implement snippet tabstop support

helix-lsp/src/lib.rs

@@ -2,7 +2,6 @@ mod client;
 pub mod file_event;
 mod file_operations;
 pub mod jsonrpc;
-pub mod snippet;
 mod transport;
 
 use arc_swap::ArcSwap;
@@ -67,7 +66,8 @@ pub enum OffsetEncoding {
 pub mod util {
     use super::*;
     use helix_core::line_ending::{line_end_byte_index, line_end_char_index};
-    use helix_core::{chars, RopeSlice, SmallVec};
+    use helix_core::snippets::{RenderedSnippet, Snippet, SnippetRenderCtx};
+    use helix_core::{chars, RopeSlice};
     use helix_core::{diagnostic::NumberOrString, Range, Rope, Selection, Tendril, Transaction};
 
     /// Converts a diagnostic in the document to [`lsp::Diagnostic`].
@@ -355,25 +355,17 @@ pub mod util {
         transaction.with_selection(selection)
     }
 
-    /// Creates a [Transaction] from the [snippet::Snippet] in a completion response.
+    /// Creates a [Transaction] from the [Snippet] in a completion response.
     /// The transaction applies the edit to all cursors.
-    #[allow(clippy::too_many_arguments)]
     pub fn generate_transaction_from_snippet(
         doc: &Rope,
         selection: &Selection,
         edit_offset: Option<(i128, i128)>,
         replace_mode: bool,
-        snippet: snippet::Snippet,
-        line_ending: &str,
-        include_placeholder: bool,
-        tab_width: usize,
-        indent_width: usize,
-    ) -> Transaction {
+        snippet: Snippet,
+        cx: &mut SnippetRenderCtx,
+    ) -> (Transaction, RenderedSnippet) {
         let text = doc.slice(..);
-
-        let mut off = 0i128;
-        let mut mapped_doc = doc.clone();
-        let mut selection_tabstops: SmallVec<[_; 1]> = SmallVec::new();
         let (removed_start, removed_end) = completion_range(
             text,
             edit_offset,
@@ -382,8 +374,7 @@ pub mod util {
         )
         .expect("transaction must be valid for primary selection");
         let removed_text = text.slice(removed_start..removed_end);
-
-        let (transaction, mut selection) = Transaction::change_by_selection_ignore_overlapping(
+        let (transaction, mapped_selection, snippet) = snippet.render(
             doc,
             selection,
             |range| {
@@ -392,108 +383,15 @@ pub mod util {
                     .filter(|(start, end)| text.slice(start..end) == removed_text)
                     .unwrap_or_else(|| find_completion_range(text, replace_mode, cursor))
             },
-            |replacement_start, replacement_end| {
-                let mapped_replacement_start = (replacement_start as i128 + off) as usize;
-                let mapped_replacement_end = (replacement_end as i128 + off) as usize;
-
-                let line_idx = mapped_doc.char_to_line(mapped_replacement_start);
-                let indent_level = helix_core::indent::indent_level_for_line(
-                    mapped_doc.line(line_idx),
-                    tab_width,
-                    indent_width,
-                ) * indent_width;
-
-                let newline_with_offset = format!(
-                    "{line_ending}{blank:indent_level$}",
-                    line_ending = line_ending,
-                    blank = ""
-                );
-
-                let (replacement, tabstops) =
-                    snippet::render(&snippet, &newline_with_offset, include_placeholder);
-                selection_tabstops.push((mapped_replacement_start, tabstops));
-                mapped_doc.remove(mapped_replacement_start..mapped_replacement_end);
-                mapped_doc.insert(mapped_replacement_start, &replacement);
-                off +=
-                    replacement_start as i128 - replacement_end as i128 + replacement.len() as i128;
-
-                Some(replacement)
-            },
+            cx,
         );
-
-        let changes = transaction.changes();
-        if changes.is_empty() {
-            return transaction;
-        }
-
-        // Don't normalize to avoid merging/reording selections which would
-        // break the association between tabstops and selections. Most ranges
-        // will be replaced by tabstops anyways and the final selection will be
-        // normalized anyways
-        selection = selection.map_no_normalize(changes);
-        let mut mapped_selection = SmallVec::with_capacity(selection.len());
-        let mut mapped_primary_idx = 0;
-        let primary_range = selection.primary();
-        for (range, (tabstop_anchor, tabstops)) in selection.into_iter().zip(selection_tabstops) {
-            if range == primary_range {
-                mapped_primary_idx = mapped_selection.len()
-            }
-
-            let tabstops = tabstops.first().filter(|tabstops| !tabstops.is_empty());
-            let Some(tabstops) = tabstops else {
-                // no tabstop normal mapping
-                mapped_selection.push(range);
-                continue;
-            };
-
-            // expand the selection to cover the tabstop to retain the helix selection semantic
-            // the tabstop closest to the range simply replaces `head` while anchor remains in place
-            // the remaining tabstops receive their own single-width cursor
-            if range.head < range.anchor {
-                let last_idx = tabstops.len() - 1;
-                let last_tabstop = tabstop_anchor + tabstops[last_idx].0;
-
-                // if selection is forward but was moved to the right it is
-                // contained entirely in the replacement text, just do a point
-                // selection (fallback below)
-                if range.anchor > last_tabstop {
-                    let range = Range::new(range.anchor, last_tabstop);
-                    mapped_selection.push(range);
-                    let rem_tabstops = tabstops[..last_idx]
-                        .iter()
-                        .map(|tabstop| Range::point(tabstop_anchor + tabstop.0));
-                    mapped_selection.extend(rem_tabstops);
-                    continue;
-                }
-            } else {
-                let first_tabstop = tabstop_anchor + tabstops[0].0;
-
-                // if selection is forward but was moved to the right it is
-                // contained entirely in the replacement text, just do a point
-                // selection (fallback below)
-                if range.anchor < first_tabstop {
-                    // we can't properly compute the the next grapheme
-                    // here because the transaction hasn't been applied yet
-                    // that is not a problem because the range gets grapheme aligned anyway
-                    // tough so just adding one will always cause head to be grapheme
-                    // aligned correctly when applied to the document
-                    let range = Range::new(range.anchor, first_tabstop + 1);
-                    mapped_selection.push(range);
-                    let rem_tabstops = tabstops[1..]
-                        .iter()
-                        .map(|tabstop| Range::point(tabstop_anchor + tabstop.0));
-                    mapped_selection.extend(rem_tabstops);
-                    continue;
-                }
-            };
-
-            let tabstops = tabstops
-                .iter()
-                .map(|tabstop| Range::point(tabstop_anchor + tabstop.0));
-            mapped_selection.extend(tabstops);
-        }
-
-        transaction.with_selection(Selection::new(mapped_selection, mapped_primary_idx))
+        let transaction = transaction.with_selection(snippet.first_selection(
+            // we keep the direction of the old primary selection in case it changed during mapping
+            // but use the primary idx from the mapped selection in case ranges had to be merged
+            selection.primary().direction(),
+            mapped_selection.primary_index(),
+        ));
+        (transaction, snippet)
     }
 
     pub fn generate_transaction_from_edits(