lua使用rust代码(第三期)--Vec<struct>
[toc]
前言
在C中,string类型可以看作char的数组。保存的是数组第一个元素的地址。那么对于真正的数组,也可以如lua使用rust代码--第二期 中处理字符串一样,处理对象数组。
示例
lib.rs
use std::ffi::CString;
use std::os::raw::{c_char, c_int};
//rust struct
#[derive(Deserialize,Debug)]
struct HostInfo {
ip:String,
port:u32,
}
#[derive(Debug)]
#[repr(C)]
pub struct CHostInfo {
ip: *const c_char,
ip_len: c_int,
port: c_int,
}
fn get_info() -> Result<Vec<HostInfo>, reqwest::Error>{
//get data through api by reqwest
let res: Vec<HostInfo> = reqwest::Client::new()
.get("http://example.com/api/host/")
.send()?
.json()?;
Ok(res)
}
#[no_mangle]
pub extern "C" fn get_all_data(len: *mut u32) -> *mut CHostInfo{
let res = get_info().expect("http request fail");
let mut data:Vec<CHostInfo> = res.into_iter()
.map(|info| {
let ip_cs = CString::new(info.ip.as_str()).unwrap();
let ip = ip_cs.as_ptr();
let ip_len = info.ip.len() as c_int;
std::mem::forget(ip_cs);
CHostInfo {
ip: ip,
ip_len:ip_len,
port: info.port as c_int,
}
})
.collect();
let ptr = data.as_mut_ptr();
unsafe {
*len = data.len() as u32;
}
std::mem::forget(data);
ptr
}
lua
ffi = require("ffi")
ffi.cdef[[
typedef struct {
char * ip;
int ip_len;
int port;
} hostinfo_t;
hostinfo_t * get_all_data(int*);
]]
rust_lib = ffi.load("./libexample.so")
function get_all_data()
local intPtr = ffi.typeof("int[1]")
local len = intPtr()
local data = rust_lib.get_all_data(len)
local res ={}
for i=0,len[0]-1 do
res[i] = {}
res[i]["ip"] = ffi.string(data[i].ip,data[i].ip_len)
res[i]["port"] = data[i].port
end
return res
end