for R < 4.0.0

update_pkg_po2

require(tools)
update_pkg_po2 <- function (pkgdir, pkg = NULL, version = NULL, copyright, bugs)
{
  same <- function(a, b) {
    tmpa <- readLines(a)
    tmpb <- readLines(b)
    tmpa <- tools:::filtergrep("^\"POT-Creation-Date:", tmpa)
    tmpb <- tools:::filtergrep("^\"POT-Creation-Date:", tmpb)
    identical(tmpa, tmpb)
  }
  pwd <- getwd()
  coll <- Sys.getlocale("LC_COLLATE")
  on.exit({
    Sys.setlocale("LC_COLLATE", coll)
    setwd(pwd)
  })
  Sys.setlocale("LC_COLLATE", "C")
  setwd(pkgdir)
  dir.create("po", FALSE)
  files <- dir("po")
  desc <- "DESCRIPTION"
  if (file.exists(desc)) {
    desc <- read.dcf(desc, fields = c("Package", "Version"))
    pkg <- name <- desc[1L]
    version <- desc[2L]
    if (missing(copyright))
      copyright <- NULL
    if (missing(bugs))
      bugs <- NULL
    stem <- file.path("inst", "po")
  }
  else {
    pkg <- basename(pkgdir)
    name <- "R"
    version <- as.character(getRversion())
    copyright <- "The R Core Team"
    bugs <- "bugs.r-project.org"
    stem <- file.path("..", "translations", "inst")
  }
  is_base <- (pkg == "base")
  have_src <- paste0(pkg, ".pot") %in% files
  ofile <- tempfile()
  xgettext2pot(".", ofile, name, version, bugs)
  potfile <- file.path("po", paste0("R-", pkg, ".pot"))
  if (file.exists(potfile) && same(potfile, ofile)) {
  }
  else file.copy(ofile, potfile, overwrite = TRUE)
  pofiles <- dir("po", pattern = "R-.*[.]po$", full.names = TRUE)
  pofiles <- pofiles[pofiles != "po/R-en@quot.po"]
  for (f in pofiles) {
    lang <- sub("^R-(.*)[.]po$", "\\1", basename(f))
    message("  R-", lang, ":", appendLF = FALSE, domain = NA)
    cmd <- paste("msgmerge --update", f, shQuote(potfile))
    if (system(cmd) != 0L) {
      warning("running msgmerge on ", sQuote(f), " failed",
              domain = NA)
      next
    }
    res <- checkPoFile(f, TRUE)
    if (nrow(res)) {
      print(res)
      message("not installing", domain = NA)
      next
    }
    dest <- file.path(stem, lang, "LC_MESSAGES")
    dir.create(dest, FALSE, TRUE)
    dest <- file.path(dest, sprintf("R-%s.mo", pkg))
    cmd <- paste("msgfmt -c --statistics -o", shQuote(dest),
                 shQuote(f))
    if (system(cmd) != 0L)
      warning(sprintf("running msgfmt on %s failed", basename(f)),
              domain = NA, immediate. = TRUE)
  }
  print("ahosine")
  if (l10n_info()[["UTF-8"]]) {
    lang <- "en@quot"
    message("  R-", lang, ":", domain = NA)
    f <- tempfile()
    en_quote(potfile, f)
    dest <- file.path(stem, lang, "LC_MESSAGES")
    dir.create(dest, FALSE, TRUE)
    dest <- file.path(dest, sprintf("R-%s.mo", pkg))
    cmd <- paste("msgfmt -c --statistics -o", shQuote(dest),
                 shQuote(f))
    if (system(cmd) != 0L)
      warning(sprintf("running msgfmt on %s failed", basename(f)),
              domain = NA, immediate. = TRUE)
  }
  print("kusoga")
  if (!(is_base || have_src))
    return(invisible())
  ofile <- tempfile()
  if (!is_base) {
    dom <- pkg
    od <- setwd("src")
    exts <- "[.](c|cc|cpp|m|mm)$"
    cfiles <- dir(".", pattern = exts)
    if (file.exists("windows"))
      cfiles <- c(cfiles, dir("windows", pattern = exts,
                              full.names = TRUE))
  }
  else {
    dom <- "R"
    od <- setwd("../../..")
    cfiles <- tools:::filtergrep("^#", readLines("po/POTFILES"))
  }
  cmd <- sprintf("xgettext --keyword=_ --keyword=N_ -o %s",
                 shQuote(ofile))
  cmd <- c(cmd, paste0("--package-name=", name), paste0("--package-version=",
                                                        version), "--add-comments=TRANSLATORS:", if (!is.null(copyright)) sprintf("--copyright-holder=\"%s\"",
                                                                                                                                  copyright), if (!is.null(bugs)) sprintf("--msgid-bugs-address=\"%s\"",
                                                                                                                                                                          bugs), if (is_base) "-C")
  cmd <- paste(c(cmd, cfiles), collapse = " ")
  if (system(cmd) != 0L)
    stop("running xgettext failed", domain = NA)
  setwd(od)
  potfile <- file.path("po", paste0(dom, ".pot"))
  if (!same(potfile, ofile))
    file.copy(ofile, potfile, overwrite = TRUE)
  pofiles <- dir("po", pattern = "^[^R].*[.]po$", full.names = TRUE)
  pofiles <- pofiles[pofiles != "po/en@quot.po"]
  for (f in pofiles) {
    lang <- sub("[.]po", "", basename(f))
    message("  ", lang, ":", appendLF = FALSE, domain = NA)
    cmd <- paste("msgmerge --update", shQuote(f), shQuote(potfile))
    if (system(cmd) != 0L) {
      warning("running msgmerge on ", f, " failed", domain = NA)
      next
    }
    res <- checkPoFile(f, TRUE)
    if (nrow(res)) {
      print(res)
      message("not installing", domain = NA)
      next
    }
    dest <- file.path(stem, lang, "LC_MESSAGES")
    dir.create(dest, FALSE, TRUE)
    dest <- file.path(dest, sprintf("%s.mo", dom))
    cmd <- paste("msgfmt -c --statistics -o", shQuote(dest),
                 shQuote(f))
    if (system(cmd) != 0L)
      warning(sprintf("running msgfmt on %s failed", basename(f)),
              domain = NA)
  }
  print("unko")
  if (l10n_info()[["UTF-8"]]) {
    lang <- "en@quot"
    message("  ", lang, ":", domain = NA)
    f <- tempfile()
    en_quote(potfile, f)
    dest <- file.path(stem, lang, "LC_MESSAGES")
    dir.create(dest, FALSE, TRUE)
    dest <- file.path(dest, sprintf("%s.mo", dom))
    cmd <- paste("msgfmt -c --statistics -o", shQuote(dest),
                 shQuote(f))
    if (system(cmd) != 0L)
      warning(sprintf("running msgfmt on %s failed", basename(f)),
              domain = NA)
  }
  invisible()
}

en_quote <- function (potfile, outfile)
{
  tfile <- tempfile()
  cmd <- paste("msginit -i", potfile, "--no-translator -l en -o",
               tfile)
  if (system(cmd, ignore.stderr = TRUE) != 0L)
    stop("running msginit failed", domain = NA)
  tfile2 <- tempfile()
  cmd <- paste("msgconv -t UTF-8 -o", tfile2, tfile)
  if (system(cmd) != 0L)
    stop("running msgconv failed", domain = NA)
  lines <- readLines(tfile2)
  starts <- which(startsWith(lines, "msgstr"))
  current <- 1L
  out <- character()
  for (s in starts) {
    if (current < s)
      out <- c(out, lines[seq.int(current, s - 1L, 1L)])
    start <- sub("([^\"]*)\"(.*)\"$", "\\1", lines[s])
    this <- sub("([^\"]*)\"(.*)\"$", "\\2", lines[s])
    current <- s + 1L
    while (startsWith(lines[current], "\"") && !is.na(lines[current])) {
      this <- c(this, sub("^\"(.*)\"$", "\\1", lines[current]))
      current <- current + 1L
    }
    nc <- nchar(this)
    n <- length(nc)
    this <- paste0(this, collapse = "")
    this <- gsub("^'([^`']*)'", "‘\\1’", this)
    this <- gsub("([^[:alpha:]]|\\\\n)'([^`']*)'", "\\1‘\\2’",
                 this)
    out <- if (n > 1L) {
      this1 <- character()
      sc <- c(0, cumsum(nc))
      for (i in seq_along(nc)) {
        if (!nc[i])
          this1 <- c(this1, "")
        else {
          this1 <- c(this1, substr(this, sc[i] + 1L,
                                   sc[i + 1]))
        }
      }
      c(out, paste0(start, "\"", this1[1L], "\""), paste0("\"",
                                                          this1[-1L], "\""))
    }
    else c(out, paste0(start, "\"", this, "\""))
  }
  if (current <= length(lines))
    out <- c(out, lines[seq.int(current, length(lines), 1L)])
  con <- file(outfile, "wb")
  writeLines(out, con, useBytes = TRUE)
  close(con)
}