Add resources op (#1119)

3 files changed, 95 insertions, 0 deletions

diff --git a/src/msg.fbs b/src/msg.fbs
index e7ebe6684..ba7031621 100644
--- a/src/msg.fbs
+++ b/src/msg.fbs
@@ -24,6 +24,8 @@ union Any {
   Rename,
   Readlink,
   ReadlinkRes,
+  Resources,
+  ResourcesRes,
   Symlink,
   Stat,
   StatRes,
@@ -270,6 +272,17 @@ table ReadlinkRes {
   path: string;
 }
 
+table Resources {}
+
+table Resource {
+  rid: int;
+  repr: string;
+}
+
+table ResourcesRes {
+  resources: [Resource];
+}
+
 table Symlink {
   oldname: string;
   newname: string;
diff --git a/src/ops.rs b/src/ops.rs
index 95522fb6b..ce123ccd2 100644
--- a/src/ops.rs
+++ b/src/ops.rs
@@ -19,6 +19,7 @@ use futures::Poll;
 use hyper;
 use hyper::rt::{Future, Stream};
 use remove_dir_all::remove_dir_all;
+use resources::table_entries;
 use std;
 use std::fs;
 use std::net::{Shutdown, SocketAddr};
@@ -94,6 +95,7 @@ pub fn dispatch(
       msg::Any::Read => op_read,
       msg::Any::Remove => op_remove,
       msg::Any::Rename => op_rename,
+      msg::Any::Resources => op_resources,
       msg::Any::SetEnv => op_set_env,
       msg::Any::Shutdown => op_shutdown,
       msg::Any::Start => op_start,
@@ -1288,3 +1290,49 @@ fn op_metrics(
     },
   ))
 }
+
+fn op_resources(
+  _state: Arc<IsolateState>,
+  base: &msg::Base,
+  data: &'static mut [u8],
+) -> Box<Op> {
+  assert_eq!(data.len(), 0);
+  let cmd_id = base.cmd_id();
+
+  let builder = &mut FlatBufferBuilder::new();
+  let serialized_resources = table_entries();
+
+  let res: Vec<_> = serialized_resources
+    .iter()
+    .map(|(key, value)| {
+      let repr = builder.create_string(value);
+
+      msg::Resource::create(
+        builder,
+        &msg::ResourceArgs {
+          rid: key.clone(),
+          repr: Some(repr),
+          ..Default::default()
+        },
+      )
+    }).collect();
+
+  let resources = builder.create_vector(&res);
+  let inner = msg::ResourcesRes::create(
+    builder,
+    &msg::ResourcesResArgs {
+      resources: Some(resources),
+      ..Default::default()
+    },
+  );
+
+  ok_future(serialize_response(
+    cmd_id,
+    builder,
+    msg::BaseArgs {
+      inner: Some(inner.as_union_value()),
+      inner_type: msg::Any::ResourcesRes,
+      ..Default::default()
+    },
+  ))
+}
diff --git a/src/resources.rs b/src/resources.rs
index a959d5c55..72fdf9777 100644
--- a/src/resources.rs
+++ b/src/resources.rs
@@ -58,6 +58,40 @@ enum Repr {
   TcpStream(tokio::net::TcpStream),
 }
 
+pub fn table_entries() -> Vec<(i32, String)> {
+  let table = RESOURCE_TABLE.lock().unwrap();
+
+  let tuples = table
+    .iter()
+    .map(|(key, value)| (key.clone(), inspect_repr(&value)))
+    .collect();
+
+  tuples
+}
+
+#[test]
+fn test_table_entries() {
+  let mut entries = table_entries();
+  entries.sort();
+  assert_eq!(entries.len(), 3);
+  assert_eq!(entries[0], (0, String::from("stdin")));
+  assert_eq!(entries[1], (1, String::from("stdout")));
+  assert_eq!(entries[2], (2, String::from("stderr")));
+}
+
+fn inspect_repr(repr: &Repr) -> String {
+  let h_repr = match repr {
+    Repr::Stdin(_) => "stdin",
+    Repr::Stdout(_) => "stdout",
+    Repr::Stderr(_) => "stderr",
+    Repr::FsFile(_) => "fsFile",
+    Repr::TcpListener(_) => "tcpListener",
+    Repr::TcpStream(_) => "tcpStream",
+  };
+
+  String::from(h_repr)
+}
+
 // Abstract async file interface.
 // Ideally in unix, if Resource represents an OS rid, it will be the same.
 #[derive(Debug)]