1 files changed, 156 insertions, 0 deletions
diff --git a/cli/resolve_addr.rs b/cli/resolve_addr.rs
new file mode 100644
index 000000000..f26655be1
--- /dev/null
+++ b/cli/resolve_addr.rs
@@ -0,0 +1,156 @@
+// Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
+
+use futures::Async;
+use futures::Future;
+use futures::Poll;
+use std::error::Error;
+use std::fmt;
+use std::net::SocketAddr;
+use std::net::ToSocketAddrs;
+
+/// Go-style network address parsing. Returns a future.
+/// Examples:
+/// "192.0.2.1:25"
+/// ":80"
+/// "[2001:db8::1]:80"
+/// "198.51.100.1:80"
+/// "deno.land:443"
+pub fn resolve_addr(address: &str) -> ResolveAddrFuture {
+  ResolveAddrFuture {
+    address: address.to_string(),
+  }
+}
+
+#[derive(Debug)]
+pub enum ResolveAddrError {
+  Syntax,
+  Resolution(std::io::Error),
+}
+
+impl fmt::Display for ResolveAddrError {
+  fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
+    fmt.write_str(self.description())
+  }
+}
+
+impl Error for ResolveAddrError {
+  fn description(&self) -> &str {
+    match self {
+      ResolveAddrError::Syntax => "invalid address syntax",
+      ResolveAddrError::Resolution(e) => e.description(),
+    }
+  }
+}
+
+pub struct ResolveAddrFuture {
+  address: String,
+}
+
+impl Future for ResolveAddrFuture {
+  type Item = SocketAddr;
+  type Error = ResolveAddrError;
+
+  fn poll(&mut self) -> Poll<Self::Item, Self::Error> {
+    // The implementation of this is not actually async at the moment,
+    // however we intend to use async DNS resolution in the future and
+    // so we expose this as a future instead of Result.
+    match split(&self.address) {
+      None => Err(ResolveAddrError::Syntax),
+      Some(addr_port_pair) => {
+        // I absolutely despise the .to_socket_addrs() API.
+        let r = addr_port_pair
+          .to_socket_addrs()
+          .map_err(ResolveAddrError::Resolution);
+
+        r.and_then(|mut iter| match iter.next() {
+          Some(a) => Ok(Async::Ready(a)),
+          None => panic!("There should be at least one result"),
+        })
+      }
+    }
+  }
+}
+
+fn split(address: &str) -> Option<(&str, u16)> {
+  address.rfind(':').and_then(|i| {
+    let (a, p) = address.split_at(i);
+    // Default to localhost if given just the port. Example: ":80"
+    let addr = if !a.is_empty() { a } else { "0.0.0.0" };
+    // If this looks like an ipv6 IP address. Example: "[2001:db8::1]"
+    // Then we remove the brackets.
+    let addr = if addr.starts_with('[') && addr.ends_with(']') {
+      let l = addr.len() - 1;
+      addr.get(1..l).unwrap()
+    } else {
+      addr
+    };
+
+    let p = p.trim_start_matches(':');
+    match p.parse::<u16>() {
+      Err(_) => None,
+      Ok(port) => Some((addr, port)),
+    }
+  })
+}
+
+#[cfg(test)]
+mod tests {
+  use super::*;
+  use std::net::Ipv4Addr;
+  use std::net::Ipv6Addr;
+  use std::net::SocketAddrV4;
+  use std::net::SocketAddrV6;
+
+  #[test]
+  fn split1() {
+    assert_eq!(split("127.0.0.1:80"), Some(("127.0.0.1", 80)));
+  }
+
+  #[test]
+  fn split2() {
+    assert_eq!(split(":80"), Some(("0.0.0.0", 80)));
+  }
+
+  #[test]
+  fn split3() {
+    assert_eq!(split("no colon"), None);
+  }
+
+  #[test]
+  fn split4() {
+    assert_eq!(split("deno.land:443"), Some(("deno.land", 443)));
+  }
+
+  #[test]
+  fn split5() {
+    assert_eq!(split("[2001:db8::1]:8080"), Some(("2001:db8::1", 8080)));
+  }
+
+  #[test]
+  fn resolve_addr1() {
+    let expected =
+      SocketAddr::V4(SocketAddrV4::new(Ipv4Addr::new(127, 0, 0, 1), 80));
+    let actual = resolve_addr("127.0.0.1:80").wait().unwrap();
+    assert_eq!(actual, expected);
+  }
+
+  #[test]
+  fn resolve_addr3() {
+    let expected =
+      SocketAddr::V4(SocketAddrV4::new(Ipv4Addr::new(192, 0, 2, 1), 25));
+    let actual = resolve_addr("192.0.2.1:25").wait().unwrap();
+    assert_eq!(actual, expected);
+  }
+
+  #[test]
+  fn resolve_addr_ipv6() {
+    let expected = SocketAddr::V6(SocketAddrV6::new(
+      Ipv6Addr::new(0x2001, 0xdb8, 0, 0, 0, 0, 0, 1),
+      8080,
+      0,
+      0,
+    ));
+    let actual = resolve_addr("[2001:db8::1]:8080").wait().unwrap();
+    assert_eq!(actual, expected);
+  }
+}