egui: get rid of FileHandlerData

src/bin/topola-egui/app.rs

@@ -1,6 +1,7 @@
 use serde::{Deserialize, Serialize};
 use std::{
     future::Future,
+    io,
     sync::{
         mpsc::{channel, Receiver, Sender},
         Arc, Mutex,
@@ -21,7 +22,6 @@ use crate::{
     activity::{ActivityStatus, ActivityStepperWithStatus},
     config::Config,
     error_dialog::ErrorDialog,
-    file_handler::FileHandlerData,
     layers::Layers,
     menu_bar::MenuBar,
     overlay::Overlay,
@@ -250,3 +250,13 @@ pub fn execute<F: Future<Output = ()> + Send + 'static>(f: F) {
 pub fn execute<F: Future<Output = ()> + 'static>(f: F) {
     wasm_bindgen_futures::spawn_local(f);
 }
+
+pub async fn handle_file(file_handle: &rfd::FileHandle) -> io::Result<impl io::BufRead + io::Seek> {
+    #[cfg(not(target_arch = "wasm32"))]
+    let res = io::BufReader::new(std::fs::File::open(file_handle.path())?);
+
+    #[cfg(target_arch = "wasm32")]
+    let res = io::Cursor::new(file_handle.read().await);
+
+    Ok(res)
+}

src/bin/topola-egui/file_handler.rs

@@ -1,61 +0,0 @@
-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 handle_file<R, E, C>(file_handle: &rfd::FileHandle, callback: C) -> Result<R, E>
-where
-    E: From<std::io::Error>,
-    C: FnOnce(FileHandlerData) -> Result<R, E>,
-{
-    #[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));
-
-    callback(res)
-}

src/bin/topola-egui/main.rs

@@ -5,7 +5,6 @@ mod activity;
 mod app;
 mod config;
 mod error_dialog;
-mod file_handler;
 mod layers;
 mod menu_bar;
 mod overlay;

src/bin/topola-egui/menu_bar.rs

@@ -21,8 +21,7 @@ use topola::{
 use crate::{
     action::{Action, Switch, Trigger},
     activity::{ActivityStatus, ActivityStepperWithStatus},
-    app::execute,
-    file_handler::{handle_file, FileHandlerData},
+    app::{execute, handle_file},
     overlay::Overlay,
     translator::Translator,
     viewport::Viewport,
@@ -243,9 +242,11 @@ impl MenuBar {
 
                     execute(async move {
                         if let Some(file_handle) = task.await {
-                            content_sender.send(handle_file(&file_handle, |data| {
-                                SpecctraDesign::load(data)
-                            }).await);
+                            let data = handle_file(&file_handle)
+                                .await
+                                .map_err(Into::into)
+                                .and_then(SpecctraDesign::load);
+                            content_sender.send(data);
                             ctx.request_repaint();
                         }
                     });
@@ -284,13 +285,14 @@ impl MenuBar {
 
                     execute(async move {
                         if let Some(file_handle) = task.await {
-                            history_sender.send(handle_file(&file_handle, |data| {
+                            let data = handle_file(&file_handle).await.and_then(|data| {
                                 match serde_json::from_reader(data) {
                                     Ok(history) => Ok(Ok(history)),
                                     Err(err) if err.is_io() => Err(err.into()),
                                     Err(err) => Ok(Err(err)),
                                 }
-                            }).await);
+                            });
+                            history_sender.send(data);
                             ctx.request_repaint();
                         }
                     });