1 files changed, 49 insertions, 0 deletions
diff --git a/library/std/src/sys_common/io.rs b/library/std/src/sys_common/io.rs
new file mode 100644
index 000000000..d1e9fed41
--- /dev/null
+++ b/library/std/src/sys_common/io.rs
@@ -0,0 +1,49 @@
+// Bare metal platforms usually have very small amounts of RAM
+// (in the order of hundreds of KB)
+pub const DEFAULT_BUF_SIZE: usize = if cfg!(target_os = "espidf") { 512 } else { 8 * 1024 };
+
+#[cfg(test)]
+#[allow(dead_code)] // not used on emscripten
+pub mod test {
+    use crate::env;
+    use crate::fs;
+    use crate::path::{Path, PathBuf};
+    use crate::thread;
+    use rand::RngCore;
+
+    pub struct TempDir(PathBuf);
+
+    impl TempDir {
+        pub fn join(&self, path: &str) -> PathBuf {
+            let TempDir(ref p) = *self;
+            p.join(path)
+        }
+
+        pub fn path(&self) -> &Path {
+            let TempDir(ref p) = *self;
+            p
+        }
+    }
+
+    impl Drop for TempDir {
+        fn drop(&mut self) {
+            // Gee, seeing how we're testing the fs module I sure hope that we
+            // at least implement this correctly!
+            let TempDir(ref p) = *self;
+            let result = fs::remove_dir_all(p);
+            // Avoid panicking while panicking as this causes the process to
+            // immediately abort, without displaying test results.
+            if !thread::panicking() {
+                result.unwrap();
+            }
+        }
+    }
+
+    pub fn tmpdir() -> TempDir {
+        let p = env::temp_dir();
+        let mut r = rand::thread_rng();
+        let ret = p.join(&format!("rust-{}", r.next_u32()));
+        fs::create_dir(&ret).unwrap();
+        TempDir(ret)
+    }
+}