Fix overflow, race condition, and format bugs

pixstrip-core/src/storage.rs

@@ -14,7 +14,7 @@ fn default_config_dir() -> PathBuf {
 }
 
 /// Write to a temporary file then rename, for crash safety.
-fn atomic_write(path: &Path, contents: &str) -> std::io::Result<()> {
+pub fn atomic_write(path: &Path, contents: &str) -> std::io::Result<()> {
     let tmp = path.with_extension("tmp");
     std::fs::write(&tmp, contents)?;
     std::fs::rename(&tmp, path)?;