R/package.R

In tfio: Interface to 'TensorFlow IO'

#' TensorFlow IO API for R
#'
#' This library provides an R interface to the
#' \href{https://github.com/tensorflow/io}{TensorFlow IO} API
#' that provides datasets and filesystem extensions maintained by SIG-IO.
#'
#' @docType package
#' @name tfio
NULL

#' @importFrom reticulate py_last_error tuple py_str py_has_attr import
#' @import tfdatasets
#' @import forge
NULL

tfio_lib <- NULL

.onLoad <- function(libname, pkgname) {

  # Delay load handler
  displayed_warning <- FALSE
  delay_load <- list(

    priority = 5,

    environment = "r-tensorflow-io",

    on_load = function() {
      if (!on_cran()) {
        check_tensorflow_version(displayed_warning)
      }
    },

    on_error = function(e) {
      if (!on_cran()) {
        stop(tf_config()$error_message, call. = FALSE)
      }
    }
  )

  if (!on_cran()) {
    if (!reticulate::py_module_available("tensorflow_io")) {
      tfio_module_not_available_message()
    } else {
      tfio_lib <<- import("tensorflow_io", delay_load = delay_load)
    }
  }
}

tfio_module_not_available_message <- function() {
  packageStartupMessage(
    paste0("tensorflow_io Python module is not available. ",
           "Please install it and try load it via library(tfio) again."))
}

check_tensorflow_version <- function(displayed_warning) {
  if (!on_cran()) {
    current_tf_ver <- tf_version()
    min_ver <- "1.13.0"
    if (current_tf_ver < min_ver) {
      if (!displayed_warning) {
        packageStartupMessage(
          "tfio requires TensorFlow version >= ", min_ver, " ",
          "(you are currently running version ", current_tf_ver, ").\n")
        displayed_warning <<- TRUE
      }
    }
  }
}

on_cran <- function() {
  !identical(Sys.getenv("NOT_CRAN"), "true")
}

.onUnload <- function(libpath) {

}

.onAttach <- function(libname, pkgname) {

}

.onDetach <- function(libpath) {

}