From fe4418bc0d0f1d34b8e57f6bb13d399aed7c2cb6 Mon Sep 17 00:00:00 2001
From: Joshua Barretto <joshua.s.barretto@gmail.com>
Date: Fri, 27 Mar 2020 13:18:16 +0000
Subject: [PATCH] Added store

---
 common/src/lib.rs   |  1 +
 common/src/store.rs | 61 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 62 insertions(+)
 create mode 100644 common/src/store.rs

diff --git a/common/src/lib.rs b/common/src/lib.rs
index f8da49935d..c9c27fc778 100644
--- a/common/src/lib.rs
+++ b/common/src/lib.rs
@@ -34,6 +34,7 @@ pub mod terrain;
 pub mod util;
 pub mod vol;
 pub mod volumes;
+pub mod store;
 
 /// The networking module containing high-level wrappers of `TcpListener` and
 /// `TcpStream` (`PostOffice` and `PostBox` respectively) and data types used by
diff --git a/common/src/store.rs b/common/src/store.rs
new file mode 100644
index 0000000000..cb0916691c
--- /dev/null
+++ b/common/src/store.rs
@@ -0,0 +1,61 @@
+use std::{
+    fmt,
+    hash,
+    cmp::{PartialEq, Eq},
+    marker::PhantomData,
+};
+
+pub struct Id<T>(usize, PhantomData<T>);
+
+impl<T> Id<T> {
+    pub fn id(&self) -> usize { self.0 }
+}
+
+impl<T> Copy for Id<T> {}
+impl<T> Clone for Id<T> {
+    fn clone(&self) -> Self { Self(self.0, PhantomData) }
+}
+impl<T> Eq for Id<T> {}
+impl<T> PartialEq for Id<T> {
+    fn eq(&self, other: &Self) -> bool { self.0 == other.0 }
+}
+impl<T> fmt::Debug for Id<T> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "Id<{}>({})", std::any::type_name::<T>(), self.0)
+    }
+}
+impl<T> hash::Hash for Id<T> {
+    fn hash<H: hash::Hasher>(&self, h: &mut H) {
+        self.0.hash(h);
+    }
+}
+
+pub struct Store<T> {
+    items: Vec<T>,
+}
+
+impl<T> Default for Store<T> {
+    fn default() -> Self { Self { items: Vec::new() } }
+}
+
+impl<T> Store<T> {
+    pub fn get(&self, id: Id<T>) -> &T { self.items.get(id.0).unwrap() }
+
+    pub fn get_mut(&mut self, id: Id<T>) -> &mut T { self.items.get_mut(id.0).unwrap() }
+
+    pub fn iter(&self) -> impl Iterator<Item = &T> { self.items.iter() }
+
+    pub fn iter_ids(&self) -> impl Iterator<Item = (Id<T>, &T)> {
+        self
+            .items
+            .iter()
+            .enumerate()
+            .map(|(i, item)| (Id(i, PhantomData), item))
+    }
+
+    pub fn insert(&mut self, item: T) -> Id<T> {
+        let id = Id(self.items.len(), PhantomData);
+        self.items.push(item);
+        id
+    }
+}