A library that is similar to a thread local storage but allows to store references / dyn Trait within a scope. It can be used to 'inject' references (if you don't own the data and Rc/Arc is not possible) into something you don't control entirely (e.g. a function you provide that gets called by a library you don't own).
+------- (set) -----------> &Data <---------- (access/read) ----------+
| |
+---------+------------+ +--------------------------------------------|-------------+
| Data | | External library | |
| (huge/context/no Rc) | | | |
+----------------------+ | +-----------+------+ |
| ---- (calls) ---> | Your function | |
| +------------------+ |
+----------------------------------------------------------+
toml
[dependencies]
thread-scoped-ref = "0"
``` use threadscopedref::{threadscopedref, scoped, with}; use std::collections::HashMap;
threadscopedref!(SOMEENVVALUES, HashMap
/// It's not possible to pass &HashMap<String, String> to this function since it's called
/// by some library you don't control...
fn readenvvalue() {
// ... so we read from the static 'SOMEENVVALUES'.
with(&SOMEENVVALUES, |maybeenvvalues| {
// don't "unwrap" in reality: Since maybe_env_values will be None if not
// called within a scope!
let envvalues = maybeenvvalues.unwrap();
asserteq!("true", envvalues.get("deleteentire_ssd").unwrap());
});
}
/// An external library you don't control or generated code. fn externallibrary(functionptr : fn()) { function_ptr(); }
let mut envvalues = HashMap::default();
envvalues.insert("deleteentiressd".tostring(), "true".tostring());
// Create a scope. Note: We only need a reference to env_values (no move required).
scoped(&SOMEENVVALUES, &envvalues, || {
externallibrary(readenvvalue);
});
```
Licensed under either of
at your option.