Merge #750

750: Move assists to a separate crate r=matklad a=matklad

I am slowly coming to conclusion that ide_api_light does not make a lot of sense after all :D 

This PR moves assists to a separate crate, so that assists can use database (so, inspect types, do name-resolution, etc)

Co-authored-by: Aleksey Kladov <[email protected]>

7 files changed, 25 insertions, 295 deletions

diff --git a/crates/ra_ide_api/Cargo.toml b/crates/ra_ide_api/Cargo.toml
index 54de9b2e3..95cccf8cf 100644
--- a/crates/ra_ide_api/Cargo.toml
+++ b/crates/ra_ide_api/Cargo.toml
@@ -24,6 +24,7 @@ ra_text_edit = { path = "../ra_text_edit" }
 ra_db = { path = "../ra_db" }
 hir = { path = "../ra_hir", package = "ra_hir" }
 test_utils = { path = "../test_utils" }
+ra_assists = { path = "../ra_assists" }
 
 [dev-dependencies]
 insta = "0.6.1"
diff --git a/crates/ra_ide_api/src/assists.rs b/crates/ra_ide_api/src/assists.rs
index 2da251df5..2a96fdf47 100644
--- a/crates/ra_ide_api/src/assists.rs
+++ b/crates/ra_ide_api/src/assists.rs
@@ -1,89 +1,24 @@
-mod fill_match_arm;
-
-use ra_syntax::{
-    TextRange, SourceFile, AstNode,
-    algo::find_node_at_offset,
-};
-use ra_ide_api_light::{
-    LocalEdit,
-    assists::{
-        Assist,
-        AssistBuilder
-    }
-};
-use crate::{
-    db::RootDatabase,
-    FileId
-};
-
-/// Return all the assists applicable at the given position.
-pub(crate) fn assists(
-    db: &RootDatabase,
-    file_id: FileId,
-    file: &SourceFile,
-    range: TextRange,
-) -> Vec<LocalEdit> {
-    let ctx = AssistCtx::new(db, file_id, file, range);
-    [fill_match_arm::fill_match_arm]
-        .iter()
-        .filter_map(|&assist| ctx.clone().apply(assist))
+use ra_db::{FileRange, FilePosition};
+
+use crate::{SourceFileEdit, SourceChange, db::RootDatabase};
+
+pub(crate) fn assists(db: &RootDatabase, frange: FileRange) -> Vec<SourceChange> {
+    ra_assists::assists(db, frange)
+        .into_iter()
+        .map(|(label, action)| {
+            let file_id = frange.file_id;
+            let file_edit = SourceFileEdit {
+                file_id,
+                edit: action.edit,
+            };
+            SourceChange {
+                label: label.label,
+                source_file_edits: vec![file_edit],
+                file_system_edits: vec![],
+                cursor_position: action
+                    .cursor_position
+                    .map(|offset| FilePosition { offset, file_id }),
+            }
+        })
         .collect()
 }
-
-#[derive(Debug, Clone)]
-pub struct AssistCtx<'a> {
-    file_id: FileId,
-    source_file: &'a SourceFile,
-    db: &'a RootDatabase,
-    range: TextRange,
-    should_compute_edit: bool,
-}
-
-impl<'a> AssistCtx<'a> {
-    pub(crate) fn new(
-        db: &'a RootDatabase,
-        file_id: FileId,
-        source_file: &'a SourceFile,
-        range: TextRange,
-    ) -> AssistCtx<'a> {
-        AssistCtx {
-            source_file,
-            file_id,
-            db,
-            range,
-            should_compute_edit: false,
-        }
-    }
-
-    pub fn apply(mut self, assist: fn(AssistCtx) -> Option<Assist>) -> Option<LocalEdit> {
-        self.should_compute_edit = true;
-        match assist(self) {
-            None => None,
-            Some(Assist::Edit(e)) => Some(e),
-            Some(Assist::Applicable) => unreachable!(),
-        }
-    }
-
-    #[allow(unused)]
-    pub fn check(mut self, assist: fn(AssistCtx) -> Option<Assist>) -> bool {
-        self.should_compute_edit = false;
-        match assist(self) {
-            None => false,
-            Some(Assist::Edit(_)) => unreachable!(),
-            Some(Assist::Applicable) => true,
-        }
-    }
-
-    fn build(self, label: impl Into<String>, f: impl FnOnce(&mut AssistBuilder)) -> Option<Assist> {
-        if !self.should_compute_edit {
-            return Some(Assist::Applicable);
-        }
-        let mut edit = AssistBuilder::default();
-        f(&mut edit);
-        Some(edit.build(label))
-    }
-
-    pub(crate) fn node_at_offset<N: AstNode>(&self) -> Option<&'a N> {
-        find_node_at_offset(self.source_file.syntax(), self.range.start())
-    }
-}
diff --git a/crates/ra_ide_api/src/assists/fill_match_arm.rs b/crates/ra_ide_api/src/assists/fill_match_arm.rs
deleted file mode 100644
index 6ae829d85..000000000
--- a/crates/ra_ide_api/src/assists/fill_match_arm.rs
+++ /dev/null
@@ -1,157 +0,0 @@
-use std::fmt::Write;
-use hir::{
-    AdtDef,
-    source_binder,
-    Ty,
-    FieldSource,
-};
-use ra_ide_api_light::{
-    assists::{
-        Assist,
-        AssistBuilder
-    }
-};
-use ra_syntax::{
-    ast::{
-        self,
-        AstNode,
-    }
-};
-
-use crate::assists::AssistCtx;
-
-pub fn fill_match_arm(ctx: AssistCtx) -> Option<Assist> {
-    let match_expr = ctx.node_at_offset::<ast::MatchExpr>()?;
-
-    // We already have some match arms, so we don't provide any assists.
-    match match_expr.match_arm_list() {
-        Some(arm_list) if arm_list.arms().count() > 0 => {
-            return None;
-        }
-        _ => {}
-    }
-
-    let expr = match_expr.expr()?;
-    let function = source_binder::function_from_child_node(ctx.db, ctx.file_id, expr.syntax())?;
-    let infer_result = function.infer(ctx.db);
-    let syntax_mapping = function.body_syntax_mapping(ctx.db);
-    let node_expr = syntax_mapping.node_expr(expr)?;
-    let match_expr_ty = infer_result[node_expr].clone();
-    match match_expr_ty {
-        Ty::Adt { def_id, .. } => match def_id {
-            AdtDef::Enum(e) => {
-                let mut buf = format!("match {} {{\n", expr.syntax().text().to_string());
-                let variants = e.variants(ctx.db);
-                for variant in variants {
-                    let name = variant.name(ctx.db)?;
-                    write!(
-                        &mut buf,
-                        "    {}::{}",
-                        e.name(ctx.db)?.to_string(),
-                        name.to_string()
-                    )
-                    .expect("write fmt");
-
-                    let pat = variant
-                        .fields(ctx.db)
-                        .into_iter()
-                        .map(|field| {
-                            let name = field.name(ctx.db).to_string();
-                            let (_, source) = field.source(ctx.db);
-                            match source {
-                                FieldSource::Named(_) => name,
-                                FieldSource::Pos(_) => "_".to_string(),
-                            }
-                        })
-                        .collect::<Vec<_>>();
-
-                    match pat.first().map(|s| s.as_str()) {
-                        Some("_") => write!(&mut buf, "({})", pat.join(", ")).expect("write fmt"),
-                        Some(_) => write!(&mut buf, "{{{}}}", pat.join(", ")).expect("write fmt"),
-                        None => (),
-                    };
-
-                    buf.push_str(" => (),\n");
-                }
-                buf.push_str("}");
-                ctx.build("fill match arms", |edit: &mut AssistBuilder| {
-                    edit.replace_node_and_indent(match_expr.syntax(), buf);
-                })
-            }
-            _ => None,
-        },
-        _ => None,
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use insta::assert_debug_snapshot_matches;
-
-    use ra_syntax::{TextRange, TextUnit};
-
-    use crate::{
-        FileRange,
-        mock_analysis::{analysis_and_position, single_file_with_position}
-};
-    use ra_db::SourceDatabase;
-
-    fn test_assit(name: &str, code: &str) {
-        let (analysis, position) = if code.contains("//-") {
-            analysis_and_position(code)
-        } else {
-            single_file_with_position(code)
-        };
-        let frange = FileRange {
-            file_id: position.file_id,
-            range: TextRange::offset_len(position.offset, TextUnit::from(1)),
-        };
-        let source_file = analysis
-            .with_db(|db| db.parse(frange.file_id))
-            .expect("source file");
-        let ret = analysis
-            .with_db(|db| crate::assists::assists(db, frange.file_id, &source_file, frange.range))
-            .expect("assists");
-
-        assert_debug_snapshot_matches!(name, ret);
-    }
-
-    #[test]
-    fn test_fill_match_arm() {
-        test_assit(
-            "fill_match_arm1",
-            r#"
-        enum A {
-            As,
-            Bs,
-            Cs(String),
-            Ds(String, String),
-            Es{x: usize, y: usize}
-        }
-
-        fn main() {
-            let a = A::As;
-            match a<|>
-        }
-        "#,
-        );
-
-        test_assit(
-            "fill_match_arm2",
-            r#"
-        enum A {
-            As,
-            Bs,
-            Cs(String),
-            Ds(String, String),
-            Es{x: usize, y: usize}
-        }
-
-        fn main() {
-            let a = A::As;
-            match a<|> {}
-        }
-        "#,
-        );
-    }
-}
diff --git a/crates/ra_ide_api/src/assists/snapshots/tests__fill_match_arm1.snap b/crates/ra_ide_api/src/assists/snapshots/tests__fill_match_arm1.snap
deleted file mode 100644
index 980726d92..000000000
--- a/crates/ra_ide_api/src/assists/snapshots/tests__fill_match_arm1.snap
+++ /dev/null
@@ -1,20 +0,0 @@
----
-created: "2019-02-03T15:38:46.094184+00:00"
-creator: [email protected]
-expression: ret
-source: crates/ra_ide_api/src/assits/fill_match_arm.rs
----
-[
-    LocalEdit {
-        label: "fill match arms",
-        edit: TextEdit {
-            atoms: [
-                AtomTextEdit {
-                    delete: [211; 218),
-                    insert: "match a {\n                A::As => (),\n                A::Bs => (),\n                A::Cs(_) => (),\n                A::Ds(_, _) => (),\n                A::Es{x, y} => (),\n            }"
-                }
-            ]
-        },
-        cursor_position: None
-    }
-]
diff --git a/crates/ra_ide_api/src/assists/snapshots/tests__fill_match_arm2.snap b/crates/ra_ide_api/src/assists/snapshots/tests__fill_match_arm2.snap
deleted file mode 100644
index cee0efe74..000000000
--- a/crates/ra_ide_api/src/assists/snapshots/tests__fill_match_arm2.snap
+++ /dev/null
@@ -1,20 +0,0 @@
----
-created: "2019-02-03T15:41:34.640074+00:00"
-creator: [email protected]
-expression: ret
-source: crates/ra_ide_api/src/assits/fill_match_arm.rs
----
-[
-    LocalEdit {
-        label: "fill match arms",
-        edit: TextEdit {
-            atoms: [
-                AtomTextEdit {
-                    delete: [211; 221),
-                    insert: "match a {\n                A::As => (),\n                A::Bs => (),\n                A::Cs(_) => (),\n                A::Ds(_, _) => (),\n                A::Es{x, y} => (),\n            }"
-                }
-            ]
-        },
-        cursor_position: None
-    }
-]
diff --git a/crates/ra_ide_api/src/imp.rs b/crates/ra_ide_api/src/imp.rs
index fd8637ad2..b139efabf 100644
--- a/crates/ra_ide_api/src/imp.rs
+++ b/crates/ra_ide_api/src/imp.rs
@@ -19,7 +19,7 @@ use ra_syntax::{
 
 use crate::{
     AnalysisChange,
-    CrateId, db, Diagnostic, FileId, FilePosition, FileRange, FileSystemEdit,
+    CrateId, db, Diagnostic, FileId, FilePosition, FileSystemEdit,
     Query, RootChange, SourceChange, SourceFileEdit,
     symbol_index::{FileSymbol, SymbolsDatabase},
     status::syntax_tree_stats
@@ -236,15 +236,6 @@ impl db::RootDatabase {
         res
     }
 
-    pub(crate) fn assists(&self, frange: FileRange) -> Vec<SourceChange> {
-        let file = self.parse(frange.file_id);
-        ra_ide_api_light::assists::assists(&file, frange.range)
-            .into_iter()
-            .chain(crate::assists::assists(self, frange.file_id, &file, frange.range).into_iter())
-            .map(|local_edit| SourceChange::from_local_edit(frange.file_id, local_edit))
-            .collect()
-    }
-
     pub(crate) fn index_resolve(&self, name_ref: &ast::NameRef) -> Vec<FileSymbol> {
         let name = name_ref.text();
         let mut query = Query::new(name.to_string());
diff --git a/crates/ra_ide_api/src/lib.rs b/crates/ra_ide_api/src/lib.rs
index 3a187d7a5..8beaba5de 100644
--- a/crates/ra_ide_api/src/lib.rs
+++ b/crates/ra_ide_api/src/lib.rs
@@ -477,7 +477,7 @@ impl Analysis {
     /// Computes assists (aks code actons aka intentions) for the given
     /// position.
     pub fn assists(&self, frange: FileRange) -> Cancelable<Vec<SourceChange>> {
-        self.with_db(|db| db.assists(frange))
+        self.with_db(|db| assists::assists(db, frange))
     }
 
     /// Computes the set of diagnostics for the given file.