egui: replace FileSender/FileReceiver with FileHandler

src/bin/topola-egui/app.rs

@@ -18,7 +18,7 @@ use crate::{
     activity::{ActivityStatus, ActivityStepperWithStatus},
     config::Config,
     error_dialog::ErrorDialog,
-    file_receiver::FileReceiver,
+    file_handler::FileHandlerData,
     layers::Layers,
     menu_bar::MenuBar,
     overlay::Overlay,
@@ -37,8 +37,14 @@ pub struct App {
 
     maybe_activity: Option<ActivityStepperWithStatus>,
 
-    content_channel: (Sender<String>, Receiver<String>),
-    history_channel: (Sender<String>, Receiver<String>),
+    content_channel: (
+        Sender<std::io::Result<FileHandlerData>>,
+        Receiver<std::io::Result<FileHandlerData>>,
+    ),
+    history_channel: (
+        Sender<std::io::Result<FileHandlerData>>,
+        Receiver<std::io::Result<FileHandlerData>>,
+    ),
 
     viewport: Viewport,
 
@@ -101,21 +107,25 @@ impl App {
     }
 
     fn update_state(&mut self) -> bool {
-        let mut content_file_receiver = FileReceiver::new(&self.content_channel.1);
-
-        if let Some(input) = content_file_receiver.try_recv() {
-            match self.load_specctra_dsn(input) {
+        if let Ok(data) = self.content_channel.1.try_recv() {
+            match data {
+                Ok(data) => match self.load_specctra_dsn(data) {
                     Ok(()) => {}
                     Err(err) => {
                         self.error_dialog.push_error("tr-module-specctra-dsn-file-loader", err);
                     }
+                },
+                Err(err) => {
+                    self.error_dialog.push_error(
+                        "tr-module-specctra-dsn-file-loader",
+                        format!("{}; {}", self.translator.text("tr-error_unable-to-read-file"), err),
+                    );
+                }
             }
         }
 
         if let Some(invoker) = self.arc_mutex_maybe_invoker.lock().unwrap().as_mut() {
-            let mut history_file_receiver = FileReceiver::new(&self.history_channel.1);
-
-            if let Some(input) = history_file_receiver.try_recv() {
+            if let Ok(input) = self.history_channel.1.try_recv() {
                 let tr = &self.translator;
                 match input {
                     Ok(bufread) => match serde_json::from_reader(bufread) {
@@ -151,12 +161,8 @@ impl App {
         false
     }
 
-    fn load_specctra_dsn<I: std::io::BufRead>(
-        &mut self,
-        input: std::io::Result<I>,
-    ) -> Result<(), String> {
+    fn load_specctra_dsn(&mut self, bufread: FileHandlerData) -> Result<(), String> {
         let tr = &self.translator;
-        let bufread = input.map_err(|err| format!("{}; {}", tr.text("tr-error_unable-to-read-file"), err))?;
         let design = SpecctraDesign::load(bufread)
             .map_err(|err| format!("{}; {}", tr.text("tr-error_failed-to-parse-as-specctra-dsn"), err))?;
         let board = design.make_board();

src/bin/topola-egui/file_handler.rs

@@ -0,0 +1,64 @@
+use std::io;
+use std::sync::mpsc::{SendError, Sender};
+
+#[repr(transparent)]
+pub enum FileHandlerData {
+    #[cfg(not(target_arch = "wasm32"))]
+    File(io::BufReader<std::fs::File>),
+
+    #[cfg(target_arch = "wasm32")]
+    Contents(io::Cursor<Vec<u8>>),
+}
+
+macro_rules! fhd_forward {
+    (match $self:expr => $fname:ident($($arg:expr,)*)) => {{
+        match $self {
+            #[cfg(not(target_arch = "wasm32"))]
+            FileHandlerData::File(brf) => brf.$fname($($arg,)*),
+
+            #[cfg(target_arch = "wasm32")]
+            FileHandlerData::Contents(curs) => curs.$fname($($arg,)*),
+        }
+    }};
+
+    (fn $fname:ident(&mut self $(,$arg:ident : $argty:ty)*)) => {
+        #[inline]
+        fn $fname(&mut self $(,$arg : $argty)*) {
+            fhd_forward!(match self => $fname($($arg,)*))
+        }
+    };
+    (fn $fname:ident(&mut self $(,$arg:ident : $argty:ty)*) -> $ret:ty) => {
+        #[inline]
+        fn $fname(&mut self $(,$arg : $argty)*) -> $ret {
+            fhd_forward!(match self => $fname($($arg,)*))
+        }
+    }
+}
+
+impl io::Read for FileHandlerData {
+    fhd_forward!(fn read(&mut self, buf: &mut [u8]) -> io::Result<usize>);
+    fhd_forward!(fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize>);
+    fhd_forward!(fn read_vectored(&mut self, bufs: &mut [io::IoSliceMut<'_>]) -> io::Result<usize>);
+}
+
+impl io::BufRead for FileHandlerData {
+    fhd_forward!(fn fill_buf(&mut self) -> io::Result<&[u8]>);
+    fhd_forward!(fn consume(&mut self, amt: usize));
+}
+
+pub async fn push_file_to_read(
+    file_handle: &rfd::FileHandle,
+    sender: Sender<std::io::Result<FileHandlerData>>,
+) {
+    let _ = sender.send(handle_text(&file_handle).await);
+}
+
+async fn handle_text(file_handle: &rfd::FileHandle) -> std::io::Result<FileHandlerData> {
+    #[cfg(not(target_arch = "wasm32"))]
+    let res = FileHandlerData::File(io::BufReader::new(std::fs::File::open(file_handle.path())?));
+
+    #[cfg(target_arch = "wasm32")]
+    let res = FileHandlerData::Contents(io::Cursor::new(file_handle.read().await));
+
+    Ok(res)
+}

src/bin/topola-egui/file_receiver.rs

@@ -1,22 +0,0 @@
-use std::io::{BufReader, Cursor};
-use std::sync::mpsc::Receiver;
-
-pub struct FileReceiver<'a> {
-    receiver: &'a Receiver<String>,
-}
-
-impl<'a> FileReceiver<'a> {
-    pub fn new(receiver: &'a Receiver<String>) -> Self {
-        Self { receiver }
-    }
-
-    #[cfg(not(target_arch = "wasm32"))]
-    pub fn try_recv(&mut self) -> Option<Result<BufReader<std::fs::File>, std::io::Error>> {
-        Some(std::fs::File::open(self.receiver.try_recv().ok()?).map(std::io::BufReader::new))
-    }
-
-    #[cfg(target_arch = "wasm32")]
-    pub fn try_recv(&mut self) -> Option<Result<Cursor<Vec<u8>>, std::io::Error>> {
-        Some(Ok(Cursor::new(self.receiver.try_recv().ok()?.into())))
-    }
-}

src/bin/topola-egui/file_sender.rs

@@ -1,27 +0,0 @@
-use std::sync::mpsc::{SendError, Sender};
-
-pub struct FileSender {
-    sender: Sender<String>,
-}
-
-impl FileSender {
-    pub fn new(sender: Sender<String>) -> Self {
-        Self { sender }
-    }
-
-    pub async fn send(&self, file_handle: rfd::FileHandle) -> Result<(), SendError<String>> {
-        self.sender.send(self.handle_text(&file_handle).await)
-    }
-
-    #[cfg(not(target_arch = "wasm32"))]
-    async fn handle_text(&self, file_handle: &rfd::FileHandle) -> String {
-        file_handle.path().to_str().unwrap().to_string()
-    }
-
-    #[cfg(target_arch = "wasm32")]
-    async fn handle_text(&self, file_handle: &rfd::FileHandle) -> String {
-        std::str::from_utf8(&file_handle.read().await)
-            .unwrap()
-            .to_string()
-    }
-}

src/bin/topola-egui/main.rs

@@ -5,8 +5,7 @@ mod activity;
 mod app;
 mod config;
 mod error_dialog;
-mod file_receiver;
-mod file_sender;
+mod file_handler;
 mod layers;
 mod menu_bar;
 mod overlay;

src/bin/topola-egui/menu_bar.rs

@@ -18,7 +18,7 @@ use crate::{
     action::{Action, Switch, Trigger},
     activity::{ActivityStatus, ActivityStepperWithStatus},
     app::execute,
-    file_sender::FileSender,
+    file_handler::{push_file_to_read, FileHandlerData},
     overlay::Overlay,
     translator::Translator,
     viewport::Viewport,
@@ -59,8 +59,8 @@ impl MenuBar {
         &mut self,
         ctx: &egui::Context,
         tr: &Translator,
-        content_sender: Sender<String>,
-        history_sender: Sender<String>,
+        content_sender: Sender<std::io::Result<FileHandlerData>>,
+        history_sender: Sender<std::io::Result<FileHandlerData>>,
         arc_mutex_maybe_invoker: Arc<Mutex<Option<Invoker<SpecctraMesadata>>>>,
         maybe_activity: &mut Option<ActivityStepperWithStatus>,
         viewport: &mut Viewport,
@@ -239,8 +239,7 @@ impl MenuBar {
 
                     execute(async move {
                         if let Some(file_handle) = task.await {
-                            let file_sender = FileSender::new(content_sender);
-                            file_sender.send(file_handle).await;
+                            push_file_to_read(&file_handle, content_sender).await;
                             ctx.request_repaint();
                         }
                     });
@@ -279,8 +278,7 @@ impl MenuBar {
 
                     execute(async move {
                         if let Some(file_handle) = task.await {
-                            let file_sender = FileSender::new(history_sender);
-                            file_sender.send(file_handle).await;
+                            push_file_to_read(&file_handle, history_sender).await;
                             ctx.request_repaint();
                         }
                     });