From 6b2d44a58c54f704c5d26c1acc14f0594aa4f806 Mon Sep 17 00:00:00 2001
From: Aaron Fenyes <aaron.fenyes@fareycircles.ooo>
Date: Mon, 18 Nov 2024 16:08:06 -0800
Subject: [PATCH 1/2] Assign each element a serial number

For future thread-safety, keep the next serial number in a static atomic
variable.
---
 app-proto/src/assembly.rs | 9 ++++++++-
 app-proto/src/outline.rs  | 2 +-
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/app-proto/src/assembly.rs b/app-proto/src/assembly.rs
index 35b4417..a00081a 100644
--- a/app-proto/src/assembly.rs
+++ b/app-proto/src/assembly.rs
@@ -1,7 +1,7 @@
 use nalgebra::{DMatrix, DVector};
 use rustc_hash::FxHashMap;
 use slab::Slab;
-use std::collections::BTreeSet;
+use std::{collections::BTreeSet, sync::atomic::{AtomicU64, Ordering}};
 use sycamore::prelude::*;
 use web_sys::{console, wasm_bindgen::JsValue}; /* DEBUG */
 
@@ -13,6 +13,8 @@ pub type ConstraintKey = usize;
 
 pub type ElementColor = [f32; 3];
 
+static NEXT_ELEMENT_SERIAL: AtomicU64 = AtomicU64::new(0);
+
 #[derive(Clone, PartialEq)]
 pub struct Element {
     pub id: String,
@@ -20,6 +22,10 @@ pub struct Element {
     pub color: ElementColor,
     pub representation: Signal<DVector<f64>>,
     pub constraints: Signal<BTreeSet<ConstraintKey>>,
+
+    // a serial number, assigned by `Element::new`, that uniquely identifies
+    // each element (until `NEXT_ELEMENT_SERIAL` wraps around)
+    pub serial: u64,
     
     // the configuration matrix column index that was assigned to this element
     // last time the assembly was realized
@@ -39,6 +45,7 @@ impl Element {
             color: color,
             representation: create_signal(representation),
             constraints: create_signal(BTreeSet::default()),
+            serial: NEXT_ELEMENT_SERIAL.fetch_add(1, Ordering::SeqCst),
             column_index: 0
         }
     }
diff --git a/app-proto/src/outline.rs b/app-proto/src/outline.rs
index ee1603f..e2cf49c 100644
--- a/app-proto/src/outline.rs
+++ b/app-proto/src/outline.rs
@@ -200,7 +200,7 @@ pub fn Outline() -> View {
                 view=|(key, elt)| view! {
                     ElementOutlineItem(key=key, element=elt)
                 },
-                key=|(key, _)| key.clone()
+                key=|(_, elt)| elt.serial
             )
         }
     }
-- 
2.34.1


From 7bc3a9eeae91f719d441dff0eeb1bef6c6e1f89a Mon Sep 17 00:00:00 2001
From: Aaron Fenyes <aaron.fenyes@fareycircles.ooo>
Date: Mon, 18 Nov 2024 20:29:53 -0800
Subject: [PATCH 2/2] Make the next element serial number thread-local

In the last revision, the next element serial number was thread-safe,
but that might be overdoing it. I suspect that elements will only ever
be created from the main thread.
---
 app-proto/src/assembly.rs | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/app-proto/src/assembly.rs b/app-proto/src/assembly.rs
index a00081a..bfbb2b8 100644
--- a/app-proto/src/assembly.rs
+++ b/app-proto/src/assembly.rs
@@ -1,7 +1,7 @@
 use nalgebra::{DMatrix, DVector};
 use rustc_hash::FxHashMap;
 use slab::Slab;
-use std::{collections::BTreeSet, sync::atomic::{AtomicU64, Ordering}};
+use std::{cell::Cell, collections::BTreeSet};
 use sycamore::prelude::*;
 use web_sys::{console, wasm_bindgen::JsValue}; /* DEBUG */
 
@@ -13,7 +13,9 @@ pub type ConstraintKey = usize;
 
 pub type ElementColor = [f32; 3];
 
-static NEXT_ELEMENT_SERIAL: AtomicU64 = AtomicU64::new(0);
+thread_local! {
+    static NEXT_ELEMENT_SERIAL: Cell<u64> = Cell::new(0);
+}
 
 #[derive(Clone, PartialEq)]
 pub struct Element {
@@ -39,13 +41,17 @@ impl Element {
         color: ElementColor,
         representation: DVector<f64>
     ) -> Element {
+        // take the next serial number
+        let serial = NEXT_ELEMENT_SERIAL.get();
+        NEXT_ELEMENT_SERIAL.set(serial.wrapping_add(1));
+        
         Element {
             id: id,
             label: label,
             color: color,
             representation: create_signal(representation),
             constraints: create_signal(BTreeSet::default()),
-            serial: NEXT_ELEMENT_SERIAL.fetch_add(1, Ordering::SeqCst),
+            serial: serial,
             column_index: 0
         }
     }
-- 
2.34.1