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json.rs
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264 lines (245 loc) · 8.99 KB
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pub(crate) use _json::make_module;
mod machinery;
#[pymodule]
mod _json {
use super::machinery;
use crate::vm::{
builtins::{PyBaseExceptionRef, PyStrRef, PyTypeRef},
convert::{ToPyObject, ToPyResult},
function::OptionalArg,
protocol::PyIterReturn,
types::{Callable, Constructor},
AsObject, Py, PyObjectRef, PyPayload, PyResult, VirtualMachine,
};
use num_bigint::BigInt;
use std::str::FromStr;
#[pyattr(name = "make_scanner")]
#[pyclass(name = "Scanner")]
#[derive(Debug, PyPayload)]
struct JsonScanner {
strict: bool,
object_hook: Option<PyObjectRef>,
object_pairs_hook: Option<PyObjectRef>,
parse_float: Option<PyObjectRef>,
parse_int: Option<PyObjectRef>,
parse_constant: PyObjectRef,
ctx: PyObjectRef,
}
impl Constructor for JsonScanner {
type Args = PyObjectRef;
fn py_new(cls: PyTypeRef, ctx: Self::Args, vm: &VirtualMachine) -> PyResult {
let strict = ctx.get_attr("strict", vm)?.try_to_bool(vm)?;
let object_hook = vm.option_if_none(ctx.get_attr("object_hook", vm)?);
let object_pairs_hook = vm.option_if_none(ctx.get_attr("object_pairs_hook", vm)?);
let parse_float = ctx.get_attr("parse_float", vm)?;
let parse_float = if vm.is_none(&parse_float) || parse_float.is(vm.ctx.types.float_type)
{
None
} else {
Some(parse_float)
};
let parse_int = ctx.get_attr("parse_int", vm)?;
let parse_int = if vm.is_none(&parse_int) || parse_int.is(vm.ctx.types.int_type) {
None
} else {
Some(parse_int)
};
let parse_constant = ctx.get_attr("parse_constant", vm)?;
Self {
strict,
object_hook,
object_pairs_hook,
parse_float,
parse_int,
parse_constant,
ctx,
}
.into_ref_with_type(vm, cls)
.map(Into::into)
}
}
#[pyclass(with(Callable, Constructor))]
impl JsonScanner {
fn parse(
&self,
s: &str,
pystr: PyStrRef,
idx: usize,
scan_once: PyObjectRef,
vm: &VirtualMachine,
) -> PyResult<PyIterReturn> {
let c = match s.chars().next() {
Some(c) => c,
None => {
return Ok(PyIterReturn::StopIteration(Some(
vm.ctx.new_int(idx).into(),
)))
}
};
let next_idx = idx + c.len_utf8();
match c {
'"' => {
return scanstring(pystr, next_idx, OptionalArg::Present(self.strict), vm)
.map(|x| PyIterReturn::Return(x.to_pyobject(vm)))
}
'{' => {
// TODO: parse the object in rust
let parse_obj = self.ctx.get_attr("parse_object", vm)?;
return PyIterReturn::from_pyresult(
vm.invoke(
&parse_obj,
(
(pystr, next_idx),
self.strict,
scan_once,
self.object_hook.clone(),
self.object_pairs_hook.clone(),
),
),
vm,
);
}
'[' => {
// TODO: parse the array in rust
let parse_array = self.ctx.get_attr("parse_array", vm)?;
return PyIterReturn::from_pyresult(
vm.invoke(&parse_array, ((pystr, next_idx), scan_once)),
vm,
);
}
_ => {}
}
macro_rules! parse_const {
($s:literal, $val:expr) => {
if s.starts_with($s) {
return Ok(PyIterReturn::Return(
vm.new_tuple(($val, idx + $s.len())).into(),
));
}
};
}
parse_const!("null", vm.ctx.none());
parse_const!("true", true);
parse_const!("false", false);
if let Some((res, len)) = self.parse_number(s, vm) {
return Ok(PyIterReturn::Return(vm.new_tuple((res?, idx + len)).into()));
}
macro_rules! parse_constant {
($s:literal) => {
if s.starts_with($s) {
return Ok(PyIterReturn::Return(
vm.new_tuple((
vm.invoke(&self.parse_constant, ($s.to_owned(),))?,
idx + $s.len(),
))
.into(),
));
}
};
}
parse_constant!("NaN");
parse_constant!("Infinity");
parse_constant!("-Infinity");
Ok(PyIterReturn::StopIteration(Some(
vm.ctx.new_int(idx).into(),
)))
}
fn parse_number(&self, s: &str, vm: &VirtualMachine) -> Option<(PyResult, usize)> {
let mut has_neg = false;
let mut has_decimal = false;
let mut has_exponent = false;
let mut has_e_sign = false;
let mut i = 0;
for c in s.chars() {
match c {
'-' if i == 0 => has_neg = true,
n if n.is_ascii_digit() => {}
'.' if !has_decimal => has_decimal = true,
'e' | 'E' if !has_exponent => has_exponent = true,
'+' | '-' if !has_e_sign => has_e_sign = true,
_ => break,
}
i += 1;
}
if i == 0 || (i == 1 && has_neg) {
return None;
}
let buf = &s[..i];
let ret = if has_decimal || has_exponent {
// float
if let Some(ref parse_float) = self.parse_float {
vm.invoke(parse_float, (buf.to_owned(),))
} else {
Ok(vm.ctx.new_float(f64::from_str(buf).unwrap()).into())
}
} else if let Some(ref parse_int) = self.parse_int {
vm.invoke(parse_int, (buf.to_owned(),))
} else {
Ok(vm.new_pyobj(BigInt::from_str(buf).unwrap()))
};
Some((ret, buf.len()))
}
}
impl Callable for JsonScanner {
type Args = (PyStrRef, isize);
fn call(zelf: &Py<Self>, (pystr, idx): Self::Args, vm: &VirtualMachine) -> PyResult {
if idx < 0 {
return Err(vm.new_value_error("idx cannot be negative".to_owned()));
}
let idx = idx as usize;
let mut chars = pystr.as_str().chars();
if idx > 0 && chars.nth(idx - 1).is_none() {
PyIterReturn::StopIteration(Some(vm.ctx.new_int(idx).into())).to_pyresult(vm)
} else {
zelf.parse(
chars.as_str(),
pystr.clone(),
idx,
zelf.to_owned().into(),
vm,
)
.and_then(|x| x.to_pyresult(vm))
}
}
}
fn encode_string(s: &str, ascii_only: bool) -> String {
let mut buf = Vec::<u8>::with_capacity(s.len() + 2);
machinery::write_json_string(s, ascii_only, &mut buf)
// SAFETY: writing to a vec can't fail
.unwrap_or_else(|_| unsafe { std::hint::unreachable_unchecked() });
// SAFETY: we only output valid utf8 from write_json_string
unsafe { String::from_utf8_unchecked(buf) }
}
#[pyfunction]
fn encode_basestring(s: PyStrRef) -> String {
encode_string(s.as_str(), false)
}
#[pyfunction]
fn encode_basestring_ascii(s: PyStrRef) -> String {
encode_string(s.as_str(), true)
}
fn py_decode_error(
e: machinery::DecodeError,
s: PyStrRef,
vm: &VirtualMachine,
) -> PyBaseExceptionRef {
let get_error = || -> PyResult<_> {
let cls = vm.try_class("json", "JSONDecodeError")?;
let exc = vm.invoke(&cls, (e.msg, s, e.pos))?;
exc.try_into_value(vm)
};
match get_error() {
Ok(x) | Err(x) => x,
}
}
#[pyfunction]
fn scanstring(
s: PyStrRef,
end: usize,
strict: OptionalArg<bool>,
vm: &VirtualMachine,
) -> PyResult<(String, usize)> {
machinery::scanstring(s.as_str(), end, strict.unwrap_or(true))
.map_err(|e| py_decode_error(e, s, vm))
}
}