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| 1 | +// Idiomatic Swift wrapper over the timer library's native C ABI. |
| 2 | +// |
| 3 | +// Each call is dispatched on the library's background FFI thread and its result |
| 4 | +// arrives on a callback; we bridge that to a synchronous Swift API with a |
| 5 | +// semaphore. A struct return (EchoResponse) is read out of the typed C-POD |
| 6 | +// inside the callback — it is valid only for the callback's lifetime. |
| 7 | +import CMyTimer |
| 8 | +import Foundation |
| 9 | + |
| 10 | +public enum TimerError: Error, CustomStringConvertible { |
| 11 | + case failed(String) |
| 12 | + public var description: String { |
| 13 | + switch self { case let .failed(m): return m } |
| 14 | + } |
| 15 | +} |
| 16 | + |
| 17 | +public struct EchoResult: Equatable { |
| 18 | + public let echoed: String |
| 19 | + public let timerName: String |
| 20 | +} |
| 21 | + |
| 22 | +public final class TimerNode { |
| 23 | + private let ctx: UnsafeMutableRawPointer |
| 24 | + |
| 25 | + /// Creates the timer context (TimerConfig by value). |
| 26 | + public init(name: String) throws { |
| 27 | + let box = Box() |
| 28 | + let ud = Unmanaged.passUnretained(box).toOpaque() |
| 29 | + let cName = strdup(name) |
| 30 | + defer { free(cName) } |
| 31 | + var cfg = TimerConfig() |
| 32 | + cfg.name = UnsafePointer(cName) |
| 33 | + guard let c = my_timer_create(cfg, ackCallback, ud) else { |
| 34 | + throw TimerError.failed("create returned null") |
| 35 | + } |
| 36 | + box.sem.wait() |
| 37 | + guard box.ret == 0 else { throw TimerError.failed(box.text) } |
| 38 | + ctx = c |
| 39 | + } |
| 40 | + |
| 41 | + /// String-returning call: the raw bytes are the version string. |
| 42 | + public func version() throws -> String { |
| 43 | + let box = Box() |
| 44 | + let ud = Unmanaged.passUnretained(box).toOpaque() |
| 45 | + guard my_timer_version(ctx, stringCallback, ud) == 0 else { |
| 46 | + throw TimerError.failed("version dispatch failed") |
| 47 | + } |
| 48 | + box.sem.wait() |
| 49 | + guard box.ret == 0 else { throw TimerError.failed(box.text) } |
| 50 | + return box.text |
| 51 | + } |
| 52 | + |
| 53 | + /// Struct param in, typed struct (EchoResponse) out. |
| 54 | + public func echo(_ message: String, delayMs: Int = 0) throws -> EchoResult { |
| 55 | + let box = EchoBox() |
| 56 | + let ud = Unmanaged.passUnretained(box).toOpaque() |
| 57 | + let cMsg = strdup(message) |
| 58 | + defer { free(cMsg) } |
| 59 | + var req = EchoRequest() |
| 60 | + req.message = UnsafePointer(cMsg) |
| 61 | + req.delayMs = Int64(delayMs) |
| 62 | + guard my_timer_echo(ctx, echoCallback, ud, req) == 0 else { |
| 63 | + throw TimerError.failed("echo dispatch failed") |
| 64 | + } |
| 65 | + box.sem.wait() |
| 66 | + guard box.ret == 0 else { throw TimerError.failed(box.text) } |
| 67 | + return EchoResult(echoed: box.echoed, timerName: box.timerName) |
| 68 | + } |
| 69 | + |
| 70 | + deinit { my_timer_destroy(ctx) } |
| 71 | +} |
| 72 | + |
| 73 | +// MARK: - callback plumbing |
| 74 | +// The library calls back on its FFI thread; we keep the Box alive on the caller |
| 75 | +// stack (passUnretained) because the caller blocks on the semaphore until the |
| 76 | +// callback fires. |
| 77 | + |
| 78 | +final class Box { |
| 79 | + var ret: Int32 = -1 |
| 80 | + var text = "" |
| 81 | + let sem = DispatchSemaphore(value: 0) |
| 82 | +} |
| 83 | +final class EchoBox { |
| 84 | + var ret: Int32 = -1 |
| 85 | + var text = "" |
| 86 | + var echoed = "" |
| 87 | + var timerName = "" |
| 88 | + let sem = DispatchSemaphore(value: 0) |
| 89 | +} |
| 90 | + |
| 91 | +private func rawText(_ msg: UnsafePointer<CChar>?, _ len: Int) -> String { |
| 92 | + guard let m = msg, len > 0 else { return "" } |
| 93 | + let bytes = UnsafeRawPointer(m).assumingMemoryBound(to: UInt8.self) |
| 94 | + return String(decoding: UnsafeBufferPointer(start: bytes, count: len), as: UTF8.self) |
| 95 | +} |
| 96 | + |
| 97 | +private func ackCallback(_ ret: Int32, _ msg: UnsafePointer<CChar>?, |
| 98 | + _ len: Int, _ ud: UnsafeMutableRawPointer?) { |
| 99 | + let box = Unmanaged<Box>.fromOpaque(ud!).takeUnretainedValue() |
| 100 | + box.ret = ret |
| 101 | + if ret != 0 { box.text = rawText(msg, len) } |
| 102 | + box.sem.signal() |
| 103 | +} |
| 104 | + |
| 105 | +private func stringCallback(_ ret: Int32, _ msg: UnsafePointer<CChar>?, |
| 106 | + _ len: Int, _ ud: UnsafeMutableRawPointer?) { |
| 107 | + let box = Unmanaged<Box>.fromOpaque(ud!).takeUnretainedValue() |
| 108 | + box.ret = ret |
| 109 | + box.text = rawText(msg, len) |
| 110 | + box.sem.signal() |
| 111 | +} |
| 112 | + |
| 113 | +private func echoCallback(_ ret: Int32, _ msg: UnsafePointer<CChar>?, |
| 114 | + _ len: Int, _ ud: UnsafeMutableRawPointer?) { |
| 115 | + let box = Unmanaged<EchoBox>.fromOpaque(ud!).takeUnretainedValue() |
| 116 | + box.ret = ret |
| 117 | + if ret == 0, let m = msg { |
| 118 | + // Native ABI: msg is a const EchoResponse* (typed struct return). |
| 119 | + let resp = UnsafeRawPointer(m).assumingMemoryBound(to: EchoResponse.self) |
| 120 | + box.echoed = resp.pointee.echoed.map { String(cString: $0) } ?? "" |
| 121 | + box.timerName = resp.pointee.timerName.map { String(cString: $0) } ?? "" |
| 122 | + } else { |
| 123 | + box.text = rawText(msg, len) |
| 124 | + } |
| 125 | + box.sem.signal() |
| 126 | +} |
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