R/helpers.r

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

tty_has_colors <- function() isTRUE(cli::num_ansi_colors() > 1L)

get_cargo_envvars <- function() {
  if (identical(.Platform$OS.type, "windows")) {
    # On Windows, PATH to Rust toolchain should be set by the installer.
    # If R >= 4.2, we need to override the linker setting.
    if (identical(R.version$crt, "ucrt")) {
      # `rustc` adds `-lgcc_eh` flags to the compiler, but Rtools' GCC doesn't have
      # `libgcc_eh` due to the compilation settings. So, in order to please the
      # compiler, we need to add empty `libgcc_eh` to the library search paths.
      #
      # For more details, please refer to
      # https://github.com/r-windows/rtools-packages/blob/2407b23f1e0925bbb20a4162c963600105236318/mingw-w64-gcc/PKGBUILD#L313-L316 # nolint: line_length_linter
      libgcc_path <- file.path(system.file(package = "rextendr"), "libgcc_mock")
      dir.create(libgcc_path, showWarnings = FALSE)
      file.create(file.path(libgcc_path, "libgcc_eh.a"))

      cargo_envvars <- c("current",
        CARGO_TARGET_X86_64_PC_WINDOWS_GNU_LINKER = "x86_64-w64-mingw32.static.posix-gcc.exe",
        LIBRARY_PATH = paste0(libgcc_path, ";", Sys.getenv("LIBRARY_PATH"))
      )
    } else {
      cargo_envvars <- NULL
    }
  } else {
    # In some environments, ~/.cargo/bin might not be included in PATH, so we need
    # to set it here to ensure cargo can be invoked. It's added to the tail as a
    # fallback, which is used only when cargo is not found in the user's PATH.
    path_envvar <- Sys.getenv("PATH", unset = "") # nolint: object_usage_linter
    cargo_path <- path.expand("~/.cargo/bin") # nolint: object_usage_linter
    # "current" means appending or overwriting the envvars in addition to the current ones.
    cargo_envvars <- c("current", PATH = glue("{path_envvar}:{cargo_path}"))
  }
  cargo_envvars
}