From 12a128366312da9fc6b6157b4bd3081b522e0104 Mon Sep 17 00:00:00 2001
From: A Thousand Ships <96648715+AThousandShips@users.noreply.github.com>
Date: Mon, 15 Apr 2024 15:45:15 +0200
Subject: [PATCH 1/2] [Core] Reduce and prevent unnecessary random-access to
 `List`

Random-access access to `List` when iterating is `O(n^2)` (`O(n)` when accessing a single element)

* Removed subscript operator, in favor of a more explicit `get`
* Added conversion from `Iterator` to `ConstIterator`
---
 include/godot_cpp/templates/list.hpp | 56 ++++++++++++++++------------
 1 file changed, 32 insertions(+), 24 deletions(-)

diff --git a/include/godot_cpp/templates/list.hpp b/include/godot_cpp/templates/list.hpp
index 376e3ea87..55e2c35f7 100644
--- a/include/godot_cpp/templates/list.hpp
+++ b/include/godot_cpp/templates/list.hpp
@@ -139,54 +139,58 @@ class List {
 
 	typedef T ValueType;
 
-	struct Iterator {
-		_FORCE_INLINE_ T &operator*() const {
+	struct ConstIterator {
+		_FORCE_INLINE_ const T &operator*() const {
 			return E->get();
 		}
-		_FORCE_INLINE_ T *operator->() const { return &E->get(); }
-		_FORCE_INLINE_ Iterator &operator++() {
+		_FORCE_INLINE_ const T *operator->() const { return &E->get(); }
+		_FORCE_INLINE_ ConstIterator &operator++() {
 			E = E->next();
 			return *this;
 		}
-		_FORCE_INLINE_ Iterator &operator--() {
+		_FORCE_INLINE_ ConstIterator &operator--() {
 			E = E->prev();
 			return *this;
 		}
 
-		_FORCE_INLINE_ bool operator==(const Iterator &b) const { return E == b.E; }
-		_FORCE_INLINE_ bool operator!=(const Iterator &b) const { return E != b.E; }
+		_FORCE_INLINE_ bool operator==(const ConstIterator &b) const { return E == b.E; }
+		_FORCE_INLINE_ bool operator!=(const ConstIterator &b) const { return E != b.E; }
 
-		Iterator(Element *p_E) { E = p_E; }
-		Iterator() {}
-		Iterator(const Iterator &p_it) { E = p_it.E; }
+		_FORCE_INLINE_ ConstIterator(const Element *p_E) { E = p_E; }
+		_FORCE_INLINE_ ConstIterator() {}
+		_FORCE_INLINE_ ConstIterator(const ConstIterator &p_it) { E = p_it.E; }
 
 	private:
-		Element *E = nullptr;
+		const Element *E = nullptr;
 	};
 
-	struct ConstIterator {
-		_FORCE_INLINE_ const T &operator*() const {
+	struct Iterator {
+		_FORCE_INLINE_ T &operator*() const {
 			return E->get();
 		}
-		_FORCE_INLINE_ const T *operator->() const { return &E->get(); }
-		_FORCE_INLINE_ ConstIterator &operator++() {
+		_FORCE_INLINE_ T *operator->() const { return &E->get(); }
+		_FORCE_INLINE_ Iterator &operator++() {
 			E = E->next();
 			return *this;
 		}
-		_FORCE_INLINE_ ConstIterator &operator--() {
+		_FORCE_INLINE_ Iterator &operator--() {
 			E = E->prev();
 			return *this;
 		}
 
-		_FORCE_INLINE_ bool operator==(const ConstIterator &b) const { return E == b.E; }
-		_FORCE_INLINE_ bool operator!=(const ConstIterator &b) const { return E != b.E; }
+		_FORCE_INLINE_ bool operator==(const Iterator &b) const { return E == b.E; }
+		_FORCE_INLINE_ bool operator!=(const Iterator &b) const { return E != b.E; }
 
-		_FORCE_INLINE_ ConstIterator(const Element *p_E) { E = p_E; }
-		_FORCE_INLINE_ ConstIterator() {}
-		_FORCE_INLINE_ ConstIterator(const ConstIterator &p_it) { E = p_it.E; }
+		Iterator(Element *p_E) { E = p_E; }
+		Iterator() {}
+		Iterator(const Iterator &p_it) { E = p_it.E; }
+
+		operator ConstIterator() const {
+			return ConstIterator(E);
+		}
 
 	private:
-		const Element *E = nullptr;
+		Element *E = nullptr;
 	};
 
 	_FORCE_INLINE_ Iterator begin() {
@@ -519,7 +523,9 @@ class List {
 		}
 	}
 
-	T &operator[](int p_index) {
+	// Random access to elements, use with care,
+	// do not use for iteration.
+	T &get(int p_index) {
 		CRASH_BAD_INDEX(p_index, size());
 
 		Element *I = front();
@@ -532,7 +538,9 @@ class List {
 		return I->get();
 	}
 
-	const T &operator[](int p_index) const {
+	// Random access to elements, use with care,
+	// do not use for iteration.
+	const T &get(int p_index) const {
 		CRASH_BAD_INDEX(p_index, size());
 
 		const Element *I = front();

From d0bdd6096c0440542245fb37690e7ab8f3e34b29 Mon Sep 17 00:00:00 2001
From: A Thousand Ships <96648715+AThousandShips@users.noreply.github.com>
Date: Tue, 7 May 2024 10:43:41 +0200
Subject: [PATCH 2/2] Optionaly add compatibility operators

---
 include/godot_cpp/templates/list.hpp | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/include/godot_cpp/templates/list.hpp b/include/godot_cpp/templates/list.hpp
index 55e2c35f7..fa5960565 100644
--- a/include/godot_cpp/templates/list.hpp
+++ b/include/godot_cpp/templates/list.hpp
@@ -523,6 +523,11 @@ class List {
 		}
 	}
 
+	// Index operator, kept for compatibility.
+	_FORCE_INLINE_ T &operator[](int p_index) {
+		return get(p_index);
+	}
+
 	// Random access to elements, use with care,
 	// do not use for iteration.
 	T &get(int p_index) {
@@ -538,6 +543,11 @@ class List {
 		return I->get();
 	}
 
+	// Index operator, kept for compatibility.
+	_FORCE_INLINE_ const T &operator[](int p_index) const {
+		return get(p_index);
+	}
+
 	// Random access to elements, use with care,
 	// do not use for iteration.
 	const T &get(int p_index) const {