mulle-brew, C/C++/Objective-C developer "sandboxing" with homebrew

Homebrew is the de facto standard package manager of OS X. It is also available on Linux as Linuxbrew.

By default homebrew installs packages system-wide into /usr/local/ (on OS X). But you can actually clone the brew repository to any place in the filesystem. brew will then install its packages into that place. This is a convenient way to create your own playground development environment of tools and libraries. mulle-brew helps you set up and share such playgrounds.

Advantages

• Keep the runtime and your system clean from temporary downloads.
• Updating brew libraries for one project, doesn't necessarily impact parallel projects
• An easy way to share the required build environments
• A uniform way to access those dependencies via a known folder name addictions
• Makes homebrew dylibs and frameworks embeddable

Installing mulle-brew

Install mulle-brew with brew, it makes sense :) :

brew install mulle-kybernetik/alpha/mulle-brew

Install and run hello world using mulle-brew

Install hello:

mulle-brew init
mulle-brew setting -g -r brews hello
mulle-brew

Run hello:

mulle-brew run hello

mulle-brew run adds addictions/bin to your PATH shell variable so that hello is found for the duration of this command. You could as well have used ./addictions/bin/hello. The use of mulle-brew run becomes more useful in more complex scenarios.

Install libraries and use them with C or cmake

Install libpng and zlib:

mulle-brew init
mulle-brew setting -g -r brews libpng
mulle-brew setting -g -r -a brews zlib
mulle-brew

Now let's create a small test program x. Here is the C Source:

cat <<EOF > x.c
#include <png.h>
#include <zlib.h>

main()
{
   printf( "png version: %u\n", png_access_version_number());
   printf( "zlib version: %s\n", zlibVersion());
   return( 0);
}
EOF

Build x with a C compiler

Build x.c as x with cc and run it:

flags="`mulle-brew paths -l cflags`"
mulle-brew run cc ${flags} -o x x.c
mulle-brew run ./x

If you are running mulle-brew paths -l cflags in /tmp it will produce this line:

-I/tmp/addictions/include -F/tmp/addictions/Frameworks -L/tmp/addictions/lib -lpng -lpng16 -lz

mulle-brew paths cflags on its own produces the -I, -F and -L flags. The -l option collects all the available libraries from addictions/lib and adds them as commandline options.

Build x with cmake

If you don't have cmake: brew install cmake.

Create a CMakeLists.txt:

cat <<EOF > CMakeLists.txt
cmake_minimum_required (VERSION 3.0)
project (x)

find_library( PNG_LIBRARY NAMES png)
find_library( ZLIB_LIBRARY NAMES z)

add_executable( x
x.c)

target_link_libraries( x
\${PNG_LIBRARY}
\${ZLIB_LIBRARY}
)
EOF

Build it with cmake and make:

mulle-brew run mkdir build
mulle-brew run cd build
mulle-brew run cmake `mulle-brew paths cmake` ..
mulle-brew run make
mulle-brew run ./x

Check with otool -L x that indeed the libraries from addictions/lib have been picked up.

Make homebrew libraries and frameworks embeddable in your OS X Applications

If you install libraries and frameworks with homebrew, you will notice that you can not embed them into your own applications, because homebrew does not build them with @rpath.

mulle-brew install -r will fix this for you.

Since mulle-brew run not only changes the PATH but also sets up DYLD_FALLBACK_LIBRARY_PATH and DYLD_FALLBACK_FRAMEWORK_PATH, binaries in addictions/bin will continue to run when executed with mulle-brew run.

Embed homebrewed Frameworks in Xcode

Assume you already have an app set up, and you want to embed a framework int it:

1. Make sure you have run mulle-brew install -r so all frameworks are relocatable
2. Link against the framework in the addictions/Frameworks folder. In Xcode locate the "Embed Frameworks" build phase. Press the + button, then choose "Add Other...". Then navigate to ../addictions/Frameworks and add the framework.
3. Build and it should work. Test the relocatability of your app by copying it to the Desktop and starting it from there.

Embed homebrewed shared libraries in Xcode

Assume you already have an app set up, and you want to embed a shared library in it:

1. Make sure you have run mulle-brew install -r so all shared libraries are relocatable
2. Link against the shared library in the addictions/lib folder. In Xcode locate the "Link Libraries with Binary" build phase. Press the + button, then choose "Add Other...". Then navigate to ../addictions/lib and add the library (don't copy). Use the most qualified version. E.g. if you have a choice between libz.dylib, libz.1.dylib, libz.1.2.11.dylib choose libz.1.2.11.dylib.
3. The library should now appear in the "Project navigator". Drag it into the "Copy Bundle Resources" build phase of your app.
4. Add the header directory addictions/include to the Header Search Paths" " (HEADER_SEARCH_PATHS) build setting of your project or target. As an alternative you can run mulle-brew xcode -a to do this step for you.
5. Build the app and it should work. Test the relocatability of your app by copying it to your Desktop and starting it from there.

Example: MulleBrewApp

MulleBrewApp is an example that shows an App embedding the Python framework and the zlib shared library using the techniques above.

The initial setup was done with:

mulle-brew init
mulle-brew setting -g -r brews zlib
mulle-brew setting -g -r -a brews python
mulle-brew install -r

The App is a stock Xcode app for Objective-C without any specialties added.

Only AppDelegate.m and MainMenu.nib have been modified to retrieve zlib and python version strings and place them into NSTextFields:

#import "AppDelegate.h"
#import <Python/Python.h>
#include <zlib.h>


@interface AppDelegate ()

@property (weak) IBOutlet NSWindow *window;
@property (weak) IBOutlet NSTextField *zlibVersion;
@property (weak) IBOutlet NSTextField *pythonVersion;

@end


@implementation AppDelegate

- (void) applicationDidFinishLaunching:(NSNotification *) aNotification
{
   [self.zlibVersion setStringValue:[NSString stringWithUTF8String:zlibVersion()]];
   [self.pythonVersion setStringValue:[NSString stringWithUTF8String:Py_GetVersion()]];
}

@end

Then the library and framework have been added as explained above:

And last but not least the search paths for the headers were set. Note that Xcode does updates the "Framework Search Paths" for you automatically.

And it just worked.

Tips

Keep a cache of homebrew locally

Cloning brew from GitHub for every project can get tedious. You can use a local cache with:

mulle-brew config -u "clone_cache" "${HOME}/Library/Caches/mulle-brew"

Use a shell to run multiple commands

Prefixing everything with mulle-brew can be tedious. Use a subshell:

mulle-brew run "${SHELL}"

Start Xcode with mulle-brew

If Xcode uses tools in your binary folder, it can be useful to start Xcode in the proper environment, so open your project like so:

mulle-brew run open Foo.xcodeproj

Sharing addictions with other projects

You might find that you have multiple projects with overlapping dependencies on brew formula and the duplication becomes tedious. You can create a "master" playground in the common parent directory with:

mulle-brew defer

And revert back to a private playground with

mulle-brew emancipate

Here the use of mulle-brew paths comes in handy, as it adapts to the new position of the addictions folder in the filesystem.

Use paths without spaces for your projects

As this simplifies things a lot. If your home directory is "My Home" though, you should note that you can give quoting options to mulle-brew paths.

To properly use quoted paths you will then need to use eval to run commands:

CFLAGS="`mulle-brew paths -1 -q "'" cflags`"
mulle-bootstrao run eval cc ${CFLAGS} x.c

GitHub and Mulle kybernetiK

The development is done on Mulle kybernetiK. Releases and bug-tracking are on GitHub.