Config transfer (#951)

* fixed config dir issue

* jackson's sync write

theseus/src/util/io.rs

@@ -1,7 +1,10 @@
 // IO error
 // A wrapper around the tokio IO functions that adds the path to the error message, instead of the uninformative std::io::Error.
 
-use std::path::Path;
+use std::{path::Path, io::Write};
+
+use tempfile::NamedTempFile;
+use tauri::async_runtime::spawn_blocking;
 
 #[derive(Debug, thiserror::Error)]
 pub enum IOError {
@@ -113,15 +116,39 @@ pub async fn write(
     path: impl AsRef<std::path::Path>,
     data: impl AsRef<[u8]>,
 ) -> Result<(), IOError> {
-    let path = path.as_ref();
-    tokio::fs::write(path, data)
-        .await
-        .map_err(|e| IOError::IOPathError {
+    let path = path.as_ref().to_owned();
+    let data = data.as_ref().to_owned();
+    spawn_blocking(move || {
+        let cloned_path = path.clone();
+        sync_write(data, path).map_err(|e| IOError::IOPathError {
             source: e,
-            path: path.to_string_lossy().to_string(),
+            path: cloned_path.to_string_lossy().to_string(),
         })
+    })
+    .await
+    .map_err(|_| {
+        std::io::Error::new(std::io::ErrorKind::Other, "background task failed")
+    })??;
+
+    Ok(())
 }
 
+fn sync_write(
+    data: impl AsRef<[u8]>,
+    path: impl AsRef<Path>,
+) -> Result<(), std::io::Error> {
+    let mut tempfile = NamedTempFile::new_in(path.as_ref().parent().ok_or_else(|| {
+        std::io::Error::new(
+            std::io::ErrorKind::Other,
+            "could not get parent directory for temporary file",
+        )
+    })?)?;
+    tempfile.write_all(data.as_ref())?;
+    let tmp_path = tempfile.into_temp_path();
+    let path = path.as_ref();
+    tmp_path.persist(path)?;
+    std::io::Result::Ok(())
+}
 // rename
 pub async fn rename(
     from: impl AsRef<std::path::Path>,