Add Windows initial code

.gitignore

@@ -1,2 +1,4 @@
 /target
 Cargo.lock
+.idea
+*.iml

Cargo.toml

@@ -7,3 +7,7 @@ edition = "2018"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+winapi = { version = "0.3.8", features = ["libloaderapi", "winuser", "windef", "minwindef"] }
+
+[[example]]
+name = "windows_demo"

examples/windows_demo.rs

@@ -0,0 +1,21 @@
+use std::ptr::null_mut;
+
+use baseview::{WindowOpenOptions, create_window, handle_msg};
+use baseview::Parent;
+
+fn main() {
+    let window = WindowOpenOptions {
+        title: "Baseview",
+        width: 800,
+        height: 400,
+        parent: Parent::None
+    };
+
+    create_window(window);
+
+    loop {
+        if !handle_msg(null_mut()) {
+            break;
+        }
+    }
+}

src/lib.rs

@@ -1,9 +1,13 @@
+mod win;
+
+pub use win::*;
+
 use std::ffi::c_void;
 
 pub enum Parent {
     None,
     AsIfParented,
-    WithParent(*mut c_void)
+    WithParent(*mut c_void),
 }
 
 pub struct WindowOpenOptions<'a> {
@@ -12,5 +16,5 @@ pub struct WindowOpenOptions<'a> {
     pub width: usize,
     pub height: usize,
 
-    pub parent: Parent
+    pub parent: Parent,
 }

src/win/mod.rs

@@ -0,0 +1,3 @@
+mod window;
+
+pub use window::*;

src/win/window.rs

@@ -0,0 +1,83 @@
+extern crate winapi;
+
+use self::winapi::_core::mem::MaybeUninit;
+use self::winapi::shared::minwindef::{LPARAM, LPVOID, LRESULT, UINT, WPARAM};
+use self::winapi::shared::windef::{HBRUSH, HICON, HMENU, HWND};
+use self::winapi::um::libloaderapi::GetModuleHandleA;
+use self::winapi::um::winuser::{
+    CreateWindowExA, DefWindowProcA, DispatchMessageA, PeekMessageA, PostQuitMessage,
+    RegisterClassA, TranslateMessage, CS_HREDRAW, CS_OWNDC, CS_VREDRAW, CW_USEDEFAULT, MSG,
+    PM_REMOVE, WM_DESTROY, WM_QUIT, WNDCLASSA, WS_OVERLAPPEDWINDOW, WS_VISIBLE,
+};
+
+use crate::WindowOpenOptions;
+
+pub fn handle_msg(_window: HWND) -> bool {
+    unsafe {
+        let mut msg: MSG = MaybeUninit::uninit().assume_init();
+        loop {
+            if PeekMessageA(&mut msg, 0 as HWND, 0, 0, PM_REMOVE) == 0 {
+                return true;
+            }
+            if msg.message == WM_QUIT {
+                return false;
+            }
+            TranslateMessage(&msg);
+            DispatchMessageA(&msg);
+        }
+    }
+}
+
+pub unsafe extern "system" fn wnd_proc(
+    hwnd: HWND,
+    msg: UINT,
+    w_param: WPARAM,
+    l_param: LPARAM,
+) -> LRESULT {
+    match msg {
+        WM_DESTROY => {
+            PostQuitMessage(0);
+        }
+        _ => {
+            return DefWindowProcA(hwnd, msg, w_param, l_param);
+        }
+    }
+    return 0;
+}
+
+pub fn create_window(w: WindowOpenOptions) {
+    unsafe {
+        let hinstance = GetModuleHandleA(0 as *const i8);
+        let wnd_class = WNDCLASSA {
+            // todo: for OpenGL, will use it later
+            style: CS_OWNDC | CS_HREDRAW | CS_VREDRAW,
+            lpfnWndProc: Some(wnd_proc),
+            hInstance: hinstance,
+            lpszClassName: "BaseviewClass\0".as_ptr() as *const i8,
+            cbClsExtra: 0,
+            cbWndExtra: 0,
+            hIcon: 0 as HICON,
+            hCursor: 0 as HICON,
+            hbrBackground: 0 as HBRUSH,
+            lpszMenuName: 0 as *const i8,
+        };
+        RegisterClassA(&wnd_class);
+
+        let _hwnd = CreateWindowExA(
+            0,
+            "BaseviewClass\0".as_ptr() as *const i8,
+            "Baseview\0".as_ptr() as *const i8,
+            // todo: fine for now, will have to change with a parent
+            WS_OVERLAPPEDWINDOW | WS_VISIBLE,
+            CW_USEDEFAULT,
+            CW_USEDEFAULT,
+            // todo: check if usize fits into i32
+            w.width as i32,
+            w.height as i32,
+            0 as HWND,
+            0 as HMENU,
+            hinstance,
+            0 as LPVOID,
+        );
+    }
+}