From cca62d3a3e19d96393a469466506d6b988baf54f Mon Sep 17 00:00:00 2001
From: Joshua Barretto <joshua.s.barretto@gmail.com>
Date: Mon, 4 Mar 2019 00:06:01 +0000
Subject: [PATCH] Added Uid marker component

Former-commit-id: b0aae7a8e6dd075996f3bee6cc7be29763f6cdaa
---
 common/Cargo.toml      |  2 +-
 common/src/comp/mod.rs |  3 ++
 common/src/comp/uid.rs | 65 ++++++++++++++++++++++++++++++++++++++++++
 common/src/net/test.rs |  8 +++---
 4 files changed, 73 insertions(+), 5 deletions(-)
 create mode 100644 common/src/comp/uid.rs

diff --git a/common/Cargo.toml b/common/Cargo.toml
index 0bd937c298..b8db18d3b3 100644
--- a/common/Cargo.toml
+++ b/common/Cargo.toml
@@ -5,7 +5,7 @@ authors = ["Joshua Barretto <joshua.s.barretto@gmail.com>", "Maciej Ćwięka <mc
 edition = "2018"
 
 [dependencies]
-specs = "0.14"
+specs = { version = "0.14", features = ["serde"] }
 shred = "0.7"
 vek = "0.9"
 dot_vox = "1.0"
diff --git a/common/src/comp/mod.rs b/common/src/comp/mod.rs
index c7bb5a311f..d822941454 100644
--- a/common/src/comp/mod.rs
+++ b/common/src/comp/mod.rs
@@ -1,9 +1,12 @@
 pub mod phys;
+pub mod uid;
 
 // External
 use specs::World as EcsWorld;
 
 pub fn register_local_components(ecs_world: &mut EcsWorld) {
+    ecs_world.register::<uid::Uid>();
+
     ecs_world.register::<phys::Pos>();
     ecs_world.register::<phys::Vel>();
     ecs_world.register::<phys::Dir>();
diff --git a/common/src/comp/uid.rs b/common/src/comp/uid.rs
new file mode 100644
index 0000000000..3f46979036
--- /dev/null
+++ b/common/src/comp/uid.rs
@@ -0,0 +1,65 @@
+use std::{
+    collections::HashMap,
+    ops::Range,
+};
+use specs::{
+    saveload::{Marker, MarkerAllocator},
+    world::EntitiesRes,
+    Component,
+    VecStorage,
+    Entity,
+    Join,
+    ReadStorage,
+};
+
+#[derive(Copy, Clone, Debug, Eq, Hash, PartialEq, Serialize, Deserialize)]
+pub struct Uid {
+    id: u64,
+    seq: u64,
+}
+
+impl Component for Uid {
+    type Storage = VecStorage<Self>;
+}
+
+impl Marker for Uid {
+    type Identifier = u64;
+    type Allocator = UidNode;
+
+    fn id(&self) -> u64 { self.id }
+
+    fn update(&mut self, update: Self) {
+        assert_eq!(self.id, update.id);
+        self.seq = update.seq;
+    }
+}
+
+pub struct UidNode {
+    pub(crate) range: Range<u64>,
+    pub(crate) mapping: HashMap<u64, Entity>,
+}
+
+impl MarkerAllocator<Uid> for UidNode {
+    fn allocate(&mut self, entity: Entity, id: Option<u64>) -> Uid {
+        let id = id.unwrap_or_else(|| {
+            self.range.next().expect("
+                Id range must be effectively endless.
+                Somehow, you ran this program for longer than the lifetime of the universe.
+                It's probably time to stop playing and prepare for your imminent extinction.
+            ")
+        });
+        self.mapping.insert(id, entity);
+        Uid { id, seq: 0 }
+    }
+
+    fn retrieve_entity_internal(&self, id: u64) -> Option<Entity> {
+        self.mapping.get(&id).cloned()
+    }
+
+    fn maintain(&mut self, entities: &EntitiesRes, storage: &ReadStorage<Uid>) {
+        self.mapping = (&*entities, storage)
+            .join()
+            .map(|(e, m)| (m.id(), e))
+            .collect();
+    }
+}
diff --git a/common/src/net/test.rs b/common/src/net/test.rs
index 98e03142f3..97532fd5cd 100644
--- a/common/src/net/test.rs
+++ b/common/src/net/test.rs
@@ -25,8 +25,8 @@ fn basic_run() {
     scon.send(String::from("foo")).unwrap();
     client.send(String::from("bar")).unwrap();
     std::thread::sleep(std::time::Duration::from_millis(10));
-    assert_eq!("foo", client.recv_iter().next().unwrap());
-    assert_eq!("bar", scon.recv_iter().next().unwrap());
+    assert_eq!("foo", client.new_messages().next().unwrap());
+    assert_eq!("bar", scon.new_messages().next().unwrap());
 }
 
 #[test]
@@ -40,7 +40,7 @@ fn huge_size_header() {
     std::thread::sleep(std::time::Duration::from_millis(10));
     client.write(&[0xffu8; 64]).unwrap();
     std::thread::sleep(std::time::Duration::from_millis(10));
-    assert_eq!(scon.recv_iter().next(), None);
+    assert_eq!(scon.new_messages().next(), None);
 }
 
 #[test]
@@ -66,7 +66,7 @@ fn disconnect() {
 
     thread::sleep(Duration::from_millis(10));
 
-    match to_client.recv_iter().next() {
+    match to_client.new_messages().next() {
         None => {},
         _ => panic!("Unexpected message!"),
     }