diff options
Diffstat (limited to 'third_party/rust/uniffi_bindgen/src/bindings/swift/templates/CallbackInterfaceTemplate.swift')
-rw-r--r-- | third_party/rust/uniffi_bindgen/src/bindings/swift/templates/CallbackInterfaceTemplate.swift | 150 |
1 files changed, 150 insertions, 0 deletions
diff --git a/third_party/rust/uniffi_bindgen/src/bindings/swift/templates/CallbackInterfaceTemplate.swift b/third_party/rust/uniffi_bindgen/src/bindings/swift/templates/CallbackInterfaceTemplate.swift new file mode 100644 index 0000000000..aec8ded930 --- /dev/null +++ b/third_party/rust/uniffi_bindgen/src/bindings/swift/templates/CallbackInterfaceTemplate.swift @@ -0,0 +1,150 @@ +{%- let cbi = ci|get_callback_interface_definition(name) %} +{%- let foreign_callback = format!("foreignCallback{}", canonical_type_name) %} +{%- if self.include_once_check("CallbackInterfaceRuntime.swift") %}{%- include "CallbackInterfaceRuntime.swift" %}{%- endif %} + +// Declaration and FfiConverters for {{ type_name }} Callback Interface + +public protocol {{ type_name }} : AnyObject { + {% for meth in cbi.methods() -%} + func {{ meth.name()|fn_name }}({% call swift::arg_list_protocol(meth) %}) {% call swift::throws(meth) -%} + {%- match meth.return_type() -%} + {%- when Some with (return_type) %} -> {{ return_type|type_name -}} + {%- else -%} + {%- endmatch %} + {% endfor %} +} + +// The ForeignCallback that is passed to Rust. +fileprivate let {{ foreign_callback }} : ForeignCallback = + { (handle: UniFFICallbackHandle, method: Int32, argsData: UnsafePointer<UInt8>, argsLen: Int32, out_buf: UnsafeMutablePointer<RustBuffer>) -> Int32 in + {% for meth in cbi.methods() -%} + {%- let method_name = format!("invoke_{}", meth.name())|fn_name %} + + func {{ method_name }}(_ swiftCallbackInterface: {{ type_name }}, _ argsData: UnsafePointer<UInt8>, _ argsLen: Int32, _ out_buf: UnsafeMutablePointer<RustBuffer>) throws -> Int32 { + {%- if meth.arguments().len() > 0 %} + var reader = createReader(data: Data(bytes: argsData, count: Int(argsLen))) + {%- endif %} + + {%- match meth.return_type() %} + {%- when Some(return_type) %} + func makeCall() throws -> Int32 { + let result = {% if meth.throws() %} try{% endif %} swiftCallbackInterface.{{ meth.name()|fn_name }}( + {% for arg in meth.arguments() -%} + {% if !config.omit_argument_labels() %}{{ arg.name()|var_name }}: {% endif %} try {{ arg|read_fn }}(from: &reader) + {%- if !loop.last %}, {% endif %} + {% endfor -%} + ) + var writer = [UInt8]() + {{ return_type|write_fn }}(result, into: &writer) + out_buf.pointee = RustBuffer(bytes: writer) + return UNIFFI_CALLBACK_SUCCESS + } + {%- when None %} + func makeCall() throws -> Int32 { + try swiftCallbackInterface.{{ meth.name()|fn_name }}( + {% for arg in meth.arguments() -%} + {% if !config.omit_argument_labels() %}{{ arg.name()|var_name }}: {% endif %} try {{ arg|read_fn }}(from: &reader) + {%- if !loop.last %}, {% endif %} + {% endfor -%} + ) + return UNIFFI_CALLBACK_SUCCESS + } + {%- endmatch %} + + {%- match meth.throws_type() %} + {%- when None %} + return try makeCall() + {%- when Some(error_type) %} + do { + return try makeCall() + } catch let error as {{ error_type|type_name }} { + out_buf.pointee = {{ error_type|lower_fn }}(error) + return UNIFFI_CALLBACK_ERROR + } + {%- endmatch %} + } + {%- endfor %} + + + switch method { + case IDX_CALLBACK_FREE: + {{ ffi_converter_name }}.drop(handle: handle) + // Sucessful return + // See docs of ForeignCallback in `uniffi_core/src/ffi/foreigncallbacks.rs` + return UNIFFI_CALLBACK_SUCCESS + {% for meth in cbi.methods() -%} + {% let method_name = format!("invoke_{}", meth.name())|fn_name -%} + case {{ loop.index }}: + let cb: {{ cbi|type_name }} + do { + cb = try {{ ffi_converter_name }}.lift(handle) + } catch { + out_buf.pointee = {{ Type::String.borrow()|lower_fn }}("{{ cbi.name() }}: Invalid handle") + return UNIFFI_CALLBACK_UNEXPECTED_ERROR + } + do { + return try {{ method_name }}(cb, argsData, argsLen, out_buf) + } catch let error { + out_buf.pointee = {{ Type::String.borrow()|lower_fn }}(String(describing: error)) + return UNIFFI_CALLBACK_UNEXPECTED_ERROR + } + {% endfor %} + // This should never happen, because an out of bounds method index won't + // ever be used. Once we can catch errors, we should return an InternalError. + // https://github.com/mozilla/uniffi-rs/issues/351 + default: + // An unexpected error happened. + // See docs of ForeignCallback in `uniffi_core/src/ffi/foreigncallbacks.rs` + return UNIFFI_CALLBACK_UNEXPECTED_ERROR + } +} + +// FfiConverter protocol for callback interfaces +fileprivate struct {{ ffi_converter_name }} { + private static let initCallbackOnce: () = { + // Swift ensures this initializer code will once run once, even when accessed by multiple threads. + try! rustCall { (err: UnsafeMutablePointer<RustCallStatus>) in + {{ cbi.ffi_init_callback().name() }}({{ foreign_callback }}, err) + } + }() + + private static func ensureCallbackinitialized() { + _ = initCallbackOnce + } + + static func drop(handle: UniFFICallbackHandle) { + handleMap.remove(handle: handle) + } + + private static var handleMap = UniFFICallbackHandleMap<{{ type_name }}>() +} + +extension {{ ffi_converter_name }} : FfiConverter { + typealias SwiftType = {{ type_name }} + // We can use Handle as the FfiType because it's a typealias to UInt64 + typealias FfiType = UniFFICallbackHandle + + public static func lift(_ handle: UniFFICallbackHandle) throws -> SwiftType { + ensureCallbackinitialized(); + guard let callback = handleMap.get(handle: handle) else { + throw UniffiInternalError.unexpectedStaleHandle + } + return callback + } + + public static func read(from buf: inout (data: Data, offset: Data.Index)) throws -> SwiftType { + ensureCallbackinitialized(); + let handle: UniFFICallbackHandle = try readInt(&buf) + return try lift(handle) + } + + public static func lower(_ v: SwiftType) -> UniFFICallbackHandle { + ensureCallbackinitialized(); + return handleMap.insert(obj: v) + } + + public static func write(_ v: SwiftType, into buf: inout [UInt8]) { + ensureCallbackinitialized(); + writeInt(&buf, lower(v)) + } +} |