Reorganize the Linux implementation and split OSMesa and X11

src/api/osmesa/mod.rs

@@ -0,0 +1,75 @@
+#![cfg(all(any(target_os = "linux", target_os = "freebsd"), feature="headless"))]
+
+extern crate osmesa_sys;
+
+use BuilderAttribs;
+use CreationError;
+use CreationError::OsError;
+use libc;
+use std::{mem, ptr};
+use std::ffi::CString;
+
+pub struct OsMesaContext {
+    context: osmesa_sys::OSMesaContext,
+    buffer: Vec<u32>,
+    width: u32,
+    height: u32,
+}
+
+impl OsMesaContext {
+    pub fn new(builder: BuilderAttribs) -> Result<OsMesaContext, CreationError> {
+        let dimensions = builder.dimensions.unwrap();
+
+        Ok(OsMesaContext {
+            width: dimensions.0,
+            height: dimensions.1,
+            buffer: ::std::iter::repeat(unsafe { mem::uninitialized() })
+                .take((dimensions.0 * dimensions.1) as usize).collect(),
+            context: unsafe {
+                let ctxt = osmesa_sys::OSMesaCreateContext(0x1908, ptr::null_mut());
+                if ctxt.is_null() {
+                    return Err(OsError("OSMesaCreateContext failed".to_string()));
+                }
+                ctxt
+            }
+        })
+    }
+
+    pub unsafe fn make_current(&self) {
+        let ret = osmesa_sys::OSMesaMakeCurrent(self.context,
+            self.buffer.as_ptr() as *mut libc::c_void,
+            0x1401, self.width as libc::c_int, self.height as libc::c_int);
+
+        if ret == 0 {
+            panic!("OSMesaMakeCurrent failed")
+        }
+    }
+
+    pub fn is_current(&self) -> bool {
+        unsafe { osmesa_sys::OSMesaGetCurrentContext() == self.context }
+    }
+
+    pub fn get_proc_address(&self, addr: &str) -> *const () {
+        unsafe {
+            let c_str = CString::new(addr.as_bytes().to_vec()).unwrap();
+            mem::transmute(osmesa_sys::OSMesaGetProcAddress(mem::transmute(c_str.as_ptr())))
+        }
+    }
+
+    /// See the docs in the crate root file.
+    pub fn get_api(&self) -> ::Api {
+        ::Api::OpenGl
+    }
+
+    pub fn set_window_resize_callback(&mut self, _: Option<fn(u32, u32)>) {
+    }
+}
+
+impl Drop for OsMesaContext {
+    fn drop(&mut self) {
+        unsafe { osmesa_sys::OSMesaDestroyContext(self.context) }
+    }
+}
+
+unsafe impl Send for OsMesaContext {}
+unsafe impl Sync for OsMesaContext {}