Apply completion edits to all cursors (#4496)

Completion edits - either basic `insert_text` strings or structured
`text_edit`s - are assumed by the LSP spec to apply to the current
cursor (or at least the trigger point). We can use the range (if any)
and text given by the Language Server to create a transaction that
changes all ranges in the current selection though, allowing auto-
complete to affect multiple cursors.

1 files changed, 24 insertions, 7 deletions

diff --git a/helix-term/src/ui/completion.rs b/helix-term/src/ui/completion.rs
index ebb4fb46..c54990e8 100644
--- a/helix-term/src/ui/completion.rs
+++ b/helix-term/src/ui/completion.rs
@@ -1,5 +1,5 @@
 use crate::compositor::{Component, Context, Event, EventResult};
-use helix_view::{apply_transaction, editor::CompleteAction};
+use helix_view::{apply_transaction, editor::CompleteAction, ViewId};
 use tui::buffer::Buffer as Surface;
 use tui::text::Spans;
 
@@ -107,6 +107,7 @@ impl Completion {
         let menu = Menu::new(items, (), move |editor: &mut Editor, item, event| {
             fn item_to_transaction(
                 doc: &Document,
+                view_id: ViewId,
                 item: &CompletionItem,
                 offset_encoding: helix_lsp::OffsetEncoding,
                 start_offset: usize,
@@ -121,9 +122,10 @@ impl Completion {
                         }
                     };
 
-                    util::generate_transaction_from_edits(
+                    util::generate_transaction_from_completion_edit(
                         doc.text(),
-                        vec![edit],
+                        doc.selection(view_id),
+                        edit,
                         offset_encoding, // TODO: should probably transcode in Client
                     )
                 } else {
@@ -132,10 +134,23 @@ impl Completion {
                     // in these cases we need to check for a common prefix and remove it
                     let prefix = Cow::from(doc.text().slice(start_offset..trigger_offset));
                     let text = text.trim_start_matches::<&str>(&prefix);
-                    Transaction::change(
-                        doc.text(),
-                        vec![(trigger_offset, trigger_offset, Some(text.into()))].into_iter(),
-                    )
+
+                    // TODO: this needs to be true for the numbers to work out correctly
+                    // in the closure below. It's passed in to a callback as this same
+                    // formula, but can the value change between the LSP request and
+                    // response? If it does, can we recover?
+                    debug_assert!(
+                        doc.selection(view_id)
+                            .primary()
+                            .cursor(doc.text().slice(..))
+                            == trigger_offset
+                    );
+
+                    Transaction::change_by_selection(doc.text(), doc.selection(view_id), |range| {
+                        let cursor = range.cursor(doc.text().slice(..));
+
+                        (cursor, cursor, Some(text.into()))
+                    })
                 };
 
                 transaction
@@ -164,6 +179,7 @@ impl Completion {
 
                     let transaction = item_to_transaction(
                         doc,
+                        view.id,
                         item,
                         offset_encoding,
                         start_offset,
@@ -185,6 +201,7 @@ impl Completion {
 
                     let transaction = item_to_transaction(
                         doc,
+                        view.id,
                         item,
                         offset_encoding,
                         start_offset,