1 files changed, 42 insertions, 0 deletions
diff --git a/src/tokio.rs b/src/tokio.rs
new file mode 100644
index 0000000..78979bf
--- /dev/null
+++ b/src/tokio.rs
@@ -0,0 +1,42 @@
+use std::os::unix::prelude::RawFd;
+
+use tokio::process::Command;
+use tokio_crate as tokio;
+
+use crate::{map_fds, preserve_fds, validate_child_fds, FdMapping, FdMappingCollision};
+
+/// Extension to add file descriptor mappings to a [`Command`].
+pub trait CommandFdAsyncExt {
+    /// Adds the given set of file descriptors to the command.
+    ///
+    /// Warning: Calling this more than once on the same command, or attempting to run the same
+    /// command more than once after calling this, may result in unexpected behaviour.
+    fn fd_mappings(&mut self, mappings: Vec<FdMapping>) -> Result<&mut Self, FdMappingCollision>;
+
+    /// Adds the given set of file descriptors to be passed on to the child process when the command
+    /// is run.
+    fn preserved_fds(&mut self, fds: Vec<RawFd>) -> &mut Self;
+}
+
+impl CommandFdAsyncExt for Command {
+    fn fd_mappings(
+        &mut self,
+        mut mappings: Vec<FdMapping>,
+    ) -> Result<&mut Self, FdMappingCollision> {
+        let child_fds = validate_child_fds(&mappings)?;
+
+        unsafe {
+            self.pre_exec(move || map_fds(&mut mappings, &child_fds));
+        }
+
+        Ok(self)
+    }
+
+    fn preserved_fds(&mut self, fds: Vec<RawFd>) -> &mut Self {
+        unsafe {
+            self.pre_exec(move || preserve_fds(&fds));
+        }
+
+        self
+    }
+}