rustpython_vm/
py_io.rs

1use crate::{
2    builtins::{PyBaseExceptionRef, PyBytes, PyStr},
3    common::ascii,
4    PyObject, PyObjectRef, PyResult, VirtualMachine,
5};
6use std::{fmt, io, ops};
7
8pub trait Write {
9    type Error;
10    fn write_fmt(&mut self, args: fmt::Arguments) -> Result<(), Self::Error>;
11}
12
13#[repr(transparent)]
14pub struct IoWriter<T>(pub T);
15
16impl<T> IoWriter<T> {
17    pub fn from_ref(x: &mut T) -> &mut Self {
18        // SAFETY: IoWriter is repr(transparent) over T
19        unsafe { &mut *(x as *mut T as *mut Self) }
20    }
21}
22
23impl<T> ops::Deref for IoWriter<T> {
24    type Target = T;
25    fn deref(&self) -> &T {
26        &self.0
27    }
28}
29impl<T> ops::DerefMut for IoWriter<T> {
30    fn deref_mut(&mut self) -> &mut T {
31        &mut self.0
32    }
33}
34
35impl<W> Write for IoWriter<W>
36where
37    W: io::Write,
38{
39    type Error = io::Error;
40    fn write_fmt(&mut self, args: fmt::Arguments) -> io::Result<()> {
41        <W as io::Write>::write_fmt(&mut self.0, args)
42    }
43}
44
45impl Write for String {
46    type Error = fmt::Error;
47    fn write_fmt(&mut self, args: fmt::Arguments) -> fmt::Result {
48        <String as fmt::Write>::write_fmt(self, args)
49    }
50}
51
52pub struct PyWriter<'vm>(pub PyObjectRef, pub &'vm VirtualMachine);
53
54impl Write for PyWriter<'_> {
55    type Error = PyBaseExceptionRef;
56    fn write_fmt(&mut self, args: fmt::Arguments) -> Result<(), Self::Error> {
57        let PyWriter(obj, vm) = self;
58        vm.call_method(obj, "write", (args.to_string(),)).map(drop)
59    }
60}
61
62pub fn file_readline(obj: &PyObject, size: Option<usize>, vm: &VirtualMachine) -> PyResult {
63    let args = size.map_or_else(Vec::new, |size| vec![vm.ctx.new_int(size).into()]);
64    let ret = vm.call_method(obj, "readline", args)?;
65    let eof_err = || {
66        vm.new_exception(
67            vm.ctx.exceptions.eof_error.to_owned(),
68            vec![vm.ctx.new_str(ascii!("EOF when reading a line")).into()],
69        )
70    };
71    let ret = match_class!(match ret {
72        s @ PyStr => {
73            let sval = s.as_str();
74            if sval.is_empty() {
75                return Err(eof_err());
76            }
77            if let Some(nonl) = sval.strip_suffix('\n') {
78                vm.ctx.new_str(nonl).into()
79            } else {
80                s.into()
81            }
82        }
83        b @ PyBytes => {
84            let buf = b.as_bytes();
85            if buf.is_empty() {
86                return Err(eof_err());
87            }
88            if buf.last() == Some(&b'\n') {
89                vm.ctx.new_bytes(buf[..buf.len() - 1].to_owned()).into()
90            } else {
91                b.into()
92            }
93        }
94        _ => return Err(vm.new_type_error("object.readline() returned non-string".to_owned())),
95    });
96    Ok(ret)
97}
rustpython_vm/py_io.rs

rustpython_vm/
py_io.rs
