Commented out Interpose+Watcher.swift

Author: lukaskubanek

Sources/InterposeKit/Interpose+Watcher.swift

@@ -0,0 +1,108 @@
+//import Foundation
+//import MachO.dyld
+//
+//// MARK: Interpose Class Load Watcher
+//
+//extension Interpose {
+//    // Separate definitions to have more relevant calling syntax when completion is not needed.
+//
+//    /// Interpose a class once available. Class is passed via `classParts` string array.
+//    @discardableResult public class func whenAvailable(_ classParts: [String],
+//                                                       builder: @escaping (Interpose) throws -> Void) throws -> Waiter {
+//        try whenAvailable(classParts, builder: builder, completion: nil)
+//    }
+//
+//    /// Interpose a class once available. Class is passed via `classParts` string array, with completion handler.
+//    @discardableResult public class func whenAvailable(_ classParts: [String],
+//                                                       builder: @escaping (Interpose) throws -> Void,
+//                                                       completion: (() -> Void)? = nil) throws -> Waiter {
+//        try whenAvailable(classParts.joined(), builder: builder, completion: completion)
+//    }
+//
+//    /// Interpose a class once available. Class is passed via `className` string.
+//    @discardableResult public class func whenAvailable(_ className: String,
+//                                                       builder: @escaping (Interpose) throws -> Void) throws -> Waiter {
+//        try whenAvailable(className, builder: builder, completion: nil)
+//    }
+//
+//    /// Interpose a class once available. Class is passed via `className` string, with completion handler.
+//    @discardableResult public class func whenAvailable(_ className: String,
+//                                                       builder: @escaping (Interpose) throws -> Void,
+//                                                       completion: (() -> Void)? = nil) throws -> Waiter {
+//        try Waiter(className: className, builder: builder, completion: completion)
+//    }
+//
+//    /// Helper that stores hooks to a specific class and executes them once the class becomes available.
+//    public struct Waiter {
+//        fileprivate let className: String
+//        private var builder: ((Interpose) throws -> Void)?
+//        private var completion: (() -> Void)?
+//
+//        /// Initialize waiter object.
+//        @discardableResult init(className: String,
+//                                builder: @escaping (Interpose) throws -> Void,
+//                                completion: (() -> Void)? = nil) throws {
+//            self.className = className
+//            self.builder = builder
+//            self.completion = completion
+//
+//            // Immediately try to execute task. If not there, install waiter.
+//            if try tryExecute() == false {
+//                InterposeWatcher.append(waiter: self)
+//            }
+//        }
+//
+//        func tryExecute() throws -> Bool {
+//            guard let builder = self.builder else { return false }
+//            let interposer = Interpose()
+//            try builder(interposer)
+//            if let completion = self.completion {
+//                completion()
+//            }
+//            return true
+//        }
+//    }
+//}
+//
+//// dyld C function cannot capture class context so we pack it in a static struct.
+//private struct InterposeWatcher {
+//    // Global list of waiters; can be multiple per class
+//    private static var globalWatchers: [Interpose.Waiter] = {
+//        // Register after Swift global registers to not deadlock
+//        DispatchQueue.main.async { InterposeWatcher.installGlobalImageLoadWatcher() }
+//        return []
+//    }()
+//
+//    fileprivate static func append(waiter: Interpose.Waiter) {
+//        InterposeWatcher.globalWatcherQueue.sync {
+//            globalWatchers.append(waiter)
+//        }
+//    }
+//
+//    // Register hook when dyld loads an image
+//    private static let globalWatcherQueue = DispatchQueue(label: "com.steipete.global-image-watcher")
+//    private static func installGlobalImageLoadWatcher() {
+//        _dyld_register_func_for_add_image { _, _ in
+//            InterposeWatcher.globalWatcherQueue.sync {
+//                // this is called on the thread the image is loaded.
+//                InterposeWatcher.globalWatchers = InterposeWatcher.globalWatchers.filter { waiter -> Bool in
+//                    do {
+//                        if try waiter.tryExecute() == false {
+//                            return true // only collect if this fails because class is not there yet
+//                        } else {
+//                            Interpose.log("\(waiter.className) was successful.")
+//                        }
+//                    } catch {
+//                        Interpose.log("Error while executing task: \(error).")
+//                        // We can't bubble up the throw into the C context.
+//                        #if DEBUG
+//                        // Instead of silently eating, it's better to crash in DEBUG.
+//                        Interpose.fail("Error while executing task: \(error).")
+//                        #endif
+//                    }
+//                    return false
+//                }
+//            }
+//        }
+//    }
+//}