CFBinearyHeapExt.swift

import Foundation

extension NSSortDescriptor {
    // CFBinaryHeapCompareContext does not actullay retains the info field which looks like a bug
    func makeBinaryHeap() -> CFBinaryHeap {
    //    let naturalOrder = NSSortDescriptor(key: "self", ascending: true)

        var heapCb = kCFStringBinaryHeapCallBacks
        var context = CFBinaryHeapCompareContext()
        heapCb.retain = kCFTypeDictionaryKeyCallBacks.retain
        heapCb.release = kCFTypeDictionaryKeyCallBacks.release
        context.copyDescription = kCFTypeDictionaryKeyCallBacks.copyDescription
        heapCb.copyDescription = kCFTypeDictionaryKeyCallBacks.copyDescription
        do {
            autoreleasepool {
                let cf = CFBundleGetBundleWithIdentifier("com.apple.CoreFoundation" as CFString)!
                let _cfRetain = CFBundleGetFunctionPointerForName(cf, "CFRetain" as CFString)
                let _cfRelease = CFBundleGetFunctionPointerForName(cf, "CFRelease" as CFString)
                context.retain = unsafeBitCast(_cfRetain, to: CFTreeRetainCallBack.self)
                context.release = unsafeBitCast(_cfRelease, to: CFTreeReleaseCallBack.self)
            }
        }
        context.info = Unmanaged.passUnretained(self).toOpaque()
        heapCb.compare = {
            let lhs =  Unmanaged<NSObjectProtocol>.fromOpaque($0!).takeUnretainedValue()
            let rhs = Unmanaged<NSObjectProtocol>.fromOpaque($1!).takeUnretainedValue()
            let descriptor = Unmanaged<NSSortDescriptor>.fromOpaque($2!).takeUnretainedValue()
            return .init(rawValue: descriptor.compare(lhs, to: rhs).rawValue)!

        }
        return CFBinaryHeapCreate(nil, 0, &heapCb, &context)!
    }
    // attach CFAllocator so that it retains the info
    func makeBinaryHeap2() -> CFBinaryHeap {
    //    let naturalOrder = NSSortDescriptor(key: "self", ascending: true)
        var allocatorContext = CFAllocatorContext()
        allocatorContext.info = Unmanaged.passUnretained(self).toOpaque()
        var heapCb = kCFStringBinaryHeapCallBacks
        var context = CFBinaryHeapCompareContext()
        heapCb.retain = kCFTypeDictionaryKeyCallBacks.retain
        heapCb.release = kCFTypeDictionaryKeyCallBacks.release
        context.copyDescription = kCFTypeDictionaryKeyCallBacks.copyDescription
        heapCb.copyDescription = kCFTypeDictionaryKeyCallBacks.copyDescription
        do {
            autoreleasepool {
                
                let cf = CFBundleGetBundleWithIdentifier("com.apple.CoreFoundation" as CFString)!
                let _cfRetain = CFBundleGetFunctionPointerForName(cf, "CFRetain" as CFString)
                let _cfRelease = CFBundleGetFunctionPointerForName(cf, "CFRelease" as CFString)
                context.retain = unsafeBitCast(_cfRetain, to: CFTreeRetainCallBack.self)
                context.release = unsafeBitCast(_cfRelease, to: CFTreeReleaseCallBack.self)
                allocatorContext.retain = context.retain
                allocatorContext.release = context.release
                allocatorContext.copyDescription = context.copyDescription

            }
        }
        context.info = Unmanaged.passUnretained(self).toOpaque()
        allocatorContext.preferredSize = {
            let _ = $2
            return CFAllocatorGetPreferredSizeForSize(nil, $0, $1)
        }
        allocatorContext.reallocate = {
            let _ = $3
            return CFAllocatorReallocate(nil, $0, $1, $2)
        }
        allocatorContext.allocate = {
            let _ = $2
            return CFAllocatorAllocate(nil, $0, $1)
        }
        allocatorContext.deallocate = {
            let _ = $1
            return CFAllocatorDeallocate(nil, $0)
        }
        let allocator = CFAllocatorCreate(nil, &allocatorContext).takeRetainedValue()
        heapCb.compare = {
            let lhs =  Unmanaged<NSObjectProtocol>.fromOpaque($0!).takeUnretainedValue()
            let rhs = Unmanaged<NSObjectProtocol>.fromOpaque($1!).takeUnretainedValue()
            let descriptor = Unmanaged<NSSortDescriptor>.fromOpaque($2!).takeUnretainedValue()
            return .init(rawValue: descriptor.compare(lhs, to: rhs).rawValue)!

        }
        return CFBinaryHeapCreate(allocator, 0, &heapCb, &context)!
    }
    
}