Make dns-sd optional

.travis.yml

@@ -14,5 +14,5 @@ before_install:
 install:
     - cargo install --git https://github.com/stepancheg/rust-protobuf --rev 921c69b protobuf
 script:
-    - cargo build --verbose
-    - cargo test --verbose
+    - cargo build --no-default-features --verbose
+    - cargo test --no-default-features --verbose

Cargo.toml

@@ -18,7 +18,6 @@ path = "protocol"
 [dependencies]
 bit-set     = "~0.2.0"
 byteorder   = "~0.4.2"
-dns-sd      = "~0.1.0"
 eventual    = "~0.1.5"
 getopts     = "~0.2.14"
 json_macros = "~0.2.6"
@@ -35,6 +34,10 @@ tempfile    = "~1.1.3"
 url         = "~0.5.2"
 vorbis      = "~0.0.13"
 
+[dependencies.dns-sd]
+version  = "~0.1.1"
+optional = true
+
 [dependencies.protobuf_macros]
 git = "https://github.com/plietar/rust-protobuf-macros.git"
 [dependencies.shannon]
@@ -45,3 +48,5 @@ git = "https://github.com/mvdnes/portaudio-rs"
 [build-dependencies]
 vergen = "~0.0.16"
 
+[features]
+default = ["dns-sd"]

src/discovery.rs

@@ -1,7 +1,7 @@
 use crypto;
 use crypto::mac::Mac;
 use crypto::digest::Digest;
-use dns_sd::DNSService;
+use zeroconf::DNSService;
 use tiny_http::{Method, Response, ResponseBox, Server};
 use num::BigUint;
 use url;

src/lib.rs

@@ -9,7 +9,6 @@
 extern crate bit_set;
 extern crate byteorder;
 extern crate crypto;
-extern crate dns_sd;
 extern crate eventual;
 extern crate num;
 extern crate portaudio;
@@ -23,6 +22,9 @@ extern crate tempfile;
 extern crate url;
 extern crate vorbis;
 
+#[cfg(feature = "dns-sd")]
+extern crate dns_sd;
+
 extern crate librespot_protocol;
 
 #[macro_use] pub mod util;
@@ -39,4 +41,5 @@ pub mod player;
 pub mod session;
 pub mod spirc;
 mod stream;
+mod zeroconf;
 

src/zeroconf.rs

@@ -0,0 +1,29 @@
+#[cfg(feature = "dns-sd")]
+pub use dns_sd::*;
+#[cfg(not(feature = "dns-sd"))]
+pub use self::stub::*;
+
+#[cfg(not(feature = "dns-sd"))]
+pub mod stub {
+    use std;
+    use std::io::Write;
+
+    #[derive(Debug)]
+    pub struct DNSService;
+
+    pub type DNSError = ();
+
+    impl DNSService {
+        pub fn register(_: Option<&str>,
+                        _: &str,
+                        _: Option<&str>,
+                        _: Option<&str>,
+                        _: u16,
+                        _: &[&str])
+                        -> std::result::Result<DNSService, DNSError> {
+            writeln!(&mut std::io::stderr(),
+                     "WARNING: dns-sd is not enabled. Service will probably not be visible").unwrap();
+            Ok(DNSService)
+        }
+    }
+}