SmallStep

A cross-platform abstraction layer for Objective-C applications targeting macOS, iOS, Linux (GNUStep), and Windows (WinObjC).

Overview

SmallStep provides a unified API for common platform-specific operations, allowing you to write code once and run it on multiple platforms. It abstracts away platform differences while maintaining access to platform-specific features when needed.

Supported Platforms

• macOS (Cocoa/AppKit)
• iOS (UIKit)
• Linux (GNUStep)
• Windows (WinObjC)

Features

Platform Detection

• Detect current platform at runtime
• Platform-specific utilities and helpers

Canvas (AppKit / GNUstep)

• CanvasView: Bitmap view with pencil/eraser tools, used by SmallPaint and SmallPhotoViewer. Optional; requires AppKit/gnustep-gui when linked.

File System Operations

• Unified file system API across all platforms
• Platform-appropriate directory handling:
  • macOS/iOS: Uses standard Cocoa directories
  • Linux: Respects XDG Base Directory Specification
  • Windows: Uses Windows standard folders (Documents, AppData, LocalAppData)
• Cross-platform file operations

Installation

As a Framework (macOS/iOS)

1. Add SmallStep to your Xcode project
2. Link against the SmallStep framework
3. Import: #import <SmallStep/SmallStep.h>

As a Library (Linux/GNUStep)

cd SmallStep
make
sudo make install

Then in your GNUmakefile:

include $(GNUSTEP_MAKEFILES)/common.make
TOOL_NAME = YourApp
YourApp_OBJC_FILES = ...
YourApp_LIBRARIES_DEPEND_UPON = -lSmallStep
include $(GNUSTEP_MAKEFILES)/tool.make

Usage

Platform Detection

#import <SmallStep/SmallStep.h>

// Check platform
if ([SSPlatform isMacOS]) {
    NSLog(@"Running on macOS");
} else if ([SSPlatform isiOS]) {
    NSLog(@"Running on iOS");
} else if ([SSPlatform isLinux]) {
    NSLog(@"Running on Linux");
} else if ([SSPlatform isWindows]) {
    NSLog(@"Running on Windows");
}

// Get platform info
NSString *platformName = [SSPlatform platformName];
NSString *version = [SSPlatform platformVersion];

File System Operations

#import <SmallStep/SmallStep.h>

SSFileSystem *fileSystem = [SSFileSystem sharedFileSystem];

// Get directories
NSString *documentsDir = [fileSystem documentsDirectory];
NSString *cacheDir = [fileSystem cacheDirectory];
NSString *appSupportDir = [fileSystem applicationSupportDirectory];

// File operations
BOOL exists = [fileSystem fileExistsAtPath:@"/path/to/file"];
NSData *data = [fileSystem readFileAtPath:@"/path/to/file" error:&error];
BOOL success = [fileSystem writeString:@"Hello" toPath:@"/path/to/file" error:&error];

Platform-Specific Features

macOS

#if TARGET_OS_MAC && !TARGET_OS_IPHONE
#import <SmallStep/SSMacOSPlatform.h>

BOOL sandboxed = [SSMacOSPlatform isSandboxed];
NSString *appSupport = [SSMacOSPlatform macOSApplicationSupportPath];
#endif

iOS

#if TARGET_OS_IPHONE
#import <SmallStep/SSiOSPlatform.h>

BOOL isExtension = [SSiOSPlatform isAppExtension];
NSString *docsDir = [SSiOSPlatform iOSDocumentsDirectory];
#endif

Linux

#if defined(__GNUSTEP__) || defined(__linux__)
#import <SmallStep/SSLinuxPlatform.h>

NSString *xdgData = [SSLinuxPlatform xdgDataHome];
NSString *xdgConfig = [SSLinuxPlatform xdgConfigHome];
NSString *xdgCache = [SSLinuxPlatform xdgCacheHome];
#endif

Windows

#if defined(WINOBJC) || defined(_WIN32)
#import <SmallStep/SSWindowsPlatform.h>

NSString *documents = [SSWindowsPlatform windowsDocumentsPath];
NSString *localAppData = [SSWindowsPlatform windowsLocalAppDataPath];
NSString *appData = [SSWindowsPlatform windowsAppDataPath];
NSString *temp = [SSWindowsPlatform windowsTempPath];
#endif

Architecture

SmallStep/
├── Core/                    # Core platform abstraction
│   ├── SSPlatform.h/m       # Platform detection
│   ├── SSFileSystem.h/m     # File system operations
│   ├── CanvasView.h/m       # Bitmap canvas (pencil/eraser; AppKit)
│   └── SmallStep.h          # Main header
└── Platform/                # Platform-specific implementations
    ├── macOS/               # macOS-specific code
    ├── iOS/                  # iOS-specific code
    └── Linux/                # Linux/GNUStep-specific code

Design Principles

1. Unified API: Same interface across all platforms
2. Platform Awareness: Detect and adapt to platform capabilities
3. Standards Compliance: Follow platform conventions (XDG on Linux, Cocoa on Apple platforms)
4. Minimal Dependencies: Only Foundation framework required
5. Lightweight: Small footprint, fast performance

Building

macOS/iOS (Xcode)

1. Open SmallStep.xcodeproj (create if needed)
2. Select target platform
3. Build framework

Linux (GNUStep)

make

Windows (WinObjC)

Build using Visual Studio with WinObjC SDK integration.

License

See LICENSE file for details.

Contributing

When adding platform-specific features:

1. Add core abstraction in Core/
2. Implement platform-specific code in Platform/[platform]/
3. Update documentation
4. Add tests if applicable