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.

4 files changed, 155 insertions, 43 deletions

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;
+            }"#]],
+    );
+}