feat: phase 2

Newfound motivation

rust/src/download_handler.rs

@@ -0,0 +1,57 @@
+use std::{collections::HashSet, path::PathBuf};
+use tauri::{AppHandle, Emitter};
+use tokio::fs::File;
+use anyhow::{anyhow, Result};
+
+use crate::pkg::{Package, PkgKey, Remote};
+
+pub struct DownloadHandler {
+    set: HashSet<String>,
+    app: AppHandle
+}
+
+impl DownloadHandler {
+    pub fn new(app: AppHandle) -> DownloadHandler {
+        DownloadHandler {
+            set: HashSet::new(),
+            app
+        }
+    }
+
+    pub fn download_zip(&mut self, zip_path: &PathBuf, pkg: &Package) -> Result<()> {
+        let rmt = pkg.rmt.as_ref()
+            .ok_or_else(|| anyhow!("Attempted to download a package without remote data"))?
+            .clone();
+        if self.set.contains(zip_path.to_string_lossy().as_ref()) {
+            Err(anyhow!("Already downloading"))
+        } else {
+            self.set.insert(zip_path.to_string_lossy().to_string());
+            tauri::async_runtime::spawn(Self::download_zip_proc(self.app.clone(), zip_path.clone(), pkg.key(), rmt));
+            Ok(())
+        }
+    }
+
+    async fn download_zip_proc(app: AppHandle, zip_path: PathBuf, pkg_key: PkgKey, rmt: Remote) -> Result<()> {
+        use futures::StreamExt;
+        use tokio::io::AsyncWriteExt;
+
+        // let zip_path_part = zip_path.add_extension("part");
+        let mut zip_path_part = zip_path.to_owned();
+        zip_path_part.set_extension("zip.part");
+
+        let mut cache_file_w = File::create(&zip_path_part).await?;
+        let mut byte_stream = reqwest::get(&rmt.download_url).await?.bytes_stream();
+
+        log::info!("Downloading: {}", rmt.download_url);
+        while let Some(item) = byte_stream.next().await {
+            let i = item?;
+            cache_file_w.write_all(&mut i.as_ref()).await?;
+        }
+        cache_file_w.sync_all().await?;
+        tokio::fs::rename(&zip_path_part, &zip_path).await?;
+
+        app.emit("download-end", pkg_key)?;
+
+        Ok(())
+    }
+}