Skip to content

Commit 1b547a5

Browse files
NiwakaDevNiwakaDev
authored
Support throwing initializers (#287)
This PR implements throwing initializers. See: https://docs.swift.org/swift-book/documentation/the-swift-programming-language/errorhandling/. Here's an example of using this feature: ```rust // Rust #[swift_bridge::bridge] mod ffi { enum ResultTransparentEnum { NamedField { data: i32 }, UnnamedFields(u8, String), NoFields, } extern "Rust" { type ThrowingInitializer; #[swift_bridge(init)] fn new(succeed: bool) -> Result<ThrowingInitializer, ResultTransparentEnum>; fn val(&self) -> i32; } } ``` ```swift // Swift do { let throwingInitializer = try ThrowingInitializer(false) } catch let error as ResultTransparentEnum { //... } catch { //... } ```
1 parent 495611b commit 1b547a5

File tree

14 files changed

+315
-23
lines changed

14 files changed

+315
-23
lines changed

‎SwiftRustIntegrationTestRunner/SwiftRustIntegrationTestRunnerTests/ResultTests.swift

+23
Original file line numberDiff line numberDiff line change
@@ -249,4 +249,27 @@ class ResultTests: XCTestCase {
249249
XCTAssertEqual(UInt32(i), value.val())
250250
}
251251
}
252+
253+
/// Verify that we can use throwing initializers defined on the Rust side.
254+
func testThrowingInitializers() throws {
255+
XCTContext.runActivity(named: "Should fail") {
256+
_ in
257+
do {
258+
let throwingInitializer = try ThrowingInitializer(false)
259+
} catch let error as ResultTransparentEnum {
260+
if case .NamedField(data: -123) = error {
261+
// This case should pass.
262+
} else {
263+
XCTFail()
264+
}
265+
} catch {
266+
XCTFail()
267+
}
268+
}
269+
XCTContext.runActivity(named: "Should succeed") {
270+
_ in
271+
let throwingInitializer = try! ThrowingInitializer(true)
272+
XCTAssertEqual(throwingInitializer.val(), 123)
273+
}
274+
}
252275
}

‎book/src/bridge-module/functions/README.md

+52
Original file line numberDiff line numberDiff line change
@@ -65,6 +65,58 @@ do {
6565

6666
## Function Attributes
6767

68+
#### #[swift_bridge(init)]
69+
Used to generate a Swift initializer for Opaque Types.
70+
71+
```rust
72+
// Rust
73+
74+
#[swift_bridge::bridge]
75+
mod ffi {
76+
extern "Rust" {
77+
type RegularInitializer;
78+
79+
#[swift_bridge(init)]
80+
fn new() -> RegularInitializer;
81+
}
82+
83+
extern "Rust" {
84+
type FailableInitializer;
85+
86+
#[swift_bridge(init)]
87+
fn new() -> Option<FailableInitializer>;
88+
}
89+
90+
enum SomeError {
91+
case1,
92+
case2
93+
}
94+
95+
extern "Rust" {
96+
type ThrowingInitializer;
97+
98+
#[swift_bridge(init)]
99+
fn new() -> Result<FailableInitializer, SomeError>;
100+
}
101+
}
102+
```
103+
104+
```swift
105+
// Swift
106+
107+
let regularInitializer = RegularInitializer()
108+
109+
if let failableInitializer = FailableInitializer() {
110+
// ...
111+
}
112+
113+
do {
114+
let throwingInitializer = try ThrowingInitializer()
115+
} catch let error {
116+
// ...
117+
}
118+
```
119+
68120
#### #[swift_bridge(Identifiable)]
69121

70122
Used to generate a Swift `Identifiable` protocol implementation.

‎crates/swift-bridge-ir/src/bridged_type.rs

+9
Original file line numberDiff line numberDiff line change
@@ -411,6 +411,7 @@ pub(crate) enum TypePosition {
411411
FnReturn(HostLang),
412412
SharedStructField,
413413
SwiftCallsRustAsyncOnCompleteReturnTy,
414+
ThrowingInit(HostLang),
414415
}
415416

416417
/// &[T]
@@ -1177,6 +1178,7 @@ impl BridgedType {
11771178
TypePosition::SwiftCallsRustAsyncOnCompleteReturnTy => {
11781179
unimplemented!()
11791180
}
1181+
TypePosition::ThrowingInit(_) => unimplemented!(),
11801182
}
11811183
}
11821184
StdLibType::Null => "()".to_string(),
@@ -1193,6 +1195,7 @@ impl BridgedType {
11931195
TypePosition::SwiftCallsRustAsyncOnCompleteReturnTy => {
11941196
unimplemented!()
11951197
}
1198+
TypePosition::ThrowingInit(_) => unimplemented!(),
11961199
},
11971200
StdLibType::Vec(ty) => match type_pos {
11981201
TypePosition::FnArg(func_host_lang, _) => {
@@ -1215,6 +1218,7 @@ impl BridgedType {
12151218
"UnsafeMutableRawPointer".to_string()
12161219
}
12171220
}
1221+
TypePosition::ThrowingInit(_) => unimplemented!(),
12181222
_ => {
12191223
format!(
12201224
"RustVec<{}>",
@@ -1243,6 +1247,7 @@ impl BridgedType {
12431247
TypePosition::SwiftCallsRustAsyncOnCompleteReturnTy => {
12441248
shared_struct.ffi_name_string()
12451249
}
1250+
TypePosition::ThrowingInit(_) => unimplemented!(),
12461251
}
12471252
}
12481253
BridgedType::Foreign(CustomBridgedType::Shared(SharedType::Enum(shared_enum))) => {
@@ -1259,6 +1264,7 @@ impl BridgedType {
12591264
TypePosition::SwiftCallsRustAsyncOnCompleteReturnTy => {
12601265
unimplemented!()
12611266
}
1267+
TypePosition::ThrowingInit(_) => unimplemented!(),
12621268
}
12631269
}
12641270
}
@@ -1567,6 +1573,7 @@ impl BridgedType {
15671573
TypePosition::SwiftCallsRustAsyncOnCompleteReturnTy => {
15681574
unimplemented!()
15691575
}
1576+
TypePosition::ThrowingInit(_) => unimplemented!(),
15701577
},
15711578
PointerKind::Mut => expression.to_string(),
15721579
},
@@ -1660,6 +1667,7 @@ impl BridgedType {
16601667
TypePosition::SwiftCallsRustAsyncOnCompleteReturnTy => {
16611668
unimplemented!()
16621669
}
1670+
TypePosition::ThrowingInit(_) => unimplemented!(),
16631671
},
16641672
},
16651673
StdLibType::Str => match type_pos {
@@ -1677,6 +1685,7 @@ impl BridgedType {
16771685
TypePosition::SwiftCallsRustAsyncOnCompleteReturnTy => {
16781686
unimplemented!()
16791687
}
1688+
TypePosition::ThrowingInit(_) => unimplemented!(),
16801689
},
16811690
StdLibType::Vec(_) => {
16821691
format!(

‎crates/swift-bridge-ir/src/bridged_type/bridgeable_result.rs

+13
Original file line numberDiff line numberDiff line change
@@ -1,4 +1,5 @@
11
use crate::bridged_type::{BridgeableType, BridgedType, CFfiStruct, TypePosition};
2+
use crate::parse::HostLang;
23
use crate::{TypeDeclarations, SWIFT_BRIDGE_PREFIX};
34
use proc_macro2::{Span, TokenStream};
45
use quote::{format_ident, quote, quote_spanned};
@@ -207,6 +208,7 @@ impl BuiltInResult {
207208
}
208209
"__private__ResultPtrAndPtr".to_string()
209210
}
211+
TypePosition::ThrowingInit(_) => todo!(),
210212
}
211213
}
212214

@@ -253,6 +255,17 @@ impl BuiltInResult {
253255
),
254256
TypePosition::SharedStructField => todo!(),
255257
TypePosition::SwiftCallsRustAsyncOnCompleteReturnTy => todo!(),
258+
TypePosition::ThrowingInit(lang) => {
259+
match lang {
260+
HostLang::Rust => format!(
261+
"let val = {expression}; if val.tag == {c_ok_name} {{ self.init(ptr: val.payload.ok) }} else {{ throw {err_swift_type} }}",
262+
expression = expression,
263+
c_ok_name = c_ok_name,
264+
err_swift_type = err_swift_type
265+
),
266+
HostLang::Swift => todo!(),
267+
}
268+
}
256269
};
257270
}
258271

‎crates/swift-bridge-ir/src/bridged_type/bridgeable_string.rs

+4
Original file line numberDiff line numberDiff line change
@@ -76,6 +76,7 @@ impl BridgeableType for BridgedString {
7676
TypePosition::SwiftCallsRustAsyncOnCompleteReturnTy => {
7777
"UnsafeMutableRawPointer?".to_string()
7878
}
79+
TypePosition::ThrowingInit(_) => todo!(),
7980
}
8081
}
8182

@@ -130,6 +131,7 @@ impl BridgeableType for BridgedString {
130131
TypePosition::SwiftCallsRustAsyncOnCompleteReturnTy => {
131132
todo!()
132133
}
134+
TypePosition::ThrowingInit(_) => todo!(),
133135
}
134136
}
135137

@@ -205,6 +207,7 @@ impl BridgeableType for BridgedString {
205207
TypePosition::SwiftCallsRustAsyncOnCompleteReturnTy => {
206208
unimplemented!()
207209
}
210+
TypePosition::ThrowingInit(_) => todo!(),
208211
}
209212
}
210213

@@ -250,6 +253,7 @@ impl BridgeableType for BridgedString {
250253
TypePosition::SwiftCallsRustAsyncOnCompleteReturnTy => {
251254
format!("RustString(ptr: {}!)", expression)
252255
}
256+
TypePosition::ThrowingInit(_) => todo!(),
253257
}
254258
}
255259

‎crates/swift-bridge-ir/src/bridged_type/bridged_opaque_type.rs

+4
Original file line numberDiff line numberDiff line change
@@ -129,6 +129,7 @@ impl BridgeableType for OpaqueForeignType {
129129
TypePosition::SwiftCallsRustAsyncOnCompleteReturnTy => {
130130
unimplemented!()
131131
}
132+
TypePosition::ThrowingInit(_) => unimplemented!(),
132133
}
133134
} else {
134135
match type_pos {
@@ -146,6 +147,7 @@ impl BridgeableType for OpaqueForeignType {
146147
TypePosition::SwiftCallsRustAsyncOnCompleteReturnTy => {
147148
unimplemented!()
148149
}
150+
TypePosition::ThrowingInit(_) => unimplemented!(),
149151
}
150152
}
151153
}
@@ -396,6 +398,7 @@ impl BridgeableType for OpaqueForeignType {
396398
TypePosition::SwiftCallsRustAsyncOnCompleteReturnTy => {
397399
unimplemented!()
398400
}
401+
TypePosition::ThrowingInit(_) => unimplemented!(),
399402
}
400403
}
401404
} else {
@@ -420,6 +423,7 @@ impl BridgeableType for OpaqueForeignType {
420423
TypePosition::SwiftCallsRustAsyncOnCompleteReturnTy => {
421424
unimplemented!()
422425
}
426+
TypePosition::ThrowingInit(_) => unimplemented!(),
423427
}
424428
}
425429
}

‎crates/swift-bridge-ir/src/bridged_type/bridged_option.rs

+2
Original file line numberDiff line numberDiff line change
@@ -324,6 +324,7 @@ impl BridgedOption {
324324
TypePosition::SwiftCallsRustAsyncOnCompleteReturnTy => {
325325
todo!()
326326
}
327+
TypePosition::ThrowingInit(_) => todo!(),
327328
},
328329
StdLibType::Vec(_) => {
329330
format!(
@@ -397,6 +398,7 @@ impl BridgedOption {
397398
TypePosition::SwiftCallsRustAsyncOnCompleteReturnTy => {
398399
unimplemented!()
399400
}
401+
TypePosition::ThrowingInit(_) => unimplemented!(),
400402
}
401403
}
402404

‎crates/swift-bridge-ir/src/bridged_type/built_in_tuple.rs

+2
Original file line numberDiff line numberDiff line change
@@ -135,6 +135,7 @@ impl BridgeableType for BuiltInTuple {
135135
}
136136
TypePosition::SharedStructField => todo!(),
137137
TypePosition::SwiftCallsRustAsyncOnCompleteReturnTy => todo!(),
138+
TypePosition::ThrowingInit(_) => todo!(),
138139
}
139140
}
140141

@@ -227,6 +228,7 @@ impl BridgeableType for BuiltInTuple {
227228
}
228229
TypePosition::SharedStructField => todo!(),
229230
TypePosition::SwiftCallsRustAsyncOnCompleteReturnTy => todo!(),
231+
TypePosition::ThrowingInit(_) => todo!(),
230232
}
231233
}
232234

‎crates/swift-bridge-ir/src/codegen/codegen_tests/opaque_rust_type_codegen_tests.rs

+79
Original file line numberDiff line numberDiff line change
@@ -527,3 +527,82 @@ void* __swift_bridge__$Foo$new(void);
527527
.test();
528528
}
529529
}
530+
531+
/// Verify that we can create a Swift class with a throwing init.
532+
mod extern_rust_class_with_throwing_init {
533+
use super::*;
534+
535+
fn bridge_module_tokens() -> TokenStream {
536+
quote! {
537+
mod foo {
538+
enum SomeErrEnum {
539+
Variant1,
540+
Variant2,
541+
}
542+
extern "Rust" {
543+
type Foo;
544+
545+
#[swift_bridge(init)]
546+
fn new() -> Result<Foo, SomeErrEnum>;
547+
}
548+
}
549+
}
550+
}
551+
552+
fn expected_rust_tokens() -> ExpectedRustTokens {
553+
ExpectedRustTokens::Contains(quote! {
554+
# [export_name = "__swift_bridge__$Foo$new"]
555+
pub extern "C" fn __swift_bridge__Foo_new() -> ResultFooAndSomeErrEnum{
556+
match super :: Foo :: new() {
557+
Ok(ok) => ResultFooAndSomeErrEnum::Ok(Box::into_raw(Box::new({
558+
let val: super::Foo = ok;
559+
val
560+
})) as *mut super::Foo),
561+
Err(err) => ResultFooAndSomeErrEnum::Err(err.into_ffi_repr()),
562+
}
563+
}
564+
})
565+
}
566+
567+
const EXPECTED_SWIFT: ExpectedSwiftCode = ExpectedSwiftCode::ContainsAfterTrim(
568+
r#"
569+
public class Foo: FooRefMut {
570+
var isOwned: Bool = true
571+
572+
public override init(ptr: UnsafeMutableRawPointer) {
573+
super.init(ptr: ptr)
574+
}
575+
576+
deinit {
577+
if isOwned {
578+
__swift_bridge__$Foo$_free(ptr)
579+
}
580+
}
581+
}
582+
extension Foo {
583+
public convenience init() throws {
584+
let val = __swift_bridge__$Foo$new(); if val.tag == __swift_bridge__$ResultFooAndSomeErrEnum$ResultOk { self.init(ptr: val.payload.ok) } else { throw val.payload.err.intoSwiftRepr() }
585+
}
586+
}
587+
"#,
588+
);
589+
590+
const EXPECTED_C_HEADER: ExpectedCHeader = ExpectedCHeader::ContainsAfterTrim(
591+
r#"
592+
typedef enum __swift_bridge__$ResultFooAndSomeErrEnum$Tag {__swift_bridge__$ResultFooAndSomeErrEnum$ResultOk, __swift_bridge__$ResultFooAndSomeErrEnum$ResultErr} __swift_bridge__$ResultFooAndSomeErrEnum$Tag;
593+
union __swift_bridge__$ResultFooAndSomeErrEnum$Fields {void* ok; struct __swift_bridge__$SomeErrEnum err;};
594+
typedef struct __swift_bridge__$ResultFooAndSomeErrEnum{__swift_bridge__$ResultFooAndSomeErrEnum$Tag tag; union __swift_bridge__$ResultFooAndSomeErrEnum$Fields payload;} __swift_bridge__$ResultFooAndSomeErrEnum;
595+
"#,
596+
);
597+
598+
#[test]
599+
fn extern_rust_class_with_throwing_init() {
600+
CodegenTest {
601+
bridge_module: bridge_module_tokens().into(),
602+
expected_rust_tokens: expected_rust_tokens(),
603+
expected_swift_code: EXPECTED_SWIFT,
604+
expected_c_header: EXPECTED_C_HEADER,
605+
}
606+
.test();
607+
}
608+
}

0 commit comments

Comments
 (0)