2 files changed, 10 insertions, 555 deletions

diff --git a/crates/ra_ide/src/lib.rs b/crates/ra_ide/src/lib.rs
index be9ab62c0..47823718f 100644
--- a/crates/ra_ide/src/lib.rs
+++ b/crates/ra_ide/src/lib.rs
@@ -70,7 +70,6 @@ pub use crate::{
     inlay_hints::{InlayHint, InlayHintsConfig, InlayKind},
     references::{Declaration, Reference, ReferenceAccess, ReferenceKind, ReferenceSearchResult},
     runnables::{Runnable, RunnableKind, TestId},
-    ssr::SsrError,
     syntax_highlighting::{
         Highlight, HighlightModifier, HighlightModifiers, HighlightTag, HighlightedRange,
     },
@@ -89,6 +88,7 @@ pub use ra_ide_db::{
     symbol_index::Query,
     RootDatabase,
 };
+pub use ra_ssr::SsrError;
 pub use ra_text_edit::{Indel, TextEdit};
 
 pub type Cancelable<T> = Result<T, Canceled>;
diff --git a/crates/ra_ide/src/ssr.rs b/crates/ra_ide/src/ssr.rs
index 762aab962..59c230f6c 100644
--- a/crates/ra_ide/src/ssr.rs
+++ b/crates/ra_ide/src/ssr.rs
@@ -1,31 +1,12 @@
-use std::{collections::HashMap, iter::once, str::FromStr};
-
-use ra_db::{SourceDatabase, SourceDatabaseExt};
+use ra_db::SourceDatabaseExt;
 use ra_ide_db::{symbol_index::SymbolsDatabase, RootDatabase};
-use ra_syntax::ast::{
-    make::try_expr_from_text, ArgList, AstToken, CallExpr, Comment, Expr, MethodCallExpr,
-    RecordField, RecordLit,
-};
-use ra_syntax::{AstNode, SyntaxElement, SyntaxKind, SyntaxNode};
-use ra_text_edit::{TextEdit, TextEditBuilder};
-use rustc_hash::FxHashMap;
 
 use crate::SourceFileEdit;
-
-#[derive(Debug, PartialEq)]
-pub struct SsrError(String);
-
-impl std::fmt::Display for SsrError {
-    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
-        write!(f, "Parse error: {}", self.0)
-    }
-}
-
-impl std::error::Error for SsrError {}
+use ra_ssr::{MatchFinder, SsrError, SsrRule};
 
 // Feature: Structural Seach and Replace
 //
-// Search and replace with named wildcards that will match any expression.
+// Search and replace with named wildcards that will match any expression, type, path, pattern or item.
 // The syntax for a structural search replace command is `<search_pattern> ==>> <replace_pattern>`.
 // A `$<name>` placeholder in the search pattern will match any AST node and `$<name>` will reference it in the replacement.
 // Available via the command `rust-analyzer.ssr`.
@@ -46,550 +27,24 @@ impl std::error::Error for SsrError {}
 // | VS Code | **Rust Analyzer: Structural Search Replace**
 // |===
 pub fn parse_search_replace(
-    query: &str,
+    rule: &str,
     parse_only: bool,
     db: &RootDatabase,
 ) -> Result<Vec<SourceFileEdit>, SsrError> {
     let mut edits = vec![];
-    let query: SsrQuery = query.parse()?;
+    let rule: SsrRule = rule.parse()?;
     if parse_only {
         return Ok(edits);
     }
+    let mut match_finder = MatchFinder::new(db);
+    match_finder.add_rule(rule);
     for &root in db.local_roots().iter() {
         let sr = db.source_root(root);
         for file_id in sr.walk() {
-            let matches = find(&query.pattern, db.parse(file_id).tree().syntax());
-            if !matches.matches.is_empty() {
-                edits.push(SourceFileEdit { file_id, edit: replace(&matches, &query.template) });
+            if let Some(edit) = match_finder.edits_for_file(file_id) {
+                edits.push(SourceFileEdit { file_id, edit });
             }
         }
     }
     Ok(edits)
 }
-
-#[derive(Debug)]
-struct SsrQuery {
-    pattern: SsrPattern,
-    template: SsrTemplate,
-}
-
-#[derive(Debug)]
-struct SsrPattern {
-    pattern: SyntaxNode,
-    vars: Vec<Var>,
-}
-
-/// Represents a `$var` in an SSR query.
-#[derive(Debug, Clone, PartialEq, Eq, Hash)]
-struct Var(String);
-
-#[derive(Debug)]
-struct SsrTemplate {
-    template: SyntaxNode,
-    placeholders: FxHashMap<SyntaxNode, Var>,
-}
-
-type Binding = HashMap<Var, SyntaxNode>;
-
-#[derive(Debug)]
-struct Match {
-    place: SyntaxNode,
-    binding: Binding,
-    ignored_comments: Vec<Comment>,
-}
-
-#[derive(Debug)]
-struct SsrMatches {
-    matches: Vec<Match>,
-}
-
-impl FromStr for SsrQuery {
-    type Err = SsrError;
-
-    fn from_str(query: &str) -> Result<SsrQuery, SsrError> {
-        let mut it = query.split("==>>");
-        let pattern = it.next().expect("at least empty string").trim();
-        let mut template = it
-            .next()
-            .ok_or_else(|| SsrError("Cannot find delemiter `==>>`".into()))?
-            .trim()
-            .to_string();
-        if it.next().is_some() {
-            return Err(SsrError("More than one delimiter found".into()));
-        }
-        let mut vars = vec![];
-        let mut it = pattern.split('$');
-        let mut pattern = it.next().expect("something").to_string();
-
-        for part in it.map(split_by_var) {
-            let (var, remainder) = part?;
-            let new_var = create_name(var, &mut vars)?;
-            pattern.push_str(new_var);
-            pattern.push_str(remainder);
-            template = replace_in_template(template, var, new_var);
-        }
-
-        let template = try_expr_from_text(&template)
-            .ok_or(SsrError("Template is not an expression".into()))?
-            .syntax()
-            .clone();
-        let mut placeholders = FxHashMap::default();
-
-        traverse(&template, &mut |n| {
-            if let Some(v) = vars.iter().find(|v| v.0.as_str() == n.text()) {
-                placeholders.insert(n.clone(), v.clone());
-                false
-            } else {
-                true
-            }
-        });
-
-        let pattern = SsrPattern {
-            pattern: try_expr_from_text(&pattern)
-                .ok_or(SsrError("Pattern is not an expression".into()))?
-                .syntax()
-                .clone(),
-            vars,
-        };
-        let template = SsrTemplate { template, placeholders };
-        Ok(SsrQuery { pattern, template })
-    }
-}
-
-fn traverse(node: &SyntaxNode, go: &mut impl FnMut(&SyntaxNode) -> bool) {
-    if !go(node) {
-        return;
-    }
-    for ref child in node.children() {
-        traverse(child, go);
-    }
-}
-
-fn split_by_var(s: &str) -> Result<(&str, &str), SsrError> {
-    let end_of_name = s.find(|c| !char::is_ascii_alphanumeric(&c)).unwrap_or_else(|| s.len());
-    let name = &s[..end_of_name];
-    is_name(name)?;
-    Ok((name, &s[end_of_name..]))
-}
-
-fn is_name(s: &str) -> Result<(), SsrError> {
-    if s.chars().all(|c| c.is_ascii_alphanumeric() || c == '_') {
-        Ok(())
-    } else {
-        Err(SsrError("Name can contain only alphanumerics and _".into()))
-    }
-}
-
-fn replace_in_template(template: String, var: &str, new_var: &str) -> String {
-    let name = format!("${}", var);
-    template.replace(&name, new_var)
-}
-
-fn create_name<'a>(name: &str, vars: &'a mut Vec<Var>) -> Result<&'a str, SsrError> {
-    let sanitized_name = format!("__search_pattern_{}", name);
-    if vars.iter().any(|a| a.0 == sanitized_name) {
-        return Err(SsrError(format!("Name `{}` repeats more than once", name)));
-    }
-    vars.push(Var(sanitized_name));
-    Ok(&vars.last().unwrap().0)
-}
-
-fn find(pattern: &SsrPattern, code: &SyntaxNode) -> SsrMatches {
-    fn check_record_lit(
-        pattern: RecordLit,
-        code: RecordLit,
-        placeholders: &[Var],
-        match_: Match,
-    ) -> Option<Match> {
-        let match_ = check_opt_nodes(pattern.path(), code.path(), placeholders, match_)?;
-
-        let mut pattern_fields: Vec<RecordField> =
-            pattern.record_field_list().map(|x| x.fields().collect()).unwrap_or_default();
-        let mut code_fields: Vec<RecordField> =
-            code.record_field_list().map(|x| x.fields().collect()).unwrap_or_default();
-
-        if pattern_fields.len() != code_fields.len() {
-            return None;
-        }
-
-        let by_name = |a: &RecordField, b: &RecordField| {
-            a.name_ref()
-                .map(|x| x.syntax().text().to_string())
-                .cmp(&b.name_ref().map(|x| x.syntax().text().to_string()))
-        };
-        pattern_fields.sort_by(by_name);
-        code_fields.sort_by(by_name);
-
-        pattern_fields.into_iter().zip(code_fields.into_iter()).fold(
-            Some(match_),
-            |accum, (a, b)| {
-                accum.and_then(|match_| check_opt_nodes(Some(a), Some(b), placeholders, match_))
-            },
-        )
-    }
-
-    fn check_call_and_method_call(
-        pattern: CallExpr,
-        code: MethodCallExpr,
-        placeholders: &[Var],
-        match_: Match,
-    ) -> Option<Match> {
-        let (pattern_name, pattern_type_args) = if let Some(Expr::PathExpr(path_exr)) =
-            pattern.expr()
-        {
-            let segment = path_exr.path().and_then(|p| p.segment());
-            (segment.as_ref().and_then(|s| s.name_ref()), segment.and_then(|s| s.type_arg_list()))
-        } else {
-            (None, None)
-        };
-        let match_ = check_opt_nodes(pattern_name, code.name_ref(), placeholders, match_)?;
-        let match_ =
-            check_opt_nodes(pattern_type_args, code.type_arg_list(), placeholders, match_)?;
-        let pattern_args = pattern.syntax().children().find_map(ArgList::cast)?.args();
-        let code_args = code.syntax().children().find_map(ArgList::cast)?.args();
-        let code_args = once(code.expr()?).chain(code_args);
-        check_iter(pattern_args, code_args, placeholders, match_)
-    }
-
-    fn check_method_call_and_call(
-        pattern: MethodCallExpr,
-        code: CallExpr,
-        placeholders: &[Var],
-        match_: Match,
-    ) -> Option<Match> {
-        let (code_name, code_type_args) = if let Some(Expr::PathExpr(path_exr)) = code.expr() {
-            let segment = path_exr.path().and_then(|p| p.segment());
-            (segment.as_ref().and_then(|s| s.name_ref()), segment.and_then(|s| s.type_arg_list()))
-        } else {
-            (None, None)
-        };
-        let match_ = check_opt_nodes(pattern.name_ref(), code_name, placeholders, match_)?;
-        let match_ =
-            check_opt_nodes(pattern.type_arg_list(), code_type_args, placeholders, match_)?;
-        let code_args = code.syntax().children().find_map(ArgList::cast)?.args();
-        let pattern_args = pattern.syntax().children().find_map(ArgList::cast)?.args();
-        let pattern_args = once(pattern.expr()?).chain(pattern_args);
-        check_iter(pattern_args, code_args, placeholders, match_)
-    }
-
-    fn check_opt_nodes(
-        pattern: Option<impl AstNode>,
-        code: Option<impl AstNode>,
-        placeholders: &[Var],
-        match_: Match,
-    ) -> Option<Match> {
-        match (pattern, code) {
-            (Some(pattern), Some(code)) => check(
-                &pattern.syntax().clone().into(),
-                &code.syntax().clone().into(),
-                placeholders,
-                match_,
-            ),
-            (None, None) => Some(match_),
-            _ => None,
-        }
-    }
-
-    fn check_iter<T, I1, I2>(
-        mut pattern: I1,
-        mut code: I2,
-        placeholders: &[Var],
-        match_: Match,
-    ) -> Option<Match>
-    where
-        T: AstNode,
-        I1: Iterator<Item = T>,
-        I2: Iterator<Item = T>,
-    {
-        pattern
-            .by_ref()
-            .zip(code.by_ref())
-            .fold(Some(match_), |accum, (a, b)| {
-                accum.and_then(|match_| {
-                    check(
-                        &a.syntax().clone().into(),
-                        &b.syntax().clone().into(),
-                        placeholders,
-                        match_,
-                    )
-                })
-            })
-            .filter(|_| pattern.next().is_none() && code.next().is_none())
-    }
-
-    fn check(
-        pattern: &SyntaxElement,
-        code: &SyntaxElement,
-        placeholders: &[Var],
-        mut match_: Match,
-    ) -> Option<Match> {
-        match (&pattern, &code) {
-            (SyntaxElement::Token(pattern), SyntaxElement::Token(code)) => {
-                if pattern.text() == code.text() {
-                    Some(match_)
-                } else {
-                    None
-                }
-            }
-            (SyntaxElement::Node(pattern), SyntaxElement::Node(code)) => {
-                if placeholders.iter().any(|n| n.0.as_str() == pattern.text()) {
-                    match_.binding.insert(Var(pattern.text().to_string()), code.clone());
-                    Some(match_)
-                } else {
-                    if let (Some(pattern), Some(code)) =
-                        (RecordLit::cast(pattern.clone()), RecordLit::cast(code.clone()))
-                    {
-                        check_record_lit(pattern, code, placeholders, match_)
-                    } else if let (Some(pattern), Some(code)) =
-                        (CallExpr::cast(pattern.clone()), MethodCallExpr::cast(code.clone()))
-                    {
-                        check_call_and_method_call(pattern, code, placeholders, match_)
-                    } else if let (Some(pattern), Some(code)) =
-                        (MethodCallExpr::cast(pattern.clone()), CallExpr::cast(code.clone()))
-                    {
-                        check_method_call_and_call(pattern, code, placeholders, match_)
-                    } else {
-                        let mut pattern_children = pattern
-                            .children_with_tokens()
-                            .filter(|element| !element.kind().is_trivia());
-                        let mut code_children = code
-                            .children_with_tokens()
-                            .filter(|element| !element.kind().is_trivia());
-                        let new_ignored_comments =
-                            code.children_with_tokens().filter_map(|element| {
-                                element.as_token().and_then(|token| Comment::cast(token.clone()))
-                            });
-                        match_.ignored_comments.extend(new_ignored_comments);
-                        pattern_children
-                            .by_ref()
-                            .zip(code_children.by_ref())
-                            .fold(Some(match_), |accum, (a, b)| {
-                                accum.and_then(|match_| check(&a, &b, placeholders, match_))
-                            })
-                            .filter(|_| {
-                                pattern_children.next().is_none() && code_children.next().is_none()
-                            })
-                    }
-                }
-            }
-            _ => None,
-        }
-    }
-    let kind = pattern.pattern.kind();
-    let matches = code
-        .descendants()
-        .filter(|n| {
-            n.kind() == kind
-                || (kind == SyntaxKind::CALL_EXPR && n.kind() == SyntaxKind::METHOD_CALL_EXPR)
-                || (kind == SyntaxKind::METHOD_CALL_EXPR && n.kind() == SyntaxKind::CALL_EXPR)
-        })
-        .filter_map(|code| {
-            let match_ =
-                Match { place: code.clone(), binding: HashMap::new(), ignored_comments: vec![] };
-            check(&pattern.pattern.clone().into(), &code.into(), &pattern.vars, match_)
-        })
-        .collect();
-    SsrMatches { matches }
-}
-
-fn replace(matches: &SsrMatches, template: &SsrTemplate) -> TextEdit {
-    let mut builder = TextEditBuilder::default();
-    for match_ in &matches.matches {
-        builder.replace(
-            match_.place.text_range(),
-            render_replace(&match_.binding, &match_.ignored_comments, template),
-        );
-    }
-    builder.finish()
-}
-
-fn render_replace(
-    binding: &Binding,
-    ignored_comments: &Vec<Comment>,
-    template: &SsrTemplate,
-) -> String {
-    let edit = {
-        let mut builder = TextEditBuilder::default();
-        for element in template.template.descendants() {
-            if let Some(var) = template.placeholders.get(&element) {
-                builder.replace(element.text_range(), binding[var].to_string())
-            }
-        }
-        for comment in ignored_comments {
-            builder.insert(template.template.text_range().end(), comment.syntax().to_string())
-        }
-        builder.finish()
-    };
-
-    let mut text = template.template.text().to_string();
-    edit.apply(&mut text);
-    text
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use ra_syntax::SourceFile;
-
-    fn parse_error_text(query: &str) -> String {
-        format!("{}", query.parse::<SsrQuery>().unwrap_err())
-    }
-
-    #[test]
-    fn parser_happy_case() {
-        let result: SsrQuery = "foo($a, $b) ==>> bar($b, $a)".parse().unwrap();
-        assert_eq!(&result.pattern.pattern.text(), "foo(__search_pattern_a, __search_pattern_b)");
-        assert_eq!(result.pattern.vars.len(), 2);
-        assert_eq!(result.pattern.vars[0].0, "__search_pattern_a");
-        assert_eq!(result.pattern.vars[1].0, "__search_pattern_b");
-        assert_eq!(&result.template.template.text(), "bar(__search_pattern_b, __search_pattern_a)");
-    }
-
-    #[test]
-    fn parser_empty_query() {
-        assert_eq!(parse_error_text(""), "Parse error: Cannot find delemiter `==>>`");
-    }
-
-    #[test]
-    fn parser_no_delimiter() {
-        assert_eq!(parse_error_text("foo()"), "Parse error: Cannot find delemiter `==>>`");
-    }
-
-    #[test]
-    fn parser_two_delimiters() {
-        assert_eq!(
-            parse_error_text("foo() ==>> a ==>> b "),
-            "Parse error: More than one delimiter found"
-        );
-    }
-
-    #[test]
-    fn parser_repeated_name() {
-        assert_eq!(
-            parse_error_text("foo($a, $a) ==>>"),
-            "Parse error: Name `a` repeats more than once"
-        );
-    }
-
-    #[test]
-    fn parser_invlid_pattern() {
-        assert_eq!(parse_error_text(" ==>> ()"), "Parse error: Pattern is not an expression");
-    }
-
-    #[test]
-    fn parser_invlid_template() {
-        assert_eq!(parse_error_text("() ==>> )"), "Parse error: Template is not an expression");
-    }
-
-    #[test]
-    fn parse_match_replace() {
-        let query: SsrQuery = "foo($x) ==>> bar($x)".parse().unwrap();
-        let input = "fn main() { foo(1+2); }";
-
-        let code = SourceFile::parse(input).tree();
-        let matches = find(&query.pattern, code.syntax());
-        assert_eq!(matches.matches.len(), 1);
-        assert_eq!(matches.matches[0].place.text(), "foo(1+2)");
-        assert_eq!(matches.matches[0].binding.len(), 1);
-        assert_eq!(
-            matches.matches[0].binding[&Var("__search_pattern_x".to_string())].text(),
-            "1+2"
-        );
-
-        let edit = replace(&matches, &query.template);
-        let mut after = input.to_string();
-        edit.apply(&mut after);
-        assert_eq!(after, "fn main() { bar(1+2); }");
-    }
-
-    fn assert_ssr_transform(query: &str, input: &str, result: &str) {
-        let query: SsrQuery = query.parse().unwrap();
-        let code = SourceFile::parse(input).tree();
-        let matches = find(&query.pattern, code.syntax());
-        let edit = replace(&matches, &query.template);
-        let mut after = input.to_string();
-        edit.apply(&mut after);
-        assert_eq!(after, result);
-    }
-
-    #[test]
-    fn ssr_function_to_method() {
-        assert_ssr_transform(
-            "my_function($a, $b) ==>> ($a).my_method($b)",
-            "loop { my_function( other_func(x, y), z + w) }",
-            "loop { (other_func(x, y)).my_method(z + w) }",
-        )
-    }
-
-    #[test]
-    fn ssr_nested_function() {
-        assert_ssr_transform(
-            "foo($a, $b, $c) ==>> bar($c, baz($a, $b))",
-            "fn main { foo  (x + value.method(b), x+y-z, true && false) }",
-            "fn main { bar(true && false, baz(x + value.method(b), x+y-z)) }",
-        )
-    }
-
-    #[test]
-    fn ssr_expected_spacing() {
-        assert_ssr_transform(
-            "foo($x) + bar() ==>> bar($x)",
-            "fn main() { foo(5) + bar() }",
-            "fn main() { bar(5) }",
-        );
-    }
-
-    #[test]
-    fn ssr_with_extra_space() {
-        assert_ssr_transform(
-            "foo($x  ) +    bar() ==>> bar($x)",
-            "fn main() { foo(  5 )  +bar(   ) }",
-            "fn main() { bar(5) }",
-        );
-    }
-
-    #[test]
-    fn ssr_keeps_nested_comment() {
-        assert_ssr_transform(
-            "foo($x) ==>> bar($x)",
-            "fn main() { foo(other(5 /* using 5 */)) }",
-            "fn main() { bar(other(5 /* using 5 */)) }",
-        )
-    }
-
-    #[test]
-    fn ssr_keeps_comment() {
-        assert_ssr_transform(
-            "foo($x) ==>> bar($x)",
-            "fn main() { foo(5 /* using 5 */) }",
-            "fn main() { bar(5)/* using 5 */ }",
-        )
-    }
-
-    #[test]
-    fn ssr_struct_lit() {
-        assert_ssr_transform(
-            "foo{a: $a, b: $b} ==>> foo::new($a, $b)",
-            "fn main() { foo{b:2, a:1} }",
-            "fn main() { foo::new(1, 2) }",
-        )
-    }
-
-    #[test]
-    fn ssr_call_and_method_call() {
-        assert_ssr_transform(
-            "foo::<'a>($a, $b)) ==>> foo2($a, $b)",
-            "fn main() { get().bar.foo::<'a>(1); }",
-            "fn main() { foo2(get().bar, 1); }",
-        )
-    }
-
-    #[test]
-    fn ssr_method_call_and_call() {
-        assert_ssr_transform(
-            "$o.foo::<i32>($a)) ==>> $o.foo2($a)",
-            "fn main() { X::foo::<i32>(x, 1); }",
-            "fn main() { x.foo2(1); }",
-        )
-    }
-}