download: clean up TLS feature guards

download/src/lib.rs

@@ -160,17 +160,39 @@ impl Backend {
             #[cfg(feature = "curl-backend")]
             Self::Curl => curl::download(url, resume_from, callback),
             #[cfg(any(feature = "reqwest-rustls-tls", feature = "reqwest-native-tls"))]
-            Self::Reqwest(tls) => reqwest_be::download(url, resume_from, callback, tls).await,
+            Self::Reqwest(tls) => tls.download(url, resume_from, callback).await,
         }
     }
 }
 
+#[cfg(any(feature = "reqwest-rustls-tls", feature = "reqwest-native-tls"))]
 #[derive(Debug, Copy, Clone)]
 pub enum TlsBackend {
+    #[cfg(feature = "reqwest-rustls-tls")]
     Rustls,
+    #[cfg(feature = "reqwest-native-tls")]
     NativeTls,
 }
 
+#[cfg(any(feature = "reqwest-rustls-tls", feature = "reqwest-native-tls"))]
+impl TlsBackend {
+    async fn download(
+        self,
+        url: &Url,
+        resume_from: u64,
+        callback: DownloadCallback<'_>,
+    ) -> Result<()> {
+        let client = match self {
+            #[cfg(feature = "reqwest-rustls-tls")]
+            Self::Rustls => &reqwest_be::CLIENT_RUSTLS_TLS,
+            #[cfg(feature = "reqwest-native-tls")]
+            Self::NativeTls => &reqwest_be::CLIENT_NATIVE_TLS,
+        };
+
+        reqwest_be::download(url, resume_from, callback, client).await
+    }
+}
+
 #[derive(Debug, Copy, Clone)]
 pub enum Event<'a> {
     ResumingPartialDownload,
@@ -298,12 +320,6 @@ pub mod curl {
 
 #[cfg(any(feature = "reqwest-rustls-tls", feature = "reqwest-native-tls"))]
 pub mod reqwest_be {
-    #[cfg(all(
-        not(feature = "reqwest-rustls-tls"),
-        not(feature = "reqwest-native-tls")
-    ))]
-    compile_error!("Must select a reqwest TLS backend");
-
     use std::io;
     #[cfg(feature = "reqwest-rustls-tls")]
     use std::sync::Arc;
@@ -320,20 +336,20 @@ pub mod reqwest_be {
     use tokio_stream::StreamExt;
     use url::Url;
 
-    use super::{DownloadError, Event, TlsBackend};
+    use super::{DownloadError, Event};
 
     pub async fn download(
         url: &Url,
         resume_from: u64,
         callback: &dyn Fn(Event<'_>) -> Result<()>,
-        tls: TlsBackend,
+        client: &Client,
     ) -> Result<()> {
         // Short-circuit reqwest for the "file:" URL scheme
         if download_from_file_url(url, resume_from, callback)? {
             return Ok(());
         }
 
-        let res = request(url, resume_from, tls)
+        let res = request(url, resume_from, client)
             .await
             .context("failed to make network request")?;
 
@@ -367,7 +383,7 @@ pub mod reqwest_be {
     }
 
     #[cfg(feature = "reqwest-rustls-tls")]
-    static CLIENT_RUSTLS_TLS: LazyLock<Client> = LazyLock::new(|| {
+    pub(super) static CLIENT_RUSTLS_TLS: LazyLock<Client> = LazyLock::new(|| {
         let catcher = || {
             client_generic()
                 .use_preconfigured_tls(
@@ -393,7 +409,7 @@ pub mod reqwest_be {
     });
 
     #[cfg(feature = "reqwest-native-tls")]
-    static CLIENT_DEFAULT_TLS: LazyLock<Client> = LazyLock::new(|| {
+    pub(super) static CLIENT_NATIVE_TLS: LazyLock<Client> = LazyLock::new(|| {
         let catcher = || {
             client_generic()
                 .user_agent(super::REQWEST_DEFAULT_TLS_USER_AGENT)
@@ -416,22 +432,8 @@ pub mod reqwest_be {
     async fn request(
         url: &Url,
         resume_from: u64,
-        backend: TlsBackend,
+        client: &Client,
     ) -> Result<Response, DownloadError> {
-        let client: &Client = match backend {
-            #[cfg(feature = "reqwest-rustls-tls")]
-            TlsBackend::Rustls => &CLIENT_RUSTLS_TLS,
-            #[cfg(not(feature = "reqwest-rustls-tls"))]
-            TlsBackend::Rustls => {
-                return Err(DownloadError::BackendUnavailable("reqwest rustls"));
-            }
-            #[cfg(feature = "reqwest-native-tls")]
-            TlsBackend::NativeTls => &CLIENT_DEFAULT_TLS,
-            #[cfg(not(feature = "reqwest-native-tls"))]
-            TlsBackend::NativeTls => {
-                return Err(DownloadError::BackendUnavailable("reqwest default TLS"));
-            }
-        };
         let mut req = client.get(url.as_str());
 
         if resume_from != 0 {