Extracting parts from #855 (#858)

* better random token generation for caller hashmap

* open up github workflow runs to all pushes and adding some install steps to elixir-ci

* fun with CI

* take back workflow/GH actions changes. i'm not smart enough for this

Author: tessi

.github/workflows/elixir-ci.yml

@@ -120,11 +120,16 @@ jobs:
         run: |
           rustup target add wasm32-unknown-unknown
           rustup target add wasm32-wasip1
+          rustup target add wasm32-wasip2
 
       - name: "Install cargo-component"
         run: cargo install --locked cargo-component
         shell: bash
 
+      - name: "Install wasm-tools"
+        run: cargo install --locked wasm-tools
+        shell: bash
+
       - uses: actions/cache@v4
         with:
           path: |

.github/workflows/rust-ci.yml

@@ -7,6 +7,8 @@ on:
   push:
     branches:
       - main
+    paths:
+      - "native/wasmex/**"
 
 defaults:
   run:

native/wasmex/src/caller.rs

@@ -30,14 +30,23 @@ pub(crate) fn get_caller_mut(token: &mut i32) -> Option<&mut Caller<'_, StoreDat
 
 pub(crate) fn set_caller(caller: Caller<StoreData>) -> i32 {
     let mut map = CALLER_MAP.lock().unwrap();
-    // TODO: prevent duplicates by throwing the dice again when the id is already known
-    let token = rand::random();
+    let token = generate_unique_random_token(&map);
+
     let caller =
         unsafe { std::mem::transmute::<Caller<'_, StoreData>, Caller<'static, StoreData>>(caller) };
     map.insert(token, caller);
     token
 }
 
+fn generate_unique_random_token(map: &HashMap<i32, Caller<'_, StoreData>>) -> i32 {
+    loop {
+        let token: i32 = rand::random();
+        if !map.contains_key(&token) {
+            break token;
+        }
+    }
+}
+
 pub(crate) fn remove_caller(token: i32) {
     let mut map = CALLER_MAP.lock().unwrap();
     map.remove(&token);