| // The compiler code necessary to support the env! extension. Eventually this |
| // should all get sucked into either the compiler syntax extension plugin |
| // interface. |
| // |
| |
| use rustc_ast::tokenstream::TokenStream; |
| use rustc_ast::{self as ast, GenericArg}; |
| use rustc_expand::base::{self, *}; |
| use rustc_span::symbol::{kw, sym, Ident, Symbol}; |
| use rustc_span::Span; |
| use std::env; |
| use thin_vec::thin_vec; |
| |
| pub fn expand_option_env<'cx>( |
| cx: &'cx mut ExtCtxt<'_>, |
| sp: Span, |
| tts: TokenStream, |
| ) -> Box<dyn base::MacResult + 'cx> { |
| let Some(var) = get_single_str_from_tts(cx, sp, tts, "option_env!") else { |
| return DummyResult::any(sp); |
| }; |
| |
| let sp = cx.with_def_site_ctxt(sp); |
| let value = env::var(var.as_str()).ok().as_deref().map(Symbol::intern); |
| cx.sess.parse_sess.env_depinfo.borrow_mut().insert((var, value)); |
| let e = match value { |
| None => { |
| let lt = cx.lifetime(sp, Ident::new(kw::StaticLifetime, sp)); |
| cx.expr_path(cx.path_all( |
| sp, |
| true, |
| cx.std_path(&[sym::option, sym::Option, sym::None]), |
| vec![GenericArg::Type(cx.ty_ref( |
| sp, |
| cx.ty_ident(sp, Ident::new(sym::str, sp)), |
| Some(lt), |
| ast::Mutability::Not, |
| ))], |
| )) |
| } |
| Some(value) => cx.expr_call_global( |
| sp, |
| cx.std_path(&[sym::option, sym::Option, sym::Some]), |
| thin_vec![cx.expr_str(sp, value)], |
| ), |
| }; |
| MacEager::expr(e) |
| } |
| |
| pub fn expand_env<'cx>( |
| cx: &'cx mut ExtCtxt<'_>, |
| sp: Span, |
| tts: TokenStream, |
| ) -> Box<dyn base::MacResult + 'cx> { |
| let mut exprs = match get_exprs_from_tts(cx, tts) { |
| Some(exprs) if exprs.is_empty() || exprs.len() > 2 => { |
| cx.span_err(sp, "env! takes 1 or 2 arguments"); |
| return DummyResult::any(sp); |
| } |
| None => return DummyResult::any(sp), |
| Some(exprs) => exprs.into_iter(), |
| }; |
| |
| let Some((var, _style)) = expr_to_string(cx, exprs.next().unwrap(), "expected string literal") else { |
| return DummyResult::any(sp); |
| }; |
| |
| let custom_msg = match exprs.next() { |
| None => None, |
| Some(second) => match expr_to_string(cx, second, "expected string literal") { |
| None => return DummyResult::any(sp), |
| Some((s, _style)) => Some(s), |
| }, |
| }; |
| |
| let sp = cx.with_def_site_ctxt(sp); |
| let value = env::var(var.as_str()).ok().as_deref().map(Symbol::intern); |
| cx.sess.parse_sess.env_depinfo.borrow_mut().insert((var, value)); |
| let e = match value { |
| None => { |
| let (msg, help) = match custom_msg { |
| None => ( |
| format!("environment variable `{var}` not defined at compile time"), |
| Some(help_for_missing_env_var(var.as_str())), |
| ), |
| Some(s) => (s.to_string(), None), |
| }; |
| let mut diag = cx.struct_span_err(sp, &msg); |
| if let Some(help) = help { |
| diag.help(help); |
| } |
| diag.emit(); |
| return DummyResult::any(sp); |
| } |
| Some(value) => cx.expr_str(sp, value), |
| }; |
| MacEager::expr(e) |
| } |
| |
| fn help_for_missing_env_var(var: &str) -> String { |
| if var.starts_with("CARGO_") |
| || var.starts_with("DEP_") |
| || matches!(var, "OUT_DIR" | "OPT_LEVEL" | "PROFILE" | "HOST" | "TARGET") |
| { |
| format!( |
| "Cargo sets build script variables at run time. Use `std::env::var(\"{var}\")` instead" |
| ) |
| } else { |
| format!("Use `std::env::var(\"{var}\")` to read the variable at run time") |
| } |
| } |