Merge #2716

2716: Allow assists with multiple selectable actions r=SomeoneToIgnore a=SomeoneToIgnore

This PR prepares an infra for https://github.com/rust-analyzer/rust-analyzer/issues/2180 task by adding a possibility to specify multiple actions in one assist as multiple edit parameters to the `applySourceChange` command.

When this is done, the command opens a selection dialog, allowing the user to pick the edit to be applied.

I have no working example to test in this PR, but here's a demo of an auto import feature (a separate PR coming later for that one) using this functionality:

![out](https://user-images.githubusercontent.com/2690773/71633614-f8ea4d80-2c1d-11ea-9b15-0e13611a7aa4.gif)

The PR is not that massive as it may seem: all the assist files' changes are very generic and similar.

Co-authored-by: Kirill Bulatov <[email protected]>

1 files changed, 35 insertions, 9 deletions

diff --git a/crates/ra_ide/src/assists.rs b/crates/ra_ide/src/assists.rs
index e00589733..a936900da 100644
--- a/crates/ra_ide/src/assists.rs
+++ b/crates/ra_ide/src/assists.rs
@@ -2,27 +2,53 @@
 
 use ra_db::{FilePosition, FileRange};
 
-use crate::{db::RootDatabase, SourceChange, SourceFileEdit};
+use crate::{db::RootDatabase, FileId, SourceChange, SourceFileEdit};
 
+use either::Either;
 pub use ra_assists::AssistId;
+use ra_assists::{AssistAction, AssistLabel};
 
 #[derive(Debug)]
 pub struct Assist {
     pub id: AssistId,
-    pub change: SourceChange,
+    pub label: String,
+    pub change_data: Either<SourceChange, Vec<SourceChange>>,
 }
 
 pub(crate) fn assists(db: &RootDatabase, frange: FileRange) -> Vec<Assist> {
     ra_assists::assists(db, frange)
         .into_iter()
-        .map(|(label, action)| {
+        .map(|assist| {
             let file_id = frange.file_id;
-            let file_edit = SourceFileEdit { file_id, edit: action.edit };
-            let id = label.id;
-            let change = SourceChange::source_file_edit(label.label, file_edit).with_cursor_opt(
-                action.cursor_position.map(|offset| FilePosition { offset, file_id }),
-            );
-            Assist { id, change }
+            let assist_label = &assist.label;
+            Assist {
+                id: assist_label.id,
+                label: assist_label.label.clone(),
+                change_data: match assist.action_data {
+                    Either::Left(action) => {
+                        Either::Left(action_to_edit(action, file_id, assist_label))
+                    }
+                    Either::Right(actions) => Either::Right(
+                        actions
+                            .into_iter()
+                            .map(|action| action_to_edit(action, file_id, assist_label))
+                            .collect(),
+                    ),
+                },
+            }
         })
         .collect()
 }
+
+fn action_to_edit(
+    action: AssistAction,
+    file_id: FileId,
+    assist_label: &AssistLabel,
+) -> SourceChange {
+    let file_edit = SourceFileEdit { file_id, edit: action.edit };
+    SourceChange::source_file_edit(
+        action.label.unwrap_or_else(|| assist_label.label.clone()),
+        file_edit,
+    )
+    .with_cursor_opt(action.cursor_position.map(|offset| FilePosition { offset, file_id }))
+}