move field list to ast/edit.rs

crates/ra_assists/src/assist_ctx.rs

@@ -178,9 +178,7 @@ impl AssistBuilder {
     }
 
     pub(crate) fn replace_ast<N: AstNode>(&mut self, old: N, new: N) {
-        for (from, to) in algo::diff(old.syntax(), new.syntax()) {
+        algo::diff(old.syntax(), new.syntax()).into_text_edit(&mut self.edit)
-            self.edit.replace(from.text_range(), to.to_string())
-        }
     }
 
     fn build(self) -> AssistAction {

crates/ra_assists/src/ast_editor.rs

@@ -1,15 +1,12 @@
 use std::{iter, ops::RangeInclusive};
 
-use arrayvec::ArrayVec;
-use rustc_hash::FxHashMap;
-
-use ra_fmt::leading_indent;
 use ra_syntax::{
     algo,
-    ast::{self, make::tokens, TypeBoundsOwner},
+    ast::{self, TypeBoundsOwner},
-    AstNode, Direction, InsertPosition, SyntaxElement, T,
+    AstNode, SyntaxElement,
 };
 use ra_text_edit::TextEditBuilder;
+use rustc_hash::FxHashMap;
 
 pub struct AstEditor<N: AstNode> {
     original_ast: N,
@@ -25,9 +22,7 @@ impl<N: AstNode> AstEditor<N> {
     }
 
     pub fn into_text_edit(self, builder: &mut TextEditBuilder) {
-        for (from, to) in algo::diff(&self.original_ast.syntax(), self.ast().syntax()) {
+        algo::diff(&self.original_ast.syntax(), self.ast().syntax()).into_text_edit(builder)
-            builder.replace(from.text_range(), to.to_string())
-        }
     }
 
     pub fn ast(&self) -> &N {
@@ -46,16 +41,6 @@ impl<N: AstNode> AstEditor<N> {
         self
     }
 
-    #[must_use]
-    fn insert_children(
-        &self,
-        position: InsertPosition<SyntaxElement>,
-        mut to_insert: impl Iterator<Item = SyntaxElement>,
-    ) -> N {
-        let new_syntax = algo::insert_children(self.ast().syntax(), position, &mut to_insert);
-        N::cast(new_syntax).unwrap()
-    }
-
     #[must_use]
     fn replace_children(
         &self,
@@ -67,84 +52,6 @@ impl<N: AstNode> AstEditor<N> {
     }
 }
 
-impl AstEditor<ast::RecordFieldList> {
-    pub fn append_field(&mut self, field: &ast::RecordField) {
-        self.insert_field(InsertPosition::Last, field)
-    }
-
-    pub fn insert_field(
-        &mut self,
-        position: InsertPosition<&'_ ast::RecordField>,
-        field: &ast::RecordField,
-    ) {
-        let is_multiline = self.ast().syntax().text().contains_char('\n');
-        let ws;
-        let space = if is_multiline {
-            ws = tokens::WsBuilder::new(&format!(
-                "\n{}    ",
-                leading_indent(self.ast().syntax()).unwrap_or("".into())
-            ));
-            ws.ws()
-        } else {
-            tokens::single_space()
-        };
-
-        let mut to_insert: ArrayVec<[SyntaxElement; 4]> = ArrayVec::new();
-        to_insert.push(space.into());
-        to_insert.push(field.syntax().clone().into());
-        to_insert.push(tokens::comma().into());
-
-        macro_rules! after_l_curly {
-            () => {{
-                let anchor = match self.l_curly() {
-                    Some(it) => it,
-                    None => return,
-                };
-                InsertPosition::After(anchor)
-            }};
-        }
-
-        macro_rules! after_field {
-            ($anchor:expr) => {
-                if let Some(comma) = $anchor
-                    .syntax()
-                    .siblings_with_tokens(Direction::Next)
-                    .find(|it| it.kind() == T![,])
-                {
-                    InsertPosition::After(comma)
-                } else {
-                    to_insert.insert(0, tokens::comma().into());
-                    InsertPosition::After($anchor.syntax().clone().into())
-                }
-            };
-        };
-
-        let position = match position {
-            InsertPosition::First => after_l_curly!(),
-            InsertPosition::Last => {
-                if !is_multiline {
-                    // don't insert comma before curly
-                    to_insert.pop();
-                }
-                match self.ast().fields().last() {
-                    Some(it) => after_field!(it),
-                    None => after_l_curly!(),
-                }
-            }
-            InsertPosition::Before(anchor) => {
-                InsertPosition::Before(anchor.syntax().clone().into())
-            }
-            InsertPosition::After(anchor) => after_field!(anchor),
-        };
-
-        self.ast = self.insert_children(position, to_insert.iter().cloned());
-    }
-
-    fn l_curly(&self) -> Option<SyntaxElement> {
-        self.ast().syntax().children_with_tokens().find(|it| it.kind() == T!['{'])
-    }
-}
-
 impl AstEditor<ast::TypeParam> {
     pub fn remove_bounds(&mut self) -> &mut Self {
         let colon = match self.ast.colon_token() {

crates/ra_ide_api/src/diagnostics.rs

@@ -2,10 +2,10 @@ use std::cell::RefCell;
 
 use hir::diagnostics::{AstDiagnostic, Diagnostic as _, DiagnosticSink};
 use itertools::Itertools;
-use ra_assists::ast_editor::AstEditor;
 use ra_db::SourceDatabase;
 use ra_prof::profile;
 use ra_syntax::{
+    algo,
     ast::{self, make, AstNode},
     Location, SyntaxNode, TextRange, T,
 };
@@ -56,15 +56,15 @@ pub(crate) fn diagnostics(db: &RootDatabase, file_id: FileId) -> Vec<Diagnostic>
         })
     })
     .on::<hir::diagnostics::MissingFields, _>(|d| {
-        let node = d.ast(db);
+        let mut field_list = d.ast(db);
-        let mut ast_editor = AstEditor::new(node);
         for f in d.missed_fields.iter() {
             let field = make::record_field(make::name_ref(&f.to_string()), Some(make::expr_unit()));
-            ast_editor.append_field(&field);
+            field_list = field_list.append_field(&field);
         }
 
         let mut builder = TextEditBuilder::default();
-        ast_editor.into_text_edit(&mut builder);
+        algo::diff(&d.ast(db).syntax(), &field_list.syntax()).into_text_edit(&mut builder);
+
         let fix =
             SourceChange::source_file_edit_from("fill struct fields", file_id, builder.finish());
         res.borrow_mut().push(Diagnostic {

crates/ra_syntax/src/algo.rs

@@ -3,6 +3,7 @@ pub mod visit;
 use std::ops::RangeInclusive;
 
 use itertools::Itertools;
+use ra_text_edit::TextEditBuilder;
 use rustc_hash::FxHashMap;
 
 use crate::{
@@ -63,6 +64,18 @@ pub enum InsertPosition<T> {
     After(T),
 }
 
+pub struct TreeDiff {
+    replacements: FxHashMap<SyntaxElement, SyntaxElement>,
+}
+
+impl TreeDiff {
+    pub fn into_text_edit(&self, builder: &mut TextEditBuilder) {
+        for (from, to) in self.replacements.iter() {
+            builder.replace(from.text_range(), to.to_string())
+        }
+    }
+}
+
 /// Finds minimal the diff, which, applied to `from`, will result in `to`.
 ///
 /// Specifically, returns a map whose keys are descendants of `from` and values
@@ -70,12 +83,12 @@ pub enum InsertPosition<T> {
 ///
 /// A trivial solution is a singletom map `{ from: to }`, but this function
 /// tries to find a more fine-grained diff.
-pub fn diff(from: &SyntaxNode, to: &SyntaxNode) -> FxHashMap<SyntaxElement, SyntaxElement> {
+pub fn diff(from: &SyntaxNode, to: &SyntaxNode) -> TreeDiff {
     let mut buf = FxHashMap::default();
     // FIXME: this is both horrible inefficient and gives larger than
     // necessary diff. I bet there's a cool algorithm to diff trees properly.
     go(&mut buf, from.clone().into(), to.clone().into());
-    return buf;
+    return TreeDiff { replacements: buf };
 
     fn go(
         buf: &mut FxHashMap<SyntaxElement, SyntaxElement>,

crates/ra_syntax/src/ast/edit.rs

@@ -12,7 +12,7 @@ use crate::{
         make::{self, tokens},
         AstNode,
     },
-    AstToken, InsertPosition, SmolStr, SyntaxElement,
+    AstToken, Direction, InsertPosition, SmolStr, SyntaxElement,
     SyntaxKind::{ATTR, COMMENT, WHITESPACE},
     SyntaxNode, T,
 };
@@ -105,6 +105,86 @@ impl ast::ItemList {
     }
 }
 
+impl ast::RecordFieldList {
+    #[must_use]
+    pub fn append_field(&self, field: &ast::RecordField) -> ast::RecordFieldList {
+        self.insert_field(InsertPosition::Last, field)
+    }
+
+    #[must_use]
+    pub fn insert_field(
+        &self,
+        position: InsertPosition<&'_ ast::RecordField>,
+        field: &ast::RecordField,
+    ) -> ast::RecordFieldList {
+        let is_multiline = self.syntax().text().contains_char('\n');
+        let ws;
+        let space = if is_multiline {
+            ws = tokens::WsBuilder::new(&format!(
+                "\n{}    ",
+                leading_indent(self.syntax()).unwrap_or("".into())
+            ));
+            ws.ws()
+        } else {
+            tokens::single_space()
+        };
+
+        let mut to_insert: ArrayVec<[SyntaxElement; 4]> = ArrayVec::new();
+        to_insert.push(space.into());
+        to_insert.push(field.syntax().clone().into());
+        to_insert.push(tokens::comma().into());
+
+        macro_rules! after_l_curly {
+            () => {{
+                let anchor = match self.l_curly() {
+                    Some(it) => it,
+                    None => return self.clone(),
+                };
+                InsertPosition::After(anchor)
+            }};
+        }
+
+        macro_rules! after_field {
+            ($anchor:expr) => {
+                if let Some(comma) = $anchor
+                    .syntax()
+                    .siblings_with_tokens(Direction::Next)
+                    .find(|it| it.kind() == T![,])
+                {
+                    InsertPosition::After(comma)
+                } else {
+                    to_insert.insert(0, tokens::comma().into());
+                    InsertPosition::After($anchor.syntax().clone().into())
+                }
+            };
+        };
+
+        let position = match position {
+            InsertPosition::First => after_l_curly!(),
+            InsertPosition::Last => {
+                if !is_multiline {
+                    // don't insert comma before curly
+                    to_insert.pop();
+                }
+                match self.fields().last() {
+                    Some(it) => after_field!(it),
+                    None => after_l_curly!(),
+                }
+            }
+            InsertPosition::Before(anchor) => {
+                InsertPosition::Before(anchor.syntax().clone().into())
+            }
+            InsertPosition::After(anchor) => after_field!(anchor),
+        };
+
+        insert_children(self, position, to_insert.iter().cloned())
+    }
+
+    fn l_curly(&self) -> Option<SyntaxElement> {
+        self.syntax().children_with_tokens().find(|it| it.kind() == T!['{'])
+    }
+}
+
 pub fn strip_attrs_and_docs<N: ast::AttrsOwner>(node: N) -> N {
     N::cast(strip_attrs_and_docs_inner(node.syntax().clone())).unwrap()
 }