require without a message doesn't show the failed expression, so we just get a useless error like

Exception in thread "main" java.lang.IllegalArgumentException: Failed requirement.
        at com.google.prefab.api.Package.<init>(Package.kt:65)
...

1. export_libraries could be optional (actually the whole module.json could be optional).
2. abi.json could contain an optional 'link' to the binary (relative to the AAR root). This way, a conventional AAR could be reused for prefab by adding a fixed prefab tree. That would be as easy as building a prefab tree structure under src/main/resources of a library module.

Well, include files may require special effort to be in sync with the source tree, but there are some tricks that make this easy on Android Studio.

Our CMake plugin doesn't currently emit version information: https://cmake.org/cmake/help/latest/manual/cmake-packages.7.html#package-version-file

This is probably a useful thing to have. This would require a schema change since we don't currently have the version information to provide, so this is probably something we'd want to tackle before 1.0.

https://github.com/google/prefab/blob/master/cmake-plugin/src/main/kotlin/com/google/prefab/cmake/CMakePlugin.kt#L154

The CMake plugin wrongly makes all targets shared libraries. Fix that to detect the type of prebuilt like the ndk-build plugin does.

The test directory is confusing the GitHub dependency graph.

Package name
libopus

Package URL
http://www.opus-codec.org/

Package source location
https://archive.mozilla.org/pub/opus/opus-1.3.1.tar.gz

Package name
SDL2

Package URL
https://www.libsdl.org/index.php

Package source location
https://www.libsdl.org/release/
https://www.libsdl.org/release/SDL2-2.0.10.zip

NOTE: vcpkg seems to use this unofficial repository to pull the sources - https://github.com/SDL-mirror/SDL/releases

Package name
ffmpeg

Package URL
https://www.ffmpeg.org/

Package source location
https://www.ffmpeg.org/download.html#get-sources

Package name
SQLite

Package URL
https://www.sqlite.org/index.html

Package source location
https://www.sqlite.org/download.html

Hi @DanAlbert . Thank you for such a great library. Just wondering is there an example on how to use a custom build aar file. I have creating my own aar file in the same manner as this project. However when I import the library in android it fails.

.m2/repository/com/vcpkg/ndk/support/jsoncpp/1.9.2/jsoncpp-1.9.2.pom

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.vcpkg.ndk.support</groupId>
    <artifactId>jsoncpp</artifactId>
    <version>1.9.2</version>
    <packaging>aar</packaging>
    <description>The Vcpkg AAR for jsoncpp</description>
    <url>https://github.com/microsoft/vcpkg.git</url>

    <dependencies>
    </dependencies>
</project>

The following is the file renamed to zip to allow uploading to GitHub
jsoncpp-1.9.2.zip

URL
https://google.github.io/prefab/#usage

Problem
The documentation refers to an executable called prefab, however, after running gradlew installDist the binary which gets created is called cli. Additionally the output from cli is:

Usage: prefab [OPTIONS] [PACKAGE_PATH]...  

Suggest either updating docs or renaming CLI executable to prefab

What is the meaning of "ndk" entry in abi.json? Should it be 20, or 20.1.5948944 ?

Package name
luajit

Package URL
http://luajit.org/

Package source location
http://luajit.org/download.html

Package name
Oboe

Package URL
https://github.com/google/oboe

Package source location
https://github.com/google/oboe

Package name
POCO c++ library

Package URL
https://pocoproject.org/

Package source location
https://github.com/pocoproject/poco

See #71 (comment)

Package name
The Google cpu_features library

Package URL
https://developer.android.com/ndk/guides/cpu-features

Package source location
https://github.com/google/cpu_features

Right now the latest version of OpenSSL on https://maven.google.com is 1.1.1.d while https://www.openssl.org/ published 1.1.1e and 1.1.1f in the meantime.

Do you plan on updating OpenSSL and other libraries regularly once you're out of the alpha stage?

I'm also curious what your thoughts are around responding to security issues in libraries.

Package name
Poco

Package URL
https://pocoproject.org/

Package source location
https://pocoproject.org/releases/poco-1.10.1/poco-1.10.1-all.tar.gz

Package name
Skia

Package URL
https://skia.org/

Package source location
https://skia.googlesource.com/skia.git

Package name
mbedtls

Package URL
https://tls.mbed.org/

Package source location
https://github.com/ARMmbed/mbedtls

Describe the bug
The CLI fails when encountering an invalid artifact i.e. an incorrectly named file under: modules/<library_name>/libs/, however, the error output is sufficiently cryptic to make debugging difficult.

To Reproduce

• On a Mac create the prefab package folder structure as described here: https://google.github.io/prefab/#package-structure

• Wait for Mac OS to populate the newly created folders with .DS_Store files

• Execute the CLI e.g.

  ./cli --build-system cmake --platform android --os-version 21 --stl c++_static --ndk-version 21 --abi x86 --output ~/Code/workspace-android/oboe-prefab/output ~/Code/workspace-android/oboe-prefab

Expected behavior
Error output includes the filename of the invalid artifact folder

Actual behavior
Exception in thread "main" com.google.prefab.api.UnsupportedPlatformException: //oboe/oboe contains artifacts for unsupported platform "" at com.google.prefab.api.Module.<init>(Module.kt:115) at com.google.prefab.api.Package.<init>(Package.kt:77) at com.google.prefab.cli.Cli$packages$2.invoke(Cli.kt:125) at com.google.prefab.cli.Cli$packages$2.invoke(Cli.kt:96) at kotlin.SynchronizedLazyImpl.getValue(LazyJVM.kt:74) at com.google.prefab.cli.Cli.getPackages(Cli.kt) at com.google.prefab.cli.Cli.validate(Cli.kt:173) at com.google.prefab.cli.Cli.run(Cli.kt:190) at com.github.ajalt.clikt.parsers.Parser.parse(Parser.kt:139) at com.github.ajalt.clikt.parsers.Parser.parse(Parser.kt:14) at com.github.ajalt.clikt.core.CliktCommand.parse(CliktCommand.kt:216) at com.github.ajalt.clikt.core.CliktCommand.parse$default(CliktCommand.kt:213) at com.github.ajalt.clikt.core.CliktCommand.main(CliktCommand.kt:231) at com.github.ajalt.clikt.core.CliktCommand.main(CliktCommand.kt:250) at com.google.prefab.cli.AppKt.main(App.kt:29)

Environment:
Prefab version: v1.0.0-alpha5

Host OS:

• Linux
• [X ] macOS
• Windows

Package name
GeographicLib

Package URL
https://geographiclib.sourceforge.io/

Package source location
https://sourceforge.net/projects/geographiclib/files/distrib/GeographicLib-1.50.1.tar.gz

It's possible for more than one library to be a compatible match, and we currently just select the first match. We can do better in a few ways:

1. If the libraries differ only by their OS version, use the highest compatible version (i.e. if there's an android-16 and an android-21 library and the user is targeting 21+, prefer the android-21 library).
2. If the libraries differ only by their NDK version, use the version that best matches the user's NDK version (if there isn't an exact match, I'm not sure whether we should prefer closest older or closest newer...)

If the libraries differ by both of those criteria we'll need to decide a precedence order. I think the order above is probably best, but I haven't given it much thought yet.

Package name
Sodium

Package URL
https://libsodium.gitbook.io/doc/

Package source location
https://github.com/jedisct1/libsodium

Describe the bug
If prefab encounters an error during a build it is not surfaced to the user in the Android Studio build log.

To Reproduce

• Clone the curl-ssl repo
• Open app/build.gradle and comment out the following line:
  arguments "-DANDROID_STL=c++_shared"
• Run gradle sync

Expected behavior
Build fails with a clear description of why it failed

Actual behavior
Build fails with the following message:

executing external native build for cmake /Users/donturner/Code/workspace-android/ndk-samples/prefab/curl-ssl/app/src/main/cpp/CMakeLists.txt
Affected Modules: app

Environment:
Prefab version: (if not using the latest, please try the latest first)

Host OS:

• Linux
• [ x] macOS
• Windows

Target platform:
Target ABI:
Target OS version:
Build system:

Additional context
It is possible to view the prefab output by opening the gradle tab then executing the curl-ssl > Tasks > build > build task. Not particularly easy to find.

Package name
dav1d

Package URL
https://code.videolan.org/videolan/dav1d

Package source location
https://code.videolan.org/videolan/dav1d

Describe the solution you'd like
I believe that most work is done with AAR packages. It would be nice if prefab command could transparently work with such archives, not expecting the user to extract the AAR manually.

Describe alternatives you've considered
I am afraid that manual extraction of the AAR may cause or hide some problems with some packages.

Platform-specific headers currently are used as a complete replacement for the module headers. Some libraries have a set of common headers and a set of platform-specific headers (ffmpeg, as an example: #71).

Adding an additive_platform_headers: true option to module.json or possibly an alternative directory name to the library directory would solve this.

The plugin API is there, we just need to add the code to load it.

Package name
basis_universal

Package URL
https://github.com/BinomialLLC/basis_universal

Package source location
https://github.com/BinomialLLC/basis_universal

Package name
libpng

Package URL
http://www.libpng.org/pub/png/libpng.html

Package source location
https://sourceforge.net/projects/libpng/files/ (packages)
git://git.code.sf.net/p/libpng/code (direct git link)
https://sourceforge.net/p/libpng/code/ci/libpng16/tree/ (git browse)

Package name
FreeType

Package URL
https://www.freetype.org/index.html
https://www.freetype.org/download.html

Package source location
The source repository for the package.
https://download.savannah.gnu.org/releases/freetype/
https://download.savannah.gnu.org/releases/freetype/ft2412.zip

Package name
OpenCV

Package URL
https://opencv.org/

Package source location
https://github.com/opencv/opencv

We currently emit the config file directly to the output directory. CMake's docs indicate that it will look in other places as well (https://cmake.org/cmake/help/latest/command/find_package.html#search-procedure), one of which is architecture specific which would make it easier to share the output directory among multi-arch builds.

I'd tried this first, but CMake didn't appear to be searching those other directories. Should spend some more time trying to figure out why.

Package name
V8

Package URL
https://v8.dev/

Package source location
https://v8.dev/

Package name
PJSIP

Package URL
https://www.pjsip.org

Package source location
https://github.com/pjsip/pjproject/archive/2.10.tar.gz

We don't currently support libraries that need to expose different headers for each platform or subplatform. Adding an optional include directory inside the library directory might be helpful for some libraries. I haven't encountered any yet, but it's possible.

Package name
Boost C++ Libraries

Package URL
https://www.boost.org/

Package source location
https://dl.bintray.com/boostorg/release/1.72.0/source/boost_1_72_0.tar.gz

Package name
Bullet

Package URL
https://pybullet.org/wordpress/

Package source location
https://github.com/bulletphysics/bullet3

Package name
IXWebSocket

Package URL
https://machinezone.github.io/IXWebSocket/

Package source location
https://github.com/machinezone/IXWebSocket

We may be able to support source debugging of distributed binaries if we package the sources (and possibly separate debug info files, depending on the platform) alongside the binaries in a predictable manner.

Package name
OpenAL Soft

Package URL
https://github.com/kcat/openal-soft

Package source location
https://openal-soft.org/

Some packages (ffmpeg, openssl) don't split up their headers by library and instead have one common include directory for all of their libraries. For these cases it would be nice to use a package-wide include directory rather than duplicating the headers into every module.

Capturing request from android/ndk#456 (comment)

Package name
libphonenumber

Package URL
https://github.com/google/libphonenumber

Package source location
https://github.com/google/libphonenumber

The Android ABI info currently has STL info, but we're not checking it.

Capturing request from android/ndk#456 (comment)

Package name
WebRTC

Package URL
https://webrtc.org/

Package source location
https://webrtc.googlesource.com/

$ prefab --platform android --abi armeabi-v7a --os-version 21 --stl c++_shared --ndk-version 21 --output ffmpeg-out --build-system cmake ffmpeg/prefab 
Exception in thread "main" java.lang.RuntimeException: Prebuilt directory contains no library artifacts: ffmpeg/prefab/modules/ffmpeg/libs/android.x86
        at com.google.prefab.api.ElfKt.findElfLibrary(Elf.kt:44)
        at com.google.prefab.api.Android.libraryFileFromDirectory(Android.kt:351)
        at com.google.prefab.api.PrebuiltLibrary.<init>(PrebuiltLibrary.kt:48)
        at com.google.prefab.api.Module.<init>(Module.kt:158)
        at com.google.prefab.api.Package.<init>(Package.kt:77)
        at com.google.prefab.cli.Cli$packages$2.invoke(Cli.kt:125)
        at com.google.prefab.cli.Cli$packages$2.invoke(Cli.kt:96)
        at kotlin.SynchronizedLazyImpl.getValue(LazyJVM.kt:74)
        at com.google.prefab.cli.Cli.getPackages(Cli.kt)
        at com.google.prefab.cli.Cli.validate(Cli.kt:173)
        at com.google.prefab.cli.Cli.run(Cli.kt:190)
        at com.github.ajalt.clikt.parsers.Parser.parse(Parser.kt:139)
        at com.github.ajalt.clikt.parsers.Parser.parse(Parser.kt:14)
        at com.github.ajalt.clikt.core.CliktCommand.parse(CliktCommand.kt:216)
        at com.github.ajalt.clikt.core.CliktCommand.parse$default(CliktCommand.kt:213)
        at com.github.ajalt.clikt.core.CliktCommand.main(CliktCommand.kt:231)
        at com.github.ajalt.clikt.core.CliktCommand.main(CliktCommand.kt:250)
        at com.google.prefab.cli.AppKt.main(App.kt:29)
$ ls ffmpeg/prefab/modules/ffmpeg/libs/android.x86
abi.json  include  libavcodec.so  libavdevice.so  libavfilter.so  libavformat.so libavutil.so libswresample.so  libswscale.so

The problem is actually that no library match libffmpeg.so or libffmpeg.a was found, but that's very unclear from the error message. This should print:

"Prebuilt directory $directory did not contain the expected library artifacts. Tried $name.a and $name.so."

Package name
GTestJNI

Package URL
https://github.com/DanAlbert/GTestJNI

Package source location
https://github.com/DanAlbert/GTestJNI

Package name
libunwindstack

Package URL
https://android.googlesource.com/platform/system/core/+/master/libunwindstack/

Package source location
https://android.googlesource.com/platform/system/core/+/master/libunwindstack/