Offering, completing, and restoring in-app purchases

At a glance

Project structure

Source bundle/
├── Objective-C/
│   ├── iOS/
│   │   ├── main.m
│   │   └── ParentViewController.m
│   ├── macOS/
│   │   ├── main.m
│   │   ├── AppDelegate.m
│   │   └── MainViewController.m
│   ├── tvOS/
│   │   ├── main.m
│   │   └── TabBarViewController.m
│   └── Common/
│       ├── StoreManager.m
│       └── StoreObserver.m
└── Swift/
    ├── Common/
    │   └── AppProtocols.swift
    ├── iOS/
    │   └── ParentViewController.swift
    └── tvOS/
        └── TabBarViewController.swift

Structure observations

• Architecturally prominent files are ranked from entry points and role-named declarations; resource-only paths are omitted.
• Primary languages: C/Objective-C header, Objective-C, Swift.
• The verified tree contains 27 project/configuration file(s) and 62 source declaration(s).

Overall architecture

flowchart LR
    Bundle["Sample bundle"]
    V1["Objective-C"]
    V2["Swift"]
    Boundary["StoreKit APIs"]
    Bundle --> V1
    V1 --> Boundary
    Bundle --> V2
    V2 --> Boundary

Reference code

Objective-C/iOS/main.m:11 — architecture anchor

int main(int argc, char * argv[]) {
    @autoreleasepool {
        return UIApplicationMain(argc, argv, nil, NSStringFromClass([AppDelegate class]));
    }
}

Interpretation

The branches represent separate entry-bearing project variants in the downloaded bundle, not runtime calls between those variants. Each branch is intentionally collapsed at the documented framework boundary; the detailed target-local flow remains in the cited files. Ownership is claimed only where the next section cites a stored property or assignment.

Ownership and state

classDiagram
    StoreManager o-- NSMutableArray : availableProducts
    StoreManager o-- NSMutableArray : invalidProductIdentifiers
    StoreManager o-- SKProductsRequest : productRequest
    StoreObserver o-- BOOL : hasRestorablePurchases

Ownership evidence

Objective-C/Common/StoreManager.m:12 — stored dependency or nearest verified ownership anchor

@property (strong) NSMutableArray *availableProducts;

/// Keeps track of all invalid product identifiers.
@property (strong) NSMutableArray *invalidProductIdentifiers;

/// Keeps a strong reference to the product request.
@property (strong) SKProductsRequest *productRequest;

Composition arrows indicate a source-visible construction expression or locally owned value state; aggregation means the owner stores or receives a dependency without proving exclusive lifetime ownership.

Class and protocol design

Swift/Common/AppProtocols.swift:12 — representative type boundary

protocol DiscloseView {
    func show()
    func hide()
}

The source explicitly defines local protocol relationships: BaseViewController → IAPTableViewDataSource, NSView → DiscloseView, UIView → DiscloseView, UIBarItem → EnableItem, ParentViewController → StoreManagerDelegate, ParentViewController → StoreObserverDelegate.

Access control

Reference code

Objective-C/Common/BaseViewController.h:12 — representative boundary

@interface BaseViewController : UITableViewController <IAPTableViewDataSource>
@property (strong) NSMutableArray *data;
@end

Swift declarations without a modifier are internal; explicit private, fileprivate, private(set), public, or open entries above are interpreted by language semantics. Objective-C/C samples instead rely on header and implementation boundaries, which are not equivalent to Swift lexical privacy.

Logic ownership and placement

Design patterns

Naming conventions

• Types: Controller: BaseViewController, MainViewController, MessagesViewController, ParentViewController, PrimaryViewController; DataSource: IAPTableViewDataSource; Delegate: AppDelegate, SettingsDelegate, StoreManagerDelegate, StoreObserverDelegate; Manager: StoreManager; Observer: StoreObserver; View: DiscloseView.
• Protocols: DiscloseView, StoreManagerDelegate, StoreObserverDelegate, SettingsDelegate, IAPTableViewDataSource, EnableItem.
• Methods: sharedInstance, init, startProductRequestWithIdentifiers, fetchProductsMatchingIdentifiers, productsRequest, request, titleMatchingIdentifier, titleMatchingPaymentTransaction.
• Files: Objective-C/Common/StoreManager.m, Objective-C/Common/StoreObserver.m, Objective-C/iOS/ParentViewController.m, Objective-C/macOS/AppDelegate.m, Objective-C/macOS/MainViewController.m, Objective-C/tvOS/TabBarViewController.m.

Architecture takeaways

• main is the main source-visible entry or composition anchor for this sample.
• Framework work reaches StoreKit, UIKit, Cocoa through a deliberately small high-level chain; the detailed API graph remains inside the cited implementation files.
• Stored-property evidence identifies lifecycle collaboration; it does not by itself prove exclusive object ownership.
• Access-control conclusions separate verified language visibility from the likely design rationale.
• Local protocol relationships provide an explicit substitution boundary.

Source map

• Official Apple documentation