build/envsetup.sh内lunch解析

 ........
 #    测试device是否存在且是一个目录 并且 只查找device目录4层以上的子目录，名字为vendorsetup.sh 并且 将命令执行的错误报告直接送往回收站 不显示在屏幕上
 #    测试vendor是否存在且是一个目录 并且 只查找vendor目录4层以上的子目录，名字为vendorsetup.sh 并且 将命令执行的错误报告直接送往回收站 不显示在屏幕上
 for f in `test -d device && find -L device -maxdepth  -name 'vendorsetup.sh' > /dev/null` \
          `test -d vendor && find -L vendor -maxdepth  -name 'vendorsetup.sh' > /dev/null`
 do
 #    打印包含这些vendorsetup.sh 并 执行这些vendorsetup.sh
     echo "including $f"
     . $f
 done
 unset f
 ........

↑第一步：build/envsetup.sh中vendrosetup.sh脚本执行

 root@book-virtual-machine:/work/android-5.0.# source build/envsetup.sh
 including device/asus/deb/vendorsetup.sh
 including device/asus/fugu/vendorsetup.sh
 including device/asus/tilapia/vendorsetup.sh
 including device/asus/flo/vendorsetup.sh
 including device/asus/grouper/vendorsetup.sh
 including device/samsung/manta/vendorsetup.sh
 including device/friendly-arm/tiny4412/vendorsetup.sh
 including device/lge/mako/vendorsetup.sh
 including device/lge/hammerhead/vendorsetup.sh
 including device/moto/shamu/vendorsetup.sh
 including device/generic/mini-emulator-mips/vendorsetup.sh
 including device/generic/mini-emulator-armv7-a-neon/vendorsetup.sh
 including device/generic/mini-emulator-arm64/vendorsetup.sh
 including device/generic/mini-emulator-x86/vendorsetup.sh
 including device/generic/mini-emulator-x86_64/vendorsetup.sh
 including sdk/bash_completion/adb.bash

↑第二步：build/envsetup.sh中vendrosetup.sh脚本执行部分的执行效果

add_lunch_combo full_tiny4412-userdebug add_lunch_combo full_tiny4412-eng

↑第三步：举例：including device/friendly-arm/tiny4412/vendorsetup.sh内容

 #    清空LUNCH_MENU_CHOICES
 unset LUNCH_MENU_CHOICES
 function add_lunch_combo()
 {
 #    new_combo局部变量化，且赋值为add_lunch_combo的参数
 #    即add_lunch_combo full_tiny4412-userdebug的full_tiny4412-userdebug
 #    局部变量化c
     local new_combo=$
     local c
 #    如果LUNCH_MENU_CHOICES有参数
     for c in ${LUNCH_MENU_CHOICES[@]} ; do
 #    如果add_lunch_combo参数1存在于LUNCH_MENU_CHOICES中 则返回
         if [ "$new_combo" = "$c" ] ; then
             return
         fi
     done
 #   如果LUNCH_MENU_CHOICES无参数，则将add_lunch_combo的参数1放入LUNCH_MENU_CHOICES
     LUNCH_MENU_CHOICES=(${LUNCH_MENU_CHOICES[@]} $new_combo)
 }

↑第四步：build/envsetup.sh中add_lunch_combo功能函数

 function lunch()
 {
 #    answer局部变量化
     local answer
 #    lunch如果有参数则answer=参数1
     if [ "$1" ] ; then
         answer=$
     else
 #    如果没有参数则打印lunch目录
         print_lunch_menu
 .......
 }

↑第五步：build/envsetup.sh中lunch功能函数的第一步，打印选项

 function print_lunch_menu()
 {
 #    系统名称局部变量化，并打印帮助信息
     local uname=$(uname)
     echo
     echo "You're building on" $uname
     echo
     echo "Lunch menu... pick a combo:"
 #    初始化局部变量i=，这个是索引编号
     local i=
 #    初始化局部变量，这个是用户输入编号或选项英文
     local choice
 #    从LUNCH_MENU_CHOICES中取出放到choice中
 #    并打印 “编号.LUNCH_MENU_CHOICE中的英文选项”
 #    编号i累加
     for choice in ${LUNCH_MENU_CHOICES[@]}
     do
         echo "     $i. $choice"
         i=$(($i+))
     done

     echo
 }

↑第六步：build/envsetup.sh中print_lunch_menu功能函数

 ......#接上面打印菜单
         echo -n "Which would you like? [aosp_arm-eng] "
 #    读取用户输入的编号或者英文选项
         read answer
     fi

     local selection=
 #    如果没有输入编号或者英文选项，则默认选择了aosp_arm-eng
     if [ -z "$answer" ]
     then
         selection=aosp_arm-eng
 #    如果输入信息为数字，且数字小于LUNCH_MENU_CHOICES个数
     elif (echo -n $answer | grep -q -e "^[0-9][0-9]*$")
     then
         if [ $answer -le ${#LUNCH_MENU_CHOICES[@]} ]
 #    将输入编号-1的英文选项放入selection（因为数组是从0开始，0对应索引1）
         then
             selection=${LUNCH_MENU_CHOICES[$(($answer-))]}
         fi
 #    如果输入信息为具有-符号的则为英文 直接放入selection
     elif (echo -n $answer | grep -q -e "^[^\-][^\-]*-[^\-][^\-]*$")
     then
         selection=$answer
     fi
 #    如果此时selection依旧为0，则打印无效lunch combo:输入值
     if [ -z "$selection" ]
     then
         echo
         echo "Invalid lunch combo: $answer"
         return
     fi
 #    导出编译使用的环境变量
     export TARGET_BUILD_APPS=
 #    提取"-"位置以前的字符串放入product，比如“full_tiny4412”
     local product=$(echo -n $selection | sed -e "s/-.*$//")
     check_product $product
     if [ $? -ne  ]
     then
         echo
         echo "** Don't have a product spec for: '$product'"
         echo "** Do you have the right repo manifest?"
         product=
     fi
 #    提取"-"位置以后的字符串放入variant，比如“userdebug”
     local variant=$(echo -n $selection | sed -e "s/^[^\-]*-//")
     check_variant $variant
     if [ $? -ne  ]
     then
         echo
         echo "** Invalid variant: '$variant'"
         echo "** Must be one of ${VARIANT_CHOICES[@]}"
         variant=
     fi
 #    如果product、variant为空则返回1
     if [ -z "$product" -o -z "$variant" ]
     then
         echo
         return
     fi
 #    导出TARGET_PRODUCT=刚刚得到的product
 #    导出TARGET_BUILD_VARIANT=刚刚得到的variant
 #    导出TARGET_BUILD_TYPE=release

     export TARGET_PRODUCT=$product
     export TARGET_BUILD_VARIANT=$variant
     export TARGET_BUILD_TYPE=release

     echo
 #    设置编译相关的环境功能函数
     set_stuff_for_environment
 #    后面会调用get_build_var report_config
 #    里面会执行make --no-print-directory -C "$T" -f build/core/config.mk dumpvar-$
 #    即 编译config.mk
     printconfig
 }

↑第七步：build/envsetup.sh中lunch功能函数

 function set_stuff_for_environment()
 {
 #    设置名称变量，比如架构、产品、主板、应用、命令行提示符
     settitle
 #    设置JAVA jdk环境变量
     set_java_home
 #    设置Android PATH、ANDROID_TOOLCHAIN、ANDROID_KERNEL_TOOLCHAIN_PATH、ANDROID_EMULATOR_PREBUILTS等路径
     setpaths
 #    设置BUILD_ENV_SEQUENCE_NUMBER
     set_sequence_number

     export ANDROID_BUILD_TOP=$(gettop)
 #    设置gcc的警告和错误可以彩色显示
     export GCC_COLORS='error=01;31:warning=01;35:note=01;36:caret=01;32:locus=01:quote=01'
 }

↑第八步：build/envsetup.sh中set_stuff_for_environment功能函数

 function settitle()
 {
     if [ "$STAY_OFF_MY_LAWN" = "" ]; then
         local arch=$(gettargetarch)
         local product=$TARGET_PRODUCT
         local variant=$TARGET_BUILD_VARIANT
         local apps=$TARGET_BUILD_APPS
 #    导出PROMPT_COMMAND，配合HISTORY_FILE设置的文件，进行记录什么用户，在什么时间，做了什么操作。
 #    PROMPT_COMMAND主要是设置打印信息格式
         if [ -z "$apps" ]; then
             export PROMPT_COMMAND="echo -ne \"\033]0;[${arch}-${product}-${variant}] ${USER}@${HOSTNAME}: ${PWD}\007\""
         else
             export PROMPT_COMMAND="echo -ne \"\033]0;[$arch $apps $variant] ${USER}@${HOSTNAME}: ${PWD}\007\""
         fi
     fi
 }

↑第九步：build/envsetup.sh中settitle功能函数

关于set_java_home setpaths set_sequence_number设置函数不在赘述，同类方法

 function printconfig()
 {
     T=$(gettop)
     if [ ! "$T" ]; then
         echo "Couldn't locate the top of the tree.  Try setting TOP." >&
         return
     fi
 #    这里继续调用get_build_var report_config
 #    get_build_var会编译config.mk详见hmm笔记
 #    report_config作为dumpvar-report_config
 #    dumpvar.mk中ifneq ($(dumpvar_goals),report_config)中会将PRINT_BUILD_CONFIG置空
 #    ifneq ($(PRINT_BUILD_CONFIG),) ：PRINT_BUILD_CONFIG为空则执行打印描述编译环境配置的变量信息
     get_build_var report_config
 }

↑第十步：build/envsetup.sh中printconfig功能函数与build/core/dumpvar.mk中打印编译环境配置

最后编译config.mk，config.mk内容见config.mk笔记