Cross-Platform Swift

A talk about writing Swift targeting multiple platforms.

Transcript

1. CROSS-PLATFORM SWIFT MOBOS CONFERENCE, FEBRUARY 2016 BORIS BÜGLING - @NEONACHO
2. COCOAPODS
3. CONTENTFUL
5. AGENDA ▸ Which platforms can we target? ▸ How to share code between them ▸ Some practical examples
6. WHICH PLATFORMS CAN WE TARGET?
7. APPLE PLATFORMS ▸ OS X ▸ iOS ▸ watchOS ▸ tvOS
8. FRAMEWORKS SHARED BETWEEN APPLE PLATFORMS CFNetwork.framework CoreData.framework CoreFoundation.framework CoreGraphics.framework CoreLocation.framework CoreText.framework Foundation.framework ImageIO.framework Security.framework
9. THERE'S MORE DEPENDING ON THE SUBSET WE TARGET Accelerate.framework AudioToolbox.framework AudioUnit.framework AVFoundation.framework AVKit.framework CloudKit.framework CoreBluetooth.framework
10. THERE'S MORE DEPENDING ON THE SUBSET WE TARGET CoreImage.framework CoreMedia.framework CoreVideo.framework EventKit.framework GameController.framework GameKit.framework GLKit.framework MapKit.framework
11. THERE'S MORE DEPENDING ON THE SUBSET WE TARGET MediaAccessibility.framework Metal.framework MobileCoreServices.framework SceneKit.framework SpriteKit.framework StoreKit.framework SystemConfiguration.framework
12. UIKIT When only targeting iOS and tvOS
13. NIBS ! If you don't feel like copy-pasting stuff between NIBs ! https://github.com/neonichu/bohne
14. OPEN SOURCE SWIFT ▸ Linux
15. OPEN SOURCE SWIFT ▸ FreeBSD (somewhat)
16. OPEN SOURCE SWIFT ▸ Android (someday, maybe) https://github.com/SwiftAndroid/swift
17. FRAMEWORKS SHARED BETWEEN all PLATFORMS Foundation.framework https://github.com/apple/swift-corelibs-foundation
18. FOUNDATION IS INCOMPLETE AND SOMETIMES DIFFERENT FROM OS X #if os(Linux) let index = p.startIndex.distanceTo(p.startIndex.successor()) path = NSString(string: p).substringFromIndex(index) #else path = p.substringFromIndex(p.startIndex.successor()) #endif
19. APPLE'S GOAL ▸ Be compatible with Swift 3.0 ▸ Scheduled to ship by the end of 2016
20. EVEN SOME THINGS IN THE STANDARD LIBRARY MIGHT NOT BE AVAILABLE #if _runtime(_ObjC) // Excluded due to use of dynamic casting and Builtin.autorelease, neither // of which correctly work without the ObjC Runtime right now. // See rdar://problem/18801510 [...] public func getVaList(args: [CVarArgType]) -> CVaListPointer {
21. EVEN LIBC IS PROBLEMATIC #if os(Linux) import Glibc #else import Darwin.C #endif
22. let flags = GLOB_TILDE | GLOB_BRACE | GLOB_MARK if system_glob(cPattern, flags, nil, &gt) == 0 { #if os(Linux) let matchc = gt.gl_pathc #else let matchc = gt.gl_matchc #endif
23. AND OTHER RANDOM FUN ./.build/debug/spectre-build /usr/bin/ld: .build/debug/Clock.a(ISO8601Parser.swift.o): undefined reference to symbol '_swift_FORCE_LOAD_$_swiftGlibc' /home/travis/.swiftenv/versions/swift-2.2-SNAPSHOT-2015-12-22-a/ usr/lib/swift/linux/libswiftGlibc.so: error adding symbols: DSO missing from command line clang: error: linker command failed with exit code 1 (use -v to see invocation)
24. => IT'S COMPLICATED
25. HOW TO SHARE CODE BETWEEN THEM
26. ▸ Shared files ▸ Shared frameworks ▸ Shared packages
27. SHARED FILES
28. BUILD CONFIGURATIONS ▸ os(): OSX, iOS, watchOS, tvOS, Linux ▸ arch(): x86_64, arm, arm64, i386
29. #if os(OSX) print("Running on OS X") #elseif os(watchOS) print("Running on watchOS") #else print("Running on any platform but OS X and watchOS") #end
30. SHARED FRAMEWORKS
31. [XCODE 7 BETA] LINKING DUAL (IPHONEOS AND WATCHOS) FRAMEWORKS WITH SAME PRODUCT NAME CAUSES ARCHIVE TO FAIL http://openradar.appspot.com/22392501
32. SHARED PACKAGES ▸ CocoaPods ▸ Carthage ▸ Swift Package Manager
33. COCOAPODS "platforms" : { "osx" : "10.10", "ios": "8.0", "watchos": "2.0", "tvos": "9.0" }
34. IF A POD DOES NOT SUPPORT A CERTAIN PLATFORM ▸ Fork and add it ▸ Submit a PR ▸ For the adventurous ! https://github.com/orta/cocoapods-expert-difficulty
35. COCOAPODS AVOIDS 22392501 ▸ Each duplicated target gets scoped ▸ <.../Build/Debug-iphoneos/Pods-UserTarget/ *.framework>
36. CONCHE $ conche build Downloading Dependencies -> PathKit 0.5.0 -> Commander 0.5.0 Building Dependencies -> PathKit -> Commander Building Conche Building Entry Points -> conche -> .conche/bin/conche
37. CARTHAGE ▸ Essentially a nicer way to do shared frameworks
38. SWIFT PACKAGE MANAGER
39. WHAT IS SWIFTPM?
40. import PackageDescription let package = Package( name: "Hello", dependencies: [ .Package(url: "ssh://git@example.com/Greeter.git", versions: Version(1,0,0)..<Version(2,0,0)), ] )
41. $ swift build Compiling Swift Module 'Clock' (2 sources) Linking Library: .build/debug/Clock.a
42. WHAT DOES IT DO? ▸ Compiles and links Swift packages ▸ Resolves, fetches and builds their dependencies
43. CURRENT STATE ▸ Currently builds static libraries or binaries ▸ Supported platforms are OS X and Ubuntu Linux ▸ Only builds Swift code, no C/C++/Objective-C/...
44. $ swift build --help OVERVIEW: Build sources into binary products USAGE: swift build [options] MODES: --configuration <value> Build with configuration (debug|release) [-c] --clean Delete all build intermediaries and products [-k] OPTIONS: --chdir <value> Change working directory before any other operation [-C] -v Increase verbosity of informational output
46. MAKING OUR OWN PACKAGE
47. ! A small library for parsing and writing ISO8601 date strings.
48. Sources/ !"" Clock #"" ISO8601Parser.swift !"" ISO8601Writer.swift 1 directory, 2 files
49. $ touch Package.swift $ swift build
50. TESTS?
51. SPECTRE describe("a person") { let person = Person(name: "Kyle") $0.it("has a name") { try expect(person.name) == "Kyle" } $0.it("returns the name as description") { try expect(person.description) == "Kyle" } }
52. SPECTRE-BUILD $ swift build $ .build/debug/spectre-build -> a person -> has a name -> returns the name as description 2 passes and 0 failures
53. import PackageDescription let package = Package( name: "Clock", testDependencies: [ .Package(url: "https://github.com/neonichu/spectre-build.git", majorVersion: 0), ] )
54. BUILD_DIR=./.build/debug .PHONY: clean lib test test: lib $(BUILD_DIR)/spectre-build clean: swift build --clean lib: swift build
55. $ make test swift build ./.build/debug/spectre-build -> Converting dates to strings -> can convert NSDate to an ISO8601 GMT string -> Parsing of localtime dates -> can parse dates -> can parse dates with negative timezone offsets -> can parse timezone offsets without colons -> Parsing of UTC dates -> can parse dates -> can parse epoch -> can parse dates without seconds -> is resilient against Y2K bugs 8 passes and 0 failures
56. SWIFT VERSIONS $ cat .swift-version swift-2.2-SNAPSHOT-2015-12-22-a ▸ Is read by either chswift or swiftenv
57. TRAVIS CI os: - linux - osx language: generic sudo: required dist: trusty osx_image: xcode7.2 install: - curl -sL https://gist.github.com/kylef/ 5c0475ff02b7c7671d2a/raw/ 621ef9b29bbb852fdfd2e10ed147b321d792c1e4/swiftenv-install.sh | bash script: - . ~/.swiftenv/init
58. GIT TAGGING ▸ Package.swift only supports tagged dependencies ▸ Don't forget to push your tags to GitHub
59. COCOAPODS ▸ chocolat-cli converts Package.swift to a JSON Podspec
60. public func parse_package(packagePath: String) throws -> PackageDescription.Package { // FIXME: We depend on `chswift` installation and use here let toolchainPath = PathKit.Path(POSIX.getenv("CHSWIFT_TOOLCHAIN") ?? "") libc.setenv("SPM_INSTALL_PATH", toolchainPath.parent().description, 1) print_if("Using libPath \(Resources.runtimeLibPath)", false) let package = (try Manifest(path: packagePath)).package print_if("Converting package \(package.name) at \(packagePath)", false) return package }
61. INTEGRATE SYSTEM LIBRARIES ▸ Empty Package.swift ▸ module.modulemap: module curl [system] { header "/usr/include/curl/curl.h" link "curl" export * }
62. let package = Package( name: "example", dependencies: [ .Package(url: "https://github.com/neonichu/curl", majorVersion: 1) ] )
63. HOW DOES IT WORK?
64. MODULES INSIDE SWIFTPACKAGEMANAGER ▸ OS abstractions: libc, POSIX, sys ▸ Package: PackageDescription ▸ Manifest: dep ▸ Downloading code: swift-get ▸ Building code: swift-build
65. DEPENDENCIES ▸ Can be local or remote Git repositories ▸ Need to be tagged ▸ Will be fetched to ./Packages/ MyPackage-0.0.1
66. ROUGH BUILD PROCESS ▸ PackageDescription generates TOML ▸ dep parses the TOML and can generate YAML ▸ Dependencies are fetched by swift-get ▸ YAML is used as input to llbuild ▸ swift-build calls out to llbuild
67. LLBUILD
68. $ cat .build/debug/Clock.o/llbuild.yaml client: name: swift-build tools: {} targets: "": [<Clock>] Clock: [<Clock>]
69. commands: <Clock-swiftc>: tool: swift-compiler executable: "/usr/bin/swiftc" inputs: ["ISO8601Parser.swift","ISO8601Writer.swift"] outputs: ["<Clock-swiftc>","Clock.swiftmodule", "ISO8601Parser.swift.o","ISO8601Writer.swift.o"] module-name: "Clock" module-output-path: "Clock.swiftmodule" is-library: true sources: ["ISO8601Parser.swift","ISO8601Writer.swift"] objects: ["ISO8601Parser.swift.o","ISO8601Writer.swift.o"] import-paths: ["/Users/boris/Projects/Clock/.build/debug"] temps-path: "/Users/boris/Projects/Clock/.build/debug/Clock.o/Clock" other-args: ["-j8","-Onone","-g","-target","x86_64-apple-macosx10.10", "-enable-testing","-sdk", "/.../Developer/SDKs/MacOSX10.11.sdk","-I","/usr/local/include"]
70. <Clock>: tool: shell inputs: ["<Clock-swiftc>","ISO8601Parser.swift.o","ISO8601Writer.swift.o"] outputs: ["<Clock>","Clock.a"] args: ["/bin/sh","-c","rm -f 'Clock.a'; ar cr 'Clock.a' 'ISO8601Parser.swift.o' 'ISO8601Writer.swift.o'"] description: "Linking Library: .build/debug/Clock.a"
71. ADDITIONAL PACKAGE.SWIFT SYNTAX
72. TARGETS import PackageDescription let package = Package( name: "Example", targets: [ Target( name: "top", dependencies: [.Target(name: "bottom")]), Target( name: "bottom") ] )
73. EXCLUSION let package = Package( name: "Example", exclude: ["tools", "docs", "Sources/libA/images"] )
74. TEST DEPENDENCIES import PackageDescription let package = Package( name: "Hello", testDependencies: [ .Package(url: "ssh://git@example.com/Tester.git", versions: Version(1,0,0)..<Version(2,0,0)), ] )
75. CUSTOMIZING BUILDS import PackageDescription var package = Package() #if os(Linux) let target = Target(name: "LinuxSources/foo") package.targets.append(target) #endif
76. You should think of it as an alpha code base that hasn't had a release yet. Yes, it is useful for doing some things [...] — Daniel Dunbar
77. SOME PRACTICAL EXAMPLES
78. SPRITEKIT EXAMPLE Can run on OS X, iOS and tvOS
79. CLOCK ~/Clock# make swift build ./.build/debug/spectre-build -> Parsing of localtime dates fatal error: init(forSecondsFromGMT:) is not yet implemented: file Foundation/NSTimeZone.swift, line 69 Illegal instruction InvocationError() Makefile:6: recipe for target 'test' failed make: *** [test] Error 1
80. ELECTRONIC MOJI $ ./.build/debug/electronic-moji car ! " # $ % & ' ( ) * + , - .
81. CONTENTFUL SDK
82. CONCLUSION ▸ It's complicated :) ▸ Still a lot of code can be shared ▸ Swift 3.0 will help a lot
83. REFERENCES ▸ https://swift.org ▸ https://github.com/apple/swift-package-manager ▸ https://github.com/apple/llbuild ▸ https://github.com/neonichu/chocolat ▸ https://github.com/neonichu/chswift ▸ https://github.com/neonichu/freedom
84. THANK YOU!
85. @NeoNacho boris@contentful.com http://buegling.com/talks