1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99

use std::collections::{HashMap, HashSet};
use std::ops::{Deref, DerefMut, Drop};
use std::any::{Any, TypeId};

use std::cell::RefCell;
use component::*;

pub struct Entity {
    pub id                       : i32,
    pub components               : RefCell<HashMap<TypeId, Box<Any>>>,
    pub removed_components       : RefCell<HashSet<TypeId>>,
    fresh                        : RefCell<bool>
}

pub struct ComponentGuard<'a, T : Any> {
    component  : Option<Box<T>>,
    collection : &'a RefCell<HashMap<TypeId, Box<Any>>>
}
impl <'a, T : Any> Deref for ComponentGuard<'a, T> {
    type Target = T;
    fn deref(&self) -> &T {
        self.component.as_ref().unwrap()
    }
}

impl <'a, T : Any> DerefMut for ComponentGuard<'a, T> {
    fn deref_mut(&mut self) -> &mut T {
        self.component.as_mut().unwrap()
    }
}
impl<'a, T : Any> Drop for ComponentGuard<'a, T> {
    fn drop(&mut self) {
        self.component.take().and_then(|component| {
            self.collection.borrow_mut().insert(TypeId::of::<T>(), component)
        });
    }
}

impl Entity {
    pub fn new(id  : i32) -> Entity {
        Entity {
            id                      : id,
            components              : RefCell::new(HashMap::new()),
            removed_components      : RefCell::new(HashSet::new()),
            fresh                   : RefCell::new(false)
        }
    }

    /// Mark this entity as not refreshed.
    /// On beginning of next frame new registered components will affect their systems.
    pub fn refresh(&self) {
        *self.fresh.borrow_mut() = false;
    }

    pub fn set_fresh(&self) {
        *self.fresh.borrow_mut() = true;
    }

    pub fn is_fresh(&self) -> bool {
        *self.fresh.borrow() == true
    }
    pub fn add_component<T : Any + Component>(&self, component : T) {
        self.components.borrow_mut().insert(TypeId::of::<T>(), Box::new(component));
    }

    /// Remove component of given type from entity
    /// Be carefull, if this component is borrowed at this moment, it will not be really deleted.
    pub fn remove_component<T : Any>(&self) {
        if self.removed_components.borrow_mut().insert(TypeId::of::<T>()) == false {
            panic!("Removing of removed components");
        }
    }

    pub fn has_component<T : Any>(&self) -> bool {
        self.components.borrow().contains_key(&TypeId::of::<T>())
    }

    /// Move component from entity to CompoentGuard. In general case, it behaves like &mut T.
    /// While component is borrowed, second get_component() with same type will cause panic
    pub fn get_component<T : Any + Component>(&self) -> ComponentGuard<T> {
        let component = self.components.borrow_mut().remove(&TypeId::of::<T>()).unwrap();
        let c : Box<T> = component.downcast().unwrap();

        ComponentGuard {
            component: Some(c),
            collection: &self.components,
        }
    }

    #[doc(hidden)]
    pub fn get_components<T : Any + Component, T1 : Any + Component>(&self) -> (ComponentGuard<T>, ComponentGuard<T1>) {
        (self.get_component::<T>(), self.get_component::<T1>())
    }
    #[doc(hidden)]
    pub fn get_components3<T : Any + Component, T1 : Any + Component, T2 : Any + Component>(&self) -> (ComponentGuard<T>, ComponentGuard<T1>, ComponentGuard<T2>) {
        (self.get_component::<T>(), self.get_component::<T1>(), self.get_component::<T2>())
    }
}