Create a RAM disk on macOS to boost up android project building.

ramdisk

#!/bin/bash
#########################################################################
# File Name:		ramdisk.sh
# Author:			Landerl Young
# e-Mail:			LanderlYoung@gmail.com
# Created Time:		Wed Aug 22 15:08:28 2018
#########################################################################

VOLUME=RAM_DISK
RAMDISK_LOCATION=/Volumes/$VOLUME
RAMDISK_CONFIG=/Volumes/$VOLUME/.ramdisk_config

#@param size in MegaBytes
function ramdisk_create() {
    if [[ -d $RAMDISK_LOCATION ]]; then
        echo "RAM_DISK already existed $RAMDISK_LOCATION"
        return
    fi
    RAMDISK_SIZE_MB=$1

    if [[ $RAMDISK_SIZE_MB -le 0 ]]; then
        echo "invalid size $RAMDISK_SIZE_MB"
        return
    fi
    echo "crate RAM DISK size ${RAMDISK_SIZE_MB}MB"
    RAMDISK_SECTORS=$((2048 * $RAMDISK_SIZE_MB))
    DISK_ID=$(hdiutil attach -nomount ram://$RAMDISK_SECTORS)
    echo "Disk ID is :$DISK_ID"
    diskutil erasevolume HFS+ "$VOLUME" ${DISK_ID}
    echo $DISK_ID > $RAMDISK_CONFIG
}

function ramdisk_delete() {
    if [[ ! -d $RAMDISK_LOCATION ]]; then
        echo "RAM_DISK does not exist $RAMDISK_LOCATION"
        return
    fi
    DISK_ID=$(<$RAMDISK_CONFIG)
    if [[ -z $DISK_ID ]];then
        echo "invalid RAM_DISK abort"
        return
    fi
    echo "Disk ID is :$DISK_ID"
    umount -f $RAMDISK_LOCATION
    hdiutil detach $DISK_ID
}

function softlink() {
    CWD=$(pwd)
    NAME=$(basename $CWD)

    FROM=$1
    SRC=$CWD/$FROM
    TARGET=$RAMDISK_LOCATION/$NAME/$FROM
    echo "ln $TARGET -> $NAME/$FROM"
    rm -rf $FROM
    mkdir -p $(basename $SRC)
    mkdir -p $TARGET
    ln -s $TARGET $SRC
}

function ramdisk_build_cache() {
    if [[ ! -d $RAMDISK_LOCATION ]]; then
        echo "RAMDISK doesn't exist, please new first"
        return 1
    fi
    CWD=$(pwd)
    NAME=$(basename $CWD)
    echo "link ramdisk for gralde project $NAME"

    for dir in *;do
        if [[ -d $dir/build || -f $dir/build.gradle ]]; then
            softlink $dir/build
        fi
    done
    softlink build

    return
}

function ramdisk_build_cache_resotre() {
    if [[ ! -d $RAMDISK_LOCATION ]]; then
        echo "RAMDISK doesn't exist, please new first"
        return 1
    fi
    CWD=$(pwd)
    NAME=$(basename $CWD)

    rm -rf build

    for dir in *; do
        if [[ -d $dir/build ]]; then
            rm -rf $dir/build
        fi
    done
}

function ramdisk_trim() {
    CWD=$(pwd)
    NAME=$(basename $CWD)

    for dir in ${RAMDISK_LOCATION}/*; do
        if [[ -d $dir && $(basename $dir) != $NAME ]]; then
            echo "rm $dir"
            rm -rf $dir
        fi
    done

    return
}

COMMAND=$1
shift
case $COMMAND in
    "new")
        ramdisk_create $@
        ;;
    "delete" )
        ramdisk_delete $@
        ;;
    "link" )
        ramdisk_build_cache $@
        ;;
    "unlink")
        ramdisk_build_cache_resotre $@
        ;;
    "trim" )
        ramdisk_trim $@
        ;;
    * )
        name=$(basename $0)
        echo "$name new|delete|link|unlink|trim"
        echo "    new [size in MB] -> create ramdisk"
        echo "    delete           -> delete ramdisk"
        echo "    link             -> link gradle project build cache to ramdisk"
        echo "    unlink           -> unlink gradle project build cache to ramdisk"
        echo "    trim             -> delete other projects' build cache in ramdisk"
        ;;
esac