wasi-c2: rewrite wasi-common in terms of system-interface

crates/wasi-c2/src/ctx.rs

@@ -0,0 +1,26 @@
+use crate::table::Table;
+use std::cell::{RefCell, RefMut};
+use std::rc::Rc;
+
+pub struct WasiCtx {
+    table: Rc<RefCell<Table>>,
+}
+
+impl WasiCtx {
+    pub fn new() -> Self {
+        WasiCtx {
+            table: Rc::new(RefCell::new(Table::new())),
+        }
+    }
+
+    pub fn table(&self) -> RefMut<Table> {
+        self.table.borrow_mut()
+    }
+}
+
+pub trait WasiDir {}
+
+pub(crate) struct DirEntry {
+    pub(crate) flags: u32,
+    pub(crate) dir: Box<dyn WasiDir>,
+}