Support drag+drop ROMs

Cargo.toml

@@ -34,6 +34,12 @@ web-sys = { version = "0.3.70", optional = true, features = [
     'Element',
     'HtmlCanvasElement',
     'Window',
+    # Features required for reading drag+dropped ROMs
+    'DragEvent',
+    'DataTransfer',
+    'DataTransferItem',
+    'DataTransferItemList',
+    'File',
 ] }
 console_log = { version = "1.0.0", optional = true }
 

src/runtime/web.rs

@@ -2,8 +2,11 @@
 use crate::{runtime::Runtime, BufferDisplay, Buttons, INes, HEIGHT, NES, WIDTH};
 use anyhow::{anyhow, Context};
 use std::{cell::RefCell, error::Error, rc::Rc};
-use wasm_bindgen::{prelude::*, Clamped};
-use web_sys::{CanvasRenderingContext2d, HtmlCanvasElement, ImageData, KeyboardEvent, Window};
+use wasm_bindgen::{convert::FromWasmAbi, prelude::*, Clamped};
+use web_sys::{
+    js_sys::{ArrayBuffer, Uint8Array},
+    CanvasRenderingContext2d, DragEvent, HtmlCanvasElement, ImageData, KeyboardEvent, Window,
+};
 
 const ROM: &[u8] = include_bytes!("../../roms/AlwasAwakening_demo.nes");
 const MS_PER_FRAME: f64 = 1000.0 / 60.0;
@@ -12,7 +15,8 @@ pub struct Web;
 
 impl Runtime for Web {
     fn run() -> Result<(), Box<dyn Error>> {
-        console_log::init_with_level(log::Level::Debug).expect("Failed to initialize logger");
+        console_log::init_with_level(log::Level::Debug)
+            .map_err(|_| anyhow!("Failed to initialize logger"))?;
 
         let ines = INes::read(ROM)?;
         let cartridge = ines.into_cartridge();
@@ -23,12 +27,63 @@ impl Runtime for Web {
         add_event_listener("keydown", move |event: KeyboardEvent| {
             let button = keycode_binding(&event.code());
             nesdown.borrow_mut().controller().press(button);
+            Ok(())
         })?;
 
         let nesup = nes.clone();
         add_event_listener("keyup", move |event: KeyboardEvent| {
             let button = keycode_binding(&event.code());
             nesup.borrow_mut().controller().release(button);
+            Ok(())
+        })?;
+
+        let nesdrop = nes.clone();
+        add_event_listener("drop", move |event: DragEvent| {
+            event.prevent_default();
+            let items = event.data_transfer().context("No data transfered")?.items();
+
+            for i in 0..items.length() {
+                let item = items.get(i).context("No data transfer item found")?;
+                if let Some(file) = item
+                    .get_as_file()
+                    .map_err(|_| anyhow!("Failed to get file"))?
+                {
+                    let nesread = nesdrop.clone();
+
+                    let success = closure(move |array_buffer: JsValue| {
+                        let array_buffer = array_buffer
+                            .dyn_into::<ArrayBuffer>()
+                            .map_err(|_| anyhow!("Failed to convert to ArrayBuffer"))?;
+
+                        let array = Uint8Array::new(&array_buffer);
+                        let mut rom = vec![0; array.length() as usize];
+                        array.copy_to(&mut rom);
+
+                        let ines = INes::read(&mut rom.as_slice())?;
+                        let cartridge = ines.into_cartridge();
+                        let display = BufferDisplay::default();
+                        let nes_new = NES::new(cartridge, display);
+
+                        nesread.replace(nes_new);
+                        Ok(())
+                    });
+                    let failure = closure(move |_| {
+                        log::error!("An error occurred getting array buffer");
+                        Ok(())
+                    });
+
+                    let _ = file.array_buffer().then2(&success, &failure);
+                    success.forget();
+                    failure.forget();
+                }
+            }
+
+            Ok(())
+        })?;
+
+        add_event_listener("dragover", move |event: DragEvent| {
+            event.prevent_default();
+            Ok(())
         })?;
 
         let context = canvas_context()?;
@@ -115,15 +170,25 @@ fn request_animation_frame(f: &Closure<dyn FnMut(f64)>) -> anyhow::Result<i32> {
         .map_err(|_| anyhow!("failed to request animation frame"))
 }
 
-fn add_event_listener(
+fn add_event_listener<T: FromWasmAbi + 'static>(
     event: &str,
-    listener: impl FnMut(KeyboardEvent) + 'static,
+    listener: impl FnMut(T) -> Result<(), Box<dyn Error>> + 'static,
 ) -> anyhow::Result<()> {
-    let closure = Closure::<dyn FnMut(KeyboardEvent)>::new(listener);
+    let closure = closure(listener);
     window()?
         .add_event_listener_with_callback(event, closure.as_ref().unchecked_ref())
         .map_err(|_| anyhow!("failed to add event listener"))?;
     // Make closure live forever
     closure.forget();
     Ok(())
 }
+
+fn closure<T: FromWasmAbi + 'static>(
+    mut function: impl FnMut(T) -> Result<(), Box<dyn Error>> + 'static,
+) -> Closure<dyn FnMut(T)> {
+    Closure::<dyn FnMut(T)>::new(move |arg| {
+        if let Err(err) = function(arg) {
+            log::error!("Error: {}", err);
+        }
+    })
+}

web/webpack.config.js

@@ -16,7 +16,7 @@ export default {
         new WasmPackPlugin({
             crateDirectory: resolve(__dirname, '..'),
             outDir: resolve(__dirname, 'pkg'),
-            forceMode: 'production',
+            // forceMode: 'production',
             extraArgs: '--no-default-features --features=web',
         }),
     ],