README.md

Localhost Demo

This demo simply sorts some random strings and prints the results to the terminal as so:

$ ant compile jar run
...
Sep 07, 2015 6:12:10 PM com.dropbox.djinni.NativeLibLoader loadLibrary
INFO: Loaded /var/folders/zj/w8zq8xmd4m9f__rdl4rmqhyr0000gn/T/libTextSortNative.dylib3424746480331627703dylib
Sep 07, 2015 6:12:10 PM com.dropbox.textsort.SortTest main
INFO: Input strings:
96901
70751
93099
10224
21918
Sep 07, 2015 6:12:10 PM com.dropbox.textsort.SortTest main
INFO: Output strings:
10224
21918
70751
93099
96901

This demo also serves to document how to build a native library using djinni and ship it inside a jar (and include djinni's small set of dependencies).

Running locally

Run ant compile jar run to compile and run.

Running in Linux via Docker

To demo running in linux, run_in_docker.sh ant clean compile jar run to run inside a Docker container, or just run_in_docker.sh to drop into a Dockerized shell. The root of this djinni repo will be mounted at /opt/djinni.

Build Details

This demo packages the native library in the application jar and uses the djinni support class com.dropbox.djinni.NativeLibLoader to unpack and load the library at runtime. This approach should work well for the majority of use cases but has several known caveats:

• The app might not have access to temp space at runtime. In this case, you must install the library locally and can use the system property djinni.native_libs_dirs to tell djinni where to find your library.
• The native library might have many other system dependencies. In this case, you must either include those shared libraries in the jar, link/compile them into the app native library, or somehow ensure the dependencies exist on the target system (e.g. run your app in a container).
• NativeLibLoader does not currently support filtering libraries by host architecture. In this scenario, you might consider building a fat library using lipo and libtool.

Note that NativeLibLoader is an entirely optional dependency. You can omit it from your app and build and include only djinni generated code. However, you will need to invoke System.load() or System.loadLibrary() manually.