build: Clean up "proxy" feature

Before, the `client` module was gated on the "proxy" feature,
which caused unnecessary coupling since proxy is only
required for the Socks5 client type.

This change removes the client module's dependency on the "proxy"
feature in favor of more precise feature gating of the Socks5 client
type and related functions calling into the `socks` module.

Note that `Client` still requires a TLS backend to be enabled
by one of "use-openssl", "use-rustls" or "use-rustls-ring".

Author: ValuedMammal

src/client.rs

@@ -17,13 +17,14 @@ use std::convert::TryFrom;
 /// [`RawClient`](client/struct.RawClient.html) and provides a more user-friendly
 /// constructor that can choose the right backend based on the url prefix.
 ///
-/// **This is available only with the `default` features, or if `proxy` and one ssl implementation are enabled**
+/// **Note the `Socks5` client type requires the "proxy" feature to be enabled.**
 pub enum ClientType {
     #[allow(missing_docs)]
     TCP(RawClient<ElectrumPlaintextStream>),
     #[allow(missing_docs)]
     SSL(RawClient<ElectrumSslStream>),
     #[allow(missing_docs)]
+    #[cfg(feature = "proxy")]
     Socks5(RawClient<ElectrumProxyStream>),
 }
 
@@ -44,6 +45,7 @@ macro_rules! impl_inner_call {
             let res = match &*read_client {
                 ClientType::TCP(inner) => inner.$name( $($args, )* ),
                 ClientType::SSL(inner) => inner.$name( $($args, )* ),
+                #[cfg(feature = "proxy")]
                 ClientType::Socks5(inner) => inner.$name( $($args, )* ),
             };
             drop(read_client);
@@ -110,6 +112,7 @@ impl ClientType {
     pub fn from_config(url: &str, config: &Config) -> Result<Self, Error> {
         if url.starts_with("ssl://") {
             let url = url.replacen("ssl://", "", 1);
+            #[cfg(feature = "proxy")]
             let client = match config.socks5() {
                 Some(socks5) => RawClient::new_proxy_ssl(
                     url.as_str(),
@@ -121,19 +124,28 @@ impl ClientType {
                     RawClient::new_ssl(url.as_str(), config.validate_domain(), config.timeout())?
                 }
             };
+            #[cfg(not(feature = "proxy"))]
+            let client =
+                RawClient::new_ssl(url.as_str(), config.validate_domain(), config.timeout())?;
 
             Ok(ClientType::SSL(client))
         } else {
             let url = url.replacen("tcp://", "", 1);
 
-            Ok(match config.socks5().as_ref() {
-                None => ClientType::TCP(RawClient::new(url.as_str(), config.timeout())?),
+            #[cfg(feature = "proxy")]
+            let client = match config.socks5() {
                 Some(socks5) => ClientType::Socks5(RawClient::new_proxy(
                     url.as_str(),
                     socks5,
                     config.timeout(),
                 )?),
-            })
+                None => ClientType::TCP(RawClient::new(url.as_str(), config.timeout())?),
+            };
+
+            #[cfg(not(feature = "proxy"))]
+            let client = ClientType::TCP(RawClient::new(url.as_str(), config.timeout())?);
+
+            Ok(client)
         }
     }
 }

src/lib.rs

@@ -43,24 +43,24 @@ extern crate serde_json;
 ))]
 extern crate webpki_roots;
 
-#[cfg(any(feature = "default", feature = "proxy"))]
+#[cfg(feature = "proxy")]
 extern crate byteorder;
 
-#[cfg(all(unix, any(feature = "default", feature = "proxy")))]
+#[cfg(all(unix, feature = "proxy"))]
 extern crate libc;
-#[cfg(all(windows, any(feature = "default", feature = "proxy")))]
+#[cfg(all(windows, feature = "proxy"))]
 extern crate winapi;
 
-#[cfg(any(feature = "default", feature = "proxy"))]
+#[cfg(feature = "proxy")]
 pub mod socks;
 
 mod api;
 mod batch;
 
 #[cfg(any(
-    all(feature = "proxy", feature = "use-openssl"),
-    all(feature = "proxy", feature = "use-rustls"),
-    all(feature = "proxy", feature = "use-rustls-ring")
+    feature = "use-openssl",
+    feature = "use-rustls",
+    feature = "use-rustls-ring",
 ))]
 pub mod client;
 
@@ -74,9 +74,9 @@ pub mod utils;
 pub use api::ElectrumApi;
 pub use batch::Batch;
 #[cfg(any(
-    all(feature = "proxy", feature = "use-openssl"),
-    all(feature = "proxy", feature = "use-rustls"),
-    all(feature = "proxy", feature = "use-rustls-ring")
+    feature = "use-openssl",
+    feature = "use-rustls",
+    feature = "use-rustls-ring",
 ))]
 pub use client::*;
 pub use config::{Config, ConfigBuilder, Socks5Config};

src/raw_client.rs

@@ -470,10 +470,10 @@ impl RawClient<ElectrumSslStream> {
     }
 }
 
-#[cfg(any(feature = "default", feature = "proxy"))]
+#[cfg(feature = "proxy")]
 /// Transport type used to establish a connection to a server through a socks proxy
 pub type ElectrumProxyStream = Socks5Stream;
-#[cfg(any(feature = "default", feature = "proxy"))]
+#[cfg(feature = "proxy")]
 impl RawClient<ElectrumProxyStream> {
     /// Creates a new socks client and tries to connect to `target_addr` using `proxy_addr` as a
     /// socks proxy server. The DNS resolution of `target_addr`, if required, is done
@@ -499,10 +499,13 @@ impl RawClient<ElectrumProxyStream> {
         Ok(stream.into())
     }
 
-    #[cfg(any(
-        feature = "use-openssl",
-        feature = "use-rustls",
-        feature = "use-rustls-ring"
+    #[cfg(all(
+        any(
+            feature = "use-openssl",
+            feature = "use-rustls",
+            feature = "use-rustls-ring",
+        ),
+        feature = "proxy",
     ))]
     /// Creates a new TLS client that connects to `target_addr` using `proxy_addr` as a socks proxy
     /// server. The DNS resolution of `target_addr`, if required, is done through the proxy. This