mv compiler to compiler/

compiler/rustc_data_structures/src/temp_dir.rs

@@ -0,0 +1,34 @@
+use std::mem::ManuallyDrop;
+use std::path::Path;
+use tempfile::TempDir;
+
+/// This is used to avoid TempDir being dropped on error paths unintentionally.
+#[derive(Debug)]
+pub struct MaybeTempDir {
+    dir: ManuallyDrop<TempDir>,
+    // Whether the TempDir should be deleted on drop.
+    keep: bool,
+}
+
+impl Drop for MaybeTempDir {
+    fn drop(&mut self) {
+        // Safety: We are in the destructor, and no further access will
+        // occur.
+        let dir = unsafe { ManuallyDrop::take(&mut self.dir) };
+        if self.keep {
+            dir.into_path();
+        }
+    }
+}
+
+impl AsRef<Path> for MaybeTempDir {
+    fn as_ref(&self) -> &Path {
+        self.dir.path()
+    }
+}
+
+impl MaybeTempDir {
+    pub fn new(dir: TempDir, keep_on_drop: bool) -> MaybeTempDir {
+        MaybeTempDir { dir: ManuallyDrop::new(dir), keep: keep_on_drop }
+    }
+}