bcabcf53cf
Change `bytes!()` to return
{
static BYTES: &'static [u8] = &[...];
BYTES
}
This gives it the `'static` lifetime, whereas before it had an rvalue
lifetime. Until recently this would have prevented assigning `bytes!()`
to a static, as in
static FOO: &'static [u8] = bytes!(1,2,3);
but #14183 fixed it so blocks are now allowed in constant expressions
(with restrictions).
Fixes #11641.
99 lines
3.5 KiB
Rust
99 lines
3.5 KiB
Rust
// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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/* The compiler code necessary to support the bytes! extension. */
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use ast;
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use codemap::Span;
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use ext::base::*;
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use ext::base;
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use ext::build::AstBuilder;
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pub fn expand_syntax_ext(cx: &mut ExtCtxt, sp: Span, tts: &[ast::TokenTree])
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-> Box<base::MacResult> {
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// Gather all argument expressions
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let exprs = match get_exprs_from_tts(cx, sp, tts) {
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None => return DummyResult::expr(sp),
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Some(e) => e,
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};
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let mut bytes = Vec::new();
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let mut err = false;
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for expr in exprs.iter() {
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match expr.node {
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// expression is a literal
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ast::ExprLit(lit) => match lit.node {
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// string literal, push each byte to vector expression
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ast::LitStr(ref s, _) => {
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for byte in s.get().bytes() {
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bytes.push(cx.expr_u8(expr.span, byte));
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}
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}
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// u8 literal, push to vector expression
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ast::LitUint(v, ast::TyU8) => {
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if v > 0xFF {
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cx.span_err(expr.span, "too large u8 literal in bytes!");
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err = true;
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} else {
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bytes.push(cx.expr_u8(expr.span, v as u8));
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}
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}
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// integer literal, push to vector expression
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ast::LitIntUnsuffixed(v) => {
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if v > 0xFF {
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cx.span_err(expr.span, "too large integer literal in bytes!");
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err = true;
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} else if v < 0 {
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cx.span_err(expr.span, "negative integer literal in bytes!");
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err = true;
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} else {
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bytes.push(cx.expr_u8(expr.span, v as u8));
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}
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}
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// char literal, push to vector expression
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ast::LitChar(v) => {
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if v.is_ascii() {
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bytes.push(cx.expr_u8(expr.span, v as u8));
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} else {
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cx.span_err(expr.span, "non-ascii char literal in bytes!");
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err = true;
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}
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}
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_ => {
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cx.span_err(expr.span, "unsupported literal in bytes!");
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err = true;
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}
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},
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_ => {
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cx.span_err(expr.span, "non-literal in bytes!");
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err = true;
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}
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}
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}
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// For some reason using quote_expr!() here aborts if we threw an error.
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// I'm assuming that the end of the recursive parse tricks the compiler
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// into thinking this is a good time to stop. But we'd rather keep going.
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if err {
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// Since the compiler will stop after the macro expansion phase anyway, we
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// don't need type info, so we can just return a DummyResult
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return DummyResult::expr(sp);
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}
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let e = cx.expr_vec_slice(sp, bytes);
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let e = quote_expr!(cx, { static BYTES: &'static [u8] = $e; BYTES});
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MacExpr::new(e)
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}
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