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use std::collections::VecDeque;
use std::marker::PhantomData;
use std::net::IpAddr;
use actix_service::Service;
use futures::{Async, Future, Poll};
use trust_dns_resolver::config::{ResolverConfig, ResolverOpts};
pub use trust_dns_resolver::error::ResolveError;
use trust_dns_resolver::lookup_ip::LookupIpFuture;
use trust_dns_resolver::system_conf::read_system_conf;
use trust_dns_resolver::{AsyncResolver, Background};
pub trait RequestHost {
fn host(&self) -> &str;
}
impl RequestHost for String {
fn host(&self) -> &str {
self.as_ref()
}
}
pub struct Resolver<T = String> {
resolver: AsyncResolver,
req: PhantomData<T>,
}
impl<T: RequestHost> Default for Resolver<T> {
fn default() -> Self {
let (cfg, opts) = if let Ok((cfg, opts)) = read_system_conf() {
(cfg, opts)
} else {
(ResolverConfig::default(), ResolverOpts::default())
};
Resolver::new(cfg, opts)
}
}
impl<T: RequestHost> Resolver<T> {
pub fn new(cfg: ResolverConfig, opts: ResolverOpts) -> Self {
let (resolver, bg) = AsyncResolver::new(cfg, opts);
tokio_current_thread::spawn(bg);
Resolver {
resolver,
req: PhantomData,
}
}
pub fn into_request<T2: RequestHost>(&self) -> Resolver<T2> {
Resolver {
resolver: self.resolver.clone(),
req: PhantomData,
}
}
}
impl<T> Clone for Resolver<T> {
fn clone(&self) -> Self {
Resolver {
resolver: self.resolver.clone(),
req: PhantomData,
}
}
}
impl<T: RequestHost> Service for Resolver<T> {
type Request = T;
type Response = (T, VecDeque<IpAddr>);
type Error = ResolveError;
type Future = ResolverFuture<T>;
fn poll_ready(&mut self) -> Poll<(), Self::Error> {
Ok(Async::Ready(()))
}
fn call(&mut self, req: T) -> Self::Future {
if let Ok(ip) = req.host().parse() {
let mut addrs = VecDeque::new();
addrs.push_back(ip);
ResolverFuture::new(req, &self.resolver, Some(addrs))
} else {
ResolverFuture::new(req, &self.resolver, None)
}
}
}
#[doc(hidden)]
pub struct ResolverFuture<T> {
req: Option<T>,
lookup: Option<Background<LookupIpFuture>>,
addrs: Option<VecDeque<IpAddr>>,
}
impl<T: RequestHost> ResolverFuture<T> {
pub fn new(addr: T, resolver: &AsyncResolver, addrs: Option<VecDeque<IpAddr>>) -> Self {
let lookup = Some(resolver.lookup_ip(addr.host()));
ResolverFuture {
lookup,
addrs,
req: Some(addr),
}
}
}
impl<T: RequestHost> Future for ResolverFuture<T> {
type Item = (T, VecDeque<IpAddr>);
type Error = ResolveError;
fn poll(&mut self) -> Poll<Self::Item, Self::Error> {
if let Some(addrs) = self.addrs.take() {
Ok(Async::Ready((self.req.take().unwrap(), addrs)))
} else {
match self.lookup.as_mut().unwrap().poll() {
Ok(Async::NotReady) => Ok(Async::NotReady),
Ok(Async::Ready(ips)) => Ok(Async::Ready((
self.req.take().unwrap(),
ips.iter().collect(),
))),
Err(err) => Err(err),
}
}
}
}