feat: add resumable calls / fuel tracking

Signed-off-by: Henry <mail@henrygressmann.de>

1 files changed, 46 insertions, 0 deletions

diff --git a/examples/resumable.rs b/examples/resumable.rs
new file mode 100644
index 0000000..6838e20
--- /dev/null
+++ b/examples/resumable.rs
@@ -0,0 +1,46 @@
+use eyre::Result;
+use tinywasm::{ExecProgress, Module, Store};
+
+const WASM: &str = r#"
+(module
+  (func (export "count_down") (param $n i32) (result i32)
+    (local $cur i32)
+    local.get $n
+    local.set $cur
+    block
+      loop
+        local.get $cur
+        i32.eqz
+        br_if 1
+        local.get $cur
+        i32.const 1
+        i32.sub
+        local.set $cur
+        br 0
+      end
+    end
+    local.get $cur))
+"#;
+
+fn main() -> Result<()> {
+    let wasm = wat::parse_str(WASM)?;
+    let module = Module::parse_bytes(&wasm)?;
+    let mut store = Store::default();
+    let instance = module.instantiate(&mut store, None)?;
+    let count_down = instance.exported_func::<i32, i32>(&store, "count_down")?;
+
+    let mut execution = count_down.call_resumable(&mut store, 10_000)?;
+    let fuel_per_round = 128;
+    let mut fuel_rounds = 0;
+
+    let result = loop {
+        fuel_rounds += 1;
+        match execution.resume_with_fuel(fuel_per_round)? {
+            ExecProgress::Completed(value) => break value,
+            ExecProgress::Suspended => {}
+        }
+    };
+
+    println!("completed in {fuel_rounds} rounds of {fuel_per_round} fuel, result={result}");
+    Ok(())
+}