Struct Resources 

pub struct Resources(/* private fields */);

Map from TypeId to type.

Implementations

impl Resources

A Resource container, which provides methods to insert, access and manage the contained resources.

Many methods take &self which works because everything is stored with interior mutability. In case you violate the borrowing rules of Rust (multiple reads xor one write), you will get a panic.

Resource Ids

Resources are identified by TypeIds, which consist of a TypeId.

pub fn new() -> Self

Creates an empty Resources map.

The map is initially created with a capacity of 0, so it will not allocate until it is first inserted into.

Examples

use resman::Resources;
let mut resources = Resources::new();

pub fn with_capacity(capacity: usize) -> Self

Creates an empty Resources map with the specified capacity.

The map will be able to hold at least capacity elements without reallocating. If capacity is 0, the map will not allocate.

Examples

use resman::Resources;
let resources: Resources = Resources::with_capacity(10);

pub fn into_inner(self) -> RtMap<TypeId, Box<dyn Resource>>

Returns the inner RtMap.

pub fn capacity(&self) -> usize

Returns the number of elements the map can hold without reallocating.

This number is a lower bound; the Resources<K, V> might be able to hold more, but is guaranteed to be able to hold at least this many.

Examples

use resman::Resources;
let resources: Resources = Resources::with_capacity(100);
assert!(resources.capacity() >= 100);

pub fn entry<R>(&mut self) -> Entry<'_, R>

where R: Resource,

Returns an entry for the resource with type R.

pub fn insert<R>(&mut self, r: R)

where R: Resource,

Inserts a resource into the map. If the resource existed before, it will be overwritten.

Examples

Every type satisfying Any + Send + Sync automatically implements Resource, thus can be added:

struct MyRes(i32);

When you have a resource, simply insert it like this:

use resman::Resources;

let mut resources = Resources::default();
resources.insert(MyRes(5));

Examples found in repository

examples/simple.rs (line 12)

fn main() {
    let mut resources = Resources::default();

    resources.insert(A(1));
    resources.insert(B(2));

    // We can validly have two mutable borrows from the `Resources` map!
    let mut a = resources.borrow_mut::<A>();
    let mut b = resources.borrow_mut::<B>();
    a.0 = 2;
    b.0 = 3;

    // We need to explicitly drop the A and B borrows, because they are runtime
    // managed borrows, and rustc doesn't know to drop them before the immutable
    // borrows after this.
    drop(a);
    drop(b);

    // Multiple immutable borrows to the same resource are valid.
    let a_0 = resources.borrow::<A>();
    let _a_1 = resources.borrow::<A>();
    let b = resources.borrow::<B>();

    println!("A: {}", a_0.0);
    println!("B: {}", b.0);

    // Trying to mutably borrow a resource that is already borrowed (immutably
    // or mutably) returns `Err`.
    let a_try_borrow_mut = resources.try_borrow_mut::<A>();
    let exists = if a_try_borrow_mut.is_ok() {
        "Ok(..)"
    } else {
        "Err"
    };
    println!("a_try_borrow_mut: {}", exists); // prints "Err"
}

pub fn insert_raw(&mut self, type_id: TypeId, resource: Box<dyn Resource>)

Inserts an already boxed resource into the map.

pub fn remove<R>(&mut self) -> R

where R: Resource,

Removes a resource of type R from this container and returns its ownership to the caller. In case there is no such resource in this, container, None will be returned.

Use this method with caution; other functions and systems might assume this resource still exists. Thus, only use this if you’re sure no system will try to access this resource after you removed it (or else you will get a panic).

Panics

Panics if the resource doesn’t exist in this container.

pub fn try_remove<R>(&mut self) -> Result<R, ResourceFetchError>

where R: Resource,

Removes a resource of type R from this container and returns its ownership to the caller. In case there is no such resource in this, container, None will be returned.

Use this method with caution; other functions and systems might assume this resource still exists. Thus, only use this if you’re sure no system will try to access this resource after you removed it (or else you will get a panic).

pub fn contains<R>(&self) -> bool

where R: Resource,

Returns true if the specified resource type R exists in self.

pub fn borrow<R>(&self) -> Ref<'_, R>

where R: Resource,

Returns the R resource in the resource map.

See try_borrow for a non-panicking version of this function.

Panics

Panics if the resource doesn’t exist. Panics if the resource is being accessed mutably.

Examples found in repository

examples/simple.rs (line 28)

fn main() {
    let mut resources = Resources::default();

    resources.insert(A(1));
    resources.insert(B(2));

    // We can validly have two mutable borrows from the `Resources` map!
    let mut a = resources.borrow_mut::<A>();
    let mut b = resources.borrow_mut::<B>();
    a.0 = 2;
    b.0 = 3;

    // We need to explicitly drop the A and B borrows, because they are runtime
    // managed borrows, and rustc doesn't know to drop them before the immutable
    // borrows after this.
    drop(a);
    drop(b);

    // Multiple immutable borrows to the same resource are valid.
    let a_0 = resources.borrow::<A>();
    let _a_1 = resources.borrow::<A>();
    let b = resources.borrow::<B>();

    println!("A: {}", a_0.0);
    println!("B: {}", b.0);

    // Trying to mutably borrow a resource that is already borrowed (immutably
    // or mutably) returns `Err`.
    let a_try_borrow_mut = resources.try_borrow_mut::<A>();
    let exists = if a_try_borrow_mut.is_ok() {
        "Ok(..)"
    } else {
        "Err"
    };
    println!("a_try_borrow_mut: {}", exists); // prints "Err"
}

pub fn try_borrow<R>(&self) -> Result<Ref<'_, R>, BorrowFail>

where R: Resource,

Returns an immutable reference to R if it exists, None otherwise.

pub fn borrow_mut<R>(&self) -> RefMut<'_, R>

where R: Resource,

Returns a mutable reference to R if it exists, None otherwise.

Panics

Panics if the resource doesn’t exist. Panics if the resource is already accessed.

Examples found in repository

examples/simple.rs (line 16)

fn main() {
    let mut resources = Resources::default();

    resources.insert(A(1));
    resources.insert(B(2));

    // We can validly have two mutable borrows from the `Resources` map!
    let mut a = resources.borrow_mut::<A>();
    let mut b = resources.borrow_mut::<B>();
    a.0 = 2;
    b.0 = 3;

    // We need to explicitly drop the A and B borrows, because they are runtime
    // managed borrows, and rustc doesn't know to drop them before the immutable
    // borrows after this.
    drop(a);
    drop(b);

    // Multiple immutable borrows to the same resource are valid.
    let a_0 = resources.borrow::<A>();
    let _a_1 = resources.borrow::<A>();
    let b = resources.borrow::<B>();

    println!("A: {}", a_0.0);
    println!("B: {}", b.0);

    // Trying to mutably borrow a resource that is already borrowed (immutably
    // or mutably) returns `Err`.
    let a_try_borrow_mut = resources.try_borrow_mut::<A>();
    let exists = if a_try_borrow_mut.is_ok() {
        "Ok(..)"
    } else {
        "Err"
    };
    println!("a_try_borrow_mut: {}", exists); // prints "Err"
}

pub fn try_borrow_mut<R>(&self) -> Result<RefMut<'_, R>, BorrowFail>

where R: Resource,

Returns a mutable reference to R if it exists, None otherwise.

Examples found in repository

examples/simple.rs (line 37)

fn main() {
    let mut resources = Resources::default();

    resources.insert(A(1));
    resources.insert(B(2));

    // We can validly have two mutable borrows from the `Resources` map!
    let mut a = resources.borrow_mut::<A>();
    let mut b = resources.borrow_mut::<B>();
    a.0 = 2;
    b.0 = 3;

    // We need to explicitly drop the A and B borrows, because they are runtime
    // managed borrows, and rustc doesn't know to drop them before the immutable
    // borrows after this.
    drop(a);
    drop(b);

    // Multiple immutable borrows to the same resource are valid.
    let a_0 = resources.borrow::<A>();
    let _a_1 = resources.borrow::<A>();
    let b = resources.borrow::<B>();

    println!("A: {}", a_0.0);
    println!("B: {}", b.0);

    // Trying to mutably borrow a resource that is already borrowed (immutably
    // or mutably) returns `Err`.
    let a_try_borrow_mut = resources.try_borrow_mut::<A>();
    let exists = if a_try_borrow_mut.is_ok() {
        "Ok(..)"
    } else {
        "Err"
    };
    println!("a_try_borrow_mut: {}", exists); // prints "Err"
}

pub fn get_mut<R: Resource>(&mut self) -> Option<&mut R>

Retrieves a resource without fetching, which is cheaper, but only available with &mut self.

pub fn get_resource_mut(&mut self, id: TypeId) -> Option<&mut dyn Resource>

Retrieves a resource without fetching, which is cheaper, but only available with &mut self.

pub fn get_raw(&self, id: &TypeId) -> Option<&Cell<Box<dyn Resource>>>

Get raw access to the underlying cell.

pub fn merge(&mut self, other: Resources)

Merges the other Resources map over this one.

Methods from Deref<Target = RtMap<TypeId, Box<dyn Resource>>>

pub fn capacity(&self) -> usize

Returns the number of elements the map can hold without reallocating.

This number is a lower bound; the RtMap<K, V> might be able to hold more, but is guaranteed to be able to hold at least this many.

Examples

use rt_map::RtMap;
let map: RtMap<i32, i32> = RtMap::with_capacity(100);
assert!(map.capacity() >= 100);

pub fn entry(&mut self, k: K) -> Entry<'_, K, V>

Gets the given key’s corresponding entry in the map for in-place manipulation.

pub fn insert(&mut self, k: K, v: V) -> Option<V>

Inserts a key-value pair into the map.

If the map did not have this key present, None is returned.

If the map did have this key present, the value is updated, and the old value is returned. The key is not updated, though; this matters for types that can be == without being identical.

Examples

use rt_map::RtMap;

let mut map = RtMap::new();
assert_eq!(map.insert(37, "a"), None);
assert_eq!(map.is_empty(), false);

map.insert(37, "b");
assert_eq!(map.insert(37, "c"), Some("b"));
assert_eq!(*map.borrow(&37), "c");

pub fn is_empty(&self) -> bool

Returns true if the map contains no elements.

Examples

use rt_map::RtMap;

let mut a = RtMap::new();
assert!(a.is_empty());
a.insert(1, "a");
assert!(!a.is_empty());

pub fn remove<Q>(&mut self, k: &Q) -> Option<V>

where Q: Hash + Eq + ?Sized, K: Borrow<Q>,

Removes a key from the map, returning the value at the key if the key was previously in the map.

The key may be any borrowed form of the map’s key type, but Hash and Eq on the borrowed form must match those for the key type.

Examples

use rt_map::RtMap;

let mut map = RtMap::new();
map.insert(1, "a");
assert_eq!(map.remove(&1), Some("a"));
assert_eq!(map.remove(&1), None);

pub fn contains_key<Q>(&self, k: &Q) -> bool

where Q: Hash + Eq + ?Sized, K: Borrow<Q>,

Returns true if the map contains a value for the specified key.

The key may be any borrowed form of the map’s key type, but Hash and Eq on the borrowed form must match those for the key type.

pub fn borrow<Q>(&self, k: &Q) -> Ref<'_, V>

where Q: Hash + Eq + Debug + ?Sized, K: Borrow<Q>,

Returns a reference to the value corresponding to the key.

The key may be any borrowed form of the map’s key type, but Hash and Eq on the borrowed form must match those for the key type.

See try_borrow for a non-panicking version of this function.

Panics

• Panics if the resource doesn’t exist.
• Panics if the resource is being accessed mutably.

pub fn try_borrow<Q>(&self, k: &Q) -> Result<Ref<'_, V>, BorrowFail>

where Q: Hash + Eq + ?Sized, K: Borrow<Q>,

Returns a reference to the value if it exists and is not mutably borrowed, None otherwise.

pub fn borrow_mut<Q>(&self, k: &Q) -> RefMut<'_, V>

where Q: Hash + Eq + Debug + ?Sized, K: Borrow<Q>,

Returns a reference to the value if it exists and is not borrowed, None otherwise.

Panics

• Panics if the resource doesn’t exist.
• Panics if the resource is already accessed.

pub fn try_borrow_mut<Q>(&self, k: &Q) -> Result<RefMut<'_, V>, BorrowFail>

where Q: Hash + Eq + ?Sized, K: Borrow<Q>,

Returns a mutable reference to R if it exists, None otherwise.

pub fn get_mut<Q>(&mut self, k: &Q) -> Option<&mut V>

where Q: Hash + Eq + ?Sized, K: Borrow<Q>,

Retrieves a resource without fetching, which is cheaper, but only available with &mut self.

pub fn get_resource_mut<Q>(&mut self, k: &Q) -> Option<&mut V>

where Q: Hash + Eq + ?Sized, K: Borrow<Q>,

Retrieves a resource without fetching, which is cheaper, but only available with &mut self.

pub fn get_raw<Q>(&self, k: &Q) -> Option<&Cell<V>>

where Q: Hash + Eq + ?Sized, K: Borrow<Q>,

Get raw access to the underlying cell.

Methods from Deref<Target = HashMap<K, Cell<V>>>

pub fn capacity(&self) -> usize

Returns the number of elements the map can hold without reallocating.

This number is a lower bound; the HashMap<K, V> might be able to hold more, but is guaranteed to be able to hold at least this many.

Examples

use std::collections::HashMap;
let map: HashMap<i32, i32> = HashMap::with_capacity(100);
assert!(map.capacity() >= 100);

pub fn keys(&self) -> Keys<'_, K, V>

An iterator visiting all keys in arbitrary order. The iterator element type is &'a K.

Examples

use std::collections::HashMap;

let map: HashMap<&str, i32> = HashMap::from([
    ("a", 1),
    ("b", 2),
    ("c", 3),
]);

let mut values: Vec<_> = map.keys().copied().collect();
values.sort();

assert_eq!(values, vec!["a", "b", "c"]);

Performance

In the current implementation, iterating over keys takes O(capacity) time instead of O(len) because it internally visits empty buckets too.

pub fn values(&self) -> Values<'_, K, V>

An iterator visiting all values in arbitrary order. The iterator element type is &'a V.

Examples

use std::collections::HashMap;

let map: HashMap<&str, i32> = HashMap::from([
    ("a", 1),
    ("b", 2),
    ("c", 3),
]);

let mut values: Vec<_> = map.values().copied().collect();
values.sort();

assert_eq!(values, vec![1, 2, 3]);

Performance

In the current implementation, iterating over values takes O(capacity) time instead of O(len) because it internally visits empty buckets too.

pub fn iter(&self) -> Iter<'_, K, V>

An iterator visiting all key-value pairs in arbitrary order. The iterator element type is (&'a K, &'a V).

Examples

use std::collections::HashMap;

let map = HashMap::from([
    ("a", 1),
    ("b", 2),
    ("c", 3),
]);

let mut count = 0;

for (_key, _val) in map.iter() {
    count += 1;
}

assert_eq!(count, 3);

Performance

In the current implementation, iterating over map takes O(capacity) time instead of O(len) because it internally visits empty buckets too.

pub fn len(&self) -> usize

Returns the number of elements in the map.

Examples

use std::collections::HashMap;

let mut a = HashMap::new();
assert_eq!(a.len(), 0);
a.insert(1, "a");
assert_eq!(a.len(), 1);

pub fn is_empty(&self) -> bool

Returns true if the map contains no elements.

Examples

use std::collections::HashMap;

let mut a = HashMap::new();
assert!(a.is_empty());
a.insert(1, "a");
assert!(!a.is_empty());

pub fn hasher(&self) -> &S

Returns a reference to the map’s BuildHasher.

Examples

use std::collections::HashMap;
use std::hash::RandomState;

let hasher = RandomState::new();
let map: HashMap<i32, i32> = HashMap::with_hasher(hasher);
let hasher: &RandomState = map.hasher();

pub fn get<Q>(&self, k: &Q) -> Option<&V>

where K: Borrow<Q>, Q: Hash + Eq + ?Sized,

Returns a reference to the value corresponding to the key.

The key may be any borrowed form of the map’s key type, but Hash and Eq on the borrowed form must match those for the key type.

Examples

use std::collections::HashMap;

let mut map = HashMap::new();
map.insert(1, "a");
assert_eq!(map.get(&1), Some(&"a"));
assert_eq!(map.get(&2), None);

pub fn get_key_value<Q>(&self, k: &Q) -> Option<(&K, &V)>

where K: Borrow<Q>, Q: Hash + Eq + ?Sized,

Returns the key-value pair corresponding to the supplied key. This is potentially useful:

• for key types where non-identical keys can be considered equal;
• for getting the &K stored key value from a borrowed &Q lookup key; or
• for getting a reference to a key with the same lifetime as the collection.

The supplied key may be any borrowed form of the map’s key type, but Hash and Eq on the borrowed form must match those for the key type.

Examples

use std::collections::HashMap;
use std::hash::{Hash, Hasher};

#[derive(Clone, Copy, Debug)]
struct S {
    id: u32,
    name: &'static str, // ignored by equality and hashing operations
}

impl PartialEq for S {
    fn eq(&self, other: &S) -> bool {
        self.id == other.id
    }
}

impl Eq for S {}

impl Hash for S {
    fn hash<H: Hasher>(&self, state: &mut H) {
        self.id.hash(state);
    }
}

let j_a = S { id: 1, name: "Jessica" };
let j_b = S { id: 1, name: "Jess" };
let p = S { id: 2, name: "Paul" };
assert_eq!(j_a, j_b);

let mut map = HashMap::new();
map.insert(j_a, "Paris");
assert_eq!(map.get_key_value(&j_a), Some((&j_a, &"Paris")));
assert_eq!(map.get_key_value(&j_b), Some((&j_a, &"Paris"))); // the notable case
assert_eq!(map.get_key_value(&p), None);

pub fn contains_key<Q>(&self, k: &Q) -> bool

where K: Borrow<Q>, Q: Hash + Eq + ?Sized,

Returns true if the map contains a value for the specified key.

The key may be any borrowed form of the map’s key type, but Hash and Eq on the borrowed form must match those for the key type.

Examples

use std::collections::HashMap;

let mut map = HashMap::new();
map.insert(1, "a");
assert_eq!(map.contains_key(&1), true);
assert_eq!(map.contains_key(&2), false);

Trait Implementations

impl Debug for Resources

Available on crate feature debug only.

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for Resources

fn default() -> Resources

Returns the “default value” for a type.

impl Deref for Resources

type Target = RtMap<TypeId, Box<dyn Resource>>

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl DerefMut for Resources

fn deref_mut(&mut self) -> &mut Self::Target

Mutably dereferences the value.