diff --git a/crates/syntax/src/algo.rs b/crates/syntax/src/algo.rs index 30adb72176..320c430c94 100644 --- a/crates/syntax/src/algo.rs +++ b/crates/syntax/src/algo.rs @@ -111,18 +111,28 @@ pub enum InsertPosition { type FxIndexMap = IndexMap>; +#[derive(Debug, Hash, PartialEq, Eq)] +enum TreeDiffInsertPos { + After(SyntaxElement), + AsFirstChild(SyntaxElement), +} + #[derive(Debug)] pub struct TreeDiff { replacements: FxHashMap, deletions: Vec, // the vec as well as the indexmap are both here to preserve order - insertions: FxIndexMap>, + insertions: FxIndexMap>, } impl TreeDiff { pub fn into_text_edit(&self, builder: &mut TextEditBuilder) { for (anchor, to) in self.insertions.iter() { - to.iter().for_each(|to| builder.insert(anchor.text_range().end(), to.to_string())); + let offset = match anchor { + TreeDiffInsertPos::After(it) => it.text_range().end(), + TreeDiffInsertPos::AsFirstChild(it) => it.text_range().start(), + }; + to.iter().for_each(|to| builder.insert(offset, to.to_string())); } for (from, to) in self.replacements.iter() { builder.replace(from.text_range(), to.to_string()) @@ -188,19 +198,20 @@ pub fn diff(from: &SyntaxNode, to: &SyntaxNode) -> TreeDiff { let lhs_child = lhs_children.next(); match (lhs_child.clone(), rhs_children.next()) { (None, None) => break, - (None, Some(element)) => match last_lhs.clone() { - Some(prev) => { - mark::hit!(diff_insert); - diff.insertions.entry(prev).or_insert_with(Vec::new).push(element); - } - // first iteration, this means we got no anchor element to insert after - // therefor replace the parent node instead - None => { - mark::hit!(diff_replace_parent); - diff.replacements.insert(lhs.clone().into(), rhs.clone().into()); - break; - } - }, + (None, Some(element)) => { + let insert_pos = match last_lhs.clone() { + Some(prev) => { + mark::hit!(diff_insert); + TreeDiffInsertPos::After(prev) + } + // first iteration, insert into out parent as the first child + None => { + mark::hit!(diff_insert_as_first_child); + TreeDiffInsertPos::AsFirstChild(lhs.clone().into()) + } + }; + diff.insertions.entry(insert_pos).or_insert_with(Vec::new).push(element); + } (Some(element), None) => { mark::hit!(diff_delete); diff.deletions.push(element); @@ -224,8 +235,15 @@ pub fn diff(from: &SyntaxNode, to: &SyntaxNode) -> TreeDiff { } } let drain = look_ahead_scratch.drain(..); - if let Some(prev) = last_lhs.clone().filter(|_| insert) { - diff.insertions.entry(prev).or_insert_with(Vec::new).extend(drain); + if insert { + let insert_pos = if let Some(prev) = last_lhs.clone().filter(|_| insert) { + TreeDiffInsertPos::After(prev) + } else { + mark::hit!(insert_first_child); + TreeDiffInsertPos::AsFirstChild(lhs.clone().into()) + }; + + diff.insertions.entry(insert_pos).or_insert_with(Vec::new).extend(drain); rhs_children = rhs_children_clone; } else { go(diff, lhs_ele, rhs_ele) @@ -632,18 +650,19 @@ mod tests { #[test] fn replace_parent() { - mark::check!(diff_replace_parent); + mark::check!(diff_insert_as_first_child); check_diff( r#""#, r#"use foo::bar;"#, expect![[r#" insertions: - + Line 0: AsFirstChild(Node(SOURCE_FILE@0..0)) + -> use foo::bar; replacements: - Line 0: Node(SOURCE_FILE@0..0) -> use foo::bar; + deletions: @@ -666,7 +685,7 @@ use baz;"#, expect![[r#" insertions: - Line 2: Node(USE@10..18) + Line 2: After(Node(USE@10..18)) -> "\n" -> use baz; @@ -694,7 +713,7 @@ use baz;"#, expect![[r#" insertions: - Line 2: Token(WHITESPACE@9..10 "\n") + Line 2: After(Token(WHITESPACE@9..10 "\n")) -> use bar; -> "\n" @@ -722,7 +741,7 @@ use baz;"#, expect![[r#" insertions: - Line 0: Token(WHITESPACE@0..1 "\n") + Line 0: After(Token(WHITESPACE@0..1 "\n")) -> use foo; -> "\n" @@ -737,6 +756,36 @@ use baz;"#, ) } + #[test] + fn first_child_insertion() { + mark::check!(insert_first_child); + check_diff( + r#"fn main() { + stdi + }"#, + r#"use foo::bar; + + fn main() { + stdi + }"#, + expect![[r#" + insertions: + + Line 0: AsFirstChild(Node(SOURCE_FILE@0..30)) + -> use foo::bar; + -> "\n\n " + + replacements: + + + + deletions: + + + "#]], + ); + } + #[test] fn delete_last() { mark::check!(diff_delete); @@ -779,7 +828,7 @@ use crate::AstNode; expect![[r#" insertions: - Line 1: Node(USE@1..35) + Line 1: After(Node(USE@1..35)) -> "\n\n" -> use crate::AstNode; @@ -845,10 +894,10 @@ use std::ops::{self, RangeInclusive}; expect![[r#" insertions: - Line 2: Node(PATH_SEGMENT@5..8) + Line 2: After(Node(PATH_SEGMENT@5..8)) -> :: -> fmt - Line 6: Token(WHITESPACE@86..87 "\n") + Line 6: After(Token(WHITESPACE@86..87 "\n")) -> use std::hash::BuildHasherDefault; -> "\n" -> use std::ops::{self, RangeInclusive}; @@ -892,14 +941,14 @@ fn main() { expect![[r#" insertions: - Line 3: Node(BLOCK_EXPR@40..63) + Line 3: After(Node(BLOCK_EXPR@40..63)) -> " " -> match Err(92) { Ok(it) => it, _ => return, } -> ; - Line 3: Node(IF_EXPR@17..63) + Line 3: After(Node(IF_EXPR@17..63)) -> "\n " -> foo(x); @@ -934,14 +983,18 @@ fn main() { _ => format!("{}", syn), }; - let insertions = diff.insertions.iter().format_with("\n", |(k, v), f| { - f(&format!( - "Line {}: {:?}\n-> {}", - line_number(k), - k, - v.iter().format_with("\n-> ", |v, f| f(&fmt_syntax(v))) - )) - }); + let insertions = + diff.insertions.iter().format_with("\n", |(k, v), f| -> Result<(), std::fmt::Error> { + f(&format!( + "Line {}: {:?}\n-> {}", + line_number(match k { + super::TreeDiffInsertPos::After(syn) => syn, + super::TreeDiffInsertPos::AsFirstChild(syn) => syn, + }), + k, + v.iter().format_with("\n-> ", |v, f| f(&fmt_syntax(v))) + )) + }); let replacements = diff .replacements