Remove the "headless" feature

src/platform/linux/mod.rs

@@ -1,7 +1,13 @@
 #![cfg(target_os = "linux")]
 
-#[cfg(feature = "headless")]
-pub use api::osmesa::OsMesaContext as HeadlessContext;
+use Api;
+use BuilderAttribs;
+use CreationError;
+use GlContext;
+use PixelFormat;
+use libc;
+
+use api::osmesa::{self, OsMesaContext};
 
 #[cfg(feature = "window")]
 pub use api::x11::{Window, WindowProxy, MonitorID, get_available_monitors, get_primary_monitor};
@@ -12,3 +18,49 @@ pub use api::x11::{WaitEventsIterator, PollEventsIterator};
 pub type Window = ();       // TODO: hack to make things work
 #[cfg(not(feature = "window"))]
 pub type MonitorID = ();       // TODO: hack to make things work
+
+pub struct HeadlessContext(OsMesaContext);
+
+impl HeadlessContext {
+    pub fn new(builder: BuilderAttribs) -> Result<HeadlessContext, CreationError> {
+        match OsMesaContext::new(builder) {
+            Ok(c) => return Ok(HeadlessContext(c)),
+            Err(osmesa::OsMesaCreationError::NotSupported) => (),
+            Err(osmesa::OsMesaCreationError::CreationError(e)) => return Err(e),
+        };
+
+        Err(CreationError::NotSupported)
+    }
+}
+
+impl GlContext for HeadlessContext {
+    #[inline]
+    unsafe fn make_current(&self) {
+        self.0.make_current()
+    }
+
+    #[inline]
+    fn is_current(&self) -> bool {
+        self.0.is_current()
+    }
+
+    #[inline]
+    fn get_proc_address(&self, addr: &str) -> *const libc::c_void {
+        self.0.get_proc_address(addr)
+    }
+
+    #[inline]
+    fn swap_buffers(&self) {
+        self.0.swap_buffers()
+    }
+
+    #[inline]
+    fn get_api(&self) -> Api {
+        self.0.get_api()
+    }
+
+    #[inline]
+    fn get_pixel_format(&self) -> PixelFormat {
+        self.0.get_pixel_format()
+    }
+}