CoreStore/Sources/Internal/NSManagedObject+Logging.swift

//
//  NSManagedObject+Logging.swift
//  CoreStore
//
//  Copyright © 2017 John Rommel Estropia
//
//  Permission is hereby granted, free of charge, to any person obtaining a copy
//  of this software and associated documentation files (the "Software"), to deal
//  in the Software without restriction, including without limitation the rights
//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
//  copies of the Software, and to permit persons to whom the Software is
//  furnished to do so, subject to the following conditions:
//
//  The above copyright notice and this permission notice shall be included in all
//  copies or substantial portions of the Software.
//
//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
//  SOFTWARE.
//

import Foundation
import CoreData


// MARK: - NSManagedObject

internal extension NSManagedObject {
    
    @nonobjc
    internal static func cs_swizzleMethodsForLogging() {
        
        struct Static {
            
            static let isSwizzled = Static.swizzle()
            
            private static func swizzle() -> Bool {
                
                NSManagedObject.cs_swizzle(
                    original: #selector(NSManagedObject.willAccessValue(forKey:)),
                    proxy: #selector(NSManagedObject.cs_willAccessValue(forKey:))
                )
                NSManagedObject.cs_swizzle(
                    original: #selector(NSManagedObject.willChangeValue(forKey:)),
                    proxy: #selector(NSManagedObject.cs_willChangeValue(forKey:))
                )
                NSManagedObject.cs_swizzle(
                    original: #selector(NSManagedObject.willChangeValue(forKey:withSetMutation:using:)),
                    proxy: #selector(NSManagedObject.cs_willChangeValue(forKey:withSetMutation:using:))
                )
                return true
            }
        }
        assert(Static.isSwizzled)
    }
    
    @nonobjc
    private static func cs_swizzle(original originalSelector: Selector, proxy swizzledSelector: Selector) {
        
        let originalMethod = class_getInstanceMethod(NSManagedObject.self, originalSelector)
        let swizzledMethod = class_getInstanceMethod(NSManagedObject.self, swizzledSelector)
        let didAddMethod = class_addMethod(
            NSManagedObject.self,
            originalSelector,
            method_getImplementation(swizzledMethod),
            method_getTypeEncoding(swizzledMethod)
        )
        if didAddMethod {
            
            class_replaceMethod(
                NSManagedObject.self,
                swizzledSelector,
                method_getImplementation(originalMethod),
                method_getTypeEncoding(originalMethod)
            )
        }
        else {
            
            method_exchangeImplementations(originalMethod, swizzledMethod)
        }
    }
    
    private dynamic func cs_willAccessValue(forKey key: String?) {
        
        self.cs_willAccessValue(forKey: key)
        
        guard CoreStore.logger.enableObjectConcurrencyDebugging else {
            
            return
        }
        
        guard let context = self.managedObjectContext else {
            
            CoreStore.log(
                .warning,
                message: "Attempted to access the \"\(key ?? "")\" key of an object of type \(cs_typeName(self)) after has been deleted from its \(cs_typeName(NSManagedObjectContext.self))."
            )
            return
        }
        if context.isTransactionContext {
            
            guard let transaction = context.parentTransaction else {
                
                CoreStore.log(
                    .warning,
                    message: "Attempted to access the \"\(key ?? "")\" key of an object of type \(cs_typeName(self)) after has been deleted from its transaction."
                )
                return
            }
            CoreStore.assert(
                transaction.isRunningInAllowedQueue(),
                "Attempted to access the \"\(key ?? "")\" key of an object of type \(cs_typeName(self)) outside its transaction's designated queue."
            )
            return
        }
        if context.isDataStackContext {
            
            guard context.parentStack != nil else {
                
                CoreStore.log(
                    .warning,
                    message: "Attempted to access the \"\(key ?? "")\" key of an object of type \(cs_typeName(self)) after has been deleted from its \(cs_typeName(DataStack.self)).")
                return
            }
            CoreStore.assert(
                Thread.isMainThread,
                "Attempted to access the \"\(key ?? "")\" key of an object of type \(cs_typeName(self)) outside the main thread."
            )
            return
        }
    }
    
    private dynamic func cs_willChangeValue(forKey key: String?) {
        
        self.cs_willChangeValue(forKey: key)
        
        guard CoreStore.logger.enableObjectConcurrencyDebugging else {
            
            return
        }
        
        guard let context = self.managedObjectContext else {
            
            CoreStore.log(
                .warning,
                message: "Attempted to change the \"\(key ?? "")\" of an object of type \(cs_typeName(self)) after has been deleted from its \(cs_typeName(NSManagedObjectContext.self))."
            )
            return
        }
        if context.isTransactionContext {
            
            guard let transaction = context.parentTransaction else {
                
                CoreStore.log(
                    .warning,
                    message: "Attempted to change the \"\(key ?? "")\" of an object of type \(cs_typeName(self)) after has been deleted from its transaction."
                )
                return
            }
            CoreStore.assert(
                transaction.isRunningInAllowedQueue(),
                "Attempted to change the \"\(key ?? "")\" of an object of type \(cs_typeName(self)) outside its transaction's designated queue."
            )
            return
        }
        if context.isDataStackContext {
            
            guard context.parentStack != nil else {
                
                CoreStore.log(
                    .warning,
                    message: "Attempted to change the \"\(key ?? "")\" of an object of type \(cs_typeName(self)) after has been deleted from its \(cs_typeName(DataStack.self)).")
                return
            }
            CoreStore.assert(
                Thread.isMainThread,
                "Attempted to change the \"\(key ?? "")\" of an object of type \(cs_typeName(self)) outside the main thread."
            )
            return
        }
    }
    
    private dynamic func cs_willChangeValue(forKey inKey: String, withSetMutation inMutationKind: NSKeyValueSetMutationKind, using inObjects: Set<AnyHashable>) {
        
        self.cs_willChangeValue(
            forKey: inKey,
            withSetMutation: inMutationKind,
            using: inObjects
        )
        
        guard CoreStore.logger.enableObjectConcurrencyDebugging else {
            
            return
        }
        
        guard let context = self.managedObjectContext else {
            
            CoreStore.log(
                .warning,
                message: "Attempted to mutate the \"\(inKey)\" of an object of type \(cs_typeName(self)) after has been deleted from its \(cs_typeName(NSManagedObjectContext.self))."
            )
            return
        }
        if context.isTransactionContext {
            
            guard let transaction = context.parentTransaction else {
                
                CoreStore.log(
                    .warning,
                    message: "Attempted to mutate the \"\(inKey)\" of an object of type \(cs_typeName(self)) after has been deleted from its transaction."
                )
                return
            }
            CoreStore.assert(
                transaction.isRunningInAllowedQueue(),
                "Attempted to mutate the \"\(inKey)\" of an object of type \(cs_typeName(self)) outside its transaction's designated queue."
            )
            return
        }
        if context.isDataStackContext {
            
            guard context.parentStack != nil else {
                
                CoreStore.log(
                    .warning,
                    message: "Attempted to mutate the \"\(inKey)\" of an object of type \(cs_typeName(self)) after has been deleted from its \(cs_typeName(DataStack.self)).")
                return
            }
            CoreStore.assert(
                Thread.isMainThread,
                "Attempted to mutate the \"\(inKey)\" of an object of type \(cs_typeName(self)) outside the main thread."
            )
            return
        }
    }
}