Method persist

src/stats.rs:210–242

Write the current snapshot to disk if configured and there are unsaved changes. Atomic: write to a sibling temp file, then rename.

(&self)

    /// Write the current snapshot to disk if configured and there are
    /// unsaved changes. Atomic: write to a sibling temp file, then rename.
    pub fn persist(&self) -> std::io::Result<()> {
        let Some(path) = self.persist_path.as_ref() else {
            return Ok(());
        };
        if !self.dirty.swap(false, Ordering::Relaxed) {
            return Ok(());
        }
        // Reset the overflow-warned flag so the next cycle can log again if
        // overflow is still happening. We do this regardless of whether the
        // write succeeds; worst case is an extra log line per cycle.
        self.overflow_warned_this_cycle
            .store(false, Ordering::Relaxed);

        let snapshot = self.snapshot();
        let content = serde_json::to_string_pretty(&snapshot)
            .map_err(|e| std::io::Error::other(format!("failed to serialize stats: {e}")))?;

        if let Some(parent) = path.parent() {
            std::fs::create_dir_all(parent)?;
        }
        let tmp_path = path.with_extension("json.tmp");
        std::fs::write(&tmp_path, content)?;

        #[cfg(unix)]
        {
            use std::os::unix::fs::PermissionsExt;
            std::fs::set_permissions(&tmp_path, std::fs::Permissions::from_mode(0o600))?;
        }

        std::fs::rename(&tmp_path, path)?;
        debug!(path = %path.display(), "stats persisted to disk");
        Ok(())
    }
}

impl std::fmt::Debug for Stats {