Android P update_engine分析（六）-- PostinstallRunnerAction的工作

上篇已经分析过了InstallPlanAction、DownloadAction、FileSystemVerityAction 三个Action的工作内容，还有一个PostinstallRunnerAction的在这篇中继续分析，每个Action都是从PerformAction开始的：

void PostinstallRunnerAction::PerformAction() {
   
  CHECK(HasInputObject());
  install_plan_ = GetInputObject();
  //确认下是否需要powerwash_, 如果有设置，一般在ApplyPayload的那个hashKey中会带有POWERWASH的key值
  if (install_plan_.powerwash_required) {
   
    if (hardware_->SchedulePowerwash()) {
   
      powerwash_scheduled_ = true;
    } else {
   
      return CompletePostinstall(ErrorCode::kPostinstallPowerwashError);
    }
  }

  // 初始化所有升级分区的权重
  partition_weight_.resize(install_plan_.partitions.size());
  total_weight_ = 0;
  for (size_t i = 0; i < install_plan_.partitions.size(); ++i) {
   
    partition_weight_[i] = install_plan_.partitions[i].run_postinstall;
    total_weight_ += partition_weight_[i];
  }
  accumulated_weight_ = 0;
  ReportProgress(0);

  PerformPartitionPostinstall();
}

上面主要做判断是否需要powerwash_，一般的升级方式不需要powerwash，然后初始升级分区的权重，同时保存这些权重值，之后开始分区升级：

void PostinstallRunnerAction::PerformPartitionPostinstall() {
   
  //判断是否在升级过程中
  if (!install_plan_.run_post_install) {
   
    LOG(INFO) << "Skipping post-install according to install plan.";
    return CompletePostinstall(ErrorCode::kSuccess);
  }
  //判断下载路