pyo3/
marshal.rs

1#![cfg(not(Py_LIMITED_API))]
2
3//! Support for the Python `marshal` format.
4
5use crate::ffi_ptr_ext::FfiPtrExt;
6use crate::py_result_ext::PyResultExt;
7use crate::types::{PyAny, PyBytes};
8use crate::{ffi, Bound};
9use crate::{PyResult, Python};
10use core::ffi::c_int;
11
12/// The current version of the marshal binary format.
13pub const VERSION: i32 = 4;
14
15/// Serialize an object to bytes using the Python built-in marshal module.
16///
17/// The built-in marshalling only supports a limited range of objects.
18/// The exact types supported depend on the version argument.
19/// The [`VERSION`] constant holds the highest version currently supported.
20///
21/// See the [Python documentation](https://docs.python.org/3/library/marshal.html) for more details.
22///
23/// # Examples
24/// ```
25/// # use pyo3::{marshal, types::PyDict, prelude::PyDictMethods};
26/// # pyo3::Python::attach(|py| {
27/// let dict = PyDict::new(py);
28/// dict.set_item("aap", "noot").unwrap();
29/// dict.set_item("mies", "wim").unwrap();
30/// dict.set_item("zus", "jet").unwrap();
31///
32/// let bytes = marshal::dumps(&dict, marshal::VERSION);
33/// # });
34/// ```
35pub fn dumps<'py>(object: &Bound<'py, PyAny>, version: i32) -> PyResult<Bound<'py, PyBytes>> {
36    // SAFETY: `object` is a valid object pointer, and a non-NULL return from
37    // `PyMarshal_WriteObjectToString` is a new owned reference to a bytes
38    // object.
39    unsafe {
40        ffi::PyMarshal_WriteObjectToString(object.as_ptr(), version as c_int)
41            .assume_owned_or_err(object.py())
42            .cast_into_unchecked()
43    }
44}
45
46/// Deserialize an object from bytes using the Python built-in marshal module.
47pub fn loads<'py, B>(py: Python<'py>, data: &B) -> PyResult<Bound<'py, PyAny>>
48where
49    B: AsRef<[u8]> + ?Sized,
50{
51    let data = data.as_ref();
52    // SAFETY: `data` and `len` come from the same byte slice, so `data` points
53    // to `len` readable bytes, and `PyMarshal_ReadObjectFromString` returns a
54    // new owned reference on success, or NULL with an exception set on error.
55    unsafe {
56        ffi::PyMarshal_ReadObjectFromString(data.as_ptr().cast(), data.len() as isize)
57            .assume_owned_or_err(py)
58    }
59}
60
61#[cfg(test)]
62mod tests {
63    use super::*;
64    use crate::types::{bytes::PyBytesMethods, dict::PyDictMethods, PyAnyMethods, PyDict};
65
66    #[test]
67    fn marshal_roundtrip() {
68        Python::attach(|py| {
69            let dict = PyDict::new(py);
70            dict.set_item("aap", "noot").unwrap();
71            dict.set_item("mies", "wim").unwrap();
72            dict.set_item("zus", "jet").unwrap();
73
74            let pybytes = dumps(&dict, VERSION).expect("marshalling failed");
75            let deserialized = loads(py, pybytes.as_bytes()).expect("unmarshalling failed");
76
77            assert!(dict.eq(&deserialized).unwrap());
78        });
79    }
80}
pyo3/marshal.rs

pyo3/
marshal.rs
