Metasepi team meeting #8': Haskell apps on Android NDK

1. Metasepi team meeting #8':
#8':
Haskell apps on Android NDK
Kiwamu Okabe

2. Who am I?
☆ http://www.masterq.net/
☆ Twitter: @master_q
☆ Organizer of Metasepi Project
☆ A developer of Ajhc Haskell compiler
☆ A Debian Maintainer
☆ 10 years' experience in developing
OS using NetBSD.

3. Agenda
☆ [1] Demo
☆ [2] What is Ajhc?
☆ [3] What is Metasepi?
☆ [4] What is compiler to build OS
☆ [5] How to use Ajhc
☆ [6] Haskell on Android NDK
☆ [7] Status report of framework

4. [1] Demo
☆ A touchable cube demo.
☆ Haskell App runs on Android NDK.
☆ GC is breaked by ndk-gdb debugger.
☆ The App is available at Google Play.
http://bit.ly/cubeplay
☆ You can watch the movie following.
http://bit.ly/jhcdroid

5. Demo hardware
Nexus 7 (2012) / NVIDIA Tegra 3

6. Demo software
github.com/ajhc/demo-android-ndk

7. [2] What is Ajhc?
http://ajhc.metasepi.org/
☆ Ajhc := A fork of jhc
☆ jhc := John's Haskell Compiler
☆ http://repetae.net/computer/jhc/
☆ Jhc outputs binary that has lowmemory-footprint and runs fast.
☆ Good for embedded software.

8. Who is John?
☆ John Meacham
☆ http://repetae.net/

9. Why need Ajhc?
☆ GHC is de facto standard on Haskell.
☆ GHC := Glasgow Haskell Compiler
☆ http://www.haskell.org/ghc/
☆ Why need another Haskell compiler?
☆ To develop kernel named "Metasepi".

10. [3] What is Metasepi?
http://metasepi.org/
☆ Unix-like OS designed by strong type.
☆ Using ML or more strong type lang.
Haskell http://www.haskell.org/
OCaml http://caml.inria.fr/
MLton http://mlton.org/
. . . and suchlike.

11. Why need Metasepi?
☆ We have already Linux or Windows.
☆ But the developers are suffering.
☆ If use the kernel changed by you,
☆ you will get many runtime error.
☆ Difficult even to reproduce it.

12. Doesn't OSS have good quality?
☆ "The Cathedral and the Bazaar"
☆ "Given enough eyeballs, all bugs are
shallow."
http://cruel.org/freeware/cathedral.html
☆ But if you develop your own product
reusing OSS...

13. Low quality out of OSS umbrella

14. Type safety
☆ Less runtime errors.
☆ "数理科学的バグ撲滅方法論のすすめ"
http://itpro.nikkeibp.co.jp/article/COLUMN/20060915/248230/

15. Kernel wants type desperately
☆ Kernels are developed with C lang.
☆ Error on user space => SEGV
☆ Error on kernel space => Halt!
☆ Should design kernel with the
greatest care.
☆ C language is safe?

16. [4] What is compiler to build OS
☆ Need strong type.
☆ Need flexibility such as C language.
☆ Create it if there are not!
☆ From scratch? No thank you...
☆ Look for our compiler base.

17. Want POSIX free compiler
Programs to print "hoge" on terminal.
The lesser depends on POSIX, the
smaller values.

18. Jhc output has only 20 undef
$ nm hs.out | grep
U
U
U
U
U
U
U
U
U
U
U
U
U
U
U
U
U
U
U
U
"U "
_IO_putc@@GLIBC_2.2.5
__libc_start_main@@GLIBC_2.2.5
_setjmp@@GLIBC_2.2.5
abort@@GLIBC_2.2.5
ctime@@GLIBC_2.2.5
exit@@GLIBC_2.2.5
fflush@@GLIBC_2.2.5
fprintf@@GLIBC_2.2.5
fputc@@GLIBC_2.2.5
fputs@@GLIBC_2.2.5
free@@GLIBC_2.2.5
fwrite@@GLIBC_2.2.5
getenv@@GLIBC_2.2.5
malloc@@GLIBC_2.2.5
memset@@GLIBC_2.2.5
posix_memalign@@GLIBC_2.2.5
realloc@@GLIBC_2.2.5
setlocale@@GLIBC_2.2.5
sysconf@@GLIBC_2.2.5
times@@GLIBC_2.2.5

19. Jhc is translator to C language

20. Easy to cross build

21. Survive burning out
Let's develop with dogfooding style.
(The method is called "Snatch".)

22. [5] How to use Ajhc
Case of Ubuntu 12.04 amd64.
$ sudo apt-get install haskell-platform libncurses5-dev gcc m4
$ cabal update
$ export PATH=$HOME/.cabal/bin/:$PATH
$ cabal install ajhc
$ which ajhc
/home/USER/.cabal/bin/ajhc
$ echo 'main = print "hoge"' > Hoge.hs
$ ajhc Hoge.hs
$ ./hs.out
"hoge"
You can use on Windows or Mac OS X.

23. Detail of usage
☆ Please read "Ajhc User's Manual".
ajhc.metasepi.org/manual.html
☆ Also you can read in Japanese.
ajhc.metasepi.org/manual_ja.html

24. [6] Haskell on Android NDK
github.com/ajhc/demo-android-ndk
☆ First, build the demo apps.
☆ Then, see more detail of the code.

25. Setup Android SDK/NDK
☆ Download Android SDK/NDK
* Android SDK (adt-bundle-linux-x86_64-20130917.zip)
http://developer.android.com/sdk/index.html
* Android NDK (android-ndk-r9-linux-x86_64.tar.bz2)
http://developer.android.com/tools/sdk/ndk/index.html
☆ Install Android SDK/NDK
$ cd $HOME
$ unzip -x adt-bundle-linux-x86_64-20130917.zip
$ mv adt-bundle-linux-x86_64-20130917/sdk $HOME/android-sdk
$ rm -f adt-bundle-linux-x86_64-20130917
$ export PATH=$PATH:$HOME/android-sdk/tools:$HOME/android-sdk/
platform-tools
$ tar xf android-ndk-r9-linux-x86_64.tar.bz2
$ mv android-ndk-r9 android-ndk
$ export PATH=$PATH:$HOME/android-ndk
$ sudo apt-get install openjdk-7-jdk ant lib32z1-dev lib32stdc++6
$ android update sdk --no-ui --force

26. Start with sample C application
Sample application "native-activity".
developer.android.com/tools/sdk/ndk/

27. Build sample C application
☆ Build
$ cd $HOME/android-ndk/samples/native-activity
$ android update project -p ./ -n native-activity -t android-10
$ ndk-build NDK_DEBUG=1
$ ant debug
$ file bin/native-activity-debug.apk
bin/native-activity-debug.apk: Java Jar file data (zip)
☆ Flash to your Android device
$ sudo adb devices
* daemon not running. starting it now on port 5037 *
* daemon started successfully *
List of devices attached
015d4906053c1605
device
$ sudo adb install -r bin/native-activity-debug.apk
1221 KB/s (156823 bytes in 0.125s)
pkg: /data/local/tmp/native-activity-debug.apk
Success

28. Build Haskell applications
☆ Checkout the source code.
$ git clone https://github.com/ajhc/demo-android-ndk.git
$ cd demo-android-ndk
☆ Build
$ make
$ find . -name "*.hl"
./lib/android-ndk-0.1.hl
$ find . -name "*debug.apk"
./cube/bin/cube-debug.apk
./native-activity/bin/native-activity-debug.apk
☆ "hl" suffix file: Ajhc library
☆ "apk" suffix file: Android application

29. Source code tree
demo-android-ndk
|-- lib
|
`-- android-ndk
|
|-- AndroidNdk
|
|
|-- EGL.hs
|
|
|-- OpenGLES.hs
|
|
`-- Storable.hs
|
|-- AndroidNdk.hs
|
`-- android-ndk.yaml
|-- cube ...
`-- native-activity
|-- AndroidManifest.xml
|-- hs_src
|
`-- Main.hs
|-- jni
|
|-- Android.mk
|
|-- Application.mk
|
|-- c_extern.h
|
|-- dummy4jhc.c
|
`-- main.c
`-- res
`-- values
`-- strings.xml
# Framework library
#
#
Application
Application
# Haskell code on application side
#
#
Stub code for Ajhc
C language code to
runtime
kick Haskell code

30. Build process on Makefile

31. [7] Status report of framework
Let's see "native-activity" demo internal.
But, the framework has no stability yet.

32. Architecture: Using C language

33. Architecture: Using Haskell

34. Code #1: Imports

35. Code #2: Some magic

36. Code #3: Main entry

37. Code #4: Handle inputs

38. Code #5: Handle cmds

39. Code #6: Draw frame

40. Code #7: Init display

41. PR: Call For Articles
☆ http://www.paraiso-lang.org/ikmsm/
☆ Fanzine of functional programming.
☆ About Haskell or OCaml or . . .
☆ Article about Ajhc in C84 book.
☆ Call me if you read it!
http://www.paraiso-lang.org/ikmsm/books/c85.html