libpdx: Add service poke logic to ServiceUtility.

#ifndef ANDROID_PDX_DEFAULT_TRANSPORT_SERVICE_UTILITY_H_

#define ANDROID_PDX_DEFAULT_TRANSPORT_SERVICE_UTILITY_H_

#include <ftw.h>

#include <pdx/client.h>

#include <pdx/default_transport/client_channel_factory.h>

#include <pdx/service.h>

    return ClientChannelFactory::GetEndpointPath(endpoint_path);

  }

  // Traverses the PDX service path space and sends a message to reload system

  // properties to each service endpoint it finds along the way.

  // NOTE: This method is used by atrace to poke PDX services. Please avoid

  // unnecessary changes to this mechanism to minimize impact on atrace.

  static bool PokeServices() {

    const int kMaxDepth = 16;

    const int result =

        nftw(GetRootEndpointPath().c_str(), PokeService, kMaxDepth, FTW_PHYS);

    return result == 0 ? true : false;

  }

 private:

  friend BASE;

  ServiceUtility(const std::string& endpoint_path, int* error = nullptr)

      : BASE(ClientChannelFactory::Create(endpoint_path)) {

      : BASE(ClientChannelFactory::Create(endpoint_path), 0) {

    if (error)

      *error = Client::error();

  }

  // Sends the sysprop_change message to the service at fpath, so it re-reads

  // its system properties. Returns 0 on success or a negated errno code on

  // failure.

  // NOTE: This method is used by atrace to poke PDX services. Please avoid

  // unnecessary changes to this mechanism to minimize impact on atrace.

  static int PokeService(const char* fpath, const struct stat* /*sb*/,

                         int typeflag, struct FTW* /*ftwbuf*/) {

    const bool kIgnoreErrors = true;

    if (typeflag == FTW_F) {

      int error;

      auto utility = ServiceUtility::Create(fpath, &error);

      if (!utility) {

        if (error != -ECONNREFUSED) {

          ALOGE("ServiceUtility::PokeService: Failed to open %s: %s.", fpath,

                strerror(-error));

        }

        return kIgnoreErrors ? 0 : error;

      }

      auto status = utility->ReloadSystemProperties();

      if (!status) {

        ALOGE(

            "ServiceUtility::PokeService: Failed to send sysprop change to %s: "

            "%s",

            fpath, status.GetErrorMessage().c_str());

        return kIgnoreErrors ? 0 : -status.error();

      }

    }

    return 0;

  }

  ServiceUtility(const ServiceUtility&) = delete;

  void operator=(const ServiceUtility&) = delete;

};