I have a c library of astronomical code that I'd like to make use of in several formats - a command line that reads and writes files, an iOS app with graphical output, etc.
Ideally I'd like to be able to leave the code in a format that would allow the most basic version (the CLI's) to be cross-compiled on other platforms, while remaining editable within Xcode for the iOS versions - if such a thing is possible.
Does anyone have a good guide on how to arrange projects in Xcode in order to make them easier to move between different targets like this, while avoiding platform lock-in as much as possible?
Related
I'm very interested in using GStreamer's iOS framework http://docs.gstreamer.com/display/GstSDK/Installing+for+iOS+development for video streaming, but when I add the framework to a blank project and add a few lines of code to take advantage of its powerful features, the final IPA is 27MB. This is just way to big to be adding to my project, what is the best way to go about stripping this down the the bare necessities as I'm sure I'm only using a small percent of the code that is included in the SDK.
Here's a pic showing the package contents of the IPA:
Thanks!
In the gst_ios_main.h you can disable all the plugins that you don't need (make sure to enable linker optimizations so that unused code is removed). If that's not enough, you can build your own stripped down version of the iOS binaries with http://cgit.freedesktop.org/gstreamer/cerbero/ (you need to remove things from the .package and .recipe files to only build what you need). Just disabling things from gst_ios_main.h should be enough in 99% of the cases though.
Note that by default you'll build applications for multiple architectures, as such the resulting application will be rather large. Depending on your use case you can drop some architectures.
On another note, gstreamer.com is providing an completely outdated version of GStreamer and is in no way related to the GStreamer project. The official website is http://gstreamer.freedesktop.org .
SDKs have their source code encapsulated away from you, the user. You get access only to header files. Thus you just can't extract some class from it because you don't have access to the implementation file.
Of course if this library is opensource you can attempt to isolate one class, but sometimes everything is so deeply connected, that it is close to impossible.
If I create an Xcode project with the iOS Single View Application template and choose Swift for the language, will the compiler exclude from the release build (binary) functions that never get called?
I'm wondering because I want to include a third-party library that has a lot of superfluous classes & functions, and I want to keep my app small & fast.
While I agree with comments, it is unlikely to impact performance in any significant way even if it was included...
Xcode 6 uses Apple LLVM Compiler Version 6.1, depending on how closely related it is to LLVM Developer Group's version the optimization feature is available http://llvm.org/docs/Passes.html with options such as -dce: Dead Code Elimination, -adce: Aggressive Dead Code Elimination.
One way to know for sure what is included is checking the assembly output using -emit-assembly option in the swift compiler and review the output, or opening the binary in a disassembler such as Hopper ( http://www.hopperapp.com/download.html )
The first thing I tried is to create a static library but later I found out that it's not supported yet. Apple Xcode Beta 4 Release Notes:
Xcode does not support building static libraries that include Swift
code. (17181019)
I was hoping that Apple will be able to add this in the next Beta release or the GA version but I read the following on their blog:
While your app’s runtime
compatibility is ensured, the Swift language itself will continue to
evolve, and the binary interface will also change. To be safe, all
components of your app should be built with the same version of Xcode
and the Swift compiler to ensure that they work together.
This means that frameworks need to be managed carefully. For instance,
if your project uses frameworks to share code with an embedded
extension, you will want to build the frameworks, app, and extensions
together. It would be dangerous to rely upon binary frameworks that
use Swift — especially from third parties. As Swift changes, those
frameworks will be incompatible with the rest of your app. When the
binary interface stabilizes in a year or two, the Swift runtime will
become part of the host OS and this limitation will no longer exist.
The news is really alarming for me a person who writes components for other developers to use and include in their apps. Is this means that I have to distribute the source code or wait for two years?. Is there any other way to distribute the library without exposing the code (company policy)?
Update:
Is Swift code obfuscation an option at this point ?
Swift is beta now, and even for 1.0 Apple has been pretty clear they're after a restricted feature set -- better to do a small number of things well than to try to do everything.
So for now, there's no way to distribute binary static libraries. Presumably that'll change sometime after Swift 1.0. For now, you can:
Distribute source
Ship a binary framework (instead of a library) if you're okay with the ABI being fragile
Use ObjC for library code
You can always combine approaches, too: e.g., implement the critical (secret) details of your library in ObjC, and ship Swift source that wraps it in a nice Swift API.
Obfuscating code written in a language that's very much subject to change sounds like a recipe for a maintenance nightmare.
I believe the whole approach is wrong. You cannot do something that is not (yet) doable by the technology you are trying to use.
Rationale: Swift is a new language, currently in Beta, and therefore changing. As I see it, this fact means not only that you are not able to ship static libraries, but that (real) developers will not be actually use third-party static libraries. What's the actual use of a library that may not work in the next release of the compiler? The issue gets bigger if you whant to use more than one library, because they might not be compatible! Therefore, even if you would be able to ship static libraries, they wouldn't be actually useful for production environment. So, what's the point?
Suggestion: write your static libraries in Objective-C (or C or whatever "non-beta"). Developers who need third-party libraries (e.g. yours) shouldn't expect them to be written in Swift until Swift is stable. You don't use experimental materials to build real bridges, right? You use well-tested, predictable ones.
From Xcode 9 beta 4, Xcode supports static library with Swift sources.
I'm developing an iOS SDK that integrates other SDKs (Facebook SDK 3.5, for example).
To prevent collisions and allow my customers to import those SDKs as well, I want to rename all of the classes/enums in my code (for example, rename FBSession to RDFBSession, etc).
Is there an easy way to do this instead of going class-by-class and using Xcode's rename feature?
Apple provide a command-line tool called tops(1) that is designed for scripting large-scale code refactoring (renaming C functions, Objective-C methods, classes, and other tokens):
tops -verbose replace "FBSession" with "RDFBSession" Sources/*.[hm]
If you have a lot of replacements, you can put all of the replace... commands into a file that you pass with the -scriptfile option. The man page has more information on the more complex commands/options (and examples).
Xcode also offers textual Search and Replace. This will be faster than individual refactors, but it is ultimately less automated. You can make the step by step refactoring faster by first minimizing the project to the relevant dependencies/sources (if possible).
However, renaming the declarations in a library will not alter the symbol names of its associated binary. If it is distributed with a binary, then renaming will just result in linker errors or (in some cases) runtime errors.
The best idea if you need to use a 3rd party library which your clients might also use is to simply inform them they need to link the library with their app, then publish the version(s) the current release supports so they know they have some extra testing if they go too far ahead with some libraries.
I think that a better approach than simply renaming your classes would be to download Facebook's open source code, rename the classes there and compile a new static library with a set of renamed header files. Then you can be sure that no collisions occur and that you're using symbols that you named yourself.
I must warn you though - working like this may make updating the SDK a nightmare regardless of how you tackle this specific issue.
I have a large (thousands of files) product that I am porting to iOS. I have an existing build structure that constructs about 50 static libraries that can then be used by a platform-specific [G]UI. Some of the libraries are 3rd-party tools like zip, ICU, and Xerces. The portable build process is managed by GNU autotools, and I have created some shell scripting to build the code for i386 (simulator), armv6 and armv7. All of this is being done on Apple's Lion with the 5.1 iOS SDK and Xcode4.
The problem I have is that it's a pain to bring these libraries into an Xcode4 project. Drag&Dropping the libraries is tedious. I've been resisting creating a "project" for the libraries in Xcode because I already have a cross-platform build system that works. I'd like to have a "simple" way to type in the list of libraries and their location(s); my searches here show solutions for Xcode3, but they don't seem to apply to Xcode4.
I am able to build an iOS app that uses these libraries, but the thrust of my question is really: How do I avoid all the drag&dropping and retain my portable build structure so that others using my libraries aren't tearing their hair out? If this were an iOS-only app, I'd just use Xcode4 for everything, of course. But since it is multi-platform and "portable" I really want to keep the process simple, where "simple" applies to both the maintenance of the packaging and to the user/developer who is working with my libraries.
An alternate question might be: is there a safe way for me to generate Xcode4 meta-files so that the end result of my autotools-driven-build just looks like a native Xcode4 project?
Two thoughts:
1) It use to be the case that Xcode supported AppleScript pretty well - I use to do such tasks with AppleScripts. Early versions of Xcode 4 were quite lacking in this support though. Not sure if you can do it with 4.4 - you might ask on the AppleScript implementors list on Apple's listserv group.
2) If you put all the libraries (or perhaps links) into one folder, then in Xcode click on the Target, BuildPhase, Link Binary with Libraries, tap the + key, navigate to your folder, then select all libraries and tap OK, you're done. [Well, almost, then in the GUI pane on left you need to select them all again and move them into the Frameworks folder, which due to this annoying bug, I keep at the top of my projects.]