From f0d7f7499f4621101bd30901c406bcf744016e1f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Moritz=20H=C3=B6lting?=
 <87192362+moritz-hoelting@users.noreply.github.com>
Date: Tue, 2 Apr 2024 17:10:57 +0200
Subject: [PATCH] Add ExtendableQueue utility and refactor code

---
 src/datapack/namespace.rs    | 26 ++++--------
 src/util/compile.rs          | 17 +++-----
 src/util/extendable_queue.rs | 82 ++++++++++++++++++++++++++++++++++++
 src/util/mod.rs              |  1 +
 4 files changed, 96 insertions(+), 30 deletions(-)
 create mode 100644 src/util/extendable_queue.rs

diff --git a/src/datapack/namespace.rs b/src/datapack/namespace.rs
index 36a384e..bc79c90 100644
--- a/src/datapack/namespace.rs
+++ b/src/datapack/namespace.rs
@@ -3,15 +3,15 @@
 use serde::{Deserialize, Serialize};
 
 use crate::{
-    util::compile::{CompileOptions, FunctionCompilerState, MutCompilerState},
+    util::{
+        compile::{CompileOptions, FunctionCompilerState, MutCompilerState},
+        extendable_queue::ExtendableQueue,
+    },
     virtual_fs::VFolder,
 };
 
 use super::{function::Function, tag::Tag};
-use std::{
-    collections::{HashMap, VecDeque},
-    sync::{Arc, Mutex},
-};
+use std::collections::{HashMap, VecDeque};
 
 /// Namespace of a datapack
 #[derive(Debug, Clone, Serialize, Deserialize)]
@@ -89,20 +89,10 @@ impl Namespace {
             functions.push_front(("main".to_string(), self.main_function.clone()));
         }
 
-        let functions = Arc::new(Mutex::new(functions));
+        let mut functions = ExtendableQueue::from(functions);
 
-        loop {
-            let Some((path, function)) = ({
-                let mut functions = functions.lock().unwrap();
-                let entry = functions.pop_front();
-                drop(functions);
-                entry
-            }) else {
-                break;
-            };
-
-            let function_state =
-                FunctionCompilerState::new(&path, &self.name, Arc::downgrade(&functions));
+        while let Some((path, function)) = functions.next() {
+            let function_state = FunctionCompilerState::new(&path, &self.name, functions.clone());
             root_folder.add_file(
                 &format!("functions/{}.mcfunction", path),
                 function.compile(options, state, &function_state),
diff --git a/src/util/compile.rs b/src/util/compile.rs
index 0336afb..7d76d18 100644
--- a/src/util/compile.rs
+++ b/src/util/compile.rs
@@ -1,16 +1,14 @@
 //! Compile options for the compiler.
 
-use std::{
-    cell::Cell,
-    collections::VecDeque,
-    sync::{Mutex, Weak},
-};
+use std::{cell::Cell, sync::Mutex};
 
 use getset::Getters;
 use serde::{Deserialize, Serialize};
 
 use crate::datapack::Function;
 
+use super::extendable_queue::ExtendableQueue;
+
 /// Compile options for the compiler.
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct CompileOptions {
@@ -46,7 +44,7 @@ pub struct FunctionCompilerState {
     functions: FunctionQueue,
 }
 
-type FunctionQueue = Weak<Mutex<VecDeque<(String, Function)>>>;
+type FunctionQueue = ExtendableQueue<(String, Function)>;
 
 impl FunctionCompilerState {
     /// Create a new function compiler state.
@@ -61,11 +59,6 @@ impl FunctionCompilerState {
 
     /// Add a function to the queue.
     pub fn add_function(&self, name: &str, function: Function) {
-        if let Some(queue) = self.functions.upgrade() {
-            queue
-                .lock()
-                .unwrap()
-                .push_back((name.to_string(), function));
-        }
+        self.functions.push((name.to_string(), function));
     }
 }
diff --git a/src/util/extendable_queue.rs b/src/util/extendable_queue.rs
new file mode 100644
index 0000000..bdda66b
--- /dev/null
+++ b/src/util/extendable_queue.rs
@@ -0,0 +1,82 @@
+//! A queue that can be extended while iterating over it.
+
+use std::{
+    collections::VecDeque,
+    sync::{Arc, RwLock, Weak},
+};
+
+/// A queue that can be extended while iterating over it.
+#[derive(Debug, Clone)]
+pub struct ExtendableQueue<T> {
+    queue: Arc<RwLock<VecDeque<T>>>,
+}
+
+impl Default for ExtendableQueue<String> {
+    fn default() -> Self {
+        Self {
+            queue: Arc::new(RwLock::new(VecDeque::new())),
+        }
+    }
+}
+
+impl<T, V> From<V> for ExtendableQueue<T>
+where
+    V: Into<VecDeque<T>>,
+{
+    fn from(value: V) -> Self {
+        Self {
+            queue: Arc::new(RwLock::new(value.into())),
+        }
+    }
+}
+
+impl<T> ExtendableQueue<T> {
+    /// Add an element to the queue.
+    pub fn push(&self, value: T) {
+        self.queue.write().unwrap().push_back(value);
+    }
+
+    /// Get the queue.
+    pub fn get(&self) -> &Arc<RwLock<VecDeque<T>>> {
+        &self.queue
+    }
+
+    /// Get a weak reference to the queue.
+    pub fn get_weak(&self) -> Weak<RwLock<VecDeque<T>>> {
+        Arc::downgrade(&self.queue)
+    }
+
+    /// Clear the queue.
+    pub fn clear(&self) {
+        self.queue.write().unwrap().clear();
+    }
+
+    /// Get the length of the queue.
+    pub fn len(&self) -> usize {
+        self.queue.read().unwrap().len()
+    }
+
+    /// Check if the queue is empty.
+    pub fn is_empty(&self) -> bool {
+        self.queue.read().unwrap().is_empty()
+    }
+
+    /// Get and remove the next item without needing mutable access.
+    pub fn pop_front(&self) -> Option<T> {
+        self.queue.write().unwrap().pop_front()
+    }
+}
+
+impl<A> Extend<A> for ExtendableQueue<A> {
+    fn extend<T: IntoIterator<Item = A>>(&mut self, iter: T) {
+        self.queue.write().unwrap().extend(iter);
+    }
+}
+
+impl<T> Iterator for ExtendableQueue<T> {
+    type Item = T;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.queue.write().unwrap().pop_front()
+    }
+}
diff --git a/src/util/mod.rs b/src/util/mod.rs
index 063a674..538f1c5 100644
--- a/src/util/mod.rs
+++ b/src/util/mod.rs
@@ -1,3 +1,4 @@
 //! Utility functions for the Shulkerbox project.
 
 pub mod compile;
+pub mod extendable_queue;