inst/templates/config.R

In extendr/rextendr: Call Rust Code from R using the 'extendr' Crate

# check the packages MSRV first
source("tools/msrv.R")

# check DEBUG and NOT_CRAN environment variables
env_debug <- Sys.getenv("DEBUG")
env_not_cran <- Sys.getenv("NOT_CRAN")

# check if the vendored zip file exists
vendor_exists <- file.exists("src/rust/vendor.tar.xz")

is_not_cran <- env_not_cran != ""
is_debug <- env_debug != ""

if (is_debug) {
  # if we have DEBUG then we set not cran to true
  # CRAN is always release build
  is_not_cran <- TRUE
  message("Creating DEBUG build.")
}

if (!is_not_cran) {
  message("Building for CRAN.")
}

# we set cran flags only if NOT_CRAN is empty and if
# the vendored crates are present.
.cran_flags <- ifelse(
  !is_not_cran && vendor_exists,
  "-j 2 --offline",
  ""
)

# when DEBUG env var is present we use `--debug` build
.profile <- ifelse(is_debug, "", "--release")
.clean_targets <- ifelse(is_debug, "", "$(TARGET_DIR)")

# when we are using a debug build we need to use target/debug instead of target/release
.libdir <- ifelse(is_debug, "debug", "release")

# read in the Makevars.in file
is_windows <- .Platform[["OS.type"]] == "windows"

# if windows we replace in the Makevars.win.in
mv_fp <- ifelse(
  is_windows,
  "src/Makevars.win.in",
  "src/Makevars.in"
)

# set the output file
mv_ofp <- ifelse(
  is_windows,
  "src/Makevars.win",
  "src/Makevars"
)

# delete the existing Makevars{.win}
if (file.exists(mv_ofp)) {
  message("Cleaning previous `", mv_ofp, "`.")
  invisible(file.remove(mv_ofp))
}

# read as a single string
mv_txt <- readLines(mv_fp)

# replace placeholder values
new_txt <- gsub("@CRAN_FLAGS@", .cran_flags, mv_txt) |>
  gsub("@PROFILE@", .profile, x = _) |>
  gsub("@CLEAN_TARGET@", .clean_targets, x = _) |>
  gsub("@LIBDIR@", .libdir, x = _)

message("Writing `", mv_ofp, "`.")
con <- file(mv_ofp, open = "wb")
writeLines(new_txt, con, sep = "\n")
close(con)

message("`tools/config.R` has finished.")