Flutter 2.0 iOS包大小优化

# 移除flutter_assets
# $res_release 为framework产物所在的位置，通常为/{FLUTTER_ROOT}/build/ios/framework/Release
# $flutter_data 为需要被分离的产物的收集目录

mv $res_release/App.xcframework/ios-arm64_armv7/App.framework/flutter_assets $flutter_data
mv $res_release/Flutter.xcframework/ios-armv7_arm64/Flutter.framework/icudtl.dat $flutter_data

# 编译模拟器架构
echo "start complie iOS debug simulator flutter engine"
./flutter/tools/gn --runtime-mode debug --simulator
./flutter/tools/gn --ios --runtime-mode debug --simulator
ninja -C out/ios_debug_sim -j 20
# 编译引擎十分消耗内存，这里我使用的是mac pro进行编译，所以设置成了20
# 可以根据自己电脑的性能调整为10或5左右

echo "simulator flutter engine complied succeed"

# 编译arm64架构
echo "start complie iOS release arm64 flutter engine"
./flutter/tools/gn --ios --runtime-mode release --ios-cpu arm64
ninja -C out/ios_release -j 20
echo "arm64 flutter engine complied succeed"

# 编译armv7架构
echo "start complie iOS release armv7 flutter engine"
./flutter/tools/gn --ios --runtime-mode release --ios-cpu arm
ninja -C out/ios_release_arm -j 20
echo "armv7 flutter engine complied succeed"

# 合并armv7和arm64架构
echo "merge framework"
rm -rf tmp/*
cp -rf out/ios_release/Flutter.framework tmp/
lipo -create -output tmp/Flutter.framework/Flutter \
out/ios_release/Flutter.framework/Flutter \
out/ios_release_arm/Flutter.framework/Flutter 

# 将编译后的 gen_snapshot 文件替换现有的 FlutterSDK 使用的 gen_snapshot
# ${FLUTTER_PATH} 为 FlutterSDK 所在的位置
cp -rf tmp/Flutter.framework "${FLUTTER_PATH}"/bin/cache/artifacts/engine/ios-release/Flutter.xcframework/ios-armv7_arm64/
cp -rf out/ios_debug_sim/Flutter.framework "${FLUTTER_PATH}"/bin/cache/artifacts/engine/ios-release/Flutter.xcframework/ios-x86_64-simulator/
cp -f out/ios_release/clang_x64/gen_snapshot "${FLUTTER_PATH}"/bin/cache/artifacts/engine/ios-release/gen_snapshot_arm64
cp -f out/ios_release_arm/clang_x64/gen_snapshot "${FLUTTER_PATH}"/bin/cache/artifacts/engine/ios-release/gen_snapshot_armv7

echo "complie end"

./flutter/tools/gn --ios --runtime-mode release --ios-cpu arm --bitcode

# 更新podspec版本号
updatePodsepcVersion(){
  podPath=${1}
  while read -r line
    do
      if [[ "$line" =~ .version ]]; then
        array=(${line//"'"/ })
        index=`expr ${#array[@]} - 1`
        lastVersion=${array[$index]}
        echo "${line}   index=${index} lastVersion=${lastVersion}"
        current_version=$(echo ${lastVersion} | awk -F. -v OFS=. 'NF==1{print ++$NF}; NF>1{if(length($NF+1)>length($NF))$(NF-1)++; $NF=sprintf("%0*d", length($NF), ($NF+1)%(10^length($NF))); print}') 
        echo "current_version = ${current_version}"
        gsed  -i "s/${line}/s.version = '${current_version}'/g" $podPath
     fi
    done < $podPath
}

# 收集所有plugin，并为产物瘦身
pluginCollect(){
  res_plugins_build=${1}
  target_plugins=${2}
  files=$(ls $res_plugins_build)

  for filename in $files; do
    sourcePath=$res_plugins_build/${filename}
    targetPath=$target_plugins/${filename}
    frameworkName=$(echo ${filename//.xcframework/})
    if [ -e $sourcePath ]; then
      if [ -e $sourcePath ]; then
        if [ $frameworkName != "App" -a $frameworkName != "Flutter" ]; then
          cp -rf $sourcePath $targetPath
          xcrunBitcode_strip $targetPath/ios-arm64_armv7/${frameworkName}.framework $frameworkName
        fi
      fi
    fi
  done
}

# 产物瘦身，仅使用arm64架构（因为我们项目只支持arm64），并移除bitcode
xcrunBitcode_strip() {
  framework_path=${1}
  framework_name=${2}
  
  cd ${framework_path}
  lipo ${framework_name} -thin arm64 -output ${framework_name}
  rm -rf arm64
  xcrun bitcode_strip -r ${framework_name} -o ${framework_name}
}

# 压缩分离的数据段等数据
packUpROData() {
  echo ">>>>>> zip snapshotData"
  zip -q -r $target_dir/FlutterSnapshot.zip $flutter_reduce
  mv $target_dir/FlutterSnapshot.zip $target_dir/FlutterSnapshot
}

# 将分离的数据段等数据上传到服务器
uploadROData() {
  echo ">>>>>> Will upload snapshotData"
  # 这里按照自己的需要上传即可
}

# 开始构建 Flutter iOS
# 我使用了fvm进行版本管理
fvm use 2.0.3
fvm flutter --version

# 解除 flutter 构建锁
lockFile="$FLUTTER_HOME/cache/lockfile"
if [[ -a "$lockFile" ]]; then
echo ">>>>>> Contains Lockfile !!";
rm -f "$lockFile"
fi

fvm flutter clean
fvm flutter packages get 
# 删除历史编译产物
rm -rf build

# 各种目录位置的定义
res_application=$PWD
res_build=$PWD/build
res_dir=$PWD/.ios/Flutter
res_flutter_plugins=$PWD/.flutter-plugins
res_source_dir=$res_dir/FlutterPluginRegistrant/Classes
res_release=$res_build/ios/framework/Release
target_dir=$PWD/LPEDU_Flutter_iOS
target_release_dir=$target_dir/Flutter_Release
target_release_plugins_dir=$target_release_dir/Plugins
target_podspec=$target_dir/LPEDU_Flutter_iOS.podspec
target_branch=master

# 创建分离数据段的目录位置
armv7=./SnapshotData/armv7
arm64=./SnapshotData/arm64
flutter_reduce=./SnapshotData/flutter_reduce
mkdir -p $armv7
mkdir -p $arm64
mkdir -p $flutter_reduce

if [ -d "$target_release_dir" ]; then
rm -rf $target_release_dir
fi
mkdir -p $target_release_dir

cd $res_application
# 执行构建命令
fvm flutter build ios-framework --release --no-debug --no-profile

# 编译分离的数据段为可用的二进制
xcrun cc -arch armv7 -c $armv7/IsolateSnapshotData.S -o $armv7/HeadIsolateData.dat
xcrun cc -arch armv7 -c $armv7/VmSnapshotData.S -o $armv7/HeadVMData.dat
# 去除多余头部
tail -c +313 $armv7/HeadIsolateData.dat > $armv7/IsolateData.dat
tail -c +313 $armv7/HeadVMData.dat > $armv7/VMData.dat

xcrun cc -arch arm64 -c $arm64/IsolateSnapshotData.S -o $arm64/HeadIsolateData.dat
xcrun cc -arch arm64 -c $arm64/VmSnapshotData.S -o $arm64/HeadVMData.dat
tail -c +313 $arm64/HeadIsolateData.dat > $arm64/IsolateData.dat
tail -c +313 $arm64/HeadVMData.dat > $arm64/VMData.dat

mkdir -p $flutter_reduce/arm64
# mkdir -p $flutter_reduce/armv7

# 不使用armv7的snasphotData
# cp -rf $armv7/IsolateData.dat $flutter_reduce/armv7
# cp -rf $armv7/VMData.dat $flutter_reduce/armv7

cp -rf $arm64/IsolateData.dat $flutter_reduce/arm64
cp -rf $arm64/VMData.dat $flutter_reduce/arm64

# 分离assets文件夹以及icudat.dat，也放到flutter_reduce目录下
mv $res_release/App.xcframework/ios-arm64_armv7/App.framework/flutter_assets $flutter_reduce
mv $res_release/Flutter.xcframework/ios-armv7_arm64/Flutter.framework/icudtl.dat $flutter_reduce

# 定义当前版本号，会随着updatePodsepcVersion方法进行更新
current_version='0.0.1'
cd $target_dir
cp -rf $res_release/App.xcframework $target_release_dir/App.xcframework
cp -rf $res_release/Flutter.xcframework $target_release_dir/Flutter.xcframework

if [ -d "$target_release_plugins_dir" ]; then
  rm -rf $target_release_plugins_dir
fi
mkdir -p $target_release_plugins_dir

# 收集plugin产物，并更新产物podspec
pluginCollect $res_release $target_release_plugins_dir
updatePodsepcVersion $target_podspec

xcrunBitcode_strip $target_release_dir/Flutter.xcframework/ios-armv7_arm64/Flutter.framework Flutter
xcrunBitcode_strip $target_release_dir/App.xcframework/ios-arm64_armv7/App.framework App
# 移除符号表
xcrun dsymutil -o $target_release_dir/Flutter.xcframework/ios-armv7_arm64/Flutter.framework.DSYM
xcrun strip -x -S $target_release_dir/Flutter.xcframework/ios-armv7_arm64/Flutter.framework/flutter

rm -rf $target_dir/FlutterSnapshot.bundle
mkdir -p $target_dir/FlutterSnapshot
cd $res_application
# 压缩数据
packUpROData
# 上传数据
uploadROData $current_version
# 创建FlutterSnapshot.bundle，用于存放分离的数据的zip文件
mv $target_dir/FlutterSnapshot $target_dir/FlutterSnapshot.bundle
rm -rf ./SnapshotData

lastCommit="version $current_version"

# git 上提交产物
cd $target_dir
git add .
git commit -m "$lastCommit"
git push origin ${target_branch}
cd -

# 清空工作区
if [ -d "$target_dir" ]; then
  rm -rf $target_dir
fi