Handle out of memory errors in fs::read/read_to_string

Author: kornelski

library/std/src/fs.rs

@@ -254,7 +254,8 @@ pub fn read<P: AsRef<Path>>(path: P) -> io::Result<Vec<u8>> {
     fn inner(path: &Path) -> io::Result<Vec<u8>> {
         let mut file = File::open(path)?;
         let size = file.metadata().map(|m| m.len() as usize).ok();
-        let mut bytes = Vec::with_capacity(size.unwrap_or(0));
+        let mut bytes = Vec::new();
+        bytes.try_reserve(size.unwrap_or(0)).map_err(|_| io::ErrorKind::OutOfMemory)?;
         io::default_read_to_end(&mut file, &mut bytes, size)?;
         Ok(bytes)
     }
@@ -296,7 +297,8 @@ pub fn read_to_string<P: AsRef<Path>>(path: P) -> io::Result<String> {
     fn inner(path: &Path) -> io::Result<String> {
         let mut file = File::open(path)?;
         let size = file.metadata().map(|m| m.len() as usize).ok();
-        let mut string = String::with_capacity(size.unwrap_or(0));
+        let mut string = String::new();
+        string.try_reserve(size.unwrap_or(0)).map_err(|_| io::ErrorKind::OutOfMemory)?;
         io::default_read_to_string(&mut file, &mut string, size)?;
         Ok(string)
     }