R/get_available_packages.R

In DominikRafacz/deepdep: Visualise and Explore the Deep Dependencies of R Packages

#' @title Get the list of available packages
#'
#' @description Get names of packages that you have locally installed or that are available to be installed.
#'
#' @param bioc A \code{logical} value. If \code{TRUE} the Bioconductor dependencies data will be taken from the
#' Bioconductor repository. For this option to work properly, \code{BiocManager} package needs to be installed.
#' @param local A \code{logical} value. If \code{TRUE} only data of locally installed packages will be used (without API usage).
#' @param reset_cache A \code{logical} value. If \code{TRUE} the cache will be cleared before obtaining the list of packages.
#'
#' @return A \code{character} vector.
#'
#' @details Function uses caching - only the first usage scraps information from servers. Those
#' objects are then saved locally in temporary file and further usages loads needed data from the file.
#'
#' Arguments \code{bioc} and \code{local} cannot be \code{TRUE} simultaneously.
#' If neither \code{local} nor \code{bioc} are \code{TRUE}, vector contains all packages available
#' currently on CRAN. If \code{bioc} is \code{TRUE}, vector contains all packages available currently
#' on CRAN and via Bioconductor. If \code{local} is \code{TRUE}, vactor contains all of the packages
#' that are currently installed.
#'
#' @examples
#' \donttest{
#'
#' library(deepdep)
#'
#' av <- get_available_packages()
#' head(av)
#'
#' }
#'
#' @export
get_available_packages <- function(bioc = FALSE, local = FALSE, reset_cache = FALSE) {
  if (local && bioc) stop("You cannot use both 'local' and 'bioc' options at once.")
  if (reset_cache) reset_cached_files("ava")
  if (local) return(get_available_packages_cached("local"))
  if (bioc) get_available_packages_cached("bioc")
  else get_available_packages_cached("CRAN")
}

#' @importFrom utils available.packages contrib.url
get_available_packages_cached <- function(repo) {
  pkgs <- get_cached_obj("ava", repo)
  if (attr(pkgs, "new")) {
    pkgs <- switch(repo,
                   CRAN = available.packages(
                     contriburl = contrib.url("https://cloud.r-project.org/"))[, 1],
                   bioc = {BiocManager::available()},
                   local = list.dirs(.libPaths()[1], full.names = FALSE, recursive = FALSE)
                   )
    attr(pkgs, "type") <- "ava"
    attr(pkgs, "repo") <- repo
    attr(pkgs, "new") <- FALSE
    save_cache(pkgs)
  }
  class(pkgs) <- c("character", "available_packages")
  pkgs
}


#' @title Print function for an object of \code{available_packages} class
#'
#' @param x An object of \code{available_packages} class.
#' @param ... other
#'
#' @examples
#' \donttest{
#' library(deepdep)
#'
#' av <- get_available_packages()
#' head(av)
#' }
#'
#' @rdname print.available_packages
#' @export
print.available_packages <- function(x, ...) {
  attributes(x) <- NULL
  x <- unname(x)
  print(x)
}