use new translate_offset_with_edit for TryConvWith

doc comments

crates/ra_editor/src/lib.rs

@@ -14,6 +14,7 @@ pub use self::{
     extend_selection::extend_selection,
     folding_ranges::{folding_ranges, Fold, FoldKind},
     line_index::{LineCol, LineIndex},
+    line_index_utils::translate_offset_with_edit,
     symbols::{file_structure, file_symbols, FileSymbol, StructureNode},
     typing::{join_lines, on_enter, on_eq_typed},
 };

crates/ra_editor/src/line_index_utils.rs

@@ -1,6 +1,6 @@
 use ra_text_edit::AtomTextEdit;
 use ra_syntax::{TextUnit, TextRange};
-use crate::{LineIndex, LineCol, line_index::Utf16Char, line_index};
+use crate::{LineIndex, LineCol, line_index::{self, Utf16Char}};
 use superslice::Ext;
 
 #[derive(Debug, Clone)]

crates/ra_lsp_server/src/conv.rs

@@ -3,7 +3,7 @@ use languageserver_types::{
     TextDocumentItem, TextDocumentPositionParams, Url, VersionedTextDocumentIdentifier, InsertTextFormat,
 };
 use ra_analysis::{FileId, FileSystemEdit, SourceChange, SourceFileEdit, FilePosition, CompletionItem, CompletionItemKind, InsertText};
-use ra_editor::{LineCol, LineIndex};
+use ra_editor::{LineCol, LineIndex, translate_offset_with_edit};
 use ra_text_edit::{AtomTextEdit, TextEdit};
 use ra_syntax::{SyntaxKind, TextRange, TextUnit};
 
@@ -261,41 +261,6 @@ impl TryConvWith for SourceChange {
     }
 }
 
-// HACK: we should translate offset to line/column using linde_index *with edits applied*.
-// A naive version of this function would be to apply `edits` to the original text,
-// construct a new line index and use that, but it would be slow.
-//
-// Writing fast & correct version is issue #105, let's use a quick hack in the meantime
-fn translate_offset_with_edit(
-    pre_edit_index: &LineIndex,
-    offset: TextUnit,
-    edits: &[AtomTextEdit],
-) -> LineCol {
-    let fallback = pre_edit_index.line_col(offset);
-    let edit = match edits.first() {
-        None => return fallback,
-        Some(edit) => edit,
-    };
-    let end_offset = edit.delete.start() + TextUnit::of_str(&edit.insert);
-    if !(edit.delete.start() <= offset && offset <= end_offset) {
-        return fallback;
-    }
-    let rel_offset = offset - edit.delete.start();
-    let in_edit_line_col = LineIndex::new(&edit.insert).line_col(rel_offset);
-    let edit_line_col = pre_edit_index.line_col(edit.delete.start());
-    if in_edit_line_col.line == 0 {
-        LineCol {
-            line: edit_line_col.line,
-            col_utf16: edit_line_col.col_utf16 + in_edit_line_col.col_utf16,
-        }
-    } else {
-        LineCol {
-            line: edit_line_col.line + in_edit_line_col.line,
-            col_utf16: in_edit_line_col.col_utf16,
-        }
-    }
-}
-
 impl TryConvWith for SourceFileEdit {
     type Ctx = ServerWorld;
     type Output = TextDocumentEdit;

crates/ra_text_edit/src/lib.rs

@@ -6,8 +6,10 @@ pub use crate::text_edit::{TextEdit, TextEditBuilder};
 
 use text_unit::{TextRange, TextUnit};
 
+/// Must not overlap with other `AtomTextEdit`s
 #[derive(Debug, Clone)]
 pub struct AtomTextEdit {
+    /// Refers to offsets in the original text
     pub delete: TextRange,
     pub insert: String,
 }