window: Adjust to image size when opening

Give LpImage a native with that should feel nice.
When opening a new window with a new image the window size
is determined by LpImage's natural width.
The image size and EXIF data is loaded before the image such
that the window can be shown in the right dimension while
loading the actual image.

src/file_model.rs

@@ -81,19 +81,19 @@ impl LpFileModel {
             vec.push(file);
         }
 
-        model.imp().directory.set(directory.clone()).unwrap();
+        model.imp().directory.set(directory).unwrap();
 
         Ok(model)
     }
 
-    pub fn load_directory(&self) -> anyhow::Result<()> {
-        let directory = self.imp().directory.get().unwrap();
+    pub async fn load_directory(&self) -> anyhow::Result<()> {
+        let directory = self.imp().directory.get().unwrap().clone();
 
-        {
-            // Here we use a nested scope so that the mutable borrow only lasts as long as we need it
-            let mut vec = self.imp().inner.borrow_mut();
-            let original_vec: Vec<Option<std::path::PathBuf>> =
-                vec.iter().map(|x| x.path()).collect();
+        let original_vec: Vec<Option<std::path::PathBuf>> =
+            self.imp().inner.borrow().iter().map(|x| x.path()).collect();
+
+        let new_files_result = util::spawn("list-files", move || {
+            let mut vec = Vec::new();
 
             let enumerator = directory
                 .enumerate_children(
@@ -105,7 +105,7 @@ impl LpFileModel {
                     gio::FileQueryInfoFlags::NONE,
                     gio::Cancellable::NONE,
                 )
-                .context(i18n("Directory does not exist."))?;
+                .context(i18n("Could not list other files in directory."))?;
 
             // Filter out non-images; For now we support "all" image types.
             enumerator.for_each(|info| {
@@ -123,8 +123,23 @@ impl LpFileModel {
                 }
             });
 
+            //anyhow::Result::Ok(vec)
+            Ok::<_, anyhow::Error>(vec)
+        })
+        .await;
+
+        let Ok(new_files) = new_files_result else {
+            log::debug!("Thread listing directory canceled.");
+            return Ok(());
+        };
+
+        {
+            // Here we use a nested scope so that the mutable borrow only lasts as long as we need it
+
+            let mut files = self.imp().inner.borrow_mut();
+            files.append(&mut new_files?);
             // Then sort by name.
-            vec.sort_by(util::compare_by_name);
+            files.sort_by(util::compare_by_name);
         }
 
         Ok(())