Improve code reuse in polling, reduce cfg usage too

wasmerio · Aug 29, 2019 · 85bf0c3 · 85bf0c3
1 parent fba6dbf
commit 85bf0c3
Showing 1 changed file with 36 additions and 84 deletions.
diff --git a/lib/wasi/src/state/types.rs b/lib/wasi/src/state/types.rs
@@ -452,26 +452,11 @@ impl WasiFile for HostFile {
         std::fs::rename(&self.host_path, new_name).map_err(Into::into)
     }
 
-    #[cfg(unix)]
-    fn bytes_available(&self) -> Result<usize, WasiFsError> {
-        use std::os::unix::io::AsRawFd;
-        let host_fd = self.inner.as_raw_fd();
-
-        let mut bytes_found = 0 as libc::c_int;
-        let result = unsafe { libc::ioctl(host_fd, libc::FIONREAD, &mut bytes_found) };
-
-        match result {
-            // success
-            0 => Ok(bytes_found.try_into().unwrap_or(0)),
-            libc::EBADF => Err(WasiFsError::InvalidFd),
-            libc::EFAULT => Err(WasiFsError::InvalidData),
-            libc::EINVAL => Err(WasiFsError::InvalidInput),
-            _ => Err(WasiFsError::IOError),
-        }
-    }
-    #[cfg(not(unix))]
     fn bytes_available(&self) -> Result<usize, WasiFsError> {
-        unimplemented!("HostFile::bytes_available in WasiFile is not implemented for non-Unix-like targets yet");
+        // unwrap is safe because of get_raw_fd implementation
+        let host_fd = self.get_raw_fd().unwrap();
+
+        host_file_bytes_available(host_fd)
     }
 
     #[cfg(unix)]
@@ -514,6 +499,26 @@ impl From<io::Error> for WasiFsError {
     }
 }
 
+#[cfg(unix)]
+fn host_file_bytes_available(host_fd: i32) -> Result<usize, WasiFsError> {
+    let mut bytes_found = 0 as libc::c_int;
+    let result = unsafe { libc::ioctl(host_fd, libc::FIONREAD, &mut bytes_found) };
+
+    match result {
+        // success
+        0 => Ok(bytes_found.try_into().unwrap_or(0)),
+        libc::EBADF => Err(WasiFsError::InvalidFd),
+        libc::EFAULT => Err(WasiFsError::InvalidData),
+        libc::EINVAL => Err(WasiFsError::InvalidInput),
+        _ => Err(WasiFsError::IOError),
+    }
+}
+
+#[cfg(not(unix))]
+fn host_file_bytes_available(raw_fd: i32) -> Result<usize, WasiFsError> {
+    unimplemented!("host_file_bytes_available not yet implemented for non-Unix-like targets.  This probably means the program tried to use wasi::poll_oneoff")
+}
+
 #[derive(Debug)]
 pub struct Stdout(pub std::io::Stdout);
 impl Read for Stdout {
@@ -579,29 +584,11 @@ impl WasiFile for Stdout {
         0
     }
 
-    #[cfg(unix)]
-    fn bytes_available(&self) -> Result<usize, WasiFsError> {
-        use std::os::unix::io::AsRawFd;
-        let host_fd = self.0.as_raw_fd();
-
-        let mut bytes_found = 0 as libc::c_int;
-        // TODO: check that this makes sense
-        let result = unsafe { libc::ioctl(host_fd, libc::FIONREAD, &mut bytes_found) };
-
-        match result {
-            // success
-            0 => Ok(bytes_found.try_into().unwrap_or(0)),
-            libc::EBADF => Err(WasiFsError::InvalidFd),
-            libc::EFAULT => Err(WasiFsError::InvalidData),
-            libc::EINVAL => Err(WasiFsError::InvalidInput),
-            _ => Err(WasiFsError::IOError),
-        }
-    }
-    #[cfg(not(unix))]
     fn bytes_available(&self) -> Result<usize, WasiFsError> {
-        unimplemented!(
-            "Stdout::bytes_available in WasiFile is not implemented for non-Unix-like targets yet"
-        );
+        // unwrap is safe because of get_raw_fd implementation
+        let host_fd = self.get_raw_fd().unwrap();
+
+        host_file_bytes_available(host_fd)
     }
 
     #[cfg(unix)]
@@ -683,29 +670,11 @@ impl WasiFile for Stderr {
         0
     }
 
-    #[cfg(unix)]
     fn bytes_available(&self) -> Result<usize, WasiFsError> {
-        use std::os::unix::io::AsRawFd;
-        let host_fd = self.0.as_raw_fd();
-
-        let mut bytes_found = 0 as libc::c_int;
-        // TODO: check that this makes sense
-        let result = unsafe { libc::ioctl(host_fd, libc::FIONREAD, &mut bytes_found) };
-
-        match result {
-            // success
-            0 => Ok(bytes_found.try_into().unwrap_or(0)),
-            libc::EBADF => Err(WasiFsError::InvalidFd),
-            libc::EFAULT => Err(WasiFsError::InvalidData),
-            libc::EINVAL => Err(WasiFsError::InvalidInput),
-            _ => Err(WasiFsError::IOError),
-        }
-    }
-    #[cfg(not(unix))]
-    fn bytes_available(&self) -> Result<usize, WasiFsError> {
-        unimplemented!(
-            "Stderr::bytes_available in WasiFile is not implemented for non-Unix-like targets yet"
-        );
+        // unwrap is safe because of get_raw_fd implementation
+        let host_fd = self.get_raw_fd().unwrap();
+
+        host_file_bytes_available(host_fd)
     }
 
     #[cfg(unix)]
@@ -787,28 +756,11 @@ impl WasiFile for Stdin {
         0
     }
 
-    #[cfg(unix)]
-    fn bytes_available(&self) -> Result<usize, WasiFsError> {
-        use std::os::unix::io::AsRawFd;
-        let host_fd = self.0.as_raw_fd();
-
-        let mut bytes_found = 0 as libc::c_int;
-        let result = unsafe { libc::ioctl(host_fd, libc::FIONREAD, &mut bytes_found) };
-
-        match result {
-            // success
-            0 => Ok(bytes_found.try_into().unwrap_or(0)),
-            libc::EBADF => Err(WasiFsError::InvalidFd),
-            libc::EFAULT => Err(WasiFsError::InvalidData),
-            libc::EINVAL => Err(WasiFsError::InvalidInput),
-            _ => Err(WasiFsError::IOError),
-        }
-    }
-    #[cfg(not(unix))]
     fn bytes_available(&self) -> Result<usize, WasiFsError> {
-        unimplemented!(
-            "Stdin::bytes_available in WasiFile is not implemented for non-Unix-like targets yet"
-        );
+        // unwrap is safe because of get_raw_fd implementation
+        let host_fd = self.get_raw_fd().unwrap();
+
+        host_file_bytes_available(host_fd)
     }
 
     #[cfg(unix)]