Running Wrench on Android devices.
==================================

Setting up the environment:
---------------------------

    Install Rust Android targets:
        rustup target add aarch64-linux-android x86_64-linux-android

    Install cargo-apk:
        cargo install cargo-apk

    Install the Android SDK and NDK via mach bootstrap:
        ./mach bootstrap --application-choice mobile_android

    This downloads NDK r29 and the Android SDK into ~/.mozbuild/. After it
    completes, install the SDK platform that matches NDK r29's max platform
    level (35), which cargo-apk requires:

        ~/.mozbuild/android-sdk-linux/cmdline-tools/20.0/bin/sdkmanager \
            "platforms;android-35" \
            --sdk_root=$HOME/.mozbuild/android-sdk-linux

    Consider adding ~/.mozbuild/android-sdk-linux/platform-tools to your
    path, for the adb commands below.

Compiling and running:
----------------------

    Compile wrench:
        cd wrench
        export ANDROID_HOME=$HOME/.mozbuild/android-sdk-linux
        export ANDROID_NDK_ROOT=$HOME/.mozbuild/android-ndk-r29
        cargo apk build --lib

    Install the APK:
        adb install -r ../target/debug/apk/wrench.apk

    Set command line arguments and env vars for wrench.
    The app data directory requires app-level permissions; use run-as with
    stdin piping since the APK is built with debuggable=true:

        adb shell run-as org.mozilla.wrench mkdir -p /data/data/org.mozilla.wrench/files/wrench

        echo "reftest" | adb shell run-as org.mozilla.wrench tee /data/data/org.mozilla.wrench/files/wrench/args
        echo "env: WRENCH_REFTEST_CONDITION_DEVICE=1" | adb shell run-as org.mozilla.wrench tee -a /data/data/org.mozilla.wrench/files/wrench/args
            # Or for an emulator:
        echo "env: WRENCH_REFTEST_CONDITION_EMULATOR=1" | adb shell run-as org.mozilla.wrench tee -a /data/data/org.mozilla.wrench/files/wrench/args

    Push reftests (if you need these files for what you're doing).
    adb push cannot write directly to app data directories, so stage via
    /data/local/tmp first:

        adb push reftests /data/local/tmp/wrench-reftests
        adb shell run-as org.mozilla.wrench cp -r /data/local/tmp/wrench-reftests /data/data/org.mozilla.wrench/files/wrench/reftests

    Run the application:
        adb shell am start -n org.mozilla.wrench/android.app.NativeActivity
            (or click the icon in the launcher)

    Inspect the output:
        adb logcat -s Wrench

        stdout and stderr are redirected to the logcat, however, long lines
        will be truncated meaning the reftest analyzer will not work correctly.
        We therefore additionally redirect the output to the file
        /data/data/org.mozilla.wrench/files/wrench/stdout, which can be pulled:

        adb shell run-as org.mozilla.wrench cat /data/data/org.mozilla.wrench/files/wrench/stdout > /tmp/wrench-stdout.txt

Release mode:
-------------

    Building in release does work as well. Use the following steps to compile wrench:
        cd wrench
        export ANDROID_HOME=$HOME/.mozbuild/android-sdk-linux
        export ANDROID_NDK_ROOT=$HOME/.mozbuild/android-ndk-r29
        cargo apk build --lib --release

    Now the APK at ../target/release/apk/wrench.apk
    should be signed and installable (you may need to uninstall the debug APK first if you
    have that installed).

Running reftests like a boss (on a local emulator):
---------------------------------------------------

    First, compile wrench as described above (debug mode).
    Then, from the root gecko source dir, run:
        ./mach python testing/mozharness/scripts/android_wrench.py --config testing/mozharness/configs/android/wrench.py
    This will automatically do the following:
        - Download the blessed android AVDs from taskcluster
        - Start the emulator (using your ~/.mozbuild/android-sdk-linux emulator binaries)
        - Install the debug APK (from gfx/wr/wrench/target/debug/apk/wrench.apk)
        - Copy the reftests to the sdcard
        - Write an args file to the sdcard
        - Run wrench
        - Wait for wrench to finish running
        - Scrape the logcat for reftest output
    Other logs (e.g. full logcat) can be found in your ~/.wrench/logs folder. Note that
    this will also leave the android emulator running, so repeating the command will be
    even faster the next time around as it won't need to redownload the AVDs or restart
    the emulator. It will reinstall the APK and re-push the reftests folder though.

    If you want to use a release APK (runs much faster), build it as per the "Release mode"
    instructions above and set the WRENCH_APK env var to point to the APK:
        export WRENCH_APK=gfx/wr/target/release/apk/wrench.apk
        ./mach python testing/mozharness/scripts/android_wrench.py --config testing/mozharness/configs/android/wrench.py

Running reftests like a boss (on a local device):
-------------------------------------------------

    Same steps as running on a local emulator, except you need to do this:
        export ANDROID_SERIAL=<your device's serial>
    before running the `./mach python` command. You can get the serial of
    your device by running `adb devices` with the device plugged in. When running
    on a device, the android_emulator_wrench.py script will skip the steps to
    download the AVDs and start the emulator.