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Merged
merged 2 commits into from
Nov 14, 2025
Merged

BridgeJS: Swift closure support #463

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3d17fda
BridgeJS: Swift closure support
krodak Oct 24, 2025
d628d2d
BridgeJS: Closure support review comments
krodak Nov 14, 2025
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BridgeJS: Closure support review comments
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@krodak
krodak committed Nov 14, 2025
commit d628d2d627b78a3d90813089215b193eef366a32
23 changes: 7 additions & 16 deletions Plugins/BridgeJS/Sources/BridgeJSCore/ExportSwift.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -28,7 +28,7 @@ public class ExportSwift {
private var exportedProtocolNameByKey: [String: String] = [:]
private var typeDeclResolver: TypeDeclResolver = TypeDeclResolver()
private let enumCodegen: EnumCodegen = EnumCodegen()
private lazy var closureCodegen = ClosureCodegen(moduleName: moduleName)
private let closureCodegen = ClosureCodegen()

public init(progress: ProgressReporting, moduleName: String) {
self.progress = progress
Expand Down Expand Up @@ -1354,6 +1354,7 @@ public class ExportSwift {
ClosureSignature(
parameters: parameters,
returnType: returnType,
moduleName: moduleName,
isAsync: isAsync,
isThrows: isThrows
)
Expand Down Expand Up @@ -1477,7 +1478,6 @@ public class ExportSwift {
}
decls.append(Self.prelude)

// Collect all unique closure signatures
var closureSignatures: Set<ClosureSignature> = []
for function in exportedFunctions {
collectClosureSignatures(from: function.parameters, into: &closureSignatures)
Expand Down Expand Up @@ -1817,20 +1817,14 @@ public class ExportSwift {
}

private struct ClosureCodegen {
let moduleName: String

func generateOptionalParameterLowering(signature: ClosureSignature) throws -> String {
var lines: [String] = []

for (index, paramType) in signature.parameters.enumerated() {
guard case .optional(let wrappedType) = paramType else {
continue
}

let paramName = "param\(index)"

// Use bridgeJSLowerParameterWithRetain for heap objects in escaping closures
// to ensure proper ownership transfer
if case .swiftHeapObject = wrappedType {
lines.append(
"let (\(paramName)IsSome, \(paramName)Value) = \(paramName).bridgeJSLowerParameterWithRetain()"
Expand Down Expand Up @@ -1859,7 +1853,7 @@ public class ExportSwift {
let closureType = "(\(closureParams))\(swiftEffects) -> \(swiftReturnType)"

var invokeParams: [(name: String, type: String)] = [("_", "Int32")]
var invokeCallArgs: [String] = ["owner.callbackId"]
var invokeCallArgs: [String] = ["callback.bridgeJSLowerParameter()"]

for (index, paramType) in signature.parameters.enumerated() {
let paramName = "param\(index)"
Expand Down Expand Up @@ -1920,7 +1914,7 @@ public class ExportSwift {
"""
}

let externName = "invoke_js_callback_\(mangledName.lowercased())"
let externName = "invoke_js_callback_\(signature.moduleName)_\(mangledName)"
let optionalLoweringCode = try generateOptionalParameterLowering(signature: signature)

return """
Expand All @@ -1938,8 +1932,8 @@ public class ExportSwift {
}

static func bridgeJSLift(_ callbackId: Int32) -> \(raw: closureType) {
let owner = _JSCallbackOwner(callbackId: callbackId)
return { [owner] \(raw: signature.parameters.indices.map { "param\($0)" }.joined(separator: ", ")) in
let callback = JSObject.bridgeJSLiftParameter(callbackId)
return { [callback] \(raw: signature.parameters.indices.map { "param\($0)" }.joined(separator: ", ")) in
#if arch(wasm32)
@_extern(wasm, module: "bjs", name: "\(raw: externName)")
func _invoke(\(raw: invokeSignature)) -> \(raw: invokeReturnType)
Expand All @@ -1955,7 +1949,7 @@ public class ExportSwift {

func renderClosureInvokeHandler(signature: ClosureSignature) throws -> DeclSyntax {
let boxClassName = "_BJS_ClosureBox_\(signature.mangleName)"
let abiName = "invoke_swift_closure_\(signature.mangleName.lowercased())"
let abiName = "invoke_swift_closure_\(signature.moduleName)_\(signature.mangleName)"

var abiParams: [(name: String, type: String)] = [("boxPtr", "UnsafeMutableRawPointer")]
var liftedParams: [String] = []
Expand Down Expand Up @@ -2471,14 +2465,12 @@ public class ExportSwift {
return decls
}

/// Collects all closure signatures from function parameters
private func collectClosureSignatures(from parameters: [Parameter], into signatures: inout Set<ClosureSignature>) {
for param in parameters {
collectClosureSignatures(from: param.type, into: &signatures)
}
}

/// Collects all closure signatures from a bridge type
private func collectClosureSignatures(from type: BridgeType, into signatures: inout Set<ClosureSignature>) {
switch type {
case .closure(let signature):
Expand Down Expand Up @@ -2933,7 +2925,6 @@ extension BridgeType {
case .namespaceEnum:
throw BridgeJSCoreError("Namespace enums are not supported to pass as parameters")
case .closure:
// Closures are returned as UnsafeMutableRawPointer (box pointer)
return .swiftHeapObject
}
}
Expand Down
57 changes: 16 additions & 41 deletions Plugins/BridgeJS/Sources/BridgeJSLink/BridgeJSLink.swift
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Original file line number Diff line number Diff line change
Expand Up @@ -696,53 +696,29 @@ struct BridgeJSLink {
}
printer.write("}")

var closureSignatures: Set<ClosureSignature> = []
for skeleton in exportedSkeletons {
var closureSignatures: Set<ClosureSignature> = []
collectClosureSignatures(from: skeleton, into: &closureSignatures)
}

var classToModule: [String: String] = [:]
for skeleton in exportedSkeletons {
for klass in skeleton.classes {
classToModule[klass.name] = skeleton.moduleName
}
}
guard !closureSignatures.isEmpty else { continue }

for signature in closureSignatures.sorted(by: { $0.mangleName < $1.mangleName }) {
let invokeFuncName = "invoke_js_callback_\(signature.mangleName.lowercased())"
printer.write(
lines: generateInvokeFunction(
signature: signature,
functionName: invokeFuncName,
classToModule: classToModule
for signature in closureSignatures.sorted(by: { $0.mangleName < $1.mangleName }) {
let invokeFuncName = "invoke_js_callback_\(skeleton.moduleName)_\(signature.mangleName)"
printer.write(
lines: generateInvokeFunction(
signature: signature,
functionName: invokeFuncName
)
)
)

let lowerFuncName = "lower_closure_\(signature.mangleName.lowercased())"
printer.write(
lines: generateLowerClosureFunction(
signature: signature,
functionName: lowerFuncName
)
)
}

if !closureSignatures.isEmpty {
printer.nextLine()
printer.write("bjs[\"release_js_callback\"] = function(id) {")
printer.indent {
printer.write("\(JSGlueVariableScope.reservedSwift).memory.release(id);")
}
printer.write("};")

printer.nextLine()
printer.write("bjs[\"release_swift_closure\"] = function(boxPtr) {")
printer.indent {
let lowerFuncName = "lower_closure_\(skeleton.moduleName)_\(signature.mangleName)"
printer.write(
"\(JSGlueVariableScope.reservedInstance).exports._release_swift_closure(boxPtr);"
lines: generateLowerClosureFunction(
signature: signature,
functionName: lowerFuncName
)
)
}
printer.write("};")
}
}
}
Expand Down Expand Up @@ -793,8 +769,7 @@ struct BridgeJSLink {

private func generateInvokeFunction(
signature: ClosureSignature,
functionName: String,
classToModule: [String: String]
functionName: String
) -> [String] {
let printer = CodeFragmentPrinter()
let scope = JSGlueVariableScope()
Expand Down Expand Up @@ -889,7 +864,7 @@ struct BridgeJSLink {

// Call the Swift invoke function
let invokeCall =
"\(JSGlueVariableScope.reservedInstance).exports.invoke_swift_closure_\(signature.mangleName.lowercased())(\(invokeArgs.joined(separator: ", ")))"
"\(JSGlueVariableScope.reservedInstance).exports.invoke_swift_closure_\(signature.moduleName)_\(signature.mangleName)(\(invokeArgs.joined(separator: ", ")))"

let returnFragment = try! IntrinsicJSFragment.closureLiftReturn(type: signature.returnType)
_ = returnFragment.printCode([invokeCall], scope, printer, cleanupCode)
Expand Down
11 changes: 5 additions & 6 deletions Plugins/BridgeJS/Sources/BridgeJSLink/JSGlueGen.swift
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Expand Up @@ -1298,14 +1298,13 @@ struct IntrinsicJSFragment: Sendable {
let base = fullName.components(separatedBy: ".").last ?? fullName
return .associatedEnumLiftReturn(enumBase: base)
case .closure(let signature):
let lowerFuncName = "lower_closure_\(signature.moduleName)_\(signature.mangleName)"
return IntrinsicJSFragment(
parameters: ["closurePtr"],
parameters: ["boxPtr"],
printCode: { arguments, scope, printer, cleanupCode in
let closurePtr = arguments[0]
let lowerFuncName = "lower_closure_\(signature.mangleName.lowercased())"
let resultVar = scope.variable("closure")
printer.write("const \(resultVar) = bjs[\"\(lowerFuncName)\"](\(closurePtr));")
return [resultVar]
let boxPtr = arguments[0]
printer.write("return bjs[\"\(lowerFuncName)\"](\(boxPtr));")
return []
}
)
case .namespaceEnum(let string):
Expand Down
59 changes: 38 additions & 21 deletions Plugins/BridgeJS/Sources/BridgeJSSkeleton/BridgeJSSkeleton.swift
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Expand Up @@ -76,22 +76,34 @@ public enum BridgeContext: Sendable {
public struct ClosureSignature: Codable, Equatable, Hashable, Sendable {
public let parameters: [BridgeType]
public let returnType: BridgeType
/// Simplified Swift ABI-style mangling with module prefix
// <moduleLength><module> + params + _ + return
// Examples:
// - 4MainSS_Si (Main module, String->Int)
// - 6MyAppSiSi_y (MyApp module, Int,Int->Void)
public let mangleName: String
public let isAsync: Bool
public let isThrows: Bool
public let mangleName: String
public let moduleName: String

public init(parameters: [BridgeType], returnType: BridgeType, isAsync: Bool = false, isThrows: Bool = false) {
public init(
parameters: [BridgeType],
returnType: BridgeType,
moduleName: String,
isAsync: Bool = false,
isThrows: Bool = false
) {
self.parameters = parameters
self.returnType = returnType
self.moduleName = moduleName
self.isAsync = isAsync
self.isThrows = isThrows

let paramPart =
parameters.isEmpty
? "Void"
: parameters.map { $0.mangleTypeName }.joined(separator: "_")
let returnPart = returnType.mangleTypeName
self.mangleName = "\(paramPart)_To_\(returnPart)"
? "y"
: parameters.map { $0.mangleTypeName }.joined()
let signaturePart = "\(paramPart)_\(returnType.mangleTypeName)"
self.mangleName = "\(moduleName.count)\(moduleName)\(signaturePart)"
}
}

Expand Down Expand Up @@ -602,31 +614,36 @@ extension BridgeType {
return false
}

/// Generates a mangled name for use in closure type names
/// Examples: "String", "Int", "MyClass", "Bool"
/// Simplified Swift ABI-style mangled name
/// https://github.com/swiftlang/swift/blob/main/docs/ABI/Mangling.rst#types
public var mangleTypeName: String {
switch self {
case .int: return "Int"
case .float: return "Float"
case .double: return "Double"
case .string: return "String"
case .bool: return "Bool"
case .void: return "Void"
case .int: return "Si"
case .float: return "Sf"
case .double: return "Sd"
case .string: return "SS"
case .bool: return "Sb"
case .void: return "y"
case .jsObject(let name):
return name ?? "JSObject"
let typeName = name ?? "JSObject"
return "\(typeName.count)\(typeName)C"
case .swiftHeapObject(let name):
return name
return "\(name.count)\(name)C"
case .optional(let wrapped):
return "Optional\(wrapped.mangleTypeName)"
return "Sq\(wrapped.mangleTypeName)"
case .caseEnum(let name),
.rawValueEnum(let name, _),
.associatedValueEnum(let name),
.namespaceEnum(let name):
return name
return "\(name.count)\(name)O"
case .swiftProtocol(let name):
return name
return "\(name.count)\(name)P"
case .closure(let signature):
return "Closure_\(signature.mangleName)"
let params =
signature.parameters.isEmpty
? "y"
: signature.parameters.map { $0.mangleTypeName }.joined()
return "K\(params)_\(signature.returnType.mangleTypeName)"
}
}

Expand Down
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