Added error handling for optional extension loading

examples/triangle/src/main.rs

@@ -42,7 +42,7 @@ fn create_surface(instance: &Instance,
         window: x11_window as vk::Window,
         dpy: x11_display as *mut vk::Display,
     };
-    let xlib_surface_loader = XlibSurface::new(&entry, &instance);
+    let xlib_surface_loader = XlibSurface::new(&entry, &instance).expect("Unable to load xlib surface");
     xlib_surface_loader.create_xlib_surface_khr(&x11_create_info)
 }
 
@@ -154,12 +154,13 @@ fn main() {
         pfn_callback: vulkan_debug_callback,
         p_user_data: ptr::null_mut(),
     };
-    let debug_report_loader = DebugReport::new(&entry, &instance);
+    let debug_report_loader = DebugReport::new(&entry, &instance).expect("Unable to load debug report");
     let debug_call_back = debug_report_loader.create_debug_report_callback_ext(&debug_info)
         .unwrap();
     let surface = create_surface(&instance, &entry, &window).unwrap();
     let pdevices = instance.enumerate_physical_devices().expect("Physical device error");
-    let surface_loader = Surface::new(&entry, &instance);
+    let surface_loader = Surface::new(&entry, &instance)
+        .expect("Unable to load the Surface extension");
     let (pdevice, queue_family_index) = pdevices.iter()
         .map(|pdevice| {
             instance.get_physical_device_queue_family_properties(*pdevice)
@@ -257,7 +258,7 @@ fn main() {
         .cloned()
         .find(|&mode| mode == vk::PresentModeKHR::Mailbox)
         .unwrap_or(vk::PresentModeKHR::Fifo);
-    let swapchain_loader = Swapchain::new(&instance, &device);
+    let swapchain_loader = Swapchain::new(&instance, &device).expect("Unable to load swapchain");
     let swapchain_create_info = vk::SwapchainCreateInfoKHR {
         s_type: vk::StructureType::SwapchainCreateInfoKhr,
         p_next: ptr::null(),

src/extensions/debug_report.rs

@@ -12,18 +12,17 @@ pub struct DebugReport {
 }
 
 impl DebugReport {
-    pub fn new(entry: &Entry, instance: &Instance) -> DebugReport {
+    pub fn new(entry: &Entry, instance: &Instance) -> Result<DebugReport, String> {
         let debug_report_fn = vk::DebugReportFn::load(|name| {
             unsafe {
                 mem::transmute(entry.static_fn
                     .get_instance_proc_addr(instance.handle, name.as_ptr()))
             }
-            })
+        })?;
-            .unwrap();
+        Ok(DebugReport {
-        DebugReport {
             handle: instance.handle,
             debug_report_fn: debug_report_fn,
-        }
+        })
     }
 
     pub fn destroy_debug_report_callback_ext(&self, debug: vk::DebugReportCallbackEXT) {

src/extensions/surface.rs

@@ -11,18 +11,17 @@ pub struct Surface {
 }
 
 impl Surface {
-    pub fn new(entry: &Entry, instance: &Instance) -> Surface {
+    pub fn new(entry: &Entry, instance: &Instance) -> Result<Surface, String> {
         let surface_fn = vk::SurfaceFn::load(|name| {
             unsafe {
                 mem::transmute(entry.static_fn
                     .get_instance_proc_addr(instance.handle, name.as_ptr()))
             }
-            })
+        })?;
-            .unwrap();
+        Ok(Surface {
-        Surface {
             handle: instance.handle,
             surface_fn: surface_fn,
-        }
+        })
     }
 
     pub fn get_physical_device_surface_support_khr(&self,
@@ -111,4 +110,3 @@ impl Surface {
         }
     }
 }
-

src/extensions/swapchain.rs

@@ -4,24 +4,24 @@ use std::mem;
 use instance::Instance;
 use device::Device;
 use vk;
+
 pub struct Swapchain {
     handle: vk::Device,
     swapchain_fn: vk::SwapchainFn,
 }
 
 impl Swapchain {
-    pub fn new(instance: &Instance, device: &Device) -> Swapchain {
+    pub fn new(instance: &Instance, device: &Device) -> Result<Swapchain, String> {
         let swapchain_fn = vk::SwapchainFn::load(|name| {
             unsafe {
                 mem::transmute(instance.instance_fn
                     .get_device_proc_addr(device.handle, name.as_ptr()))
             }
-            })
+        })?;
-            .unwrap();
+        Ok(Swapchain {
-        Swapchain {
             handle: device.handle,
             swapchain_fn: swapchain_fn,
-        }
+        })
     }
 
     pub fn destroy_swapchain_khr(&self, swapchain: vk::SwapchainKHR) {

src/extensions/xlibsurface.rs

@@ -11,18 +11,17 @@ pub struct XlibSurface {
 }
 
 impl XlibSurface {
-    pub fn new(entry: &Entry, instance: &Instance) -> XlibSurface {
+    pub fn new(entry: &Entry, instance: &Instance) -> Result<XlibSurface, String> {
         let surface_fn = vk::XlibSurfaceFn::load(|name| {
             unsafe {
                 mem::transmute(entry.static_fn
                     .get_instance_proc_addr(instance.handle, name.as_ptr()))
             }
-            })
+        })?;
-            .unwrap();
+        Ok(XlibSurface {
-        XlibSurface {
             handle: instance.handle,
             xlib_surface_fn: surface_fn,
-        }
+        })
     }
 
     pub fn create_xlib_surface_khr(&self,

src/instance.rs

@@ -19,7 +19,6 @@ pub struct Instance {
     pub instance_fn: vk::InstanceFn,
 }
 
-
 impl Instance {
     pub unsafe fn from_raw(handle: vk::Instance, instance_fn: vk::InstanceFn) -> Self {
         Instance {