1 files changed, 62 insertions, 0 deletions
diff --git a/library/std/src/sys/wasi/args.rs b/library/std/src/sys/wasi/args.rs
new file mode 100644
index 000000000..c42c310e3
--- /dev/null
+++ b/library/std/src/sys/wasi/args.rs
@@ -0,0 +1,62 @@
+#![deny(unsafe_op_in_unsafe_fn)]
+
+use crate::ffi::{CStr, OsStr, OsString};
+use crate::fmt;
+use crate::os::wasi::ffi::OsStrExt;
+use crate::vec;
+
+pub struct Args {
+    iter: vec::IntoIter<OsString>,
+}
+
+impl !Send for Args {}
+impl !Sync for Args {}
+
+/// Returns the command line arguments
+pub fn args() -> Args {
+    Args { iter: maybe_args().unwrap_or(Vec::new()).into_iter() }
+}
+
+fn maybe_args() -> Option<Vec<OsString>> {
+    unsafe {
+        let (argc, buf_size) = wasi::args_sizes_get().ok()?;
+        let mut argv = Vec::with_capacity(argc);
+        let mut buf = Vec::with_capacity(buf_size);
+        wasi::args_get(argv.as_mut_ptr(), buf.as_mut_ptr()).ok()?;
+        argv.set_len(argc);
+        let mut ret = Vec::with_capacity(argc);
+        for ptr in argv {
+            let s = CStr::from_ptr(ptr.cast());
+            ret.push(OsStr::from_bytes(s.to_bytes()).to_owned());
+        }
+        Some(ret)
+    }
+}
+
+impl fmt::Debug for Args {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        self.iter.as_slice().fmt(f)
+    }
+}
+
+impl Iterator for Args {
+    type Item = OsString;
+    fn next(&mut self) -> Option<OsString> {
+        self.iter.next()
+    }
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.iter.size_hint()
+    }
+}
+
+impl ExactSizeIterator for Args {
+    fn len(&self) -> usize {
+        self.iter.len()
+    }
+}
+
+impl DoubleEndedIterator for Args {
+    fn next_back(&mut self) -> Option<OsString> {
+        self.iter.next_back()
+    }
+}