1 files changed, 167 insertions, 0 deletions

diff --git a/crates/ra_assists/src/handlers/change_visibility.rs b/crates/ra_assists/src/handlers/change_visibility.rs
new file mode 100644
index 000000000..f325b6f92
--- /dev/null
+++ b/crates/ra_assists/src/handlers/change_visibility.rs
@@ -0,0 +1,167 @@
+use ra_syntax::{
+    ast::{self, NameOwner, VisibilityOwner},
+    AstNode,
+    SyntaxKind::{
+        ATTR, COMMENT, ENUM_DEF, FN_DEF, IDENT, MODULE, STRUCT_DEF, TRAIT_DEF, VISIBILITY,
+        WHITESPACE,
+    },
+    SyntaxNode, TextUnit, T,
+};
+
+use crate::{Assist, AssistCtx, AssistId};
+
+// Assist: change_visibility
+//
+// Adds or changes existing visibility specifier.
+//
+// ```
+// <|>fn frobnicate() {}
+// ```
+// ->
+// ```
+// pub(crate) fn frobnicate() {}
+// ```
+pub(crate) fn change_visibility(ctx: AssistCtx) -> Option<Assist> {
+    if let Some(vis) = ctx.find_node_at_offset::<ast::Visibility>() {
+        return change_vis(ctx, vis);
+    }
+    add_vis(ctx)
+}
+
+fn add_vis(ctx: AssistCtx) -> Option<Assist> {
+    let item_keyword = ctx.token_at_offset().find(|leaf| match leaf.kind() {
+        T![fn] | T![mod] | T![struct] | T![enum] | T![trait] => true,
+        _ => false,
+    });
+
+    let (offset, target) = if let Some(keyword) = item_keyword {
+        let parent = keyword.parent();
+        let def_kws = vec![FN_DEF, MODULE, STRUCT_DEF, ENUM_DEF, TRAIT_DEF];
+        // Parent is not a definition, can't add visibility
+        if !def_kws.iter().any(|&def_kw| def_kw == parent.kind()) {
+            return None;
+        }
+        // Already have visibility, do nothing
+        if parent.children().any(|child| child.kind() == VISIBILITY) {
+            return None;
+        }
+        (vis_offset(&parent), keyword.text_range())
+    } else {
+        let ident = ctx.token_at_offset().find(|leaf| leaf.kind() == IDENT)?;
+        let field = ident.parent().ancestors().find_map(ast::RecordFieldDef::cast)?;
+        if field.name()?.syntax().text_range() != ident.text_range() && field.visibility().is_some()
+        {
+            return None;
+        }
+        (vis_offset(field.syntax()), ident.text_range())
+    };
+
+    ctx.add_assist(AssistId("change_visibility"), "Change visibility to pub(crate)", |edit| {
+        edit.target(target);
+        edit.insert(offset, "pub(crate) ");
+        edit.set_cursor(offset);
+    })
+}
+
+fn vis_offset(node: &SyntaxNode) -> TextUnit {
+    node.children_with_tokens()
+        .skip_while(|it| match it.kind() {
+            WHITESPACE | COMMENT | ATTR => true,
+            _ => false,
+        })
+        .next()
+        .map(|it| it.text_range().start())
+        .unwrap_or_else(|| node.text_range().start())
+}
+
+fn change_vis(ctx: AssistCtx, vis: ast::Visibility) -> Option<Assist> {
+    if vis.syntax().text() == "pub" {
+        return ctx.add_assist(
+            AssistId("change_visibility"),
+            "Change Visibility to pub(crate)",
+            |edit| {
+                edit.target(vis.syntax().text_range());
+                edit.replace(vis.syntax().text_range(), "pub(crate)");
+                edit.set_cursor(vis.syntax().text_range().start())
+            },
+        );
+    }
+    if vis.syntax().text() == "pub(crate)" {
+        return ctx.add_assist(AssistId("change_visibility"), "Change visibility to pub", |edit| {
+            edit.target(vis.syntax().text_range());
+            edit.replace(vis.syntax().text_range(), "pub");
+            edit.set_cursor(vis.syntax().text_range().start());
+        });
+    }
+    None
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::helpers::{check_assist, check_assist_target};
+
+    #[test]
+    fn change_visibility_adds_pub_crate_to_items() {
+        check_assist(change_visibility, "<|>fn foo() {}", "<|>pub(crate) fn foo() {}");
+        check_assist(change_visibility, "f<|>n foo() {}", "<|>pub(crate) fn foo() {}");
+        check_assist(change_visibility, "<|>struct Foo {}", "<|>pub(crate) struct Foo {}");
+        check_assist(change_visibility, "<|>mod foo {}", "<|>pub(crate) mod foo {}");
+        check_assist(change_visibility, "<|>trait Foo {}", "<|>pub(crate) trait Foo {}");
+        check_assist(change_visibility, "m<|>od {}", "<|>pub(crate) mod {}");
+        check_assist(
+            change_visibility,
+            "unsafe f<|>n foo() {}",
+            "<|>pub(crate) unsafe fn foo() {}",
+        );
+    }
+
+    #[test]
+    fn change_visibility_works_with_struct_fields() {
+        check_assist(
+            change_visibility,
+            "struct S { <|>field: u32 }",
+            "struct S { <|>pub(crate) field: u32 }",
+        )
+    }
+
+    #[test]
+    fn change_visibility_pub_to_pub_crate() {
+        check_assist(change_visibility, "<|>pub fn foo() {}", "<|>pub(crate) fn foo() {}")
+    }
+
+    #[test]
+    fn change_visibility_pub_crate_to_pub() {
+        check_assist(change_visibility, "<|>pub(crate) fn foo() {}", "<|>pub fn foo() {}")
+    }
+
+    #[test]
+    fn change_visibility_handles_comment_attrs() {
+        check_assist(
+            change_visibility,
+            "
+            /// docs
+
+            // comments
+
+            #[derive(Debug)]
+            <|>struct Foo;
+            ",
+            "
+            /// docs
+
+            // comments
+
+            #[derive(Debug)]
+            <|>pub(crate) struct Foo;
+            ",
+        )
+    }
+
+    #[test]
+    fn change_visibility_target() {
+        check_assist_target(change_visibility, "<|>fn foo() {}", "fn");
+        check_assist_target(change_visibility, "pub(crate)<|> fn foo() {}", "pub(crate)");
+        check_assist_target(change_visibility, "struct S { <|>field: u32 }", "field");
+    }
+}