Merge 'Add time querying to I/O trait for deterministic simulation' from mason

Follow-up PR to this [issue](https://github.com/penberg/limbo/issues/272).

Closes #307

bindings/wasm/lib.rs

@@ -92,6 +92,11 @@ impl limbo_core::IO for PlatformIO {
         let random_f64 = Math_random();
         (random_f64 * i64::MAX as f64) as i64
     }
+
+    fn get_current_time(&self) -> String {
+        let date = Date::new();
+        date.toISOString()
+    }
 }
 
 #[wasm_bindgen]
@@ -99,6 +104,17 @@ extern "C" {
     fn Math_random() -> f64;
 }
 
+#[wasm_bindgen]
+extern "C" {
+    type Date;
+
+    #[wasm_bindgen(constructor)]
+    fn new() -> Date;
+
+    #[wasm_bindgen(method, getter)]
+    fn toISOString(this: &Date) -> String;
+}
+
 pub struct DatabaseStorage {
     file: Rc<dyn limbo_core::File>,
 }

core/io/darwin.rs

@@ -110,6 +110,10 @@ impl IO for DarwinIO {
         getrandom::getrandom(&mut buf).unwrap();
         i64::from_ne_bytes(buf)
     }
+
+    fn get_current_time(&self) -> String {
+        chrono::Local::now().format("%Y-%m-%d %H:%M:%S").to_string()
+    }
 }
 
 enum CompletionCallback {

core/io/generic.rs

@@ -30,6 +30,10 @@ impl IO for GenericIO {
         getrandom::getrandom(&mut buf).unwrap();
         i64::from_ne_bytes(buf)
     }
+
+    fn get_current_time(&self) -> String {
+        chrono::Local::now().format("%Y-%m-%d %H:%M:%S").to_string()
+    }
 }
 
 pub struct GenericFile {

core/io/linux.rs

@@ -111,6 +111,10 @@ impl IO for LinuxIO {
         getrandom::getrandom(&mut buf).unwrap();
         i64::from_ne_bytes(buf)
     }
+
+    fn get_current_time(&self) -> String {
+        chrono::Local::now().format("%Y-%m-%d %H:%M:%S").to_string()
+    }
 }
 
 pub struct LinuxFile {

core/io/mod.rs

@@ -22,6 +22,8 @@ pub trait IO {
     fn run_once(&self) -> Result<()>;
 
     fn generate_random_number(&self) -> i64;
+
+    fn get_current_time(&self) -> String;
 }
 
 pub type Complete = dyn Fn(Rc<RefCell<Buffer>>);

core/io/windows.rs

@@ -30,6 +30,10 @@ impl IO for WindowsIO {
         getrandom::getrandom(&mut buf).unwrap();
         i64::from_ne_bytes(buf)
     }
+
+    fn get_current_time(&self) -> String {
+        chrono::Local::now().format("%Y-%m-%d %H:%M:%S").to_string()
+    }
 }
 
 pub struct WindowsFile {

simulator/main.rs

@@ -113,6 +113,10 @@ impl IO for SimulatorIO {
     fn generate_random_number(&self) -> i64 {
         self.rng.borrow_mut().next_u64() as i64
     }
+
+    fn get_current_time(&self) -> String {
+        "2024-01-01 00:00:00".to_string()
+    }
 }
 
 struct SimulatorFile {