feat(ffi): Initial C API for hyper

src/ffi/mod.rs

@@ -0,0 +1,55 @@
+// We have a lot of c-types in here, stop warning about their names!
+#![allow(non_camel_case_types)]
+
+// We may eventually allow the FFI to be enabled without `client` or `http1`,
+// that is why we don't auto enable them as `ffi = ["client", "http1"]` in
+// the `Cargo.toml`.
+//
+// But for now, give a clear message that this compile error is expected.
+#[cfg(not(all(feature = "client", feature = "http1")))]
+compile_error!("The `ffi` feature currently requires the `client` and `http1` features.");
+
+#[cfg(not(hyper_unstable_ffi))]
+compile_error!(
+    "\
+    The `ffi` feature is unstable, and requires the \
+    `RUSTFLAGS='--cfg hyper_unstable_ffi'` environment variable to be set.\
+"
+);
+
+#[macro_use]
+mod macros;
+
+mod body;
+mod client;
+mod error;
+mod http_types;
+mod io;
+mod task;
+
+pub(crate) use self::body::UserBody;
+
+pub const HYPER_ITER_CONTINUE: libc::c_int = 0;
+#[allow(unused)]
+pub const HYPER_ITER_BREAK: libc::c_int = 1;
+
+pub const HYPER_HTTP_VERSION_NONE: libc::c_int = 0;
+pub const HYPER_HTTP_VERSION_1_0: libc::c_int = 10;
+pub const HYPER_HTTP_VERSION_1_1: libc::c_int = 11;
+pub const HYPER_HTTP_VERSION_2: libc::c_int = 20;
+
+struct UserDataPointer(*mut std::ffi::c_void);
+
+// We don't actually know anything about this pointer, it's up to the user
+// to do the right thing.
+unsafe impl Send for UserDataPointer {}
+
+/// cbindgen:ignore
+static VERSION_CSTR: &str = concat!(env!("CARGO_PKG_VERSION"), "\0");
+
+ffi_fn! {
+    /// Returns a static ASCII (null terminated) string of the hyper version.
+    fn hyper_version() -> *const libc::c_char {
+        VERSION_CSTR.as_ptr() as _
+    }
+}