Start splitting win32::init into multiple functions

src/win32/init.rs

@@ -1,7 +1,10 @@
 use std::sync::atomic::AtomicBool;
 use std::ptr;
+use std::mem;
+use std::os;
 use super::callback;
 use super::Window;
+use super::MonitorID;
 use BuilderAttribs;
 use CreationError;
 use CreationError::OsError;
@@ -23,9 +26,6 @@ unsafe impl Send for ContextHack {}
 pub fn new_window(builder: BuilderAttribs<'static>, builder_sharelists: Option<ContextHack>)
                   -> Result<Window, CreationError>
 {
-    use std::mem;
-    use std::os;
-
     // initializing variables to be sent to the task
     let title = builder.title.as_slice().utf16_units()
         .chain(Some(0).into_iter()).collect::<Vec<u16>>();    // title to utf16
@@ -36,36 +36,39 @@ pub fn new_window(builder: BuilderAttribs<'static>, builder_sharelists: Option<C
     //  so we create a new thread dedicated to this window.
     // This is the only safe method. Using `nosend` wouldn't work for non-native runtime.
     ::std::thread::Thread::spawn(move || {
+        // sending
+        match init(title, builder, builder_sharelists) {
+            Ok(w) => tx.send(Ok(w)).ok(),
+            Err(e) => {
+                tx.send(Err(e)).ok();
+                return;
+            }
+        };
+
+        // now that the `Window` struct is initialized, the main `Window::new()` function will
+        //  return and this events loop will run in parallel
+        loop {
+            let mut msg = unsafe { mem::uninitialized() };
+
+            if unsafe { user32::GetMessageW(&mut msg, ptr::null_mut(), 0, 0) } == 0 {
+                break;
+            }
+
+            unsafe { user32::TranslateMessage(&msg) };
+            unsafe { user32::DispatchMessageW(&msg) };     // calls `callback` (see below)
+        }
+    });
+
+    rx.recv().unwrap()
+}
+
+fn init(title: Vec<u16>, builder: BuilderAttribs<'static>, builder_sharelists: Option<ContextHack>)
+        -> Result<Window, CreationError>
+{
     let builder_sharelists = builder_sharelists.map(|s| s.0);
 
     // registering the window class
-        let class_name = {
-            let class_name: Vec<u16> = "Window Class".utf16_units().chain(Some(0).into_iter())
-                .collect::<Vec<u16>>();
-            
-            let class = winapi::WNDCLASSEXW {
-                cbSize: mem::size_of::<winapi::WNDCLASSEXW>() as winapi::UINT,
-                style: winapi::CS_HREDRAW | winapi::CS_VREDRAW | winapi::CS_OWNDC,
-                lpfnWndProc: callback::callback,
-                cbClsExtra: 0,
-                cbWndExtra: 0,
-                hInstance: unsafe { kernel32::GetModuleHandleW(ptr::null()) },
-                hIcon: ptr::null_mut(),
-                hCursor: ptr::null_mut(),
-                hbrBackground: ptr::null_mut(),
-                lpszMenuName: ptr::null(),
-                lpszClassName: class_name.as_ptr(),
-                hIconSm: ptr::null_mut(),
-            };
-
-            // We ignore errors because registering the same window class twice would trigger
-            //  an error, and because errors here are detected during CreateWindowEx anyway.
-            // Also since there is no weird element in the struct, there is no reason for this
-            //  call to fail.
-            unsafe { user32::RegisterClassExW(&class) };
-
-            class_name
-        };
+    let class_name = register_window_class();
 
     // building a RECT object with coordinates
     let mut rect = winapi::RECT {
@@ -78,31 +81,7 @@ pub fn new_window(builder: BuilderAttribs<'static>, builder_sharelists: Option<C
     //  and change the monitor's resolution if necessary
     if builder.monitor.is_some() {
         let monitor = builder.monitor.as_ref().unwrap();
-
-            // adjusting the rect
-            {
-                let pos = monitor.get_position();
-                rect.left += pos.0 as winapi::LONG;
-                rect.right += pos.0 as winapi::LONG;
-                rect.top += pos.1 as winapi::LONG;
-                rect.bottom += pos.1 as winapi::LONG;
-            }
-
-            // changing device settings
-            let mut screen_settings: winapi::DEVMODEW = unsafe { mem::zeroed() };
-            screen_settings.dmSize = mem::size_of::<winapi::DEVMODEW>() as winapi::WORD;
-            screen_settings.dmPelsWidth = (rect.right - rect.left) as winapi::DWORD;
-            screen_settings.dmPelsHeight = (rect.bottom - rect.top) as winapi::DWORD;
-            screen_settings.dmBitsPerPel = 32;      // TODO: ?
-            screen_settings.dmFields = winapi::DM_BITSPERPEL | winapi::DM_PELSWIDTH | winapi::DM_PELSHEIGHT;
-
-            let result = unsafe { user32::ChangeDisplaySettingsExW(monitor.get_system_name().as_ptr(),
-                &mut screen_settings, ptr::null_mut(), winapi::CDS_FULLSCREEN, ptr::null_mut()) };
-            
-            if result != winapi::DISP_CHANGE_SUCCESSFUL {
-                tx.send(Err(OsError(format!("ChangeDisplaySettings failed: {}", result))));
-                return;
-            }
+        switch_to_fullscreen(&mut rect, monitor);
     }
 
     // computing the style and extended style of the window
@@ -130,10 +109,8 @@ pub fn new_window(builder: BuilderAttribs<'static>, builder_sharelists: Option<C
                 ptr::null_mut());
 
             if handle.is_null() {
-                    use std::os;
-                    tx.send(Err(OsError(format!("CreateWindowEx function failed: {}",
-                        os::error_string(os::errno() as usize)))));
-                    return;
+                return Err(OsError(format!("CreateWindowEx function failed: {}",
+                    os::error_string(os::errno() as usize))));
             }
 
             handle
@@ -143,10 +120,10 @@ pub fn new_window(builder: BuilderAttribs<'static>, builder_sharelists: Option<C
         let dummy_hdc = {
             let hdc = unsafe { user32::GetDC(dummy_window) };
             if hdc.is_null() {
-                    tx.send(Err(OsError(format!("GetDC function failed: {}",
-                        os::error_string(os::errno() as usize)))));
+                let err = Err(OsError(format!("GetDC function failed: {}",
+                    os::error_string(os::errno() as usize))));
                 unsafe { user32::DestroyWindow(dummy_window); }
-                    return;
+                return err;
             }
             hdc
         };
@@ -171,19 +148,19 @@ pub fn new_window(builder: BuilderAttribs<'static>, builder_sharelists: Option<C
             let pf_index = unsafe { gdi32::ChoosePixelFormat(dummy_hdc, &output) };
 
             if pf_index == 0 {
-                    tx.send(Err(OsError(format!("ChoosePixelFormat function failed: {}",
-                        os::error_string(os::errno() as usize)))));
+                let err = Err(OsError(format!("ChoosePixelFormat function failed: {}",
+                    os::error_string(os::errno() as usize))));
                 unsafe { user32::DestroyWindow(dummy_window); }
-                    return;
+                return err;
             }
 
             if unsafe { gdi32::DescribePixelFormat(dummy_hdc, pf_index,
                 mem::size_of::<winapi::PIXELFORMATDESCRIPTOR>() as winapi::UINT, &mut output) } == 0
             {
-                    tx.send(Err(OsError(format!("DescribePixelFormat function failed: {}",
-                        os::error_string(os::errno() as usize)))));
+                let err = Err(OsError(format!("DescribePixelFormat function failed: {}",
+                    os::error_string(os::errno() as usize))));
                 unsafe { user32::DestroyWindow(dummy_window); }
-                    return;
+                return err;
             }
 
             output
@@ -192,10 +169,10 @@ pub fn new_window(builder: BuilderAttribs<'static>, builder_sharelists: Option<C
         // calling SetPixelFormat
         unsafe {
             if gdi32::SetPixelFormat(dummy_hdc, 1, &pixel_format) == 0 {
-                    tx.send(Err(OsError(format!("SetPixelFormat function failed: {}",
-                        os::error_string(os::errno() as usize)))));
+                let err = Err(OsError(format!("SetPixelFormat function failed: {}",
+                    os::error_string(os::errno() as usize))));
                 user32::DestroyWindow(dummy_window);
-                    return;
+                return err;
             }
         }
 
@@ -203,10 +180,10 @@ pub fn new_window(builder: BuilderAttribs<'static>, builder_sharelists: Option<C
         let dummy_context = {
             let ctxt = unsafe { gl::wgl::CreateContext(dummy_hdc as *const libc::c_void) };
             if ctxt.is_null() {
-                    tx.send(Err(OsError(format!("wglCreateContext function failed: {}",
-                        os::error_string(os::errno() as usize)))));
+                let err = Err(OsError(format!("wglCreateContext function failed: {}",
+                    os::error_string(os::errno() as usize))));
                 unsafe { user32::DestroyWindow(dummy_window); }
-                    return;
+                return err;
             }
             ctxt
         };
@@ -261,10 +238,8 @@ pub fn new_window(builder: BuilderAttribs<'static>, builder_sharelists: Option<C
             ptr::null_mut());
 
         if handle.is_null() {
-                use std::os;
-                tx.send(Err(OsError(format!("CreateWindowEx function failed: {}",
-                    os::error_string(os::errno() as usize)))));
-                return;
+            return Err(OsError(format!("CreateWindowEx function failed: {}",
+                os::error_string(os::errno() as usize))));
         }
 
         handle
@@ -274,10 +249,10 @@ pub fn new_window(builder: BuilderAttribs<'static>, builder_sharelists: Option<C
     let hdc = {
         let hdc = unsafe { user32::GetDC(real_window) };
         if hdc.is_null() {
-                tx.send(Err(OsError(format!("GetDC function failed: {}",
-                    os::error_string(os::errno() as usize)))));
+            let err = Err(OsError(format!("GetDC function failed: {}",
+                os::error_string(os::errno() as usize))));
             unsafe { user32::DestroyWindow(real_window); }
-                return;
+            return err;
         }
         hdc
     };
@@ -285,10 +260,10 @@ pub fn new_window(builder: BuilderAttribs<'static>, builder_sharelists: Option<C
     // calling SetPixelFormat
     unsafe {
         if gdi32::SetPixelFormat(hdc, 1, &pixel_format) == 0 {
-                tx.send(Err(OsError(format!("SetPixelFormat function failed: {}",
-                    os::error_string(os::errno() as usize)))));
+            let err = Err(OsError(format!("SetPixelFormat function failed: {}",
+                os::error_string(os::errno() as usize))));
             user32::DestroyWindow(real_window);
-                return;
+            return err;
         }
     }
 
@@ -330,10 +305,10 @@ pub fn new_window(builder: BuilderAttribs<'static>, builder_sharelists: Option<C
         };
 
         if ctxt.is_null() {
-                tx.send(Err(OsError(format!("OpenGL context creation failed: {}",
-                    os::error_string(os::errno() as usize)))));
+            let err = Err(OsError(format!("OpenGL context creation failed: {}",
+                os::error_string(os::errno() as usize))));
             unsafe { user32::DestroyWindow(real_window); }
-                return;
+            return err;
         }
 
         ctxt
@@ -360,11 +335,11 @@ pub fn new_window(builder: BuilderAttribs<'static>, builder_sharelists: Option<C
             .collect::<Vec<u16>>().as_ptr();
         let lib = unsafe { kernel32::LoadLibraryW(name) };
         if lib.is_null() {
-                tx.send(Err(OsError(format!("LoadLibrary function failed: {}",
-                    os::error_string(os::errno() as usize)))));
+            let err = Err(OsError(format!("LoadLibrary function failed: {}",
+                                          os::error_string(os::errno() as usize))));
             unsafe { gl::wgl::DeleteContext(context); }
             unsafe { user32::DestroyWindow(real_window); }
-                return;
+            return err;
         }
         lib
     };
@@ -374,10 +349,9 @@ pub fn new_window(builder: BuilderAttribs<'static>, builder_sharelists: Option<C
         if extra_functions.SwapIntervalEXT.is_loaded() {
             unsafe { gl::wgl::MakeCurrent(hdc as *const libc::c_void, context) };
             if unsafe { extra_functions.SwapIntervalEXT(1) } == 0 {
-                    tx.send(Err(OsError(format!("wglSwapIntervalEXT failed"))));
                 unsafe { gl::wgl::DeleteContext(context); }
                 unsafe { user32::DestroyWindow(real_window); }
-                    return;
+                return Err(OsError(format!("wglSwapIntervalEXT failed")));
             }
 
             // it is important to remove the current context, otherwise you get very weird
@@ -387,31 +361,68 @@ pub fn new_window(builder: BuilderAttribs<'static>, builder_sharelists: Option<C
     }
 
     // building the struct
-        let window = Window{
+    Ok(Window {
         window: real_window,
         hdc: hdc as winapi::HDC,
         context: context as winapi::HGLRC,
         gl_library: gl_library,
         events_receiver: events_receiver,
         is_closed: AtomicBool::new(false),
+    })
+}
+
+fn register_window_class() -> Vec<u16> {
+    let class_name: Vec<u16> = "Window Class".utf16_units().chain(Some(0).into_iter())
+                                             .collect::<Vec<u16>>();
+    
+    let class = winapi::WNDCLASSEXW {
+        cbSize: mem::size_of::<winapi::WNDCLASSEXW>() as winapi::UINT,
+        style: winapi::CS_HREDRAW | winapi::CS_VREDRAW | winapi::CS_OWNDC,
+        lpfnWndProc: callback::callback,
+        cbClsExtra: 0,
+        cbWndExtra: 0,
+        hInstance: unsafe { kernel32::GetModuleHandleW(ptr::null()) },
+        hIcon: ptr::null_mut(),
+        hCursor: ptr::null_mut(),
+        hbrBackground: ptr::null_mut(),
+        lpszMenuName: ptr::null(),
+        lpszClassName: class_name.as_ptr(),
+        hIconSm: ptr::null_mut(),
     };
 
-        // sending
-        tx.send(Ok(window));
+    // We ignore errors because registering the same window class twice would trigger
+    //  an error, and because errors here are detected during CreateWindowEx anyway.
+    // Also since there is no weird element in the struct, there is no reason for this
+    //  call to fail.
+    unsafe { user32::RegisterClassExW(&class) };
 
-        // now that the `Window` struct is initialized, the main `Window::new()` function will
-        //  return and this events loop will run in parallel
-        loop {
-            let mut msg = unsafe { mem::uninitialized() };
-
-            if unsafe { user32::GetMessageW(&mut msg, ptr::null_mut(), 0, 0) } == 0 {
-                break;
-            }
-
-            unsafe { user32::TranslateMessage(&msg) };
-            unsafe { user32::DispatchMessageW(&msg) };     // calls `callback` (see below)
-        }
-    });
-
-    rx.recv().unwrap()
+    class_name
+}
+
+fn switch_to_fullscreen(rect: &mut winapi::RECT, monitor: &MonitorID) -> Result<(), CreationError> {
+    // adjusting the rect
+    {
+        let pos = monitor.get_position();
+        rect.left += pos.0 as winapi::LONG;
+        rect.right += pos.0 as winapi::LONG;
+        rect.top += pos.1 as winapi::LONG;
+        rect.bottom += pos.1 as winapi::LONG;
+    }
+
+    // changing device settings
+    let mut screen_settings: winapi::DEVMODEW = unsafe { mem::zeroed() };
+    screen_settings.dmSize = mem::size_of::<winapi::DEVMODEW>() as winapi::WORD;
+    screen_settings.dmPelsWidth = (rect.right - rect.left) as winapi::DWORD;
+    screen_settings.dmPelsHeight = (rect.bottom - rect.top) as winapi::DWORD;
+    screen_settings.dmBitsPerPel = 32;      // TODO: ?
+    screen_settings.dmFields = winapi::DM_BITSPERPEL | winapi::DM_PELSWIDTH | winapi::DM_PELSHEIGHT;
+
+    let result = unsafe { user32::ChangeDisplaySettingsExW(monitor.get_system_name().as_ptr(),
+        &mut screen_settings, ptr::null_mut(), winapi::CDS_FULLSCREEN, ptr::null_mut()) };
+    
+    if result != winapi::DISP_CHANGE_SUCCESSFUL {
+        return Err(OsError(format!("ChangeDisplaySettings failed: {}", result)));
+    }
+
+    Ok(())
 }