[AltStoreCore] Backports iOS 15+ NSManagedObjectContext.performAndWait<T>()

Simplifies returning values and throwing errors from managed object contexts.

AltStore.xcodeproj/project.pbxproj

@@ -373,6 +373,7 @@
 		D57FE84428C7DB7100216002 /* ErrorLogViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D57FE84328C7DB7100216002 /* ErrorLogViewController.swift */; };
 		D586D39B28EF58B0000E101F /* AltTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = D586D39A28EF58B0000E101F /* AltTests.swift */; };
 		D58916FE28C7C55C00E39C8B /* LoggedError.swift in Sources */ = {isa = PBXBuildFile; fileRef = D58916FD28C7C55C00E39C8B /* LoggedError.swift */; };
+		D5893F802A1419E800E767CD /* NSManagedObjectContext+Conveniences.swift in Sources */ = {isa = PBXBuildFile; fileRef = D5893F7E2A14183200E767CD /* NSManagedObjectContext+Conveniences.swift */; };
 		D58D5F2E26DFE68E00E55E38 /* LaunchAtLogin in Frameworks */ = {isa = PBXBuildFile; productRef = D58D5F2D26DFE68E00E55E38 /* LaunchAtLogin */; };
 		D59162AB29BA60A9005CBF47 /* SourceHeaderView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D59162AA29BA60A9005CBF47 /* SourceHeaderView.swift */; };
 		D59162AD29BA616A005CBF47 /* SourceHeaderView.xib in Resources */ = {isa = PBXBuildFile; fileRef = D59162AC29BA616A005CBF47 /* SourceHeaderView.xib */; };
@@ -894,6 +895,7 @@
 		D586D39828EF58B0000E101F /* AltTests.xctest */ = {isa = PBXFileReference; explicitFileType = wrapper.cfbundle; includeInIndex = 0; path = AltTests.xctest; sourceTree = BUILT_PRODUCTS_DIR; };
 		D586D39A28EF58B0000E101F /* AltTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AltTests.swift; sourceTree = "<group>"; };
 		D58916FD28C7C55C00E39C8B /* LoggedError.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LoggedError.swift; sourceTree = "<group>"; };
+		D5893F7E2A14183200E767CD /* NSManagedObjectContext+Conveniences.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "NSManagedObjectContext+Conveniences.swift"; sourceTree = "<group>"; };
 		D59162AA29BA60A9005CBF47 /* SourceHeaderView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SourceHeaderView.swift; sourceTree = "<group>"; };
 		D59162AC29BA616A005CBF47 /* SourceHeaderView.xib */ = {isa = PBXFileReference; lastKnownFileType = file.xib; path = SourceHeaderView.xib; sourceTree = "<group>"; };
 		D5927D6529DCC89000D6898E /* UINavigationBarAppearance+TintColor.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "UINavigationBarAppearance+TintColor.swift"; sourceTree = "<group>"; };
@@ -1440,6 +1442,7 @@
 				BF66EEE42501AED0007EE018 /* UserDefaults+AltStore.swift */,
 				BF6A531F246DC1B0004F59C8 /* FileManager+SharedDirectories.swift */,
 				D5F48B4729CCF21B002B52A4 /* AltStore+Async.swift */,
+				D5893F7E2A14183200E767CD /* NSManagedObjectContext+Conveniences.swift */,
 			);
 			path = Extensions;
 			sourceTree = "<group>";
@@ -2698,6 +2701,7 @@
 				BF66EEDD2501AECA007EE018 /* AppPermission.swift in Sources */,
 				D58916FE28C7C55C00E39C8B /* LoggedError.swift in Sources */,
 				BFBF331B2526762200B7B8C9 /* AltStore8ToAltStore9.xcmappingmodel in Sources */,
+				D5893F802A1419E800E767CD /* NSManagedObjectContext+Conveniences.swift in Sources */,
 				D5CA0C4E280E249E00469595 /* AltStore9ToAltStore10.xcmappingmodel in Sources */,
 				D51AD27F29356B7B00967AAA /* ALTWrappedError.m in Sources */,
 				BF989184250AACFC002ACF50 /* Date+RelativeDate.swift in Sources */,

AltStoreCore/Extensions/NSManagedObjectContext+Conveniences.swift

@@ -0,0 +1,37 @@
+//
+//  NSManagedObjectContext+Conveniences.swift
+//  AltStore
+//
+//  Created by Riley Testut on 5/16/23.
+//  Copyright © 2023 Riley Testut. All rights reserved.
+//
+
+import CoreData
+
+public extension NSManagedObjectContext
+{
+    // Non-throwing
+    func performAndWait<T>(_ closure: @escaping () -> T) -> T
+    {
+        var result: T!
+        
+        self.performAndWait {
+            result = closure()
+        }
+        
+        return result
+    }
+    
+    // Throwing
+    func performAndWait<T>(_ closure: @escaping () throws -> T) throws -> T
+    {
+        var result: Result<T, Error>!
+        
+        self.performAndWait {
+            result = Result { try closure() }
+        }
+        
+        let value = try result.get()
+        return value
+    }
+}

AltStoreCore/Types/Managed.swift

@@ -40,12 +40,12 @@ public extension Managed
     // Non-throwing
     func perform<T>(_ closure: @escaping (ManagedObject) -> T) -> T
     {
-        var result: T!
+        let result: T
         
         if let context = self.managedObjectContext
         {
-            context.performAndWait {
+            result = context.performAndWait {
-                result = closure(self.wrappedValue)
+                closure(self.wrappedValue)
             }
         }
         else
@@ -59,21 +59,20 @@ public extension Managed
     // Throwing
     func perform<T>(_ closure: @escaping (ManagedObject) throws -> T) throws -> T
     {
-        var result: Result<T, Error>!
+        let result: T
         
         if let context = self.managedObjectContext
         {
-            context.performAndWait {
+            result = try context.performAndWait {
-                result = Result { try closure(self.wrappedValue) }
+                try closure(self.wrappedValue)
             }
         }
         else
         {
-            result = Result { try closure(self.wrappedValue) }
+            result = try closure(self.wrappedValue)
         }
         
-        let value = try result.get()
+        return result
-        return value
     }
 }