Add getter/setter assists

Finish implementing `generate_setter` assists

Make `generate_impl_text` util generic

generate getter methods

Fix getter / setter naming

It's now in-line with the Rust API naming guidelines: https://rust-lang.github.io/api-guidelines/naming.html#getter-names-follow-rust-convention-c-getter

apply clippy

Improve examples

crates/assists/src/handlers/generate_enum_match_method.rs

@@ -1,10 +1,11 @@
+use ast::Adt;
 use stdx::{format_to, to_lower_snake_case};
 use syntax::ast::VisibilityOwner;
 use syntax::ast::{self, AstNode, NameOwner};
 use test_utils::mark;
 
 use crate::{
-    utils::{find_impl_block, find_struct_impl},
+    utils::{find_impl_block, find_struct_impl, generate_impl_text},
     AssistContext, AssistId, AssistKind, Assists,
 };
 
@@ -49,7 +50,7 @@ pub(crate) fn generate_enum_match_method(acc: &mut Assists, ctx: &AssistContext)
     // Return early if we've found an existing new fn
     let impl_def = find_struct_impl(
         &ctx,
-        &ast::Adt::Enum(parent_enum.clone()),
+        &Adt::Enum(parent_enum.clone()),
         format!("is_{}", fn_name).as_str(),
     )?;
 
@@ -82,7 +83,7 @@ pub(crate) fn generate_enum_match_method(acc: &mut Assists, ctx: &AssistContext)
             let start_offset = impl_def
                 .and_then(|impl_def| find_impl_block(impl_def, &mut buf))
                 .unwrap_or_else(|| {
-                    buf = generate_impl_text(&parent_enum, &buf);
+                    buf = generate_impl_text(&Adt::Enum(parent_enum.clone()), &buf);
                     parent_enum.syntax().text_range().end()
                 });
 
@@ -91,16 +92,6 @@ pub(crate) fn generate_enum_match_method(acc: &mut Assists, ctx: &AssistContext)
     )
 }
 
-// Generates the surrounding `impl Type { <code> }` including type and lifetime
-// parameters
-fn generate_impl_text(strukt: &ast::Enum, code: &str) -> String {
-    let mut buf = String::with_capacity(code.len());
-    buf.push_str("\n\nimpl ");
-    buf.push_str(strukt.name().unwrap().text());
-    format_to!(buf, " {{\n{}\n}}", code);
-    buf
-}
-
 #[cfg(test)]
 mod tests {
     use test_utils::mark;

crates/assists/src/handlers/generate_getter.rs

@@ -0,0 +1,156 @@
+use ast::Adt;
+use stdx::{format_to, to_lower_snake_case};
+use syntax::ast::VisibilityOwner;
+use syntax::ast::{self, AstNode, NameOwner};
+
+use crate::{
+    utils::{find_impl_block, find_struct_impl, generate_impl_text},
+    AssistContext, AssistId, AssistKind, Assists,
+};
+
+// Assist: generate_getter
+//
+// Generate a getter method.
+//
+// ```
+// struct Person {
+//     nam$0e: String,
+// }
+// ```
+// ->
+// ```
+// struct Person {
+//     name: String,
+// }
+//
+// impl Person {
+//     /// Get a reference to the person's name.
+//     fn name(&self) -> &String {
+//         &self.name
+//     }
+// }
+// ```
+pub(crate) fn generate_getter(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let strukt = ctx.find_node_at_offset::<ast::Struct>()?;
+    let field = ctx.find_node_at_offset::<ast::RecordField>()?;
+
+    let strukt_name = strukt.name()?;
+    let field_name = field.name()?;
+    let field_ty = field.ty()?;
+
+    let fn_name = to_lower_snake_case(&field_name.to_string());
+    let fn_name_spaced = fn_name.replace('_', " ");
+    let strukt_name_spaced = to_lower_snake_case(&strukt_name.to_string()).replace('_', " ");
+
+    // Return early if we've found an existing fn
+    let impl_def = find_struct_impl(&ctx, &Adt::Struct(strukt.clone()), fn_name.as_str())?;
+
+    let target = field.syntax().text_range();
+    acc.add(
+        AssistId("generate_getter", AssistKind::Generate),
+        "Generate a getter method",
+        target,
+        |builder| {
+            let mut buf = String::with_capacity(512);
+
+            if impl_def.is_some() {
+                buf.push('\n');
+            }
+
+            let vis = strukt.visibility().map_or(String::new(), |v| format!("{} ", v));
+            format_to!(
+                buf,
+                "    /// Get a reference to the {}'s {}.
+    {}fn {}(&self) -> &{} {{
+        &self.{}
+    }}",
+                strukt_name_spaced,
+                fn_name_spaced,
+                vis,
+                fn_name,
+                field_ty,
+                fn_name,
+            );
+
+            let start_offset = impl_def
+                .and_then(|impl_def| find_impl_block(impl_def, &mut buf))
+                .unwrap_or_else(|| {
+                    buf = generate_impl_text(&Adt::Struct(strukt.clone()), &buf);
+                    strukt.syntax().text_range().end()
+                });
+
+            builder.insert(start_offset, buf);
+        },
+    )
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_assist, check_assist_not_applicable};
+
+    use super::*;
+
+    fn check_not_applicable(ra_fixture: &str) {
+        check_assist_not_applicable(generate_getter, ra_fixture)
+    }
+
+    #[test]
+    fn test_generate_getter_from_field() {
+        check_assist(
+            generate_getter,
+            r#"
+struct Context<T: Clone> {
+    dat$0a: T,
+}"#,
+            r#"
+struct Context<T: Clone> {
+    data: T,
+}
+
+impl<T: Clone> Context<T> {
+    /// Get a reference to the context's data.
+    fn data(&self) -> &T {
+        &self.data
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_generate_getter_already_implemented() {
+        check_not_applicable(
+            r#"
+struct Context<T: Clone> {
+    dat$0a: T,
+}
+
+impl<T: Clone> Context<T> {
+    fn data(&self) -> &T {
+        &self.data
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_generate_getter_from_field_with_visibility_marker() {
+        check_assist(
+            generate_getter,
+            r#"
+pub(crate) struct Context<T: Clone> {
+    dat$0a: T,
+}"#,
+            r#"
+pub(crate) struct Context<T: Clone> {
+    data: T,
+}
+
+impl<T: Clone> Context<T> {
+    /// Get a reference to the context's data.
+    pub(crate) fn data(&self) -> &T {
+        &self.data
+    }
+}"#,
+        );
+    }
+}

crates/assists/src/handlers/generate_getter_mut.rs

@@ -0,0 +1,157 @@
+use ast::Adt;
+use stdx::{format_to, to_lower_snake_case};
+use syntax::ast::VisibilityOwner;
+use syntax::ast::{self, AstNode, NameOwner};
+
+use crate::{
+    utils::{find_impl_block, find_struct_impl, generate_impl_text},
+    AssistContext, AssistId, AssistKind, Assists,
+};
+
+// Assist: generate_getter_mut
+//
+// Generate a mut getter method.
+//
+// ```
+// struct Person {
+//     nam$0e: String,
+// }
+// ```
+// ->
+// ```
+// struct Person {
+//     name: String,
+// }
+//
+// impl Person {
+//     /// Get a mutable reference to the person's name.
+//     fn name_mut(&mut self) -> &mut String {
+//         &mut self.name
+//     }
+// }
+// ```
+pub(crate) fn generate_getter_mut(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
+    let strukt = ctx.find_node_at_offset::<ast::Struct>()?;
+    let field = ctx.find_node_at_offset::<ast::RecordField>()?;
+
+    let strukt_name = strukt.name()?;
+    let field_name = field.name()?;
+    let field_ty = field.ty()?;
+
+    let fn_name = to_lower_snake_case(&field_name.to_string());
+    let fn_name_spaced = fn_name.replace('_', " ");
+    let strukt_name_spaced = to_lower_snake_case(&strukt_name.to_string()).replace('_', " ");
+
+    // Return early if we've found an existing fn
+    let impl_def =
+        find_struct_impl(&ctx, &Adt::Struct(strukt.clone()), format!("{}_mut", fn_name).as_str())?;
+
+    let target = field.syntax().text_range();
+    acc.add(
+        AssistId("generate_getter_mut", AssistKind::Generate),
+        "Generate a mut getter method",
+        target,
+        |builder| {
+            let mut buf = String::with_capacity(512);
+
+            if impl_def.is_some() {
+                buf.push('\n');
+            }
+
+            let vis = strukt.visibility().map_or(String::new(), |v| format!("{} ", v));
+            format_to!(
+                buf,
+                "    /// Get a mutable reference to the {}'s {}.
+    {}fn {}_mut(&mut self) -> &mut {} {{
+        &mut self.{}
+    }}",
+                strukt_name_spaced,
+                fn_name_spaced,
+                vis,
+                fn_name,
+                field_ty,
+                fn_name,
+            );
+
+            let start_offset = impl_def
+                .and_then(|impl_def| find_impl_block(impl_def, &mut buf))
+                .unwrap_or_else(|| {
+                    buf = generate_impl_text(&Adt::Struct(strukt.clone()), &buf);
+                    strukt.syntax().text_range().end()
+                });
+
+            builder.insert(start_offset, buf);
+        },
+    )
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::tests::{check_assist, check_assist_not_applicable};
+
+    use super::*;
+
+    fn check_not_applicable(ra_fixture: &str) {
+        check_assist_not_applicable(generate_getter_mut, ra_fixture)
+    }
+
+    #[test]
+    fn test_generate_getter_mut_from_field() {
+        check_assist(
+            generate_getter_mut,
+            r#"
+struct Context<T: Clone> {
+    dat$0a: T,
+}"#,
+            r#"
+struct Context<T: Clone> {
+    data: T,
+}
+
+impl<T: Clone> Context<T> {
+    /// Get a mutable reference to the context's data.
+    fn data_mut(&mut self) -> &mut T {
+        &mut self.data
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_generate_getter_mut_already_implemented() {
+        check_not_applicable(
+            r#"
+struct Context<T: Clone> {
+    dat$0a: T,
+}
+
+impl<T: Clone> Context<T> {
+    fn data_mut(&mut self) -> &mut T {
+        &mut self.data
+    }
+}"#,
+        );
+    }
+
+    #[test]
+    fn test_generate_getter_mut_from_field_with_visibility_marker() {
+        check_assist(
+            generate_getter_mut,
+            r#"
+pub(crate) struct Context<T: Clone> {
+    dat$0a: T,
+}"#,
+            r#"
+pub(crate) struct Context<T: Clone> {
+    data: T,
+}
+
+impl<T: Clone> Context<T> {
+    /// Get a mutable reference to the context's data.
+    pub(crate) fn data_mut(&mut self) -> &mut T {
+        &mut self.data
+    }
+}"#,
+        );
+    }
+}