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move diff to ra_syntax

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This commit is contained in:
Aleksey Kladov 2019-09-26 15:56:52 +03:00
parent 3882231f32
commit 1a4b424005
2 changed files with 45 additions and 24 deletions
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27
crates/ra_assists/src/ast_editor.rs
View file

@ -7,7 +7,7 @@ use ra_fmt::leading_indent;
use ra_syntax::{
algo,
ast::{self, TypeBoundsOwner},
AstNode, Direction, InsertPosition, NodeOrToken, SyntaxElement,
AstNode, Direction, InsertPosition, SyntaxElement,
SyntaxKind::*,
T,
};
@ -27,29 +27,8 @@ impl<N: AstNode> AstEditor<N> {
}
pub fn into_text_edit(self, builder: &mut TextEditBuilder) {
// FIXME: this is both horrible inefficient and gives larger than
// necessary diff. I bet there's a cool algorithm to diff trees properly.
go(builder, self.original_ast.syntax().clone().into(), self.ast().syntax().clone().into());
fn go(buf: &mut TextEditBuilder, lhs: SyntaxElement, rhs: SyntaxElement) {
if lhs.kind() == rhs.kind() && lhs.text_range().len() == rhs.text_range().len() {
if match (&lhs, &rhs) {
(NodeOrToken::Node(lhs), NodeOrToken::Node(rhs)) => lhs.text() == rhs.text(),
(NodeOrToken::Token(lhs), NodeOrToken::Token(rhs)) => lhs.text() == rhs.text(),
_ => false,
} {
return;
}
}
if let (Some(lhs), Some(rhs)) = (lhs.as_node(), rhs.as_node()) {
if lhs.children_with_tokens().count() == rhs.children_with_tokens().count() {
for (lhs, rhs) in lhs.children_with_tokens().zip(rhs.children_with_tokens()) {
go(buf, lhs, rhs)
}
return;
}
}
buf.replace(lhs.text_range(), rhs.to_string())
for (from, to) in algo::diff(&self.original_ast.syntax(), self.ast().syntax()) {
builder.replace(from.text_range(), to.to_string())
}
}

42
crates/ra_syntax/src/algo.rs
View file

@ -63,6 +63,48 @@ pub enum InsertPosition<T> {
After(T),
}
/// Finds minimal the diff, which, applied to `from`, will result in `to`.
///
/// Specifically, returns a map whose keys are descendants of `from` and values
/// are descendants of `to`, such that `replace_descendants(from, map) == to`.
///
/// 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> {
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;
fn go(
buf: &mut FxHashMap<SyntaxElement, SyntaxElement>,
lhs: SyntaxElement,
rhs: SyntaxElement,
) {
if lhs.kind() == rhs.kind() && lhs.text_range().len() == rhs.text_range().len() {
if match (&lhs, &rhs) {
(NodeOrToken::Node(lhs), NodeOrToken::Node(rhs)) => {
lhs.green() == rhs.green() || lhs.text() == rhs.text()
}
(NodeOrToken::Token(lhs), NodeOrToken::Token(rhs)) => lhs.text() == rhs.text(),
_ => false,
} {
return;
}
}
if let (Some(lhs), Some(rhs)) = (lhs.as_node(), rhs.as_node()) {
if lhs.children_with_tokens().count() == rhs.children_with_tokens().count() {
for (lhs, rhs) in lhs.children_with_tokens().zip(rhs.children_with_tokens()) {
go(buf, lhs, rhs)
}
return;
}
}
buf.insert(lhs, rhs);
}
}
/// Adds specified children (tokens or nodes) to the current node at the
/// specific position.
///