Make file preview callback optional

When Picker and FilePicker are merged, not all Pickers will be able to
show a preview.

Co-authored-by: Gokul Soumya <gokulps15@gmail.com>

2 files changed, 22 insertions, 19 deletions

diff --git a/helix-term/src/ui/mod.rs b/helix-term/src/ui/mod.rs
index ec328ec5..c5e66d86 100644
--- a/helix-term/src/ui/mod.rs
+++ b/helix-term/src/ui/mod.rs
@@ -217,21 +217,17 @@ pub fn file_picker(root: PathBuf, config: &helix_view::editor::Config) -> FilePi
 
     log::debug!("file_picker init {:?}", Instant::now().duration_since(now));
 
-    FilePicker::new(
-        files,
-        root,
-        move |cx, path: &PathBuf, action| {
-            if let Err(e) = cx.editor.open(path, action) {
-                let err = if let Some(err) = e.source() {
-                    format!("{}", err)
-                } else {
-                    format!("unable to open \"{}\"", path.display())
-                };
-                cx.editor.set_error(err);
-            }
-        },
-        |_editor, path| Some((path.clone().into(), None)),
-    )
+    FilePicker::new(files, root, move |cx, path: &PathBuf, action| {
+        if let Err(e) = cx.editor.open(path, action) {
+            let err = if let Some(err) = e.source() {
+                format!("{}", err)
+            } else {
+                format!("unable to open \"{}\"", path.display())
+            };
+            cx.editor.set_error(err);
+        }
+    })
+    .with_preview(|_editor, path| Some((path.clone().into(), None)))
 }
 
 pub mod completers {
diff --git a/helix-term/src/ui/picker.rs b/helix-term/src/ui/picker.rs
index c06918d4..001526c4 100644
--- a/helix-term/src/ui/picker.rs
+++ b/helix-term/src/ui/picker.rs
@@ -141,7 +141,7 @@ pub struct FilePicker<T: Item> {
     preview_cache: HashMap<PathBuf, CachedPreview>,
     read_buffer: Vec<u8>,
     /// Given an item in the picker, return the file path and line number to display.
-    file_fn: FileCallback<T>,
+    file_fn: Option<FileCallback<T>>,
 }
 
 impl<T: Item + 'static> FilePicker<T> {
@@ -149,7 +149,6 @@ impl<T: Item + 'static> FilePicker<T> {
         options: Vec<T>,
         editor_data: T::Data,
         callback_fn: impl Fn(&mut Context, &T, Action) + 'static,
-        preview_fn: impl Fn(&Editor, &T) -> Option<FileLocation> + 'static,
     ) -> Self {
         let prompt = Prompt::new(
             "".into(),
@@ -173,7 +172,7 @@ impl<T: Item + 'static> FilePicker<T> {
             widths: Vec::new(),
             preview_cache: HashMap::new(),
             read_buffer: Vec::with_capacity(1024),
-            file_fn: Box::new(preview_fn),
+            file_fn: None,
 
             picker: unimplemented!(),
         };
@@ -202,6 +201,14 @@ impl<T: Item + 'static> FilePicker<T> {
         self
     }
 
+    pub fn with_preview(
+        mut self,
+        preview_fn: impl Fn(&Editor, &T) -> Option<FileLocation> + 'static,
+    ) -> Self {
+        self.file_fn = Some(Box::new(preview_fn));
+        self
+    }
+
     pub fn set_options(&mut self, new_options: Vec<T>) {
         self.options = new_options;
         self.cursor = 0;
@@ -372,7 +379,7 @@ impl<T: Item + 'static> FilePicker<T> {
     fn current_file(&self, editor: &Editor) -> Option<FileLocation> {
         self.picker
             .selection()
-            .and_then(|current| (self.file_fn)(editor, current))
+            .and_then(|current| (self.file_fn.as_ref()?)(editor, current))
             .and_then(|(path_or_id, line)| path_or_id.get_canonicalized().ok().zip(Some(line)))
     }