Fix issues with MIDI port numbers (#26)

CHANGELOG.md

@@ -7,6 +7,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Fixed
+
+- Connection to MIDI port 0 on Windows doesn't result in crash anymore
+- When creating new MIDI source use minimal port number by default
+
 ## [0.3.0] - 2024-10-22
 
 ### Added

src/audio_engine.rs

@@ -31,6 +31,7 @@ use std::{
     time::Duration,
 };
 
+use anyhow::anyhow;
 use midir::{MidiOutput, MidiOutputConnection};
 use midly::live::LiveEvent;
 use rusty_link::SessionState;
@@ -254,24 +255,33 @@ async fn audio_engine_main_midi(
 
         {
             let output: &mut MidiOutputConnection = {
-                if midi_source.associated_port == 0 {
+                let port_number = midi_source
+                    .associated_port
+                    .max(crate::handlers::MIN_PORT_NUMBER);
+                if port_number == 0 {
                     #[cfg(windows)]
                     unreachable!();
 
                     #[cfg(unix)]
                     &mut virtual_output
                 } else {
                     let out = MidiOutput::new("harmonia")?;
-
-                    let midi_port = &out.ports()[midi_source.associated_port - 1];
+                    let ports = out.ports();
+                    let Some(midi_port) = ports.get(port_number - 1) else {
+                        return Err(anyhow!(
+                            "failed to connect to unknown midi port number {} (max {})",
+                            port_number,
+                            ports.len()
+                        ));
+                    };
                     info!(
                         "outputing to output port #{} named: {}",
                         midi_source.associated_port,
-                        out.port_name(midi_port).unwrap(),
+                        out.port_name(&midi_port).unwrap(),
                     );
 
                     conn_storage = Some(
-                        out.connect(midi_port, /* TODO: Better name */ "harmonia-play")
+                        out.connect(&midi_port, /* TODO: Better name */ "harmonia-play")
                             .map_err(|err| {
                                 anyhow::Error::msg(format!("failed to connect to midi port: {err}"))
                             })?,

src/handlers.rs

@@ -69,11 +69,9 @@ pub async fn index(app_state: State<Arc<AppState>>) -> Markup {
                                 let cache = cache_path();
                                 let c: &std::path::Path = &cache;
 
-                                // TODO: On Windows don't use "~" as HOME since it may not work,
-                                // use environment variable instead
                                 dirs::home_dir()
                                     .and_then(|home| c.strip_prefix(home).ok())
-                                    .map(|p| PathBuf::from("~").join(p))
+                                    .map(|p| PathBuf::from(if cfg!(unix) { "~" } else { "%HOMEPATH%" }).join(p))
                                     .unwrap_or(cache)
                                     .to_str()
                                     .unwrap()
@@ -485,7 +483,7 @@ pub struct SetPort {
 ///
 /// On windows it is 1 since we don't have virtual ports.
 /// On unix'es it's 0 since we have virtual ports.
-const MIN_PORT_NUMBER: usize = if cfg!(unix) { 0 } else { 1 };
+pub const MIN_PORT_NUMBER: usize = if cfg!(unix) { 0 } else { 1 };
 
 /// Set port for MIDI block
 pub async fn set_port_for_midi(
@@ -636,7 +634,7 @@ pub async fn add_new_midi_source_block(
         let midi_source = block::MidiSource {
             bytes: data,
             file_name: file_name.clone(),
-            associated_port: 0,
+            associated_port: MIN_PORT_NUMBER,
         };
 
         let block = block::Block {