aws_smithy_types/config_bag.rs
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/*
* Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
* SPDX-License-Identifier: Apache-2.0
*/
//! Layers and layered bags of configuration data.
//!
//! The [`ConfigBag`](crate::config_bag::ConfigBag) structure is used to store and pass around configuration for client operations.
//! Interacting with it may be required in order to write an `Interceptor` or `RuntimePlugin` to
//! customize a client.
//!
//! A `ConfigBag` is essentially a stack of several immutable and sharable layers, with a single _mutable_ layer at
//! the top of the stack that is called "interceptor state". The intent of this last mutable layer is to allow for
//! more performant mutation of config within the execution of an operation.
//!
//! There are three separate layer types to be aware of when using a `ConfigBag`:
//! 1. [`Layer`](crate::config_bag::Layer) - A mutable layer. This is usually only used for adding config
//! to the `ConfigBag`, but is also used for the interceptor state.
//! 2. [`CloneableLayer`](crate::config_bag::CloneableLayer) - Identical to `Layer`, except that it requires
//! `Clone` bounds on the items added to it so that it can be deep cloned. Can be converted to a `Layer`
//! while retaining the cloneability of its items such that the resulting layer could be cloned as long as
//! nothing else is added to it later. A `Layer` cannot be converted back into a `CloneableLayer`.
//! 3. [`FrozenLayer`](crate::config_bag::FrozenLayer) - Basically an [`Arc`](std::sync::Arc) wrapper around
//! a `Layer`. This wrapper is used to make the layer immutable, and to make it shareable between multiple
//! `ConfigBag` instances. The frozen layer can be converted back to a `Layer` if there is only a single reference to it.
//!
//! All of `Layer`, `CloneableLayer`, `FrozenLayer`, and `ConfigBag` are considered to be "bag" types.
//! That is, they store arbitrary types so long as they implement the [`Storable`](crate::config_bag::Storable) trait.
//!
//! A `Storable` requires a `Storer` to be configured, and the storer allows for storables to be stored
//! in two different modes:
//! 1. [`StoreReplace`](crate::config_bag::StoreReplace) - Only one value of this type is allowed in a bag, and
//! calling [`store_put()`](crate::config_bag::Layer::store_put) multiple times will replace the existing value
//! in the bag. Calling [`load::<T>()`](crate::config_bag::Layer::load) returns exactly one value, if present.
//! 2. [`StoreAppend`](crate::config_bag::StoreAppend) - Multiple values of this type are allowed in a bag, and
//! calling [`store_append()`](crate::config_bag::Layer::store_append) will add an additional value of this type
//! to the bag. Calling [`load::<T>()`](crate::config_bag::Layer::load) returns an iterator over multiple values.
//!
//! # Examples
//!
//! Creating a storable data type with `StoreReplace`:
//!
//! ```no_run
//! use aws_smithy_types::config_bag::{Storable, StoreReplace};
//!
//! #[derive(Debug)]
//! struct SomeDataType {
//! some_data: String,
//! }
//! impl Storable for SomeDataType {
//! type Storer = StoreReplace<Self>;
//! }
//! ```
//!
//! Creating a storable data type with `StoreAppend`:
//!
//! ```no_run
//! use aws_smithy_types::config_bag::{Storable, StoreAppend};
//!
//! #[derive(Debug)]
//! struct SomeDataType {
//! some_data: String,
//! }
//! impl Storable for SomeDataType {
//! type Storer = StoreAppend<Self>;
//! }
//! ```
//!
//! Storing a storable in a bag when it is configured for `StoreReplace`:
//!
//! ```no_run
//! # use aws_smithy_types::config_bag::{Storable, StoreReplace};
//! # #[derive(Clone, Debug)]
//! # struct SomeDataType { some_data: String }
//! # impl Storable for SomeDataType { type Storer = StoreReplace<Self>; }
//! use aws_smithy_types::config_bag::{CloneableLayer, Layer};
//!
//! let mut layer = Layer::new("example");
//! layer.store_put(SomeDataType { some_data: "some data".to_string() });
//!
//! // `store_put` can be called again to replace the original value:
//! layer.store_put(SomeDataType { some_data: "replacement".to_string() });
//!
//! // Note: `SomeDataType` below must implement `Clone` to work with `CloneableLayer`
//! let mut cloneable = CloneableLayer::new("example");
//! cloneable.store_put(SomeDataType { some_data: "some data".to_string() });
//! ```
//!
//! Storing a storable in a bag when it is configured for `StoreAppend`:
//!
//! ```no_run
//! # use aws_smithy_types::config_bag::{Storable, StoreAppend};
//! # #[derive(Clone, Debug)]
//! # struct SomeDataType { some_data: String }
//! # impl Storable for SomeDataType { type Storer = StoreAppend<Self>; }
//! use aws_smithy_types::config_bag::{CloneableLayer, Layer};
//!
//! let mut layer = Layer::new("example");
//! layer.store_append(SomeDataType { some_data: "1".to_string() });
//! layer.store_append(SomeDataType { some_data: "2".to_string() });
//! ```
//!
//! Loading a `StoreReplace` value from a bag:
//!
//! ```no_run
//! # use aws_smithy_types::config_bag::{Storable, StoreReplace};
//! # #[derive(Clone, Debug)]
//! # struct SomeDataType { some_data: String }
//! # impl Storable for SomeDataType { type Storer = StoreReplace<Self>; }
//! # use aws_smithy_types::config_bag::Layer;
//! # let layer = Layer::new("example");
//! let maybe_value: Option<&SomeDataType> = layer.load::<SomeDataType>();
//! ```
//!
//! Loading a `StoreAppend` value from a bag:
//!
//! ```no_run
//! # use aws_smithy_types::config_bag::{Storable, StoreAppend};
//! # #[derive(Clone, Debug)]
//! # struct SomeDataType { some_data: String }
//! # impl Storable for SomeDataType { type Storer = StoreAppend<Self>; }
//! # use aws_smithy_types::config_bag::Layer;
//! # let layer = Layer::new("example");
//! let values: Vec<SomeDataType> = layer.load::<SomeDataType>().cloned().collect();
//!
//! // or iterate over them directly:
//! for value in layer.load::<SomeDataType>() {
//! # let _ = value;
//! // ...
//! }
//! ```
//!
mod storable;
mod typeid_map;
use crate::config_bag::typeid_map::TypeIdMap;
use crate::type_erasure::TypeErasedBox;
use std::any::{type_name, TypeId};
use std::borrow::Cow;
use std::fmt::{Debug, Formatter};
use std::iter::Rev;
use std::marker::PhantomData;
use std::ops::Deref;
use std::slice::Iter;
use std::sync::Arc;
pub use storable::{AppendItemIter, Storable, Store, StoreAppend, StoreReplace};
/// [`FrozenLayer`] is the immutable and shareable form of [`Layer`].
///
/// See the [module docs](crate::config_bag) for more documentation.
#[derive(Clone, Debug)]
#[must_use]
pub struct FrozenLayer(Arc<Layer>);
impl FrozenLayer {
/// Attempts to convert this bag directly into a [`Layer`] if no other references exist.
pub fn try_modify(self) -> Option<Layer> {
Arc::try_unwrap(self.0).ok()
}
}
impl Deref for FrozenLayer {
type Target = Layer;
fn deref(&self) -> &Self::Target {
&self.0
}
}
impl From<Layer> for FrozenLayer {
fn from(layer: Layer) -> Self {
FrozenLayer(Arc::new(layer))
}
}
/// Private module to keep Value type while avoiding "private type in public latest"
pub(crate) mod value {
#[derive(Clone, Debug)]
pub enum Value<T> {
Set(T),
ExplicitlyUnset(&'static str),
}
impl<T: Default> Default for Value<T> {
fn default() -> Self {
Self::Set(Default::default())
}
}
}
use value::Value;
/// [`CloneableLayer`] allows itself to be cloned. This is useful when a type that implements
/// `Clone` wishes to store a config layer.
///
/// It ensures that all the items in `CloneableLayer` are `Clone` upon entry, e.g. when they are
/// first stored, the mutable methods require that they have a `Clone` bound on them.
///
/// While [`FrozenLayer`] is also cloneable, which is a shallow clone via `Arc`, `CloneableLayer`
/// performs a deep clone that newly allocates all the items stored in it.
///
/// Cloneable enforces that non clone items cannot be added
/// ```rust,compile_fail
/// use aws_smithy_types::config_bag::Storable;
/// use aws_smithy_types::config_bag::StoreReplace;
/// use aws_smithy_types::config_bag::CloneableLayer;
/// #[derive(Debug)]
/// struct MyNotCloneStruct;
///
/// impl Storable for MyNotCloneStruct {
/// type Storer = StoreReplace<MyNotCloneStruct>;
/// }
/// let mut layer = CloneableLayer::new("layer");
/// layer.store_put(MyNotCloneStruct);
/// ```
///
/// See the [module docs](crate::config_bag) for more documentation.
#[derive(Debug, Default)]
pub struct CloneableLayer(Layer);
impl Deref for CloneableLayer {
type Target = Layer;
fn deref(&self) -> &Self::Target {
&self.0
}
}
impl Clone for CloneableLayer {
fn clone(&self) -> Self {
Self(
self.try_clone()
.expect("only cloneable types can be inserted"),
)
}
}
impl From<CloneableLayer> for Layer {
fn from(cloneable_layer: CloneableLayer) -> Layer {
cloneable_layer.0
}
}
// We need to "override" the mutable methods to encode the information that an item being stored
// implements `Clone`. For the immutable methods, they can just be delegated via the `Deref` trait.
impl CloneableLayer {
/// Creates a new `CloneableLayer` with a given name
pub fn new(name: impl Into<Cow<'static, str>>) -> Self {
Self(Layer::new(name))
}
/// Converts this layer into a frozen layer that can no longer be mutated.
pub fn freeze(self) -> FrozenLayer {
self.0.into()
}
/// Removes `T` from this bag
pub fn unset<T: Send + Sync + Clone + Debug + 'static>(&mut self) -> &mut Self {
self.put_directly_cloneable::<StoreReplace<T>>(Value::ExplicitlyUnset(type_name::<T>()));
self
}
fn put_directly_cloneable<T: Store>(&mut self, value: T::StoredType) -> &mut Self
where
T::StoredType: Clone,
{
self.0.props.insert(
TypeId::of::<T::StoredType>(),
TypeErasedBox::new_with_clone(value),
);
self
}
/// Stores `item` of type `T` into the config bag, overriding a previous value of the same type
pub fn store_put<T>(&mut self, item: T) -> &mut Self
where
T: Storable<Storer = StoreReplace<T>> + Clone,
{
self.put_directly_cloneable::<StoreReplace<T>>(Value::Set(item));
self
}
/// Stores `item` of type `T` into the config bag, overriding a previous value of the same type,
/// or unsets it by passing a `None`
pub fn store_or_unset<T>(&mut self, item: Option<T>) -> &mut Self
where
T: Storable<Storer = StoreReplace<T>> + Clone,
{
let item = match item {
Some(item) => Value::Set(item),
None => Value::ExplicitlyUnset(type_name::<T>()),
};
self.put_directly_cloneable::<StoreReplace<T>>(item);
self
}
/// Stores `item` of type `T` into the config bag, appending it to the existing list of the same
/// type
pub fn store_append<T>(&mut self, item: T) -> &mut Self
where
T: Storable<Storer = StoreAppend<T>> + Clone,
{
match self.get_mut_or_default::<StoreAppend<T>>() {
Value::Set(list) => list.push(item),
v @ Value::ExplicitlyUnset(_) => *v = Value::Set(vec![item]),
}
self
}
/// Clears the value of type `T` from the config bag
pub fn clear<T>(&mut self)
where
T: Storable<Storer = StoreAppend<T>> + Clone,
{
self.put_directly_cloneable::<StoreAppend<T>>(Value::ExplicitlyUnset(type_name::<T>()));
}
fn get_mut_or_default<T: Send + Sync + Store + 'static>(&mut self) -> &mut T::StoredType
where
T::StoredType: Default + Clone,
{
self.0
.props
.entry(TypeId::of::<T::StoredType>())
.or_insert_with(|| TypeErasedBox::new_with_clone(T::StoredType::default()))
.downcast_mut()
.expect("typechecked")
}
}
/// A named layer comprising a config bag
///
/// See the [module docs](crate::config_bag) for more documentation.
#[derive(Default)]
pub struct Layer {
name: Cow<'static, str>,
props: TypeIdMap<TypeErasedBox>,
}
impl Debug for Layer {
fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
struct Items<'a>(&'a Layer);
impl Debug for Items<'_> {
fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
f.debug_list().entries(self.0.props.values()).finish()
}
}
f.debug_struct("Layer")
.field("name", &self.name)
.field("items", &Items(self))
.finish()
}
}
impl Layer {
fn try_clone(&self) -> Option<Self> {
let new_props = self
.props
.iter()
.flat_map(|(tyid, erased)| erased.try_clone().map(|e| (*tyid, e)))
.collect::<TypeIdMap<_>>();
if new_props.len() == self.props.len() {
Some(Layer {
name: self.name.clone(),
props: new_props,
})
} else {
None
}
}
/// Inserts `value` into the layer directly
fn put_directly<T: Store>(&mut self, value: T::StoredType) -> &mut Self {
self.props
.insert(TypeId::of::<T::StoredType>(), TypeErasedBox::new(value));
self
}
/// Returns true if this layer is empty.
pub fn is_empty(&self) -> bool {
self.props.is_empty()
}
/// Converts this layer into a frozen layer that can no longer be mutated.
pub fn freeze(self) -> FrozenLayer {
self.into()
}
/// Create a new Layer with a given name
pub fn new(name: impl Into<Cow<'static, str>>) -> Self {
let name = name.into();
Self {
name,
props: Default::default(),
}
}
/// Changes the name of this layer.
pub fn with_name(self, name: impl Into<Cow<'static, str>>) -> Self {
Self {
name: name.into(),
props: self.props,
}
}
/// Load a storable item from the bag
pub fn load<T: Storable>(&self) -> <T::Storer as Store>::ReturnedType<'_> {
T::Storer::merge_iter(ItemIter {
inner: BagIter {
head: Some(self),
tail: [].iter().rev(),
},
t: Default::default(),
})
}
/// Remove `T` from this bag
pub fn unset<T: Send + Sync + Debug + 'static>(&mut self) -> &mut Self {
self.put_directly::<StoreReplace<T>>(Value::ExplicitlyUnset(type_name::<T>()));
self
}
/// Stores `item` of type `T` into the config bag, overriding a previous value of the same type
pub fn store_put<T>(&mut self, item: T) -> &mut Self
where
T: Storable<Storer = StoreReplace<T>>,
{
self.put_directly::<StoreReplace<T>>(Value::Set(item));
self
}
/// Stores `item` of type `T` into the config bag, overriding a previous value of the same type,
/// or unsets it by passing a `None`
pub fn store_or_unset<T>(&mut self, item: Option<T>) -> &mut Self
where
T: Storable<Storer = StoreReplace<T>>,
{
let item = match item {
Some(item) => Value::Set(item),
None => Value::ExplicitlyUnset(type_name::<T>()),
};
self.put_directly::<StoreReplace<T>>(item);
self
}
/// This can only be used for types that use [`StoreAppend`]
/// ```
/// use aws_smithy_types::config_bag::{ConfigBag, Layer, Storable, StoreAppend, StoreReplace};
/// let mut layer_1 = Layer::new("example");
/// #[derive(Debug, PartialEq, Eq)]
/// struct Interceptor(&'static str);
/// impl Storable for Interceptor {
/// type Storer = StoreAppend<Interceptor>;
/// }
///
/// layer_1.store_append(Interceptor("321"));
/// layer_1.store_append(Interceptor("654"));
///
/// let mut layer_2 = Layer::new("second layer");
/// layer_2.store_append(Interceptor("987"));
///
/// let bag = ConfigBag::of_layers(vec![layer_1, layer_2]);
///
/// assert_eq!(
/// bag.load::<Interceptor>().collect::<Vec<_>>(),
/// vec![&Interceptor("987"), &Interceptor("654"), &Interceptor("321")]
/// );
/// ```
pub fn store_append<T>(&mut self, item: T) -> &mut Self
where
T: Storable<Storer = StoreAppend<T>>,
{
match self.get_mut_or_default::<StoreAppend<T>>() {
Value::Set(list) => list.push(item),
v @ Value::ExplicitlyUnset(_) => *v = Value::Set(vec![item]),
}
self
}
/// Clears the value of type `T` from the config bag
///
/// This internally marks the item of type `T` as cleared as opposed to wiping it out from the
/// config bag.
pub fn clear<T>(&mut self)
where
T: Storable<Storer = StoreAppend<T>>,
{
self.put_directly::<StoreAppend<T>>(Value::ExplicitlyUnset(type_name::<T>()));
}
/// Retrieves the value of type `T` from this layer if exists
fn get<T: Send + Sync + Store + 'static>(&self) -> Option<&T::StoredType> {
self.props
.get(&TypeId::of::<T::StoredType>())
.map(|t| t.downcast_ref().expect("typechecked"))
}
/// Returns a mutable reference to `T` if it is stored in this layer
fn get_mut<T: Send + Sync + Store + 'static>(&mut self) -> Option<&mut T::StoredType> {
self.props
.get_mut(&TypeId::of::<T::StoredType>())
.map(|t| t.downcast_mut().expect("typechecked"))
}
/// Returns a mutable reference to `T` if it is stored in this layer, otherwise returns the
/// [`Default`] implementation of `T`
fn get_mut_or_default<T: Send + Sync + Store + 'static>(&mut self) -> &mut T::StoredType
where
T::StoredType: Default,
{
self.props
.entry(TypeId::of::<T::StoredType>())
.or_insert_with(|| TypeErasedBox::new(T::StoredType::default()))
.downcast_mut()
.expect("typechecked")
}
}
/// Layered configuration structure
///
/// See the [module docs](crate::config_bag) for more documentation.
#[must_use]
pub struct ConfigBag {
interceptor_state: Layer,
tail: Vec<FrozenLayer>,
}
impl Debug for ConfigBag {
fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
struct Layers<'a>(&'a ConfigBag);
impl Debug for Layers<'_> {
fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
f.debug_list().entries(self.0.layers()).finish()
}
}
f.debug_struct("ConfigBag")
.field("layers", &Layers(self))
.finish()
}
}
impl ConfigBag {
/// Create a new config bag "base".
pub fn base() -> Self {
ConfigBag {
interceptor_state: Layer {
name: Cow::Borrowed("interceptor_state"),
props: Default::default(),
},
tail: vec![],
}
}
/// Create a [`ConfigBag`] consisting of the given layers.
pub fn of_layers(layers: impl IntoIterator<Item = Layer>) -> Self {
let mut bag = ConfigBag::base();
for layer in layers {
bag.push_layer(layer);
}
bag
}
/// Add the given layer to the config bag.
pub fn push_layer(&mut self, layer: Layer) -> &mut Self {
self.tail.push(layer.freeze());
self
}
/// Add a frozen/shared layer to the config bag.
pub fn push_shared_layer(&mut self, layer: FrozenLayer) -> &mut Self {
self.tail.push(layer);
self
}
/// Return a reference to the mutable interceptor state.
pub fn interceptor_state(&mut self) -> &mut Layer {
&mut self.interceptor_state
}
/// Load a value (or values) of type `T` depending on how `T` implements [`Storable`]
pub fn load<T: Storable>(&self) -> <T::Storer as Store>::ReturnedType<'_> {
self.sourced_get::<T::Storer>()
}
/// Return a mutable reference to `T` if it is stored in the top layer of the bag
pub fn get_mut<T>(&mut self) -> Option<&mut T>
where
T: Storable<Storer = StoreReplace<T>> + Send + Sync + Debug + Clone + 'static,
{
// this code looks weird to satisfy the borrow checker—we can't keep the result of `get_mut`
// alive (even in a returned branch) and then call `store_put`. So: drop the borrow immediately
// store, the value, then pull it right back
if self
.interceptor_state
.get_mut::<StoreReplace<T>>()
.is_none()
{
let new_item = match self.tail.iter().find_map(|b| b.load::<T>()) {
Some(item) => item.clone(),
None => return None,
};
self.interceptor_state.store_put(new_item);
self.get_mut()
} else if matches!(
self.interceptor_state.get::<StoreReplace<T>>(),
Some(Value::ExplicitlyUnset(_))
) {
None
} else if let Some(Value::Set(t)) = self.interceptor_state.get_mut::<StoreReplace<T>>() {
Some(t)
} else {
unreachable!()
}
}
/// Returns a mutable reference to `T` if it is stored in the top layer of the bag
///
/// - If `T` is in a deeper layer of the bag, that value will be cloned and inserted into the top layer
/// - If `T` is not present in the bag, the [`Default`] implementation will be used.
pub fn get_mut_or_default<T>(&mut self) -> &mut T
where
T: Storable<Storer = StoreReplace<T>> + Send + Sync + Debug + Clone + Default + 'static,
{
self.get_mut_or_else(|| T::default())
}
/// Returns a mutable reference to `T` if it is stored in the top layer of the bag
///
/// - If `T` is in a deeper layer of the bag, that value will be cloned and inserted into the top layer
/// - If `T` is not present in the bag, `default` will be used to construct a new value
pub fn get_mut_or_else<T>(&mut self, default: impl Fn() -> T) -> &mut T
where
T: Storable<Storer = StoreReplace<T>> + Send + Sync + Debug + Clone + 'static,
{
// this code looks weird to satisfy the borrow checker—we can't keep the result of `get_mut`
// alive (even in a returned branch) and then call `store_put`. So: drop the borrow immediately
// store, the value, then pull it right back
if self.get_mut::<T>().is_none() {
self.interceptor_state.store_put((default)());
return self
.get_mut()
.expect("item was just stored in the top layer");
}
// above it was None
self.get_mut().unwrap()
}
/// Add another layer to this configuration bag
///
/// Hint: If you want to re-use this layer, call `freeze` first.
///
/// # Examples
/// ```
/// use aws_smithy_types::config_bag::{ConfigBag, Layer, Storable, StoreReplace};
///
/// #[derive(Debug, Eq, PartialEq)]
/// struct ExampleStr(&'static str);
/// impl Storable for ExampleStr {
/// type Storer = StoreReplace<Self>;
/// }
///
/// #[derive(Debug, Eq, PartialEq)]
/// struct ExampleInt(i32);
/// impl Storable for ExampleInt {
/// type Storer = StoreReplace<Self>;
/// }
///
/// let mut bag = ConfigBag::base();
/// bag = bag.with_fn("first", |layer: &mut Layer| { layer.store_put(ExampleStr("a")); });
///
/// // We can now load the example string out
/// assert_eq!(bag.load::<ExampleStr>(), Some(&ExampleStr("a")));
///
/// // But there isn't a number stored in the bag yet
/// assert_eq!(bag.load::<ExampleInt>(), None);
///
/// // Add a layer with an example int
/// bag = bag.with_fn("second", |layer: &mut Layer| { layer.store_put(ExampleInt(1)); });
///
/// // Now the example int can be retrieved
/// assert_eq!(bag.load::<ExampleInt>(), Some(&ExampleInt(1)));
/// ```
pub fn with_fn(
self,
name: impl Into<Cow<'static, str>>,
next: impl Fn(&mut Layer),
) -> ConfigBag {
let mut new_layer = Layer::new(name);
next(&mut new_layer);
let ConfigBag {
interceptor_state: head,
mut tail,
} = self;
tail.push(head.freeze());
ConfigBag {
interceptor_state: new_layer,
tail,
}
}
/// Add a new layer with `name` after freezing the top layer so far
pub fn add_layer(self, name: impl Into<Cow<'static, str>>) -> ConfigBag {
self.with_fn(name, |_| {})
}
/// Return a value (or values) of type `T` depending on how it has been stored in a `ConfigBag`
///
/// It flexibly chooses to return a single value vs. an iterator of values depending on how
/// `T` implements a [`Store`] trait.
pub fn sourced_get<T: Store>(&self) -> T::ReturnedType<'_> {
let stored_type_iter = ItemIter {
inner: self.layers(),
t: PhantomData,
};
T::merge_iter(stored_type_iter)
}
fn layers(&self) -> BagIter<'_> {
BagIter {
head: Some(&self.interceptor_state),
tail: self.tail.iter().rev(),
}
}
}
/// Iterator of items returned from [`ConfigBag`].
pub struct ItemIter<'a, T> {
inner: BagIter<'a>,
t: PhantomData<T>,
}
impl<'a, T> Debug for ItemIter<'a, T> {
fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
write!(f, "ItemIter")
}
}
impl<'a, T: 'a> Iterator for ItemIter<'a, T>
where
T: Store,
{
type Item = &'a T::StoredType;
fn next(&mut self) -> Option<Self::Item> {
match self.inner.next() {
Some(layer) => layer.get::<T>().or_else(|| self.next()),
None => None,
}
}
}
/// Iterator over the layers of a config bag
struct BagIter<'a> {
head: Option<&'a Layer>,
tail: Rev<Iter<'a, FrozenLayer>>,
}
impl<'a> Iterator for BagIter<'a> {
type Item = &'a Layer;
fn next(&mut self) -> Option<Self::Item> {
if let Some(head) = self.head.take() {
Some(head)
} else {
self.tail.next().map(|t| t.deref())
}
}
}
#[cfg(test)]
mod test {
use super::ConfigBag;
use crate::config_bag::{CloneableLayer, Layer, Storable, StoreAppend, StoreReplace};
#[test]
fn layered_property_bag() {
#[derive(Debug)]
struct Prop1;
impl Storable for Prop1 {
type Storer = StoreReplace<Self>;
}
#[derive(Debug)]
struct Prop2;
impl Storable for Prop2 {
type Storer = StoreReplace<Self>;
}
let layer_a = |bag: &mut Layer| {
bag.store_put(Prop1);
};
let layer_b = |bag: &mut Layer| {
bag.store_put(Prop2);
};
#[derive(Debug)]
struct Prop3;
impl Storable for Prop3 {
type Storer = StoreReplace<Self>;
}
let mut base_bag = ConfigBag::base()
.with_fn("a", layer_a)
.with_fn("b", layer_b);
base_bag.interceptor_state().store_put(Prop3);
assert!(base_bag.load::<Prop1>().is_some());
#[derive(Debug)]
struct Prop4;
impl Storable for Prop4 {
type Storer = StoreReplace<Self>;
}
let layer_c = |bag: &mut Layer| {
bag.store_put(Prop4);
bag.unset::<Prop3>();
};
let final_bag = base_bag.with_fn("c", layer_c);
assert!(final_bag.load::<Prop4>().is_some());
assert!(final_bag.load::<Prop1>().is_some());
assert!(final_bag.load::<Prop2>().is_some());
// we unset prop3
assert!(final_bag.load::<Prop3>().is_none());
println!("{:#?}", final_bag);
}
#[test]
fn config_bag() {
let bag = ConfigBag::base();
#[derive(Debug)]
struct Region(&'static str);
impl Storable for Region {
type Storer = StoreReplace<Self>;
}
let bag = bag.with_fn("service config", |layer: &mut Layer| {
layer.store_put(Region("asdf"));
});
assert_eq!(bag.load::<Region>().unwrap().0, "asdf");
#[derive(Debug)]
struct SigningName(&'static str);
impl Storable for SigningName {
type Storer = StoreReplace<Self>;
}
let operation_config = bag.with_fn("operation", |layer: &mut Layer| {
layer.store_put(SigningName("s3"));
});
assert_eq!(operation_config.load::<SigningName>().unwrap().0, "s3");
#[derive(Debug)]
struct Prop;
impl Storable for Prop {
type Storer = StoreReplace<Self>;
}
let mut open_bag = operation_config.with_fn("my_custom_info", |_bag: &mut Layer| {});
open_bag.interceptor_state().store_put(Prop);
assert_eq!(open_bag.layers().count(), 4);
}
#[test]
fn store_append() {
let mut layer = Layer::new("test");
#[derive(Debug, PartialEq, Eq)]
struct Interceptor(&'static str);
impl Storable for Interceptor {
type Storer = StoreAppend<Interceptor>;
}
layer.clear::<Interceptor>();
// you can only call store_append because interceptor is marked with a vec
layer.store_append(Interceptor("123"));
layer.store_append(Interceptor("456"));
let mut second_layer = Layer::new("next");
second_layer.store_append(Interceptor("789"));
let mut bag = ConfigBag::of_layers(vec![layer, second_layer]);
assert_eq!(
bag.load::<Interceptor>().collect::<Vec<_>>(),
vec![
&Interceptor("789"),
&Interceptor("456"),
&Interceptor("123")
]
);
let mut final_layer = Layer::new("final");
final_layer.clear::<Interceptor>();
bag.push_layer(final_layer);
assert_eq!(bag.load::<Interceptor>().count(), 0);
}
#[test]
fn store_append_many_layers() {
#[derive(Debug, PartialEq, Eq, Clone)]
struct TestItem(i32, i32);
impl Storable for TestItem {
type Storer = StoreAppend<TestItem>;
}
let mut expected = vec![];
let mut bag = ConfigBag::base();
for layer_idx in 0..100 {
let mut layer = Layer::new(format!("{}", layer_idx));
for item in 0..100 {
expected.push(TestItem(layer_idx, item));
layer.store_append(TestItem(layer_idx, item));
}
bag.push_layer(layer);
}
expected.reverse();
assert_eq!(
bag.load::<TestItem>().cloned().collect::<Vec<_>>(),
expected
);
}
#[test]
fn adding_layers() {
let mut layer_1 = Layer::new("layer1");
let mut layer_2 = Layer::new("layer2");
#[derive(Clone, Debug, PartialEq, Eq, Default)]
struct Foo(usize);
impl Storable for Foo {
type Storer = StoreReplace<Foo>;
}
layer_1.store_put(Foo(0));
layer_2.store_put(Foo(1));
let layer_1 = layer_1.freeze();
let layer_2 = layer_2.freeze();
let mut bag_1 = ConfigBag::base();
let mut bag_2 = ConfigBag::base();
bag_1
.push_shared_layer(layer_1.clone())
.push_shared_layer(layer_2.clone());
bag_2.push_shared_layer(layer_2).push_shared_layer(layer_1);
// bags have same layers but in different orders
assert_eq!(bag_1.load::<Foo>(), Some(&Foo(1)));
assert_eq!(bag_2.load::<Foo>(), Some(&Foo(0)));
bag_1.interceptor_state().store_put(Foo(3));
assert_eq!(bag_1.load::<Foo>(), Some(&Foo(3)));
}
#[test]
fn get_mut_or_else() {
#[derive(Clone, Debug, PartialEq, Eq, Default)]
struct Foo(usize);
impl Storable for Foo {
type Storer = StoreReplace<Foo>;
}
let mut bag = ConfigBag::base();
assert_eq!(bag.get_mut::<Foo>(), None);
assert_eq!(bag.get_mut_or_default::<Foo>(), &Foo(0));
bag.get_mut_or_default::<Foo>().0 += 1;
assert_eq!(bag.load::<Foo>(), Some(&Foo(1)));
let old_ref = bag.load::<Foo>().unwrap();
assert_eq!(old_ref, &Foo(1));
// there is one in the bag, so it can be returned
//let mut next = bag.add_layer("next");
bag.get_mut::<Foo>().unwrap().0 += 1;
let new_ref = bag.load::<Foo>().unwrap();
assert_eq!(new_ref, &Foo(2));
bag.interceptor_state().unset::<Foo>();
// if it was unset, we can't clone the current one, that would be wrong
assert_eq!(bag.get_mut::<Foo>(), None);
assert_eq!(bag.get_mut_or_default::<Foo>(), &Foo(0));
}
#[test]
fn cloning_layers() {
#[derive(Clone, Debug)]
struct TestStr(String);
impl Storable for TestStr {
type Storer = StoreReplace<TestStr>;
}
let mut layer_1 = CloneableLayer::new("layer_1");
let expected_str = "I can be cloned";
layer_1.store_put(TestStr(expected_str.to_owned()));
let layer_1_cloned = layer_1.clone();
assert_eq!(expected_str, &layer_1_cloned.load::<TestStr>().unwrap().0);
// Should still be cloneable after unsetting a field
layer_1.unset::<TestStr>();
assert!(layer_1.try_clone().unwrap().load::<TestStr>().is_none());
// It is cloneable multiple times in succession
let _ = layer_1
.try_clone()
.expect("clone 1")
.try_clone()
.expect("clone 2");
#[derive(Clone, Debug)]
struct Rope(String);
impl Storable for Rope {
type Storer = StoreAppend<Rope>;
}
let mut layer_2 = CloneableLayer::new("layer_2");
layer_2.store_append(Rope("A".to_owned()));
layer_2.store_append(Rope("big".to_owned()));
layer_2.store_append(Rope("rope".to_owned()));
let layer_2_cloned = layer_2.clone();
let rope = layer_2_cloned.load::<Rope>().cloned().collect::<Vec<_>>();
assert_eq!(
"A big rope",
rope.iter()
.rev()
.map(|r| r.0.clone())
.collect::<Vec<_>>()
.join(" ")
);
}
}