feat: implement docstring handling

bindgen/Cargo.toml

@@ -27,3 +27,4 @@ camino = "1.0.8"
 fs-err = "2.7.0"
 paste = "1.0"
 serde_json = "1.0.0"
+textwrap = "0.16"

bindgen/src/gen_go/mod.rs

@@ -487,6 +487,15 @@ pub mod filters {
     pub fn enum_variant_name(nm: &str) -> Result<String, askama::Error> {
         Ok(oracle().enum_variant_name(nm))
     }
+
+    /// Get the idiomatic go rendering of docstring
+    pub fn docstring(docstring: &str, tabs: &i32) -> Result<String, askama::Error> {
+        let middle = textwrap::indent(&textwrap::dedent(docstring), "// ");
+        let wrapped = format!("{middle}");
+
+        let tabs = usize::try_from(*tabs).unwrap_or_default();
+        Ok(textwrap::indent(&wrapped, &"\t".repeat(tabs)))
+    }
 }
 
 /// Renders Go helper code for all types

bindgen/templates/CallbackInterfaceTemplate.go

@@ -6,8 +6,11 @@
 {{- self.add_import("sync") }}
 
 // Declaration and FfiConverters for {{ type_name }} Callback Interface
+
+{%- call go::docstring(cbi, 0) %}
 type {{ type_name }} interface {
 	{% for meth in cbi.methods() -%}
+	{%- call go::docstring(meth, 4) %}
 	{{ meth.name()|fn_name }}({% call go::arg_list_decl(meth) %}) {% call go::return_type_decl_cb(meth) %}
 	{% endfor %}
 }

bindgen/templates/EnumTemplate.go

@@ -4,11 +4,12 @@
 
 {% let e = ci.get_enum_definition(name).expect("missing enum") -%}
 {%- if e.is_flat() -%}
-
+{%- call go::docstring(e, 0) %}
 type {{ type_name }} uint
 
 const (
 	{%- for variant in e.variants() %}
+	{%- call go::docstring(variant, 4) %}
 	{{ type_name }}{{ variant.name()|enum_variant_name }} {{ type_name }} = {{ loop.index }}
 	{%- endfor %}
 )
@@ -19,8 +20,10 @@ type {{ type_name }} interface {
 }
 
 {%- for variant in e.variants() %}
+{%- call go::docstring(variant, 0) %}
 type {{ type_name }}{{ variant.name()|class_name }} struct {
 	{%- for field in variant.fields() %}
+	{%- call go::docstring(field, 4) %}
 	{{ field.name()|field_name }} {{ field|type_name}}
 	{%- endfor %}
 }

bindgen/templates/ErrorTemplate.go

@@ -2,6 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */#}
 
+{%- call go::docstring(e, 0) %}
 type {{ type_name|class_name }} struct {
 	err error
 }
@@ -17,12 +18,14 @@ func (err {{ type_name|class_name }}) Unwrap() error {
 // Err* are used for checking error type with `errors.Is`
 {%- for variant in e.variants() %}
 {%- let variant_class_name = (type_name.clone() + variant.name())|class_name %}
+{%- call go::docstring(variant, 0) %}
 var Err{{ variant_class_name }} = fmt.Errorf("{{ variant_class_name }}")
 {%- endfor %}
 
 // Variant structs
 {%- for variant in e.variants() %}
 {%- let variant_class_name = (type_name.clone() + variant.name())|class_name %}
+{%- call go::docstring(variant, 0) %}
 type {{ variant_class_name }} struct {
 	{%- if e.is_flat() %}
 	message string

bindgen/templates/ObjectTemplate.go

@@ -8,25 +8,29 @@
 {%- let obj_name = obj.name()|class_name %}
 {%- if self.include_once_check("ObjectRuntime.go") %}{% include "ObjectRuntime.go" %}{% endif %}
 
+{%- call go::docstring(obj, 0) %}
 type {{ obj_name }} struct {
 	ffiObject FfiObject
 }
 
 {%- match obj.primary_constructor() %}
 {%- when Some with (cons) %}
+{%- call go::docstring(cons, 0) %}
 func New{{ obj_name }}({% call go::arg_list_decl(cons) -%}) {% call go::return_type_decl(cons) %} {
 	{% call go::ffi_call_binding(func, "") %}
 }
 {%- when None %}
 {%- endmatch %}
 
 {% for cons in obj.alternate_constructors() -%}
+{%- call go::docstring(cons, 0) %}
 func {{ obj_name }}{{ cons.name()|fn_name }}({% call go::arg_list_decl(cons) %}) {% call go::return_type_decl(cons) %} {
 	{% call go::ffi_call_binding(func, "") %}
 }
 {% endfor %}
 
 {% for func in obj.methods() -%}
+{%- call go::docstring(func, 0) %}
 func (_self {{ type_name }}){{ func.name()|fn_name }}({%- call go::arg_list_decl(func) -%}) {% call go::return_type_decl(func) %} {
 	_pointer := _self.ffiObject.incrementPointer("{{ type_name }}")
 	defer _self.ffiObject.decrementPointer()

bindgen/templates/RecordTemplate.go

@@ -4,8 +4,10 @@
 
 {%- let rec = ci.get_record_definition(name).expect("missing record") %}
 
+{%- call go::docstring(rec, 0) %}
 type {{ type_name }} struct {
 	{%- for field in rec.fields() %}
+	{%- call go::docstring(field, 0) %}
 	{{ field.name()|field_name }} {{ field|type_name -}}
 	{%- endfor %}
 }

bindgen/templates/macros.go

@@ -205,3 +205,11 @@ RustBufferFromExternal({{ arg|lower_fn }}({{ arg.name()|var_name }}))
 {%- endmacro -%}
 
 
+
+{%- macro docstring(defn, indent_spaces) %}
+{%- match defn.docstring() %}
+{%- when Some(docstring) %}
+{{ docstring|docstring(indent_spaces) }}
+{%- else %}
+{%- endmatch %}
+{%- endmacro %}

bindgen/templates/wrapper.go

@@ -2,6 +2,8 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */#}
 
+{%- call go::docstring(ci.namespace_definition(), 0) %}
+
 package {{ ci.namespace() }}
 
 // #include <{{ config.header_filename() }}>

binding_tests/docstring_test.go

@@ -0,0 +1,28 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package binding_tests
+
+import (
+	"testing"
+
+	"github.com/NordSecurity/uniffi-bindgen-go/binding_tests/generated/uniffi_docstring"
+)
+
+func TestDocstring(_ *testing.T) {
+	_ = uniffi_docstring.EnumTestOne
+	_ = uniffi_docstring.AssociatedEnumTestTest{}
+	_ = uniffi_docstring.NewErrorTestOne()
+
+	_ = uniffi_docstring.NewObjectTest()
+	obj2 := uniffi_docstring.ObjectTestNewAlternate()
+	obj2.Test()
+
+	rec := uniffi_docstring.RecordTest { Test: 123 }
+	_ = rec.Test
+
+	// class CallbackImpls: CallbackTest {
+	// 	func test() {}
+	// }
+}

fixtures/Cargo.toml

@@ -36,6 +36,7 @@ uniffi-fixture-simple-iface = { path = "../3rd-party/uniffi-rs/fixtures/simple-i
 uniffi-fixture-trait-methods = { path = "../3rd-party/uniffi-rs/fixtures/trait-methods" }
 uniffi-fixture-type-limits = { path = "../3rd-party/uniffi-rs/fixtures/type-limits" }
 uniffi-fixture-time = { path = "../3rd-party/uniffi-rs/fixtures/uniffi-fixture-time" }
+uniffi-fixture-docstring = { path = "../3rd-party/uniffi-rs/fixtures/docstring" }
 
 # Go specific
 uniffi-go-fixture-destroy = { path = "destroy" }

fixtures/src/lib.rs

@@ -33,6 +33,8 @@ mod uniffi_fixtures {
     uniffi_trait_methods::uniffi_reexport_scaffolding!();
     uniffi_type_limits::uniffi_reexport_scaffolding!();
 
+    uniffi_fixture_docstring::uniffi_reexport_scaffolding!();
+
     // Go specific
     uniffi_go_destroy::uniffi_reexport_scaffolding!();
     uniffi_go_errors::uniffi_reexport_scaffolding!();