From b307dce2abcf24f141d3a63cc48a65dc4b655224 Mon Sep 17 00:00:00 2001
From: Pat Hickey <pat@moreproductive.org>
Date: Mon, 26 Apr 2021 14:43:16 -0700
Subject: [PATCH] add readable and writable futures to WasiFile trait

---
 crates/wasi-common/cap-std-sync/src/file.rs  |  6 ++++++
 crates/wasi-common/cap-std-sync/src/stdio.rs | 12 ++++++++++++
 crates/wasi-common/src/file.rs               |  3 +++
 crates/wasi-common/src/pipe.rs               | 12 ++++++++++++
 crates/wasi-common/tokio/src/file.rs         |  6 ++++++
 5 files changed, 39 insertions(+)

diff --git a/crates/wasi-common/cap-std-sync/src/file.rs b/crates/wasi-common/cap-std-sync/src/file.rs
index ba9ff2743a..751c5f21b1 100644
--- a/crates/wasi-common/cap-std-sync/src/file.rs
+++ b/crates/wasi-common/cap-std-sync/src/file.rs
@@ -119,6 +119,12 @@ impl WasiFile for File {
     async fn num_ready_bytes(&self) -> Result<u64, Error> {
         Ok(self.0.num_ready_bytes()?)
     }
+    async fn readable(&mut self) -> Result<(), Error> {
+        Err(Error::badf())
+    }
+    async fn writable(&mut self) -> Result<(), Error> {
+        Err(Error::badf())
+    }
 }
 
 pub fn filetype_from(ft: &cap_std::fs::FileType) -> FileType {
diff --git a/crates/wasi-common/cap-std-sync/src/stdio.rs b/crates/wasi-common/cap-std-sync/src/stdio.rs
index d4d515cfeb..d86d181399 100644
--- a/crates/wasi-common/cap-std-sync/src/stdio.rs
+++ b/crates/wasi-common/cap-std-sync/src/stdio.rs
@@ -103,6 +103,12 @@ impl WasiFile for Stdin {
     async fn num_ready_bytes(&self) -> Result<u64, Error> {
         Ok(self.0.num_ready_bytes()?)
     }
+    async fn readable(&mut self) -> Result<(), Error> {
+        Err(Error::badf())
+    }
+    async fn writable(&mut self) -> Result<(), Error> {
+        Err(Error::badf())
+    }
 }
 #[cfg(windows)]
 impl AsRawHandle for Stdin {
@@ -203,6 +209,12 @@ macro_rules! wasi_file_write_impl {
             async fn num_ready_bytes(&self) -> Result<u64, Error> {
                 Ok(0)
             }
+            async fn readable(&mut self) -> Result<(), Error> {
+                Err(Error::badf())
+            }
+            async fn writable(&mut self) -> Result<(), Error> {
+                Err(Error::badf())
+            }
         }
         #[cfg(windows)]
         impl AsRawHandle for $ty {
diff --git a/crates/wasi-common/src/file.rs b/crates/wasi-common/src/file.rs
index b8eadb3673..dede0c0dc3 100644
--- a/crates/wasi-common/src/file.rs
+++ b/crates/wasi-common/src/file.rs
@@ -36,6 +36,9 @@ pub trait WasiFile {
     async fn seek(&self, pos: std::io::SeekFrom) -> Result<u64, Error>; // file op that generates a new stream from a file will supercede this
     async fn peek(&self, buf: &mut [u8]) -> Result<u64, Error>; // read op
     async fn num_ready_bytes(&self) -> Result<u64, Error>; // read op
+
+    async fn readable(&mut self) -> Result<(), Error>;
+    async fn writable(&mut self) -> Result<(), Error>;
 }
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
diff --git a/crates/wasi-common/src/pipe.rs b/crates/wasi-common/src/pipe.rs
index 5e5d418767..192fe5d10a 100644
--- a/crates/wasi-common/src/pipe.rs
+++ b/crates/wasi-common/src/pipe.rs
@@ -183,6 +183,12 @@ impl<R: Read + Any> WasiFile for ReadPipe<R> {
     async fn num_ready_bytes(&self) -> Result<u64, Error> {
         Ok(0)
     }
+    async fn readable(&mut self) -> Result<(), Error> {
+        Err(Error::badf())
+    }
+    async fn writable(&mut self) -> Result<(), Error> {
+        Err(Error::badf())
+    }
 }
 
 /// A virtual pipe write end.
@@ -336,4 +342,10 @@ impl<W: Write + Any> WasiFile for WritePipe<W> {
     async fn num_ready_bytes(&self) -> Result<u64, Error> {
         Ok(0)
     }
+    async fn readable(&mut self) -> Result<(), Error> {
+        Err(Error::badf())
+    }
+    async fn writable(&mut self) -> Result<(), Error> {
+        Err(Error::badf())
+    }
 }
diff --git a/crates/wasi-common/tokio/src/file.rs b/crates/wasi-common/tokio/src/file.rs
index 503e2168c4..a47e6b4ccf 100644
--- a/crates/wasi-common/tokio/src/file.rs
+++ b/crates/wasi-common/tokio/src/file.rs
@@ -184,6 +184,12 @@ impl WasiFile for File {
         use unsafe_io::AsUnsafeFile;
         asyncify(|| self.0.as_file_view().num_ready_bytes()).await
     }
+    async fn readable(&mut self) -> Result<(), Error> {
+        todo!("implement this in terms of tokio::io::AsyncFd")
+    }
+    async fn writable(&mut self) -> Result<(), Error> {
+        todo!("implement this in terms of tokio::io::AsyncFd")
+    }
 }
 pub fn filetype_from(ft: &cap_std::fs::FileType) -> FileType {
     use cap_fs_ext::FileTypeExt;