: array
88                .child_data()
89                .iter()
90                .map(|c| unsafe { Self::from_array(c, region_start, region_len) })
91                .collect::<Result<_, _>>()?,
92        })
93    }
94}
dora_core/metadata.rs

dora_core/
metadata.rs
