fs: add read_to_string (#1664)

tokio-fs/src/lib.rs

@@ -49,6 +49,7 @@ pub mod os;
 mod read;
 mod read_dir;
 mod read_link;
+mod read_to_string;
 mod remove_dir;
 mod remove_dir_all;
 mod remove_file;
@@ -69,6 +70,7 @@ pub use crate::open_options::OpenOptions;
 pub use crate::read::read;
 pub use crate::read_dir::{read_dir, DirEntry, ReadDir};
 pub use crate::read_link::read_link;
+pub use crate::read_to_string::read_to_string;
 pub use crate::remove_dir::remove_dir;
 pub use crate::remove_dir_all::remove_dir_all;
 pub use crate::remove_file::remove_file;

tokio-fs/src/read_to_string.rs

@@ -0,0 +1,27 @@
+use crate::asyncify;
+
+use std::{io, path::Path};
+
+/// Creates a future which will open a file for reading and read the entire
+/// contents into a string and return said string.
+///
+/// This is the async equivalent of `std::fs::read_to_string`.
+///
+/// # Examples
+///
+/// ```no_run
+/// use tokio::fs;
+///
+/// # async fn dox() -> std::io::Result<()> {
+/// let contents = fs::read_to_string("foo.txt").await?;
+/// println!("foo.txt contains {} bytes", contents.len());
+/// # Ok(())
+/// # }
+/// ```
+pub async fn read_to_string<P>(path: P) -> io::Result<String>
+where
+    P: AsRef<Path>,
+{
+    let path = path.as_ref().to_owned();
+    asyncify(move || std::fs::read_to_string(path)).await
+}

tokio/src/fs.rs

@@ -8,7 +8,7 @@
 //! function.
 
 pub use tokio_fs::{
-    create_dir, create_dir_all, hard_link, metadata, os, read, read_dir, read_link, remove_dir,
-    remove_dir_all, remove_file, rename, set_permissions, symlink_metadata, write, File,
-    OpenOptions,
+    create_dir, create_dir_all, hard_link, metadata, os, read, read_dir, read_link, read_to_string,
+    remove_dir, remove_dir_all, remove_file, rename, set_permissions, symlink_metadata, write,
+    File, OpenOptions,
 };