SSR: Restrict to current selection if any

The selection is also used to avoid unnecessary work, but only to the
file level. Further restricting unnecessary work is left for later.

10 files changed, 181 insertions, 50 deletions

diff --git a/crates/ra_ide/src/lib.rs b/crates/ra_ide/src/lib.rs
index 4c4d9f6fa..0fede0d87 100644
--- a/crates/ra_ide/src/lib.rs
+++ b/crates/ra_ide/src/lib.rs
@@ -510,9 +510,10 @@ impl Analysis {
         query: &str,
         parse_only: bool,
         position: FilePosition,
+        selections: Vec<FileRange>,
     ) -> Cancelable<Result<SourceChange, SsrError>> {
         self.with_db(|db| {
-            let edits = ssr::parse_search_replace(query, parse_only, db, position)?;
+            let edits = ssr::parse_search_replace(query, parse_only, db, position, selections)?;
             Ok(SourceChange::from(edits))
         })
     }
diff --git a/crates/ra_ide/src/ssr.rs b/crates/ra_ide/src/ssr.rs
index 95d8f79b8..63010677a 100644
--- a/crates/ra_ide/src/ssr.rs
+++ b/crates/ra_ide/src/ssr.rs
@@ -1,4 +1,4 @@
-use ra_db::FilePosition;
+use ra_db::{FilePosition, FileRange};
 use ra_ide_db::RootDatabase;
 
 use crate::SourceFileEdit;
@@ -24,6 +24,9 @@ use ra_ssr::{MatchFinder, SsrError, SsrRule};
 // Method calls should generally be written in UFCS form. e.g. `foo::Bar::baz($s, $a)` will match
 // `$s.baz($a)`, provided the method call `baz` resolves to the method `foo::Bar::baz`.
 //
+// The scope of the search / replace will be restricted to the current selection if any, otherwise
+// it will apply to the whole workspace.
+//
 // Placeholders may be given constraints by writing them as `${<name>:<constraint1>:<constraint2>...}`.
 //
 // Supported constraints:
@@ -57,9 +60,10 @@ pub fn parse_search_replace(
     parse_only: bool,
     db: &RootDatabase,
     position: FilePosition,
+    selections: Vec<FileRange>,
 ) -> Result<Vec<SourceFileEdit>, SsrError> {
     let rule: SsrRule = rule.parse()?;
-    let mut match_finder = MatchFinder::in_context(db, position);
+    let mut match_finder = MatchFinder::in_context(db, position, selections);
     match_finder.add_rule(rule)?;
     if parse_only {
         return Ok(Vec::new());
diff --git a/crates/ra_ssr/src/lib.rs b/crates/ra_ssr/src/lib.rs
index 7014a6ac6..73abfecb2 100644
--- a/crates/ra_ssr/src/lib.rs
+++ b/crates/ra_ssr/src/lib.rs
@@ -52,6 +52,7 @@ pub struct MatchFinder<'db> {
     sema: Semantics<'db, ra_ide_db::RootDatabase>,
     rules: Vec<ResolvedRule>,
     resolution_scope: resolving::ResolutionScope<'db>,
+    restrict_ranges: Vec<FileRange>,
 }
 
 impl<'db> MatchFinder<'db> {
@@ -60,10 +61,17 @@ impl<'db> MatchFinder<'db> {
     pub fn in_context(
         db: &'db ra_ide_db::RootDatabase,
         lookup_context: FilePosition,
+        mut restrict_ranges: Vec<FileRange>,
     ) -> MatchFinder<'db> {
+        restrict_ranges.retain(|range| !range.range.is_empty());
         let sema = Semantics::new(db);
         let resolution_scope = resolving::ResolutionScope::new(&sema, lookup_context);
-        MatchFinder { sema: Semantics::new(db), rules: Vec::new(), resolution_scope }
+        MatchFinder {
+            sema: Semantics::new(db),
+            rules: Vec::new(),
+            resolution_scope,
+            restrict_ranges,
+        }
     }
 
     /// Constructs an instance using the start of the first file in `db` as the lookup context.
@@ -79,6 +87,7 @@ impl<'db> MatchFinder<'db> {
             Ok(MatchFinder::in_context(
                 db,
                 FilePosition { file_id: first_file_id, offset: 0.into() },
+                vec![],
             ))
         } else {
             bail!("No files to search");
diff --git a/crates/ra_ssr/src/matching.rs b/crates/ra_ssr/src/matching.rs
index 4862622bd..c1b66748e 100644
--- a/crates/ra_ssr/src/matching.rs
+++ b/crates/ra_ssr/src/matching.rs
@@ -706,8 +706,8 @@ mod tests {
         let rule: SsrRule = "foo($x) ==>> bar($x)".parse().unwrap();
         let input = "fn foo() {} fn bar() {} fn main() { foo(1+2); }";
 
-        let (db, position) = crate::tests::single_file(input);
-        let mut match_finder = MatchFinder::in_context(&db, position);
+        let (db, position, selections) = crate::tests::single_file(input);
+        let mut match_finder = MatchFinder::in_context(&db, position, selections);
         match_finder.add_rule(rule).unwrap();
         let matches = match_finder.matches();
         assert_eq!(matches.matches.len(), 1);
diff --git a/crates/ra_ssr/src/search.rs b/crates/ra_ssr/src/search.rs
index bcf0f0468..0f512cb62 100644
--- a/crates/ra_ssr/src/search.rs
+++ b/crates/ra_ssr/src/search.rs
@@ -5,12 +5,13 @@ use crate::{
     resolving::{ResolvedPath, ResolvedPattern, ResolvedRule},
     Match, MatchFinder,
 };
-use ra_db::FileRange;
+use ra_db::{FileId, FileRange};
 use ra_ide_db::{
     defs::Definition,
     search::{Reference, SearchScope},
 };
 use ra_syntax::{ast, AstNode, SyntaxKind, SyntaxNode};
+use rustc_hash::FxHashSet;
 use test_utils::mark;
 
 /// A cache for the results of find_usages. This is for when we have multiple patterns that have the
@@ -54,11 +55,7 @@ impl<'db> MatchFinder<'db> {
                         mark::hit!(use_declaration_with_braces);
                         continue;
                     }
-                    if let Ok(m) =
-                        matching::get_match(false, rule, &node_to_match, &None, &self.sema)
-                    {
-                        matches_out.push(m);
-                    }
+                    self.try_add_match(rule, &node_to_match, &None, matches_out);
                 }
             }
         }
@@ -121,25 +118,39 @@ impl<'db> MatchFinder<'db> {
         // FIXME: We should ideally have a test that checks that we edit local roots and not library
         // roots. This probably would require some changes to fixtures, since currently everything
         // seems to get put into a single source root.
-        use ra_db::SourceDatabaseExt;
-        use ra_ide_db::symbol_index::SymbolsDatabase;
         let mut files = Vec::new();
-        for &root in self.sema.db.local_roots().iter() {
-            let sr = self.sema.db.source_root(root);
-            files.extend(sr.iter());
-        }
+        self.search_files_do(|file_id| {
+            files.push(file_id);
+        });
         SearchScope::files(&files)
     }
 
     fn slow_scan(&self, rule: &ResolvedRule, matches_out: &mut Vec<Match>) {
-        use ra_db::SourceDatabaseExt;
-        use ra_ide_db::symbol_index::SymbolsDatabase;
-        for &root in self.sema.db.local_roots().iter() {
-            let sr = self.sema.db.source_root(root);
-            for file_id in sr.iter() {
-                let file = self.sema.parse(file_id);
-                let code = file.syntax();
-                self.slow_scan_node(code, rule, &None, matches_out);
+        self.search_files_do(|file_id| {
+            let file = self.sema.parse(file_id);
+            let code = file.syntax();
+            self.slow_scan_node(code, rule, &None, matches_out);
+        })
+    }
+
+    fn search_files_do(&self, mut callback: impl FnMut(FileId)) {
+        if self.restrict_ranges.is_empty() {
+            // Unrestricted search.
+            use ra_db::SourceDatabaseExt;
+            use ra_ide_db::symbol_index::SymbolsDatabase;
+            for &root in self.sema.db.local_roots().iter() {
+                let sr = self.sema.db.source_root(root);
+                for file_id in sr.iter() {
+                    callback(file_id);
+                }
+            }
+        } else {
+            // Search is restricted, deduplicate file IDs (generally only one).
+            let mut files = FxHashSet::default();
+            for range in &self.restrict_ranges {
+                if files.insert(range.file_id) {
+                    callback(range.file_id);
+                }
             }
         }
     }
@@ -154,9 +165,7 @@ impl<'db> MatchFinder<'db> {
         if !is_search_permitted(code) {
             return;
         }
-        if let Ok(m) = matching::get_match(false, rule, &code, restrict_range, &self.sema) {
-            matches_out.push(m);
-        }
+        self.try_add_match(rule, &code, restrict_range, matches_out);
         // If we've got a macro call, we already tried matching it pre-expansion, which is the only
         // way to match the whole macro, now try expanding it and matching the expansion.
         if let Some(macro_call) = ast::MacroCall::cast(code.clone()) {
@@ -178,6 +187,38 @@ impl<'db> MatchFinder<'db> {
             self.slow_scan_node(&child, rule, restrict_range, matches_out);
         }
     }
+
+    fn try_add_match(
+        &self,
+        rule: &ResolvedRule,
+        code: &SyntaxNode,
+        restrict_range: &Option<FileRange>,
+        matches_out: &mut Vec<Match>,
+    ) {
+        if !self.within_range_restrictions(code) {
+            mark::hit!(replace_nonpath_within_selection);
+            return;
+        }
+        if let Ok(m) = matching::get_match(false, rule, code, restrict_range, &self.sema) {
+            matches_out.push(m);
+        }
+    }
+
+    /// Returns whether `code` is within one of our range restrictions if we have any. No range
+    /// restrictions is considered unrestricted and always returns true.
+    fn within_range_restrictions(&self, code: &SyntaxNode) -> bool {
+        if self.restrict_ranges.is_empty() {
+            // There is no range restriction.
+            return true;
+        }
+        let node_range = self.sema.original_range(code);
+        for range in &self.restrict_ranges {
+            if range.file_id == node_range.file_id && range.range.contains_range(node_range.range) {
+                return true;
+            }
+        }
+        false
+    }
 }
 
 /// Returns whether we support matching within `node` and all of its ancestors.
diff --git a/crates/ra_ssr/src/tests.rs b/crates/ra_ssr/src/tests.rs
index 18ef2506a..6a44ef378 100644
--- a/crates/ra_ssr/src/tests.rs
+++ b/crates/ra_ssr/src/tests.rs
@@ -1,9 +1,9 @@
 use crate::{MatchFinder, SsrRule};
 use expect::{expect, Expect};
-use ra_db::{salsa::Durability, FileId, FilePosition, SourceDatabaseExt};
+use ra_db::{salsa::Durability, FileId, FilePosition, FileRange, SourceDatabaseExt};
 use rustc_hash::FxHashSet;
 use std::sync::Arc;
-use test_utils::mark;
+use test_utils::{mark, RangeOrOffset};
 
 fn parse_error_text(query: &str) -> String {
     format!("{}", query.parse::<SsrRule>().unwrap_err())
@@ -60,20 +60,32 @@ fn parser_undefined_placeholder_in_replacement() {
 }
 
 /// `code` may optionally contain a cursor marker `<|>`. If it doesn't, then the position will be
-/// the start of the file.
-pub(crate) fn single_file(code: &str) -> (ra_ide_db::RootDatabase, FilePosition) {
+/// the start of the file. If there's a second cursor marker, then we'll return a single range.
+pub(crate) fn single_file(code: &str) -> (ra_ide_db::RootDatabase, FilePosition, Vec<FileRange>) {
     use ra_db::fixture::WithFixture;
     use ra_ide_db::symbol_index::SymbolsDatabase;
-    let (mut db, position) = if code.contains(test_utils::CURSOR_MARKER) {
-        ra_ide_db::RootDatabase::with_position(code)
+    let (mut db, file_id, range_or_offset) = if code.contains(test_utils::CURSOR_MARKER) {
+        ra_ide_db::RootDatabase::with_range_or_offset(code)
     } else {
         let (db, file_id) = ra_ide_db::RootDatabase::with_single_file(code);
-        (db, FilePosition { file_id, offset: 0.into() })
+        (db, file_id, RangeOrOffset::Offset(0.into()))
     };
+    let selections;
+    let position;
+    match range_or_offset {
+        RangeOrOffset::Range(range) => {
+            position = FilePosition { file_id, offset: range.start() };
+            selections = vec![FileRange { file_id, range: range }];
+        }
+        RangeOrOffset::Offset(offset) => {
+            position = FilePosition { file_id, offset };
+            selections = vec![];
+        }
+    }
     let mut local_roots = FxHashSet::default();
     local_roots.insert(ra_db::fixture::WORKSPACE);
     db.set_local_roots_with_durability(Arc::new(local_roots), Durability::HIGH);
-    (db, position)
+    (db, position, selections)
 }
 
 fn assert_ssr_transform(rule: &str, input: &str, expected: Expect) {
@@ -81,8 +93,8 @@ fn assert_ssr_transform(rule: &str, input: &str, expected: Expect) {
 }
 
 fn assert_ssr_transforms(rules: &[&str], input: &str, expected: Expect) {
-    let (db, position) = single_file(input);
-    let mut match_finder = MatchFinder::in_context(&db, position);
+    let (db, position, selections) = single_file(input);
+    let mut match_finder = MatchFinder::in_context(&db, position, selections);
     for rule in rules {
         let rule: SsrRule = rule.parse().unwrap();
         match_finder.add_rule(rule).unwrap();
@@ -112,8 +124,8 @@ fn print_match_debug_info(match_finder: &MatchFinder, file_id: FileId, snippet:
 }
 
 fn assert_matches(pattern: &str, code: &str, expected: &[&str]) {
-    let (db, position) = single_file(code);
-    let mut match_finder = MatchFinder::in_context(&db, position);
+    let (db, position, selections) = single_file(code);
+    let mut match_finder = MatchFinder::in_context(&db, position, selections);
     match_finder.add_search_pattern(pattern.parse().unwrap()).unwrap();
     let matched_strings: Vec<String> =
         match_finder.matches().flattened().matches.iter().map(|m| m.matched_text()).collect();
@@ -124,8 +136,8 @@ fn assert_matches(pattern: &str, code: &str, expected: &[&str]) {
 }
 
 fn assert_no_match(pattern: &str, code: &str) {
-    let (db, position) = single_file(code);
-    let mut match_finder = MatchFinder::in_context(&db, position);
+    let (db, position, selections) = single_file(code);
+    let mut match_finder = MatchFinder::in_context(&db, position, selections);
     match_finder.add_search_pattern(pattern.parse().unwrap()).unwrap();
     let matches = match_finder.matches().flattened().matches;
     if !matches.is_empty() {
@@ -135,8 +147,8 @@ fn assert_no_match(pattern: &str, code: &str) {
 }
 
 fn assert_match_failure_reason(pattern: &str, code: &str, snippet: &str, expected_reason: &str) {
-    let (db, position) = single_file(code);
-    let mut match_finder = MatchFinder::in_context(&db, position);
+    let (db, position, selections) = single_file(code);
+    let mut match_finder = MatchFinder::in_context(&db, position, selections);
     match_finder.add_search_pattern(pattern.parse().unwrap()).unwrap();
     let mut reasons = Vec::new();
     for d in match_finder.debug_where_text_equal(position.file_id, snippet) {
@@ -490,9 +502,10 @@ fn no_match_split_expression() {
 
 #[test]
 fn replace_function_call() {
+    // This test also makes sure that we ignore empty-ranges.
     assert_ssr_transform(
         "foo() ==>> bar()",
-        "fn foo() {} fn bar() {} fn f1() {foo(); foo();}",
+        "fn foo() {<|><|>} fn bar() {} fn f1() {foo(); foo();}",
         expect![["fn foo() {} fn bar() {} fn f1() {bar(); bar();}"]],
     );
 }
@@ -922,3 +935,52 @@ fn replace_local_variable_reference() {
         "#]],
     )
 }
+
+#[test]
+fn replace_path_within_selection() {
+    assert_ssr_transform(
+        "foo ==>> bar",
+        r#"
+        fn main() {
+            let foo = 41;
+            let bar = 42;
+            do_stuff(foo);
+            do_stuff(foo);<|>
+            do_stuff(foo);
+            do_stuff(foo);<|>
+            do_stuff(foo);
+        }"#,
+        expect![[r#"
+            fn main() {
+                let foo = 41;
+                let bar = 42;
+                do_stuff(foo);
+                do_stuff(foo);
+                do_stuff(bar);
+                do_stuff(bar);
+                do_stuff(foo);
+            }"#]],
+    );
+}
+
+#[test]
+fn replace_nonpath_within_selection() {
+    mark::check!(replace_nonpath_within_selection);
+    assert_ssr_transform(
+        "$a + $b ==>> $b * $a",
+        r#"
+        fn main() {
+            let v = 1 + 2;<|>
+            let v2 = 3 + 3;
+            let v3 = 4 + 5;<|>
+            let v4 = 6 + 7;
+        }"#,
+        expect![[r#"
+            fn main() {
+                let v = 1 + 2;
+                let v2 = 3 * 3;
+                let v3 = 5 * 4;
+                let v4 = 6 + 7;
+            }"#]],
+    );
+}
diff --git a/crates/rust-analyzer/src/handlers.rs b/crates/rust-analyzer/src/handlers.rs
index cd309ed74..1350bd400 100644
--- a/crates/rust-analyzer/src/handlers.rs
+++ b/crates/rust-analyzer/src/handlers.rs
@@ -1026,9 +1026,18 @@ pub(crate) fn handle_ssr(
     params: lsp_ext::SsrParams,
 ) -> Result<lsp_types::WorkspaceEdit> {
     let _p = profile("handle_ssr");
+    let selections = params
+        .selections
+        .iter()
+        .map(|range| from_proto::file_range(&snap, params.position.text_document.clone(), *range))
+        .collect::<Result<Vec<_>, _>>()?;
     let position = from_proto::file_position(&snap, params.position)?;
-    let source_change =
-        snap.analysis.structural_search_replace(&params.query, params.parse_only, position)??;
+    let source_change = snap.analysis.structural_search_replace(
+        &params.query,
+        params.parse_only,
+        position,
+        selections,
+    )??;
     to_proto::workspace_edit(&snap, source_change)
 }
 
diff --git a/crates/rust-analyzer/src/lsp_ext.rs b/crates/rust-analyzer/src/lsp_ext.rs
index 113e0e070..3976b6529 100644
--- a/crates/rust-analyzer/src/lsp_ext.rs
+++ b/crates/rust-analyzer/src/lsp_ext.rs
@@ -221,6 +221,9 @@ pub struct SsrParams {
     /// position.
     #[serde(flatten)]
     pub position: lsp_types::TextDocumentPositionParams,
+
+    /// Current selections. Search/replace will be restricted to these if non-empty.
+    pub selections: Vec<lsp_types::Range>,
 }
 
 pub enum StatusNotification {}
diff --git a/editors/code/src/commands.ts b/editors/code/src/commands.ts
index c21e5597c..d0faf4745 100644
--- a/editors/code/src/commands.ts
+++ b/editors/code/src/commands.ts
@@ -190,6 +190,7 @@ export function ssr(ctx: Ctx): Cmd {
         if (!editor || !client) return;
 
         const position = editor.selection.active;
+        const selections = editor.selections;
         const textDocument = { uri: editor.document.uri.toString() };
 
         const options: vscode.InputBoxOptions = {
@@ -198,7 +199,7 @@ export function ssr(ctx: Ctx): Cmd {
             validateInput: async (x: string) => {
                 try {
                     await client.sendRequest(ra.ssr, {
-                        query: x, parseOnly: true, textDocument, position,
+                        query: x, parseOnly: true, textDocument, position, selections,
                     });
                 } catch (e) {
                     return e.toString();
@@ -215,7 +216,7 @@ export function ssr(ctx: Ctx): Cmd {
             cancellable: false,
         }, async (_progress, _token) => {
             const edit = await client.sendRequest(ra.ssr, {
-                query: request, parseOnly: false, textDocument, position
+                query: request, parseOnly: false, textDocument, position, selections,
             });
 
             await vscode.workspace.applyEdit(client.protocol2CodeConverter.asWorkspaceEdit(edit));
diff --git a/editors/code/src/lsp_ext.ts b/editors/code/src/lsp_ext.ts
index 149f9a0d6..494d51c83 100644
--- a/editors/code/src/lsp_ext.ts
+++ b/editors/code/src/lsp_ext.ts
@@ -95,6 +95,7 @@ export interface SsrParams {
     parseOnly: boolean;
     textDocument: lc.TextDocumentIdentifier;
     position: lc.Position;
+    selections: lc.Range[];
 }
 export const ssr = new lc.RequestType<SsrParams, lc.WorkspaceEdit, void>('experimental/ssr');