R/serialize.R

In nanxstats/r-serialize-timemachine: Running Serialization on Multiple R Versions

#' Extract R binary, run payload, and clean up
#'
#' @param installer R installer path
#' @param version Installer R version
#' @param dir_output RDS file output directory
#' @param ... Other arguments for `extract_r_installer()`
serialize_versioned <- function(installer, version, dir_output = "output/", ...) {
  # Prepare payload files ------------------------------------------------------
  path_rds <- normalizePath(dir_output, winslash = "/")

  # R >= 2.4.0 switched the default to `compress = TRUE` so set it to FALSE here
  payload_nodot <- paste0(
    'saveRDS("ABCDEF", compress = FALSE, file = paste(', "\"",
    path_rds,
    '/R-", paste(R.version$major, R.version$minor, sep = "."), ".rds", sep = ""))'
  )
  payload_dot <- paste0(
    '.saveRDS("ABCDEF", compress = FALSE, file = paste(', "\"",
    path_rds,
    '/R-", paste(R.version$major, R.version$minor, sep = "."), ".rds", sep = ""))'
  )

  writeLines(payload_dot, "payload-dot.R")
  writeLines(payload_nodot, "payload-nodot.R")

  # Extract R binaries from installer ------------------------------------------
  output <- extract_r_installer(installer, version = version, ...)

  # Construct and run command line calls ---------------------------------------

  # Only R >= 2.5.0 versions have Rscript.exe. Use Rterm.exe or Rcmd.exe before that.
  rcmd <- if (is_geq(version, "2.5.0")) {
    paste(normalizePath(file.path(output, "app/bin/Rscript.exe")), "--vanilla")
  } else {
    paste(normalizePath(file.path(output, "app/bin/R.exe")), "CMD BATCH --no-restore --no-save")
  }

  # Only R >= 2.13.0 versions have saveRDS(). Use .saveRDS() before that.
  payload <- if (is_geq(version, "2.13.0")) {
    normalizePath("payload-nodot.R")
  } else {
    normalizePath("payload-dot.R")
  }

  invisible(system(paste(rcmd, payload)))

  # Clean up -------------------------------------------------------------------
  fs::dir_delete(output)

  invisible(NULL)
}