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//! This module contains data types for interacting with `Scope`s.
//!
//! ## Relevant examples
//! - [Counter](https://github.com/yewstack/yew/tree/master/examples/counter)
//! - [Timer](https://github.com/yewstack/yew/tree/master/examples/timer)
use std::fmt;
use std::rc::Rc;
use crate::html::ImplicitClone;
macro_rules! generate_callback_impls {
($callback:ident, $in_ty:ty, $out_var:ident => $out_val:expr) => {
impl<IN, OUT, F: Fn($in_ty) -> OUT + 'static> From<F> for $callback<IN, OUT> {
fn from(func: F) -> Self {
$callback { cb: Rc::new(func) }
}
}
impl<IN, OUT> Clone for $callback<IN, OUT> {
fn clone(&self) -> Self {
Self {
cb: self.cb.clone(),
}
}
}
// We are okay with comparisons from different compilation units to result in false
// not-equal results. This should only lead in the worst-case to some unneeded re-renders.
#[allow(ambiguous_wide_pointer_comparisons)]
impl<IN, OUT> PartialEq for $callback<IN, OUT> {
fn eq(&self, other: &$callback<IN, OUT>) -> bool {
let ($callback { cb }, $callback { cb: rhs_cb }) = (self, other);
Rc::ptr_eq(cb, rhs_cb)
}
}
impl<IN, OUT> fmt::Debug for $callback<IN, OUT> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "$callback<_>")
}
}
impl<IN, OUT> $callback<IN, OUT> {
/// This method calls the callback's function.
pub fn emit(&self, value: $in_ty) -> OUT {
(*self.cb)(value)
}
}
impl<IN> $callback<IN> {
/// Creates a "no-op" callback which can be used when it is not suitable to use an
/// `Option<$callback>`.
pub fn noop() -> Self {
Self::from(|_: $in_ty| ())
}
}
impl<IN> Default for $callback<IN> {
fn default() -> Self {
Self::noop()
}
}
impl<IN: 'static, OUT: 'static> $callback<IN, OUT> {
/// Creates a new [`Callback`] from another callback and a function.
///
/// That when emitted will call that function and will emit the original callback
pub fn reform<F, T>(&self, func: F) -> Callback<T, OUT>
where
F: Fn(T) -> IN + 'static,
{
let this = self.clone();
let func = move |input: T| {
#[allow(unused_mut)]
let mut $out_var = func(input);
this.emit($out_val)
};
func.into()
}
/// Creates a new [`CallbackRef`] from another callback and a function.
///
/// That when emitted will call that function and will emit the original callback
pub fn reform_ref<F, T>(&self, func: F) -> CallbackRef<T, OUT>
where
F: Fn(&T) -> $in_ty + 'static,
{
let this = self.clone();
let func = move |input: &T| {
#[allow(unused_mut)]
let mut $out_var = func(input);
this.emit($out_val)
};
func.into()
}
/// Creates a new [`CallbackRefMut`] from another callback and a function.
///
/// That when emitted will call that function and will emit the original callback
pub fn reform_ref_mut<F, T>(&self, func: F) -> CallbackRefMut<T, OUT>
where
F: Fn(&mut T) -> $in_ty + 'static,
{
let this = self.clone();
let func = move |input: &mut T| {
#[allow(unused_mut)]
let mut $out_var = func(input);
this.emit($out_val)
};
func.into()
}
/// Creates a new [`Callback`] from another callback and a function.
///
/// When emitted will call the function and, only if it returns `Some(value)`, will emit
/// `value` to the original callback.
pub fn filter_reform<F, T>(&self, func: F) -> Callback<T, Option<OUT>>
where
F: Fn(T) -> Option<IN> + 'static,
{
let this = self.clone();
let func = move |input: T| {
func(input).map(
#[allow(unused_mut)]
|mut $out_var| this.emit($out_val),
)
};
func.into()
}
/// Creates a new [`CallbackRef`] from another callback and a function.
///
/// When emitted will call the function and, only if it returns `Some(value)`, will emit
/// `value` to the original callback.
pub fn filter_reform_ref<F, T>(&self, func: F) -> CallbackRef<T, Option<OUT>>
where
F: Fn(&T) -> Option<$in_ty> + 'static,
{
let this = self.clone();
let func = move |input: &T| {
func(input).map(
#[allow(unused_mut)]
|mut $out_var| this.emit($out_val),
)
};
func.into()
}
/// Creates a new [`CallbackRefMut`] from another callback and a function.
///
/// When emitted will call the function and, only if it returns `Some(value)`, will emit
/// `value` to the original callback.
pub fn filter_reform_ref_mut<F, T>(&self, func: F) -> CallbackRefMut<T, Option<OUT>>
where
F: Fn(&mut T) -> Option<$in_ty> + 'static,
{
let this = self.clone();
let func = move |input: &mut T| {
func(input).map(
#[allow(unused_mut)]
|mut $out_var| this.emit($out_val),
)
};
func.into()
}
}
impl<IN, OUT> ImplicitClone for $callback<IN, OUT> {}
};
}
/// Universal callback wrapper.
///
/// An `Rc` wrapper is used to make it cloneable.
pub struct Callback<IN, OUT = ()> {
/// A callback which can be called multiple times
pub(crate) cb: Rc<dyn Fn(IN) -> OUT>,
}
generate_callback_impls!(Callback, IN, output => output);
/// Universal callback wrapper with reference in argument.
///
/// An `Rc` wrapper is used to make it cloneable.
pub struct CallbackRef<IN, OUT = ()> {
/// A callback which can be called multiple times
pub(crate) cb: Rc<dyn Fn(&IN) -> OUT>,
}
generate_callback_impls!(CallbackRef, &IN, output => #[allow(clippy::needless_borrow)] &output);
/// Universal callback wrapper with mutable reference in argument.
///
/// An `Rc` wrapper is used to make it cloneable.
pub struct CallbackRefMut<IN, OUT = ()> {
/// A callback which can be called multiple times
pub(crate) cb: Rc<dyn Fn(&mut IN) -> OUT>,
}
generate_callback_impls!(CallbackRefMut, &mut IN, output => &mut output);
#[cfg(test)]
mod test {
use std::sync::Mutex;
use super::*;
/// emit the callback with the provided value
fn emit<T, I, R: 'static + Clone, F, OUT>(values: I, f: F) -> Vec<R>
where
I: IntoIterator<Item = T>,
F: FnOnce(Callback<R, ()>) -> Callback<T, OUT>,
{
let result = Rc::new(Mutex::new(Vec::new()));
let cb_result = result.clone();
let cb = f(Callback::<R, ()>::from(move |v| {
cb_result.lock().unwrap().push(v);
}));
for value in values {
cb.emit(value);
}
let x = result.lock().unwrap().clone();
x
}
#[test]
fn test_callback() {
assert_eq!(*emit([true, false], |cb| cb), vec![true, false]);
}
#[test]
fn test_reform() {
assert_eq!(
*emit([true, false], |cb| cb.reform(|v: bool| !v)),
vec![false, true]
);
}
#[test]
fn test_filter_reform() {
assert_eq!(
*emit([1, 2, 3], |cb| cb.filter_reform(|v| match v {
1 => Some(true),
2 => Some(false),
_ => None,
})),
vec![true, false]
);
}
#[test]
fn test_ref() {
let callback: CallbackRef<usize, usize> = CallbackRef::from(|x: &usize| *x);
assert_eq!(callback.emit(&42), 42);
}
#[test]
fn test_ref_mut() {
let callback: CallbackRefMut<usize, ()> = CallbackRefMut::from(|x: &mut usize| *x = 42);
let mut value: usize = 0;
callback.emit(&mut value);
assert_eq!(value, 42);
}
#[test]
fn test_reform_ref() {
let callback: Callback<usize, usize> = Callback::from(|x: usize| x + 1);
let reformed: CallbackRef<usize, usize> = callback.reform_ref(|x: &usize| *x + 2);
assert_eq!(reformed.emit(&42), 45);
}
#[test]
fn test_reform_ref_mut() {
let callback: CallbackRefMut<usize, ()> = CallbackRefMut::from(|x: &mut usize| *x += 1);
let reformed: CallbackRefMut<usize, ()> = callback.reform_ref_mut(|x: &mut usize| {
*x += 2;
x
});
let mut value: usize = 42;
reformed.emit(&mut value);
assert_eq!(value, 45);
}
#[test]
fn test_filter_reform_ref() {
let callback: Callback<usize, usize> = Callback::from(|x: usize| x + 1);
let reformed: CallbackRef<usize, Option<usize>> =
callback.filter_reform_ref(|x: &usize| Some(*x + 2));
assert_eq!(reformed.emit(&42), Some(45));
}
#[test]
fn test_filter_reform_ref_mut() {
let callback: CallbackRefMut<usize, ()> = CallbackRefMut::from(|x: &mut usize| *x += 1);
let reformed: CallbackRefMut<usize, Option<()>> =
callback.filter_reform_ref_mut(|x: &mut usize| {
*x += 2;
Some(x)
});
let mut value: usize = 42;
reformed.emit(&mut value).expect("is some");
assert_eq!(value, 45);
}
}