Read picked import files through the fs plugin so Android content URIs work

On Android the open dialog returns a content:// URI, which std::fs can't
open, so ManaBox/library and deck imports failed with "no such file or
directory". Read them via tauri-plugin-fs, which resolves content URIs and
falls through to plain paths on desktop.

Closes #24

src-tauri/Cargo.toml

@@ -16,6 +16,9 @@ tauri-build = { version = "2", features = [] }
 [dependencies]
 tauri = { version = "2", features = [] }
 tauri-plugin-dialog = "2"
+# Reads the files the dialog picks: on Android those are content:// URIs, which
+# std::fs can't open.
+tauri-plugin-fs = "2"
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"
 mtgc-core = { path = "../crates/mtgc-core" }

src-tauri/src/commands.rs

@@ -11,6 +11,7 @@ use mtgc_core::{
 };
 use serde::Serialize;
 use tauri::{AppHandle, Emitter, State};
+use tauri_plugin_fs::{FilePath, FsExt};
 
 use crate::state::AppState;
 
@@ -416,10 +417,17 @@ pub fn export_deck(db: Db, deck_id: i64, path: String) -> Res<()> {
     std::fs::write(&path, text).map_err(|e| e.to_string())
 }
 
+/// Read a text file the open dialog picked. On Android that's a content:// URI
+/// rather than a filesystem path, so it has to go through the fs plugin.
+fn read_picked_text(app: &AppHandle, path: &str) -> Res<String> {
+    let path: FilePath = path.parse().unwrap();
+    app.fs().read_to_string(path).map_err(|e| e.to_string())
+}
+
 #[tauri::command]
-pub fn import_deck(db: Db, path: String, name: String) -> Res<DeckImportResult> {
+pub fn import_deck(app: AppHandle, db: Db, path: String, name: String) -> Res<DeckImportResult> {
+    let text = read_picked_text(&app, &path)?;
     let s = db.lock().unwrap();
-    let text = std::fs::read_to_string(&path).map_err(|e| e.to_string())?;
     let (deck, unresolved) = s.catalog()?.import_deck(&name, &text).map_err(|e| e.to_string())?;
     Ok(DeckImportResult { deck, unresolved })
 }
@@ -452,7 +460,7 @@ pub async fn import_library_cards(
     location: Option<String>,
 ) -> Res<LibraryImportResult> {
     crate::sync::blocking(move || {
-        let text = std::fs::read_to_string(&path).map_err(|e| e.to_string())?;
+        let text = read_picked_text(&app, &path)?;
         let s = crate::sync::lock(&app);
         // At most one event per percent, so a big file doesn't flood the UI.
         let mut last_percent = None;

src-tauri/src/lib.rs

@@ -37,6 +37,7 @@ pub(crate) fn logged<T>(what: &str, result: Result<T, String>) -> Result<T, Stri
 #[cfg_attr(mobile, tauri::mobile_entry_point)]
 pub fn run() {
     let builder = tauri::Builder::default().plugin(tauri_plugin_dialog::init())
+        .plugin(tauri_plugin_fs::init())
         .plugin(tauri_plugin_opener::init());
     // Android gets sync sign-ins back through the `mtgc://` scheme; desktop
     // uses a loopback port instead and needs no scheme registered.