io: expose std{in, out, err} under io feature (#1759)

This exposes `std{in, out, err}` under io feature by moving
`fs::blocking` module into `io::blocking`.
As `fs` feature depends on `io-trait` feature, `fs` implementations can
always access `io` module.

tokio/Cargo.toml

@@ -28,6 +28,7 @@ default = [
   "blocking",
   "fs",
   "io-util",
+  "io",
   "net",
   "process",
   "rt-full",
@@ -42,6 +43,7 @@ dns = ["blocking"]
 fs = ["blocking"]
 io-driver = ["mio", "lazy_static", "sync"] # TODO: get rid of sync
 io-util = ["memchr"]
+io = ["io-util", "blocking"]
 macros = ["tokio-macros"]
 net = ["dns", "tcp", "udp", "uds"]
 process = [

tokio/src/fs/file.rs

@@ -3,8 +3,8 @@
 //! [`File`]: file/struct.File.html
 
 use self::State::*;
-use crate::fs::blocking::Buf;
 use crate::fs::{asyncify, sys};
+use crate::io::blocking::Buf;
 use crate::io::{AsyncRead, AsyncWrite};
 
 use std::fmt;

tokio/src/fs/mod.rs

@@ -22,8 +22,6 @@
 //!
 //! [`AsyncRead`]: https://docs.rs/tokio-io/0.1/tokio_io/trait.AsyncRead.html
 
-pub(crate) mod blocking;
-
 mod create_dir;
 pub use self::create_dir::create_dir;
 

tokio/src/io/blocking.rs

@@ -1,4 +1,4 @@
-use crate::fs::sys;
+use crate::io::sys;
 use crate::io::{AsyncRead, AsyncWrite};
 
 use std::cmp;
@@ -35,6 +35,7 @@ enum State<T> {
 }
 
 impl<T> Blocking<T> {
+    #[cfg(feature = "io")]
     pub(crate) fn new(inner: T) -> Blocking<T> {
         Blocking {
             inner: Some(inner),
@@ -264,6 +265,7 @@ impl Buf {
         res
     }
 
+    #[cfg(feature = "fs")]
     pub(crate) fn discard_read(&mut self) -> i64 {
         let ret = -(self.bytes().len() as i64);
         self.pos = 0;

tokio/src/io/mod.rs

@@ -36,6 +36,9 @@
 //! [`ErrorKind`]: enum.ErrorKind.html
 //! [`Result`]: type.Result.html
 
+#[cfg(any(feature = "io", feature = "fs"))]
+pub(crate) mod blocking;
+
 mod async_buf_read;
 pub use self::async_buf_read::AsyncBufRead;
 
@@ -58,24 +61,30 @@ pub use self::util::{
     BufWriter, Copy, Empty, Lines, Repeat, Sink, Split, Take,
 };
 
-// TODO: These should not be guarded by `fs`
-
-#[cfg(feature = "fs")]
+#[cfg(feature = "io")]
 mod stderr;
-#[cfg(feature = "fs")]
+#[cfg(feature = "io")]
 pub use self::stderr::{stderr, Stderr};
 
-#[cfg(feature = "fs")]
+#[cfg(feature = "io")]
 mod stdin;
-#[cfg(feature = "fs")]
+#[cfg(feature = "io")]
 pub use self::stdin::{stdin, Stdin};
 
-#[cfg(feature = "fs")]
+#[cfg(feature = "io")]
 mod stdout;
-#[cfg(feature = "fs")]
+#[cfg(feature = "io")]
 pub use self::stdout::{stdout, Stdout};
 
 // Re-export io::Error so that users don't have to deal
 // with conflicts when `use`ing `tokio::io` and `std::io`.
 #[cfg(feature = "io-util")]
 pub use std::io::{Error, ErrorKind, Result};
+
+/// Types in this module can be mocked out in tests.
+#[cfg(any(feature = "io", feature = "fs"))]
+mod sys {
+    // TODO: don't rename
+    pub(crate) use crate::blocking::spawn_blocking as run;
+    pub(crate) use crate::task::JoinHandle as Blocking;
+}

tokio/src/io/stderr.rs

@@ -1,4 +1,4 @@
-use crate::fs::blocking::Blocking;
+use crate::io::blocking::Blocking;
 use crate::io::AsyncWrite;
 
 use std::io;

tokio/src/io/stdin.rs

@@ -1,4 +1,4 @@
-use crate::fs::blocking::Blocking;
+use crate::io::blocking::Blocking;
 use crate::io::AsyncRead;
 
 use std::io;

tokio/src/io/stdout.rs

@@ -1,4 +1,4 @@
-use crate::fs::blocking::Blocking;
+use crate::io::blocking::Blocking;
 use crate::io::AsyncWrite;
 
 use std::io;

tokio/tests/fs_file_mocked.rs

@@ -18,7 +18,7 @@ mod file;
 use file::File;
 
 #[allow(warnings)]
-#[path = "../src/fs/blocking.rs"]
+#[path = "../src/io/blocking.rs"]
 mod blocking;
 
 // Load mocked types
@@ -29,9 +29,16 @@ mod support {
 pub(crate) use support::mock_pool as pool;
 
 // Place them where the source expects them
-pub(crate) mod fs {
+pub(crate) mod io {
+    pub(crate) use tokio::io::*;
+
     pub(crate) use crate::blocking;
 
+    pub(crate) mod sys {
+        pub(crate) use crate::support::mock_pool::{run, Blocking};
+    }
+}
+pub(crate) mod fs {
     pub(crate) mod sys {
         pub(crate) use crate::support::mock_file::File;
         pub(crate) use crate::support::mock_pool::{run, Blocking};
@@ -41,7 +48,6 @@ pub(crate) mod fs {
 }
 use fs::sys;
 
-use tokio::io;
 use tokio::prelude::*;
 use tokio_test::{assert_pending, assert_ready, assert_ready_err, assert_ready_ok, task};