workspace: Add NewFileSplit action with direction (#39726)

Add new `workspace::NewFileSplit` action which expects a
`SplitDirection` argument, allowing users to programmatically control
the direction of the split in keymaps, for example:

```json
{
    "context": "Editor",
    "bindings": {
        "ctrl-s ctrl-h": ["workspace::NewFileSplit", "left"],
        "ctrl-s ctrl-j": ["workspace::NewFileSplit", "down"],
        "ctrl-s ctrl-k": ["workspace::NewFileSplit", "up"],
        "ctrl-s ctrl-l": ["workspace::NewFileSplit", "right"]
    }
}
```

Release Notes:

- Added `workspace::NewFileSplit` action, which can be used to
programmatically split the editor in the provided direction.

Co-authored-by: Rian Drake <[email protected]>
Co-authored-by: dino <[email protected]>

Author: 3 people

crates/editor/src/editor.rs

@@ -358,6 +358,7 @@ pub fn init(cx: &mut App) {
     cx.observe_new(
         |workspace: &mut Workspace, _: Option<&mut Window>, _cx: &mut Context<Workspace>| {
             workspace.register_action(Editor::new_file);
+            workspace.register_action(Editor::new_file_split);
             workspace.register_action(Editor::new_file_vertical);
             workspace.register_action(Editor::new_file_horizontal);
             workspace.register_action(Editor::cancel_language_server_work);
@@ -2683,6 +2684,15 @@ impl Editor {
         Self::new_file_in_direction(workspace, SplitDirection::horizontal(cx), window, cx)
     }
 
+    fn new_file_split(
+        workspace: &mut Workspace,
+        action: &workspace::NewFileSplit,
+        window: &mut Window,
+        cx: &mut Context<Workspace>,
+    ) {
+        Self::new_file_in_direction(workspace, action.0, window, cx)
+    }
+
     fn new_file_in_direction(
         workspace: &mut Workspace,
         direction: SplitDirection,

crates/workspace/src/workspace.rs

@@ -302,6 +302,12 @@ pub struct MoveItemToPaneInDirection {
     pub clone: bool,
 }
 
+/// Creates a new file in a split of the desired direction.
+#[derive(Clone, Deserialize, PartialEq, JsonSchema, Action)]
+#[action(namespace = workspace)]
+#[serde(deny_unknown_fields)]
+pub struct NewFileSplit(pub SplitDirection);
+
 fn default_right() -> SplitDirection {
     SplitDirection::Right
 }

crates/zed/src/zed.rs

@@ -4563,6 +4563,7 @@ mod tests {
                     | "workspace::ActivatePane"
                     | "workspace::MoveItemToPane"
                     | "workspace::MoveItemToPaneInDirection"
+                    | "workspace::NewFileSplit"
                     | "workspace::OpenTerminal"
                     | "workspace::SendKeystrokes"
                     | "agent::NewNativeAgentThreadFromSummary"