Method load_graph

rust-core/src/storage/persistence.rs:100–112

(&self, project_id: &str)

    }

    pub fn load_graph(&self, project_id: &str) -> io::Result<Option<PetCodeGraph>> {
        match self.storage_mode {
            StorageMode::Json => self.load_graph_json(project_id),
            StorageMode::Binary => self.load_graph_binary(project_id),
            StorageMode::Both => {
                // 优先尝试加载二进制格式（更快），如果失败则加载JSON格式
                match self.load_graph_binary(project_id) {
                    Ok(graph) => Ok(graph),
                    Err(_) => self.load_graph_json(project_id),
                }
            },
        }
    }

    fn load_graph_json(&self, project_id: &str) -> io::Result<Option<PetCodeGraph>> {
        let graph_file = self.project_dir(project_id).join("graph.json");