From ee705192c98c7ffa90999457535461c90070a155 Mon Sep 17 00:00:00 2001
From: Erick Tryzelaar <etryzelaar@google.com>
Date: Mon, 11 Mar 2019 14:52:48 -0700
Subject: [PATCH] Optionally disable pulling in the tokio runtime

Before this patch, hyper-rustls required pulling in the tokio runtime
due to it's use of `hyper::client::HttpConnector`. Unfortunately
Fuchsia does not support tokio, which prevents our use of this
library. This PR allows us to optionally disable pulling in tokio,
and instead swap in our own version of the hyper `HttpConnector`.
---
 .travis.yml      |  2 ++
 Cargo.toml       | 20 +++++++++++++++++---
 src/connector.rs |  7 +++++--
 src/lib.rs       | 28 ++++++++++++++++------------
 4 files changed, 40 insertions(+), 17 deletions(-)

diff --git a/.travis.yml b/.travis.yml
index feb247b..23ffce6 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -20,6 +20,8 @@ before_script:
 
 script:
   - cargo test
+  - cargo test --all-features
+  - cargo test --no-default-features
   - bash -c 'if [[ "$TRAVIS_RUST_VERSION" == "$CLIPPY_RUST_VERSION" ]]; then
       cargo clippy -- -D warnings;
     fi'
diff --git a/Cargo.toml b/Cargo.toml
index 5b23ea9..1637e9b 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -10,15 +10,29 @@ repository = "https://github.com/ctz/hyper-rustls"
 
 [dependencies]
 bytes = "0.4"
-ct-logs = "0.5"
+ct-logs = { version = "0.5", optional = true }
 futures = "0.1.21"
-hyper = "0.12.14"
+hyper = { version = "0.12.14", default-features = false }
 rustls = "0.15"
 tokio-io = "0.1.1"
 tokio-rustls = "0.9"
 webpki = "0.19.0"
-webpki-roots = "0.16"
+webpki-roots = { version = "0.16", optional = true }
 
 [dev-dependencies]
 tokio = "0.1"
 tokio-tcp = "0.1"
+
+[features]
+default = ["tokio-runtime"]
+tokio-runtime = ["hyper/runtime", "ct-logs", "webpki-roots"]
+
+[[example]]
+name = "client"
+path = "examples/client.rs"
+required-features = ["tokio-runtime"]
+
+[[example]]
+name = "server"
+path = "examples/server.rs"
+required-features = ["tokio-runtime"]
diff --git a/src/connector.rs b/src/connector.rs
index 9187faa..95d8975 100644
--- a/src/connector.rs
+++ b/src/connector.rs
@@ -1,13 +1,12 @@
-use ct_logs;
 use futures::{Future, Poll};
 use hyper::client::connect::{self, Connect};
+#[cfg(feature = "tokio-runtime")]
 use hyper::client::HttpConnector;
 use rustls::{ClientConfig, Session};
 use std::sync::Arc;
 use std::{fmt, io};
 use tokio_rustls::TlsConnector;
 use webpki::{DNSName, DNSNameRef};
-use webpki_roots;
 
 use stream::MaybeHttpsStream;
 
@@ -18,11 +17,15 @@ pub struct HttpsConnector<T> {
     tls_config: Arc<ClientConfig>,
 }
 
+#[cfg(feature = "tokio-runtime")]
 impl HttpsConnector<HttpConnector> {
     /// Construct a new `HttpsConnector`.
     ///
     /// Takes number of DNS worker threads.
     pub fn new(threads: usize) -> Self {
+        use ct_logs;
+        use webpki_roots;
+
         let mut http = HttpConnector::new(threads);
         http.enforce_http(false);
         let mut config = ClientConfig::new();
diff --git a/src/lib.rs b/src/lib.rs
index e5a2526..84682b5 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -5,25 +5,28 @@
 //! ## Example
 //!
 //! ```no_run
-//! extern crate hyper;
-//! extern crate hyper_rustls;
-//! extern crate tokio;
-//!
+//! # #[cfg(feature = "tokio-runtime")]
+//! # extern crate hyper;
+//! #
+//! # #[cfg(feature = "tokio-runtime")]
+//! # fn main() {
 //! use hyper::{Body, Client, StatusCode, Uri};
 //!
-//! fn main() {
-//!     let mut rt = tokio::runtime::Runtime::new().unwrap();
-//!     let url = ("https://hyper.rs").parse().unwrap();
-//!     let https = hyper_rustls::HttpsConnector::new(4);
+//! let mut rt = tokio::runtime::Runtime::new().unwrap();
+//! let url = ("https://hyper.rs").parse().unwrap();
+//! let https = hyper_rustls::HttpsConnector::new(4);
 //!
-//!     let client: Client<_, hyper::Body> = Client::builder().build(https);
+//! let client: Client<_, hyper::Body> = Client::builder().build(https);
 //!
-//!     let res = rt.block_on(client.get(url)).unwrap();
-//!     assert_eq!(res.status(), StatusCode::OK);
-//! }
+//! let res = rt.block_on(client.get(url)).unwrap();
+//! assert_eq!(res.status(), StatusCode::OK);
+//! # }
+//! # #[cfg(not(feature = "tokio-runtime"))]
+//! # fn main() {}
 //! ```
 
 extern crate bytes;
+#[cfg(feature = "tokio-runtime")]
 extern crate ct_logs;
 extern crate futures;
 extern crate hyper;
@@ -31,6 +34,7 @@ extern crate rustls;
 extern crate tokio_io;
 extern crate tokio_rustls;
 extern crate webpki;
+#[cfg(feature = "tokio-runtime")]
 extern crate webpki_roots;
 
 mod connector;