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use std::collections::HashMap;
use std::mem;
use std::ops::RangeInclusive;
use indexmap::IndexMap;
use crate::obj::objtuple::PyTuple;
use crate::obj::objtype::{isinstance, PyClassRef};
use crate::pyobject::{
IntoPyObject, PyObjectRef, PyRef, PyResult, PyValue, TryFromObject, TypeProtocol,
};
use crate::vm::VirtualMachine;
use self::OptionalArg::*;
/// The `PyFuncArgs` struct is one of the most used structs then creating
/// a rust function that can be called from python. It holds both positional
/// arguments, as well as keyword arguments passed to the function.
#[derive(Debug, Default, Clone)]
pub struct PyFuncArgs {
pub args: Vec<PyObjectRef>,
// sorted map, according to https://www.python.org/dev/peps/pep-0468/
pub kwargs: IndexMap<String, PyObjectRef>,
}
/// Conversion from vector of python objects to function arguments.
impl From<Vec<PyObjectRef>> for PyFuncArgs {
fn from(args: Vec<PyObjectRef>) -> Self {
PyFuncArgs {
args,
kwargs: IndexMap::new(),
}
}
}
impl From<PyObjectRef> for PyFuncArgs {
fn from(arg: PyObjectRef) -> Self {
PyFuncArgs {
args: vec![arg],
kwargs: IndexMap::new(),
}
}
}
impl From<(&Args, &KwArgs)> for PyFuncArgs {
fn from(arg: (&Args, &KwArgs)) -> Self {
let Args(args) = arg.0;
let KwArgs(kwargs) = arg.1;
PyFuncArgs {
args: args.clone(),
kwargs: kwargs.iter().map(|(k, v)| (k.clone(), v.clone())).collect(),
}
}
}
impl FromArgs for PyFuncArgs {
fn from_args(_vm: &VirtualMachine, args: &mut PyFuncArgs) -> Result<Self, ArgumentError> {
Ok(mem::replace(args, Default::default()))
}
}
impl PyFuncArgs {
pub fn new(mut args: Vec<PyObjectRef>, kwarg_names: Vec<String>) -> PyFuncArgs {
// last `kwarg_names.len()` elements of args in order of appearance in the call signature
let kwarg_values = args.drain((args.len() - kwarg_names.len())..);
let mut kwargs = IndexMap::new();
for (name, value) in kwarg_names.iter().zip(kwarg_values) {
kwargs.insert(name.clone(), value);
}
PyFuncArgs { args, kwargs }
}
pub fn insert(&self, item: PyObjectRef) -> PyFuncArgs {
let mut args = PyFuncArgs {
args: self.args.clone(),
kwargs: self.kwargs.clone(),
};
args.args.insert(0, item);
args
}
pub fn shift(&mut self) -> PyObjectRef {
self.args.remove(0)
}
pub fn get_kwarg(&self, key: &str, default: PyObjectRef) -> PyObjectRef {
self.kwargs
.get(key)
.cloned()
.unwrap_or_else(|| default.clone())
}
pub fn get_optional_kwarg(&self, key: &str) -> Option<PyObjectRef> {
self.kwargs.get(key).cloned()
}
pub fn get_optional_kwarg_with_type(
&self,
key: &str,
ty: PyClassRef,
vm: &VirtualMachine,
) -> Result<Option<PyObjectRef>, PyObjectRef> {
match self.get_optional_kwarg(key) {
Some(kwarg) => {
if isinstance(&kwarg, &ty) {
Ok(Some(kwarg))
} else {
let expected_ty_name = vm.to_pystr(&ty)?;
let actual_ty_name = vm.to_pystr(&kwarg.class())?;
Err(vm.new_type_error(format!(
"argument of type {} is required for named parameter `{}` (got: {})",
expected_ty_name, key, actual_ty_name
)))
}
}
None => Ok(None),
}
}
pub fn take_positional(&mut self) -> Option<PyObjectRef> {
if self.args.is_empty() {
None
} else {
Some(self.args.remove(0))
}
}
pub fn take_positional_keyword(&mut self, name: &str) -> Option<PyObjectRef> {
self.take_positional().or_else(|| self.take_keyword(name))
}
pub fn take_keyword(&mut self, name: &str) -> Option<PyObjectRef> {
self.kwargs.remove(name)
}
pub fn remaining_keywords<'a>(
&'a mut self,
) -> impl Iterator<Item = (String, PyObjectRef)> + 'a {
self.kwargs.drain(..)
}
/// Binds these arguments to their respective values.
///
/// If there is an insufficient number of arguments, there are leftover
/// arguments after performing the binding, or if an argument is not of
/// the expected type, a TypeError is raised.
///
/// If the given `FromArgs` includes any conversions, exceptions raised
/// during the conversion will halt the binding and return the error.
pub fn bind<T: FromArgs>(mut self, vm: &VirtualMachine) -> PyResult<T> {
let given_args = self.args.len();
let bound = match T::from_args(vm, &mut self) {
Ok(args) => args,
Err(ArgumentError::TooFewArgs) => {
return Err(vm.new_type_error(format!(
"Expected at least {} arguments ({} given)",
T::arity().start(),
given_args,
)));
}
Err(ArgumentError::TooManyArgs) => {
return Err(vm.new_type_error(format!(
"Expected at most {} arguments ({} given)",
T::arity().end(),
given_args,
)));
}
Err(ArgumentError::InvalidKeywordArgument(name)) => {
return Err(vm.new_type_error(format!("{} is an invalid keyword argument", name)));
}
Err(ArgumentError::RequiredKeywordArgument(name)) => {
return Err(vm.new_type_error(format!("Required keyqord only argument {}", name)));
}
Err(ArgumentError::Exception(ex)) => {
return Err(ex);
}
};
if !self.args.is_empty() {
Err(vm.new_type_error(format!(
"Expected at most {} arguments ({} given)",
T::arity().end(),
given_args,
)))
} else if !self.kwargs.is_empty() {
Err(vm.new_type_error(format!(
"Unexpected keyword argument {}",
self.kwargs.keys().next().unwrap()
)))
} else {
Ok(bound)
}
}
}
/// An error encountered while binding arguments to the parameters of a Python
/// function call.
pub enum ArgumentError {
/// The call provided fewer positional arguments than the function requires.
TooFewArgs,
/// The call provided more positional arguments than the function accepts.
TooManyArgs,
/// The function doesn't accept a keyword argument with the given name.
InvalidKeywordArgument(String),
/// The function require a keyword argument with the given name, but one wasn't provided
RequiredKeywordArgument(String),
/// An exception was raised while binding arguments to the function
/// parameters.
Exception(PyObjectRef),
}
impl From<PyObjectRef> for ArgumentError {
fn from(ex: PyObjectRef) -> Self {
ArgumentError::Exception(ex)
}
}
/// Implemented by any type that can be accepted as a parameter to a built-in
/// function.
///
pub trait FromArgs: Sized {
/// The range of positional arguments permitted by the function signature.
///
/// Returns an empty range if not applicable.
fn arity() -> RangeInclusive<usize> {
0..=0
}
/// Extracts this item from the next argument(s).
fn from_args(vm: &VirtualMachine, args: &mut PyFuncArgs) -> Result<Self, ArgumentError>;
}
/// A map of keyword arguments to their values.
///
/// A built-in function with a `KwArgs` parameter is analagous to a Python
/// function with `**kwargs`. All remaining keyword arguments are extracted
/// (and hence the function will permit an arbitrary number of them).
///
/// `KwArgs` optionally accepts a generic type parameter to allow type checks
/// or conversions of each argument.
///
/// Note:
///
/// KwArgs is only for functions that accept arbitrary keyword arguments. For
/// functions that accept only *specific* named arguments, a rust struct with
/// an appropriate FromArgs implementation must be created.
pub struct KwArgs<T = PyObjectRef>(HashMap<String, T>);
impl<T> KwArgs<T> {
pub fn pop_kwarg(&mut self, name: &str) -> Option<T> {
self.0.remove(name)
}
}
impl<T> FromArgs for KwArgs<T>
where
T: TryFromObject,
{
fn from_args(vm: &VirtualMachine, args: &mut PyFuncArgs) -> Result<Self, ArgumentError> {
let mut kwargs = HashMap::new();
for (name, value) in args.remaining_keywords() {
kwargs.insert(name, T::try_from_object(vm, value)?);
}
Ok(KwArgs(kwargs))
}
}
impl<T> IntoIterator for KwArgs<T> {
type Item = (String, T);
type IntoIter = std::collections::hash_map::IntoIter<String, T>;
fn into_iter(self) -> Self::IntoIter {
self.0.into_iter()
}
}
/// A list of positional argument values.
///
/// A built-in function with a `Args` parameter is analagous to a Python
/// function with `*args`. All remaining positional arguments are extracted
/// (and hence the function will permit an arbitrary number of them).
///
/// `Args` optionally accepts a generic type parameter to allow type checks
/// or conversions of each argument.
#[derive(Clone)]
pub struct Args<T = PyObjectRef>(Vec<T>);
impl<T> Args<T> {
pub fn into_vec(self) -> Vec<T> {
self.0
}
}
impl<T: PyValue> Args<PyRef<T>> {
pub fn into_tuple(self, vm: &VirtualMachine) -> PyObjectRef {
vm.ctx
.new_tuple(self.0.into_iter().map(PyRef::into_object).collect())
}
}
impl<T> FromArgs for Args<T>
where
T: TryFromObject,
{
fn from_args(vm: &VirtualMachine, args: &mut PyFuncArgs) -> Result<Self, ArgumentError> {
let mut varargs = Vec::new();
while let Some(value) = args.take_positional() {
varargs.push(T::try_from_object(vm, value)?);
}
Ok(Args(varargs))
}
}
impl<T> IntoIterator for Args<T> {
type Item = T;
type IntoIter = std::vec::IntoIter<T>;
fn into_iter(self) -> Self::IntoIter {
self.0.into_iter()
}
}
impl<T> FromArgs for T
where
T: TryFromObject,
{
fn arity() -> RangeInclusive<usize> {
1..=1
}
fn from_args(vm: &VirtualMachine, args: &mut PyFuncArgs) -> Result<Self, ArgumentError> {
if let Some(value) = args.take_positional() {
Ok(T::try_from_object(vm, value)?)
} else {
Err(ArgumentError::TooFewArgs)
}
}
}
/// An argument that may or may not be provided by the caller.
///
/// This style of argument is not possible in pure Python.
#[derive(Debug)]
pub enum OptionalArg<T = PyObjectRef> {
Present(T),
Missing,
}
impl<T> OptionalArg<T> {
#[inline]
pub fn is_present(&self) -> bool {
match self {
Present(_) => true,
Missing => false,
}
}
#[inline]
pub fn into_option(self) -> Option<T> {
match self {
Present(value) => Some(value),
Missing => None,
}
}
pub fn unwrap_or(self, default: T) -> T {
match self {
Present(value) => value,
Missing => default,
}
}
pub fn unwrap_or_else<F>(self, f: F) -> T
where
F: FnOnce() -> T,
{
match self {
Present(value) => value,
Missing => f(),
}
}
pub fn map_or_else<U, D, F>(self, default: D, f: F) -> U
where
D: FnOnce() -> U,
F: FnOnce(T) -> U,
{
match self {
Present(value) => f(value),
Missing => default(),
}
}
}
pub type OptionalOption<T> = OptionalArg<Option<T>>;
impl<T> OptionalOption<T> {
#[inline]
pub fn flat_option(self) -> Option<T> {
match self {
Present(Some(value)) => Some(value),
_ => None,
}
}
}
impl<T> FromArgs for OptionalArg<T>
where
T: TryFromObject,
{
fn arity() -> RangeInclusive<usize> {
0..=1
}
fn from_args(vm: &VirtualMachine, args: &mut PyFuncArgs) -> Result<Self, ArgumentError> {
if let Some(value) = args.take_positional() {
Ok(Present(T::try_from_object(vm, value)?))
} else {
Ok(Missing)
}
}
}
// For functions that accept no arguments. Implemented explicitly instead of via
// macro below to avoid unused warnings.
impl FromArgs for () {
fn from_args(_vm: &VirtualMachine, _args: &mut PyFuncArgs) -> Result<Self, ArgumentError> {
Ok(())
}
}
// A tuple of types that each implement `FromArgs` represents a sequence of
// arguments that can be bound and passed to a built-in function.
//
// Technically, a tuple can contain tuples, which can contain tuples, and so on,
// so this actually represents a tree of values to be bound from arguments, but
// in practice this is only used for the top-level parameters.
macro_rules! tuple_from_py_func_args {
($($T:ident),+) => {
impl<$($T),+> FromArgs for ($($T,)+)
where
$($T: FromArgs),+
{
fn arity() -> RangeInclusive<usize> {
let mut min = 0;
let mut max = 0;
$(
let (start, end) = $T::arity().into_inner();
min += start;
max += end;
)+
min..=max
}
fn from_args(vm: &VirtualMachine, args: &mut PyFuncArgs) -> Result<Self, ArgumentError> {
Ok(($($T::from_args(vm, args)?,)+))
}
}
};
}
// Implement `FromArgs` for up to 5-tuples, allowing built-in functions to bind
// up to 5 top-level parameters (note that `Args`, `KwArgs`, nested tuples, etc.
// count as 1, so this should actually be more than enough).
tuple_from_py_func_args!(A);
tuple_from_py_func_args!(A, B);
tuple_from_py_func_args!(A, B, C);
tuple_from_py_func_args!(A, B, C, D);
tuple_from_py_func_args!(A, B, C, D, E);
tuple_from_py_func_args!(A, B, C, D, E, F);
/// A built-in Python function.
pub type PyNativeFunc = Box<dyn Fn(&VirtualMachine, PyFuncArgs) -> PyResult + 'static>;
/// Implemented by types that are or can generate built-in functions.
///
/// For example, any function that:
///
/// - Accepts a sequence of types that implement `FromArgs`, followed by a
/// `&VirtualMachine`
/// - Returns some type that implements `IntoPyObject`
///
/// will generate a `PyNativeFunc` that performs the appropriate type and arity
/// checking, any requested conversions, and then if successful call the function
/// with the bound values.
///
/// A bare `PyNativeFunc` also implements this trait, allowing the above to be
/// done manually, for rare situations that don't fit into this model.
pub trait IntoPyNativeFunc<T, R> {
fn into_func(self) -> PyNativeFunc;
}
impl<F> IntoPyNativeFunc<PyFuncArgs, PyResult> for F
where
F: Fn(&VirtualMachine, PyFuncArgs) -> PyResult + 'static,
{
fn into_func(self) -> PyNativeFunc {
Box::new(self)
}
}
pub struct OwnedParam<T>(std::marker::PhantomData<T>);
pub struct RefParam<T>(std::marker::PhantomData<T>);
// This is the "magic" that allows rust functions of varying signatures to
// generate native python functions.
//
// Note that this could be done without a macro - it is simply to avoid repetition.
macro_rules! into_py_native_func_tuple {
($(($n:tt, $T:ident)),*) => {
impl<F, $($T,)* R> IntoPyNativeFunc<($(OwnedParam<$T>,)*), R> for F
where
F: Fn($($T,)* &VirtualMachine) -> R + 'static,
$($T: FromArgs,)*
R: IntoPyObject,
{
fn into_func(self) -> PyNativeFunc {
Box::new(move |vm, args| {
let ($($n,)*) = args.bind::<($($T,)*)>(vm)?;
(self)($($n,)* vm).into_pyobject(vm)
})
}
}
impl<F, S, $($T,)* R> IntoPyNativeFunc<(RefParam<S>, $(OwnedParam<$T>,)*), R> for F
where
F: Fn(&S, $($T,)* &VirtualMachine) -> R + 'static,
S: PyValue,
$($T: FromArgs,)*
R: IntoPyObject,
{
fn into_func(self) -> PyNativeFunc {
Box::new(move |vm, args| {
let (zelf, $($n,)*) = args.bind::<(PyRef<S>, $($T,)*)>(vm)?;
(self)(&zelf, $($n,)* vm).into_pyobject(vm)
})
}
}
};
}
into_py_native_func_tuple!();
into_py_native_func_tuple!((a, A));
into_py_native_func_tuple!((a, A), (b, B));
into_py_native_func_tuple!((a, A), (b, B), (c, C));
into_py_native_func_tuple!((a, A), (b, B), (c, C), (d, D));
into_py_native_func_tuple!((a, A), (b, B), (c, C), (d, D), (e, E));
/// Tests that the predicate is True on a single value, or if the value is a tuple a tuple, then
/// test that any of the values contained within the tuples satisfies the predicate. Type parameter
/// T specifies the type that is expected, if the input value is not of that type or a tuple of
/// values of that type, then a TypeError is raised.
pub fn single_or_tuple_any<T: PyValue, F: Fn(PyRef<T>) -> PyResult<bool>>(
obj: PyObjectRef,
predicate: F,
message: fn(&PyObjectRef) -> String,
vm: &VirtualMachine,
) -> PyResult<bool> {
match_class!(obj,
obj @ T => predicate(obj),
tuple @ PyTuple => {
for obj in tuple.elements.iter() {
let inner_val = PyRef::<T>::try_from_object(vm, obj.clone())?;
if predicate(inner_val)? {
return Ok(true);
}
}
Ok(false)
},
obj => Err(vm.new_type_error(message(&obj)))
)
}