refactor(download): remove curl backend

Cargo.toml

@@ -11,15 +11,11 @@ repository = "https://github.com/rust-lang/rustup"
 build = "build.rs"
 
 [features]
-curl-backend = ["download/curl-backend"]
 default = [
-    "curl-backend",
-    "reqwest-backend",
     "reqwest-default-tls",
     "reqwest-rustls-tls",
 ]
 
-reqwest-backend = ["download/reqwest-backend"]
 vendored-openssl = ['openssl/vendored']
 
 reqwest-default-tls = ["download/reqwest-default-tls"]
@@ -61,7 +57,7 @@ itertools = "0.12"
 libc = "0.2"
 once_cell.workspace = true
 opener = "0.7.0"
-# `openssl` is used by `curl` or `reqwest` backend although it isn't imported by rustup: this
+# `openssl` is used by or `reqwest` backend although it isn't imported by rustup: this
 # allows controlling the vendoring status without exposing the presence of the download crate.
 # HACK: We temporarily pin the OpenSSL version due to build issues encountered in
 # https://github.com/rust-lang/rustup/pull/3668.
@@ -192,4 +188,4 @@ opt-level = 0
 
 [package.metadata.cargo-all-features]
 # Building with no web backend will error.
-always_include_features = ["reqwest-backend", "reqwest-rustls-tls"]
+always_include_features = ["reqwest-rustls-tls"]

ci/run.bash

@@ -8,7 +8,7 @@ rustc -vV
 cargo -vV
 
 
-FEATURES=('--no-default-features' '--features' 'curl-backend,reqwest-backend,reqwest-default-tls')
+FEATURES=('--no-default-features' '--features' 'reqwest-default-tls')
 case "$(uname -s)" in
   *NT* ) ;; # Windows NT
   * ) FEATURES+=('--features' 'vendored-openssl') ;;
@@ -39,7 +39,7 @@ target_cargo() {
 target_cargo build
 
 download_pkg_test() {
-  features=('--no-default-features' '--features' 'curl-backend,reqwest-backend,reqwest-default-tls')
+  features=('--no-default-features' '--features' 'reqwest-default-tls')
   case "$TARGET" in
     # these platforms aren't supported by ring:
     powerpc* ) ;;

download/Cargo.toml

@@ -6,17 +6,14 @@ license = "MIT OR Apache-2.0"
 
 [features]
 
-default = ["reqwest-backend", "reqwest-rustls-tls", "reqwest-default-tls"]
+default = ["reqwest-rustls-tls", "reqwest-default-tls"]
 
-curl-backend = ["curl"]
-reqwest-backend = ["reqwest", "env_proxy"]
 reqwest-default-tls = ["reqwest/default-tls", "dep:once_cell"]
 reqwest-rustls-tls = ["reqwest/rustls-tls-native-roots", "dep:once_cell"]
 
 [dependencies]
 anyhow.workspace = true
-curl = { version = "0.4.44", optional = true }
-env_proxy = { version = "0.4.1", optional = true }
+env_proxy = "0.4.1"
 once_cell = { workspace = true, optional = true }
 reqwest = { version = "0.12", default-features = false, features = ["blocking", "gzip", "socks"], optional = true }
 thiserror.workspace = true

download/src/errors.rs

@@ -12,10 +12,6 @@ pub enum DownloadError {
     Message(String),
     #[error(transparent)]
     IoError(#[from] std::io::Error),
-    #[cfg(feature = "reqwest-backend")]
     #[error(transparent)]
     Reqwest(#[from] ::reqwest::Error),
-    #[cfg(feature = "curl-backend")]
-    #[error(transparent)]
-    CurlError(#[from] curl::Error),
 }

download/src/lib.rs

@@ -16,7 +16,6 @@ const USER_AGENT: &str = concat!("rustup/", env!("CARGO_PKG_VERSION"));
 
 #[derive(Debug, Copy, Clone)]
 pub enum Backend {
-    Curl,
     Reqwest(TlsBackend),
 }
 
@@ -35,20 +34,19 @@ pub enum Event<'a> {
     DownloadDataReceived(&'a [u8]),
 }
 
+type DownloadCallback<'a> = &'a dyn Fn(Event<'_>) -> Result<()>;
+
 fn download_with_backend(
     backend: Backend,
     url: &Url,
     resume_from: u64,
-    callback: &dyn Fn(Event<'_>) -> Result<()>,
+    callback: DownloadCallback<'_>,
 ) -> Result<()> {
     match backend {
-        Backend::Curl => curl::download(url, resume_from, callback),
         Backend::Reqwest(tls) => reqwest_be::download(url, resume_from, callback, tls),
     }
 }
 
-type DownloadCallback<'a> = &'a dyn Fn(Event<'_>) -> Result<()>;
-
 pub fn download_to_path_with_backend(
     backend: Backend,
     url: &Url,
@@ -141,125 +139,6 @@ pub fn download_to_path_with_backend(
     })
 }
 
-#[cfg(all(not(feature = "reqwest-backend"), not(feature = "curl-backend")))]
-compile_error!("Must enable at least one backend");
-
-/// Download via libcurl; encrypt with the native (or OpenSSl) TLS
-/// stack via libcurl
-#[cfg(feature = "curl-backend")]
-pub mod curl {
-    use std::cell::RefCell;
-    use std::str;
-    use std::time::Duration;
-
-    use anyhow::{Context, Result};
-    use curl::easy::Easy;
-    use url::Url;
-
-    use super::Event;
-    use crate::errors::*;
-
-    pub fn download(
-        url: &Url,
-        resume_from: u64,
-        callback: &dyn Fn(Event<'_>) -> Result<()>,
-    ) -> Result<()> {
-        // Fetch either a cached libcurl handle (which will preserve open
-        // connections) or create a new one if it isn't listed.
-        //
-        // Once we've acquired it, reset the lifetime from 'static to our local
-        // scope.
-        thread_local!(static EASY: RefCell<Easy> = RefCell::new(Easy::new()));
-        EASY.with(|handle| {
-            let mut handle = handle.borrow_mut();
-
-            handle.url(url.as_ref())?;
-            handle.follow_location(true)?;
-            handle.useragent(super::USER_AGENT)?;
-
-            if resume_from > 0 {
-                handle.resume_from(resume_from)?;
-            } else {
-                // an error here indicates that the range header isn't supported by underlying curl,
-                // so there's nothing to "clear" - safe to ignore this error.
-                let _ = handle.resume_from(0);
-            }
-
-            // Take at most 30s to connect
-            handle.connect_timeout(Duration::new(30, 0))?;
-
-            {
-                let cberr = RefCell::new(None);
-                let mut transfer = handle.transfer();
-
-                // Data callback for libcurl which is called with data that's
-                // downloaded. We just feed it into our hasher and also write it out
-                // to disk.
-                transfer.write_function(|data| {
-                    match callback(Event::DownloadDataReceived(data)) {
-                        Ok(()) => Ok(data.len()),
-                        Err(e) => {
-                            *cberr.borrow_mut() = Some(e);
-                            Ok(0)
-                        }
-                    }
-                })?;
-
-                // Listen for headers and parse out a `Content-Length` (case-insensitive) if it
-                // comes so we know how much we're downloading.
-                transfer.header_function(|header| {
-                    if let Ok(data) = str::from_utf8(header) {
-                        let prefix = "content-length: ";
-                        if data.to_ascii_lowercase().starts_with(prefix) {
-                            if let Ok(s) = data[prefix.len()..].trim().parse::<u64>() {
-                                let msg = Event::DownloadContentLengthReceived(s + resume_from);
-                                match callback(msg) {
-                                    Ok(()) => (),
-                                    Err(e) => {
-                                        *cberr.borrow_mut() = Some(e);
-                                        return false;
-                                    }
-                                }
-                            }
-                        }
-                    }
-                    true
-                })?;
-
-                // If an error happens check to see if we had a filesystem error up
-                // in `cberr`, but we always want to punt it up.
-                transfer.perform().or_else(|e| {
-                    // If the original error was generated by one of our
-                    // callbacks, return it.
-                    match cberr.borrow_mut().take() {
-                        Some(cberr) => Err(cberr),
-                        None => {
-                            // Otherwise, return the error from curl
-                            if e.is_file_couldnt_read_file() {
-                                Err(e).context(DownloadError::FileNotFound)
-                            } else {
-                                Err(e).context("error during download")?
-                            }
-                        }
-                    }
-                })?;
-            }
-
-            // If we didn't get a 20x or 0 ("OK" for files) then return an error
-            let code = handle.response_code()?;
-            match code {
-                0 | 200..=299 => {}
-                _ => {
-                    return Err(DownloadError::HttpStatus(code).into());
-                }
-            };
-
-            Ok(())
-        })
-    }
-}
-
-#[cfg(feature = "reqwest-backend")]
 pub mod reqwest_be {
     #[cfg(all(
         not(feature = "reqwest-rustls-tls"),
@@ -332,11 +211,10 @@ pub mod reqwest_be {
         let catcher = || client_generic().use_rustls_tls().build();
 
         // woah, an unwrap?!
-        // It's OK. This is the same as what is happening in curl.
+        // It's OK.
         //
-        // The curl::Easy::new() internally assert!s that the initialized
-        // Easy is not null. Inside reqwest, the errors here would be from
-        // the TLS library returning a null pointer as well.
+        // Inside reqwest, the errors here would be from the TLS library
+        // returning a null pointer.
         catcher().unwrap()
     });
 
@@ -345,11 +223,10 @@ pub mod reqwest_be {
         let catcher = || client_generic().build();
 
         // woah, an unwrap?!
-        // It's OK. This is the same as what is happening in curl.
+        // It's OK.
         //
-        // The curl::Easy::new() internally assert!s that the initialized
-        // Easy is not null. Inside reqwest, the errors here would be from
-        // the TLS library returning a null pointer as well.
+        // Inside reqwest, the errors here would be from the TLS library
+        // returning a null pointer.
         catcher().unwrap()
     });
 
@@ -423,41 +300,3 @@ pub mod reqwest_be {
         }
     }
 }
-
-#[cfg(not(feature = "curl-backend"))]
-pub mod curl {
-
-    use anyhow::{anyhow, Result};
-
-    use super::Event;
-    use crate::errors::*;
-    use url::Url;
-
-    pub fn download(
-        _url: &Url,
-        _resume_from: u64,
-        _callback: &dyn Fn(Event<'_>) -> Result<()>,
-    ) -> Result<()> {
-        Err(anyhow!(DownloadError::BackendUnavailable("curl")))
-    }
-}
-
-#[cfg(not(feature = "reqwest-backend"))]
-pub mod reqwest_be {
-
-    use anyhow::{anyhow, Result};
-
-    use super::Event;
-    use super::TlsBackend;
-    use crate::errors::*;
-    use url::Url;
-
-    pub fn download(
-        _url: &Url,
-        _resume_from: u64,
-        _callback: &dyn Fn(Event<'_>) -> Result<()>,
-        _tls: TlsBackend,
-    ) -> Result<()> {
-        Err(anyhow!(DownloadError::BackendUnavailable("reqwest")))
-    }
-}