dukeify / Fake Jni
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fake-jni
DEPRECATION WARNING
This fork was the original prototype and is currently unmaintained. Any issues or PRs posted for this version will be closed without question. There is a production-ready version coming soon, stay posted for a new upstream with full unit and integration test coverage and cross-platform + cross-architecture support.
Cloning
git clone --depth 1 --recursive https://github.com/meme/fake-jni.git
Requirements
fake-jni has no runtime dependencies :)
Build Requirements
-
CMake>= 3.8 libdl-
makeorninja
Usage
To include fake-jni in your CMake project, clone it into your project's root directory and add the following lines to your CMakeLists.txt:
project(my_project)
#define any desired fake-jni build variables BEFORE including fake-jni
add_subdirectory(fake-jni)
target_link_libraries(my_project fake-jni)
Building
Build Flags
| Flag | Usage | Default | Description |
|---|---|---|---|
BUILD_FAKE_JNI_TESTS |
=[ON OFF] |
ON |
Builds and runs the test suite |
BUILD_FAKE_JNI_EXAMPLES |
=[ON OFF] |
ON |
Builds and runs the examples |
BUILD_FAKE_JNI_DEBUG |
=[ON OFF] |
OFF |
Builds a debug release |
BUILD_FAKE_JNI_ASAN |
=[ON OFF] |
OFF |
Builds with ASAN |
FFI_CC |
={DESIRED_C_COMPILER} |
${CMAKE_C_COMPILER} |
Set the C compiler for libffi
|
FFI_CXX |
={DESIRED_CXX_COMPILER} |
${CMAKE_CXX_COMPILER} |
Set the C++ compiler for libffi
|
FFI_CONFIGURE_FLAGS |
={CONFIGURE_FLAGS} |
`` | Set the configure flags for libffi
|
UNWIND_CC |
={DESIRED_C_COMPILER} |
${CMAKE_C_COMPILER} |
Set the C compiler for libunwind
|
UNWIND_CXX |
={DESIRED_CXX_COMPILER} |
${CMAKE_CXX_COMPILER} |
Set the C++ compiler for libunwind
|
UNWIND_CONFIGURE_FLAGS |
={CONFIGURE_FLAGS} |
`` | Set the configure flags for libunwind
|
Simply build as usual:
mkdir build
cd build
env CC=clang CXX=clang++ cmake ..
make -j
or optionally build with ninja:
mkdir build
cd build
env CC=clang CXX=clang++ cmake -GNinja ..
ninja -j0
Cross Compiling
To compile for another host you must set the following environment variables:
-
CMAKE_CXX_COMPILER_TARGET- The target architecture -
CC- The C cross-compiler -
CXX- The C++ cross-compiler
Optionally, you may also set the following variables:
FFI_CCFFI_CXXUNWIND_CCUNWIND_CXX
Note: When compiling for Android you must set both FFI_CC and FFI_CXX to their respective toolchains, otherwise libffi will fail to compile.
The compilers will be located inside of your distribution's NDK installation, under $ANDROID_NDK/toolchains/llvm/prebuilt/linux-x86_64/bin.
For example, to compile fake-jni for Android API level 21 and the AArch64 architecture, your CMakeLists.txt would look like the following:
project(my_project)
#these build variables must be set BEFORE including fake-jni
set(FFI_CC aarch64-linux-android21-clang)
set(FFI_CXX aarch64-linux-android21-clang++)
add_subdirectory(fake-jni)
target_link_libraries(my_project fake-jni)
Then to build, run the following:
export PATH=$ANDROID_NDK/toolchains/llvm/prebuilt/linux-x86_64/bin:$PATH
mkdir build
cd build
cmake -GNinja -DCMAKE_TOOLCHAIN_FILE=$ANDROID_NDK/build/cmake/android.toolchain.cmake -DANDROID_ABI=arm64-v8a -DANDROID_PLATFORM=android-21 ..
ninja -j0
Goals
- Binary compatability with JNI 1.8
- Drop-in replacement for an actual JVM, allowing users to compile against
fake-jniwhile retaining full functionality - The definition and linking of C++ classes through
fake-jnito act as proxies for Java classes, that would otherwise be running on an actual JVM - Portability to other platforms and architectures
Licensing
The JNI headers are licensed under the GPL, with the "classpath" exception, meaning that we are free to use and implement the JNI headers in fake-jni, however, any changes made to include/jni.h or include/jni_md.h will be made under the GPL, in complete compliance with the licensing. The rest of fake-jni, including implementations of other GPL licensed headers, are licensed under the GPLv3 license.