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denoland-deno/core/gotham_state.rs

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// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.
// Forked from Gotham:
// https://github.com/gotham-rs/gotham/blob/bcbbf8923789e341b7a0e62c59909428ca4e22e2/gotham/src/state/mod.rs
// Copyright 2017 Gotham Project Developers. MIT license.
2021-03-26 12:34:25 -04:00
use log::trace;
use std::any::type_name;
use std::any::Any;
use std::any::TypeId;
use std::collections::BTreeMap;
#[derive(Default)]
pub struct GothamState {
data: BTreeMap<TypeId, Box<dyn Any>>,
}
impl GothamState {
/// Puts a value into the `GothamState` storage. One value of each type is retained.
/// Successive calls to `put` will overwrite the existing value of the same
/// type.
pub fn put<T: 'static>(&mut self, t: T) {
let type_id = TypeId::of::<T>();
trace!(" inserting record to state for type_id `{:?}`", type_id);
self.data.insert(type_id, Box::new(t));
}
/// Determines if the current value exists in `GothamState` storage.
pub fn has<T: 'static>(&self) -> bool {
let type_id = TypeId::of::<T>();
self.data.get(&type_id).is_some()
}
/// Tries to borrow a value from the `GothamState` storage.
pub fn try_borrow<T: 'static>(&self) -> Option<&T> {
let type_id = TypeId::of::<T>();
trace!(" borrowing state data for type_id `{:?}`", type_id);
self.data.get(&type_id).and_then(|b| b.downcast_ref())
}
/// Borrows a value from the `GothamState` storage.
pub fn borrow<T: 'static>(&self) -> &T {
self.try_borrow().unwrap_or_else(|| missing::<T>())
}
/// Tries to mutably borrow a value from the `GothamState` storage.
pub fn try_borrow_mut<T: 'static>(&mut self) -> Option<&mut T> {
let type_id = TypeId::of::<T>();
trace!(" mutably borrowing state data for type_id `{:?}`", type_id);
self.data.get_mut(&type_id).and_then(|b| b.downcast_mut())
}
/// Mutably borrows a value from the `GothamState` storage.
pub fn borrow_mut<T: 'static>(&mut self) -> &mut T {
self.try_borrow_mut().unwrap_or_else(|| missing::<T>())
}
/// Tries to move a value out of the `GothamState` storage and return ownership.
pub fn try_take<T: 'static>(&mut self) -> Option<T> {
let type_id = TypeId::of::<T>();
trace!(
" taking ownership from state data for type_id `{:?}`",
type_id
);
self
.data
.remove(&type_id)
.and_then(|b| b.downcast().ok())
.map(|b| *b)
}
/// Moves a value out of the `GothamState` storage and returns ownership.
///
/// # Panics
///
/// If a value of type `T` is not present in `GothamState`.
pub fn take<T: 'static>(&mut self) -> T {
self.try_take().unwrap_or_else(|| missing::<T>())
}
}
fn missing<T: 'static>() -> ! {
panic!(
"required type {} is not present in GothamState container",
type_name::<T>()
);
}
#[cfg(test)]
mod tests {
use super::GothamState;
struct MyStruct {
value: i32,
}
struct AnotherStruct {
value: &'static str,
}
type Alias1 = String;
type Alias2 = String;
#[test]
fn put_borrow1() {
let mut state = GothamState::default();
state.put(MyStruct { value: 1 });
assert_eq!(state.borrow::<MyStruct>().value, 1);
}
#[test]
fn put_borrow2() {
let mut state = GothamState::default();
assert!(!state.has::<AnotherStruct>());
state.put(AnotherStruct { value: "a string" });
assert!(state.has::<AnotherStruct>());
assert!(!state.has::<MyStruct>());
state.put(MyStruct { value: 100 });
assert!(state.has::<MyStruct>());
assert_eq!(state.borrow::<MyStruct>().value, 100);
assert_eq!(state.borrow::<AnotherStruct>().value, "a string");
}
#[test]
fn try_borrow() {
let mut state = GothamState::default();
state.put(MyStruct { value: 100 });
assert!(state.try_borrow::<MyStruct>().is_some());
assert_eq!(state.try_borrow::<MyStruct>().unwrap().value, 100);
assert!(state.try_borrow::<AnotherStruct>().is_none());
}
#[test]
fn try_borrow_mut() {
let mut state = GothamState::default();
state.put(MyStruct { value: 100 });
if let Some(a) = state.try_borrow_mut::<MyStruct>() {
a.value += 10;
}
assert_eq!(state.borrow::<MyStruct>().value, 110);
}
#[test]
fn borrow_mut() {
let mut state = GothamState::default();
state.put(MyStruct { value: 100 });
{
let a = state.borrow_mut::<MyStruct>();
a.value += 10;
}
assert_eq!(state.borrow::<MyStruct>().value, 110);
assert!(state.try_borrow_mut::<AnotherStruct>().is_none());
}
#[test]
fn try_take() {
let mut state = GothamState::default();
state.put(MyStruct { value: 100 });
assert_eq!(state.try_take::<MyStruct>().unwrap().value, 100);
assert!(state.try_take::<MyStruct>().is_none());
assert!(state.try_borrow_mut::<MyStruct>().is_none());
assert!(state.try_borrow::<MyStruct>().is_none());
assert!(state.try_take::<AnotherStruct>().is_none());
}
#[test]
fn take() {
let mut state = GothamState::default();
state.put(MyStruct { value: 110 });
assert_eq!(state.take::<MyStruct>().value, 110);
assert!(state.try_take::<MyStruct>().is_none());
assert!(state.try_borrow_mut::<MyStruct>().is_none());
assert!(state.try_borrow::<MyStruct>().is_none());
}
#[test]
fn type_alias() {
let mut state = GothamState::default();
state.put::<Alias1>("alias1".to_string());
state.put::<Alias2>("alias2".to_string());
assert_eq!(state.take::<Alias1>(), "alias2");
assert!(state.try_take::<Alias1>().is_none());
assert!(state.try_take::<Alias2>().is_none());
}
#[test]
#[should_panic(
expected = "required type deno_core::gotham_state::tests::MyStruct is not present in GothamState container"
)]
fn missing() {
let state = GothamState::default();
let _ = state.borrow::<MyStruct>();
}
}