add apply ssr assist

Author: JoshMcguigan

crates/ide/src/lib.rs

@@ -59,7 +59,10 @@ use ide_db::{
     symbol_index::{self, FileSymbol},
     LineIndexDatabase,
 };
-use syntax::SourceFile;
+use syntax::{
+    ast::{self, AstNode, AstToken},
+    SourceFile,
+};
 
 use crate::display::ToNav;
 
@@ -504,7 +507,11 @@ impl Analysis {
         resolve: bool,
         frange: FileRange,
     ) -> Cancelable<Vec<Assist>> {
-        self.with_db(|db| Assist::get(db, config, resolve, frange))
+        self.with_db(|db| {
+            let mut acc = Assist::get(db, config, resolve, frange);
+            add_ssr_assist(db, &mut acc, resolve, frange);
+            acc
+        })
     }
 
     /// Computes the set of diagnostics for the given file.
@@ -579,6 +586,33 @@ impl Analysis {
     }
 }
 
+fn add_ssr_assist(
+    db: &RootDatabase,
+    base: &mut Vec<Assist>,
+    resolve: bool,
+    frange: FileRange,
+) -> Option<()> {
+    let comment = {
+        let file = db.parse(frange.file_id);
+        file.tree().syntax().token_at_offset(frange.range.start()).find_map(ast::Comment::cast)
+    }?;
+    let match_finder = ide_ssr::ssr_from_comment(db, frange, &comment).ok()?;
+
+    let mut assist = Assist {
+        id: AssistId("ssr", AssistKind::RefactorRewrite),
+        label: Label::new("Apply SSR"),
+        group: None,
+        target: comment.syntax().text_range(),
+        source_change: None,
+    };
+    if resolve {
+        assist.source_change = Some(SourceChange::from_edits(match_finder.edits(), Vec::new()));
+    }
+
+    base.push(assist);
+    Some(())
+}
+
 #[test]
 fn analysis_is_send() {
     fn is_send<T: Send>() {}

crates/ide_ssr/src/from_comment.rs

@@ -0,0 +1,26 @@
+//! This module allows building an SSR MatchFinder by parsing the SSR rule
+//! from a comment.
+
+use ide_db::{
+    base_db::{FilePosition, FileRange},
+    RootDatabase,
+};
+use syntax::ast::{self, AstToken};
+
+use crate::{MatchFinder, SsrError};
+
+pub fn ssr_from_comment<'db>(
+    db: &'db RootDatabase,
+    frange: FileRange,
+    comment: &ast::Comment,
+) -> Result<MatchFinder<'db>, SsrError> {
+    let comment_text_without_prefix = comment.text().strip_prefix(comment.prefix()).unwrap();
+    let ssr_rule = comment_text_without_prefix.parse()?;
+
+    let lookup_context = FilePosition { file_id: frange.file_id, offset: frange.range.start() };
+
+    let mut match_finder = MatchFinder::in_context(db, lookup_context, vec![]);
+    match_finder.add_rule(ssr_rule)?;
+
+    Ok(match_finder)
+}

crates/ide_ssr/src/lib.rs

@@ -58,6 +58,7 @@
 // | VS Code | **Rust Analyzer: Structural Search Replace**
 // |===
 
+mod from_comment;
 mod matching;
 mod nester;
 mod parsing;
@@ -71,6 +72,7 @@ mod tests;
 
 use crate::errors::bail;
 pub use crate::errors::SsrError;
+pub use crate::from_comment::ssr_from_comment;
 pub use crate::matching::Match;
 use crate::matching::MatchFailureReason;
 use hir::Semantics;