fill in more implementations, support preopens

crates/wasi-c2/src/ctx.rs

@@ -1,18 +1,50 @@
+use crate::file::{FileCaps, FileEntry, WasiFile};
 use crate::table::Table;
 use std::cell::{RefCell, RefMut};
+use std::collections::HashMap;
+use std::path::PathBuf;
 use std::rc::Rc;
 
 pub struct WasiCtx {
     table: Rc<RefCell<Table>>,
+    preopen_paths: RefCell<HashMap<u32, Option<PathBuf>>>,
 }
 
 impl WasiCtx {
     pub fn new() -> Self {
         WasiCtx {
             table: Rc::new(RefCell::new(Table::new())),
+            preopen_paths: RefCell::new(HashMap::new()),
         }
     }
 
+    pub fn preopen_file(
+        &self,
+        fd: u32,
+        file: Box<dyn WasiFile>,
+        base_caps: FileCaps,
+        inheriting_caps: FileCaps,
+        path: Option<PathBuf>,
+    ) {
+        let e = FileEntry {
+            base_caps,
+            inheriting_caps,
+            file,
+        };
+        self.table().insert_at(fd, e);
+        self.preopen_paths.borrow_mut().insert(fd, path);
+    }
+
+    pub fn preopen_dir(&self, fd: u32, dir: Box<dyn WasiDir>, flags: u32, path: PathBuf) {
+        let e = DirEntry { flags, dir };
+        self.table().insert_at(fd, e);
+        self.preopen_paths.borrow_mut().insert(fd, Some(path));
+    }
+
+    pub fn is_preopen(&self, fd: u32) -> bool {
+        self.preopen_paths.borrow().contains_key(&fd)
+    }
+
     pub fn table(&self) -> RefMut<Table> {
         self.table.borrow_mut()
     }