1 files changed, 54 insertions, 0 deletions
diff --git a/azalea-world/src/container.rs b/azalea-world/src/container.rs
new file mode 100644
index 00000000..acdc9b05
--- /dev/null
+++ b/azalea-world/src/container.rs
@@ -0,0 +1,54 @@
+use crate::WeakWorld;
+use azalea_core::ResourceLocation;
+use log::error;
+use std::{
+    collections::HashMap,
+    sync::{Arc, Weak},
+};
+
+/// A container of [`WeakWorld`]s. Worlds are stored as a Weak pointer here, so
+/// if no clients are using a world it will be forgotten.
+#[derive(Default)]
+pub struct WeakWorldContainer {
+    pub worlds: HashMap<ResourceLocation, Weak<WeakWorld>>,
+}
+
+impl WeakWorldContainer {
+    pub fn new() -> Self {
+        WeakWorldContainer {
+            worlds: HashMap::new(),
+        }
+    }
+
+    /// Get a world from the container.
+    pub fn get(&self, name: &ResourceLocation) -> Option<Arc<WeakWorld>> {
+        self.worlds.get(name).and_then(|world| world.upgrade())
+    }
+
+    /// Add an empty world to the container (or not if it already exists) and
+    /// returns a strong reference to the world.
+    #[must_use = "the world will be immediately forgotten if unused"]
+    pub fn insert(&mut self, name: ResourceLocation, height: u32, min_y: i32) -> Arc<WeakWorld> {
+        if let Some(existing) = self.worlds.get(&name).and_then(|world| world.upgrade()) {
+            if existing.height() != height {
+                error!(
+                    "Shared dimension height mismatch: {} != {}",
+                    existing.height(),
+                    height,
+                );
+            }
+            if existing.min_y() != min_y {
+                error!(
+                    "Shared world min_y mismatch: {} != {}",
+                    existing.min_y(),
+                    min_y,
+                );
+            }
+            existing
+        } else {
+            let world = Arc::new(WeakWorld::new(height, min_y));
+            self.worlds.insert(name, Arc::downgrade(&world));
+            world
+        }
+    }
+}