target=$1CM_DEVICES_ONLY="true" #只编译CM支持的设备unset LUNCH_MENU_CHOICESadd_lunch_combo full-eng#vendor/cm/vendorsetup.sh 该脚本会从github上下载cm支持的产品，#并添加至LUNCH_MENU_CHOICES变量 ，该变量表示产品列表for f in `/bin/ls vendor/cm/vendorsetup.sh 2> /dev/null`     do        echo "including $f"        . $f      doneunset f  #如果没有带任何参数，那么调用lunch函数，让用户选择产品if [ $# -eq 0 ]; then         lunchelse#target格式：$product-$build_variant 或者 $product #  示例 cm_i9100-userdebug 或 i9100    echo "z$target" | grep -q "-"    #如果用户输入的产品格式是$product-$build_variant 那么直接调用lunch    if [ $? -eq 0 ]; then         # A buildtype was specified, assume a full device name        lunch $target    else         #如果用户输入的产品格式是$product，        #那么扩展该变量为cm_$target-userdebug格式       # This is probably just the CM model name        lunch cm_$target-userdebug    fifireturn $?

local answerif [ "$1" ] ; then    answer=$1else    #若调用者没有指定产品，那么打印产品列表，让用户选择    print_lunch_menu    echo -n "Which would you like? [full-eng] "    read answerfilocal selection=if [ -z "$answer" ] #默认产品为full-engthen    selection=full-engelif (echo -n $answer | grep -q -e "^[0-9][0-9]*$")#用户如输入的是数字then    if [ $answer -le ${#LUNCH_MENU_CHOICES[@]} ]    then        selection=${LUNCH_MENU_CHOICES[$(($answer-1))]}    fi#选择的产品为$product-$build_variant格式    elif (echo -n $answer | grep -q -e "^[^\-][^\-]*-[^\-][^\-]*$")then    selection=$answerfi if [ -z "$selection" ]#selection格式为$product-$build_variantthen    echo    echo "Invalid lunch combo: $answer"    return 1fi export TARGET_BUILD_APPS=  #提取product变量 product示例cm_i9100local product=$(echo -n $selection | sed -e "s/-.*$//")check_product $product #检查产品是否支持if [ $? -ne 0 ]#若产品不支持then    #if we can't find a product, try to grab it off the CM github    T=$(gettop)    pushd $T > /dev/null    #下载prouct的配置 放在device/$vendor/$product目录    build/tools/roomservice.py $product     popd > /dev/null    check_product $product #再次检查产品是否支持else    #获取最新配置 更新device/$vendor/$product    build/tools/roomservice.py $product truefiif [ $? -ne 0 ]then    echo    echo "** Don't have a product spec for: '$product'"    echo "** Do you have the right repo manifest?"    product=fi#从$product-$build_variant里提取$variantlocal variant=$(echo -n $selection | sed -e "s/^[^\-]*-//")check_variant $variantif [ $? -ne 0 ]then    echo    echo "** Invalid variant: '$variant'"    echo "** Must be one of ${VARIANT_CHOICES[@]}"    variant=fi if [ -z "$product" -o -z "$variant" ]then    echo    return 1fi export TARGET_PRODUCT=$productexport TARGET_BUILD_VARIANT=$variantexport TARGET_BUILD_TYPE=release fixup_common_out_dir #建立$(OUT_DIR)/target/common目录 #设置PROMPT_COMMAND变量，java_home，PATH目录，set_sequence_numberset_stuff_for_environment# 打印选择产品后的重要环境变量printconfig

T=$(gettop)if [ ! "$T" ]; then    echo "Couldn't locate the top of the tree.  Try setting TOP." >&2    returnfi if (echo -n $1 | grep -q -e "^cm_") ; then   CM_BUILD=$(echo -n $1 | sed -e 's/^cm_//g')else   CM_BUILD=fiexport CM_BUILDCALLED_FROM_SETUP=true BUILD_SYSTEM=build/core \    TARGET_PRODUCT=$1 \    TARGET_BUILD_VARIANT= \    TARGET_BUILD_TYPE= \    TARGET_BUILD_APPS= \    get_build_var TARGET_DEVICE > /dev/null

T=$(gettop)if [ ! "$T" ]; then    echo "Couldn't locate the top of the tree.  Try setting TOP." >&2    returnfiCALLED_FROM_SETUP=true BUILD_SYSTEM=build/core \ #$1的值可能为TARGET_DEVICE  make --no-print-directory -C "$T" -f build/core/config.mk dumpvar-$1

T=$(gettop)if [ ! "$T" ]; then    echo "Couldn't locate the top of the tree.  Try setting TOP." >&2    returnfiget_build_var report_config

local MM_MAKE=makelocal ARG=for ARG in $@ ; do #如果参数中有mka，那么利用mka进行编译    if [ "$ARG" = mka ]; then        MM_MAKE=mka    fidone#如果处在根目录 利用Android根目录的makefile编译选中目标if [ -f build/core/envsetup.mk -a -f Makefile ]; then     $MM_MAKE $@ else        T=$(gettop)    #找到最近的makfile，即当前目录所在工程的makefile    local M=$(findmakefile)     # Remove the path to top as the makefilepath needs to be relative    local M=`echo $M|sed 's:'$T'/::'`    if [ ! "$T" ]; then        echo "Couldn't locate the top of the tree.  Try setting TOP."    elif [ ! "$M" ]; then        echo "Couldn't locate a makefile from the current directory."    else        #使用ONE_SHOT_MAKEFILE关键字确定工程所用的makefile，        #并利用Android根目录的makefile进行编译        ONE_SHOT_MAKEFILE=$M $MM_MAKE -C $T all_modules $@     fifi

local MMM_MAKE=makeT=$(gettop)if [ "$T" ]; then    local MAKEFILE=    local MODULES=    local ARGS=    local DIR TO_CHOP    #提取编译选项(用-指定编译参数)    local DASH_ARGS=$(echo "$@" | awk -v RS=" " -v ORS=" " '/^-.*$/')     #提取编译目录    local DIRS=$(echo "$@" | awk -v RS=" " -v ORS=" " '/^[^-].*$/')    for DIR in $DIRS ; do        MODULES=`echo $DIR | sed -n -e 's/.*:\(.*$\)/\1/p' | sed 's/,/ /'`        #提取模块 dir格式:dirname:modulename        if [ "$MODULES" = "" ]; then            MODULES=all_modules        fi        DIR=`echo $DIR | sed -e 's/:.*//' -e 's:/$::'`        #如果指定目录有Android.mk，计算出MAKEFILE变量的值        if [ -f $DIR/Android.mk ]; then             TO_CHOP=`(cd -P -- $T && pwd -P) | wc -c | tr -d ' '`            TO_CHOP=`expr $TO_CHOP + 1`            START=`PWD= /bin/pwd`            MFILE=`echo $START | cut -c${TO_CHOP}-`            if [ "$MFILE" = "" ] ; then                MFILE=$DIR/Android.mk            else                MFILE=$MFILE/$DIR/Android.mk            fi            MAKEFILE="$MAKEFILE $MFILE"         else #特殊目标 其实是做编译参数            if [ "$DIR" = snod ]; then                ARGS="$ARGS snod"            elif [ "$DIR" = showcommands ]; then                ARGS="$ARGS showcommands"            elif [ "$DIR" = dist ]; then                ARGS="$ARGS dist"            elif [ "$DIR" = incrementaljavac ]; then                ARGS="$ARGS incrementaljavac"            elif [ "$DIR" = mka ]; then                MMM_MAKE=mka            else                echo "No Android.mk in $DIR."                return 1            fi        fi    done    #使用ONE_SHOT_MAKEFILE关键字确定工程所用的makefile，    #并利用Android根目录的makefile进行编译    ONE_SHOT_MAKEFILE="$MAKEFILE" $MMM_MAKE -C $T $DASH_ARGS $MODULES $ARGSelse    echo "Couldn't locate the top of the tree.  Try setting TOP."fi