stream_device_prj/android/学习.md

源码包编译流程梳理

教程都是先执行这个

    source ./build/envsetup.sh
    lunch WW_Tinker_Board_2-userdebug
    ./build.sh

备注:build.sh代码第一行会自动source /build/envsetup.sh 因为lunch是在envsetup.sh中定义所以第一次不能省略source ./build/envsetup.sh

1. envsetup.sh 这个envsetup.sh中定义了很多环境设置环境变量的工具和函数 包含lunch mmm等函数

2. lunch WW_Tinker_Board_2-userdebug lunch的代码

   function lunch()
   {
       local answer
   
       if [ "$1" ] ; then
           answer=$1
       else
           print_lunch_menu
           echo -n "Which would you like? [aosp_arm-eng] "
           read answer
       fi
   
       local selection=
   
       if [ -z "$answer" ]
       then
           selection=aosp_arm-eng
       elif (echo -n $answer | grep -q -e "^[0-9][0-9]*$")
       then
           local choices=($(TARGET_BUILD_APPS= get_build_var COMMON_LUNCH_CHOICES))
           if [ $answer -le ${#choices[@]} ]
           then
               # array in zsh starts from 1 instead of 0.
               if [ -n "$ZSH_VERSION" ]
               then
                   selection=${choices[$(($answer))]}
               else
                   selection=${choices[$(($answer-1))]}
               fi
           fi
       else
           selection=$answer
       fi
   
       export TARGET_BUILD_APPS=
   
       local product variant_and_version variant version
   
       product=${selection%%-*} # Trim everything after first dash
       variant_and_version=${selection#*-} # Trim everything up to first dash
       if [ "$variant_and_version" != "$selection" ]; then
           variant=${variant_and_version%%-*}
           if [ "$variant" != "$variant_and_version" ]; then
               version=${variant_and_version#*-}
           fi
       fi
   
       if [ -z "$product" ]
       then
           echo
           echo "Invalid lunch combo: $selection"
           return 1
       fi
   
       TARGET_PRODUCT=$product \
       TARGET_BUILD_VARIANT=$variant \
       TARGET_PLATFORM_VERSION=$version \
       build_build_var_cache
       if [ $? -ne 0 ]
       then
           return 1
       fi
   
       export TARGET_PRODUCT=$(get_build_var TARGET_PRODUCT)
       export TARGET_BUILD_VARIANT=$(get_build_var TARGET_BUILD_VARIANT)
       if [ -n "$version" ]; then
       export TARGET_PLATFORM_VERSION=$(get_build_var TARGET_PLATFORM_VERSION)
       else
       unset TARGET_PLATFORM_VERSION
       fi
       export TARGET_BUILD_TYPE=release
   
       echo
   
       set_stuff_for_environment
       printconfig
       destroy_build_var_cache
   }
   

   lunch看起来就是根据给定的参数定义 三个环境变量

   TARGET_PRODUCT=$product \
   TARGET_BUILD_VARIANT=$variant \
   TARGET_PLATFORM_VERSION=$version \
   

   问题:参数传进来再哪里用 如果build.sh没有直接调用 要找到在哪调用了 全局搜索示例传入的参数获取一些信息 后再分析build.sh 竟然后26个文件7000多出有 写死的WW_Tinker_Board_2 的定义 看似不合理 应该是替换的原版android的某个名称 达到自定义名称的目的 否则这么一个一开始就需要全局引入的参数 应该是用变量实现 全局环境变量都有了 应该是调用 当然为这个配置项写死的配置应该很多 那应该以文件为单位 不应该出现一个文件多出该变量定义

3. build.sh 发现build.sh脚本中依然有写死的WW_Tinker_Board_2

       usage()
       {
       echo "USAGE: [-U] [-CK] [-A] [-p] [-o] [-u] [-v VERSION_NAME] [-n BUILD_NUMBER]"
           echo "No ARGS means use default build option                  "
           echo "WHERE: -U = build uboot                                 "
           echo "       -C = build kernel with Clang                     "
           echo "       -K = build kernel                                "
           echo "       -A = build android                               "
           echo "       -p = will build packaging in IMAGE      "
           echo "       -o = build OTA package                           "
           echo "       -u = build update.img                            "
           echo "       -v = build android with 'user' or 'userdebug'    "
           echo "       -n = set build number    "
           echo "       -r = pack the release    "
           echo "       -d = huild kernel dts name    "
           echo "       -V = build version    "
           echo "       -J = build jobs    "
           exit 1
       }
   

   支持的参数 不用解释 看说明就行

   source build/envsetup.sh >/dev/null
   BUILD_UBOOT=false
   BUILD_KERNEL_WITH_CLANG=false
   BUILD_KERNEL=false
   BUILD_ANDROID=false
   BUILD_AB_IMAGE=false
   BUILD_UPDATE_IMG=false
   BUILD_OTA=false
   BUILD_PACKING=false
   BUILD_VARIANT=`get_build_var TARGET_BUILD_VARIANT`
   KERNEL_DTS=""
   #BUILD_VERSION=""
   BUILD_JOBS=16
   PACK_RELEASE=false
   
   BUILD_NUMBER="eng"-"$USER"-"$(date  +%Y%m%d.%H%M)"
   RELEASE_NAME=Tinker_Board_2-Android11-"$BUILD_NUMBER"