src/libsyntax_ext/source_util.rs

   1 use syntax_expand::panictry;
   2 use syntax_expand::base::{self, *};
   3 use syntax::ast;
   4 use syntax::parse::{self, token, DirectoryOwnership};
   5 use syntax::print::pprust;
   6 use syntax::ptr::P;
   7 use syntax::symbol::Symbol;
   8 use syntax::tokenstream::TokenStream;
   9 use syntax::early_buffered_lints::BufferedEarlyLintId;
  10
  11 use smallvec::SmallVec;
  12 use syntax_pos::{self, Pos, Span};
  13
  14 use rustc_data_structures::sync::Lrc;
  15
  16 // These macros all relate to the file system; they either return
  17 // the column/row/filename of the expression, or they include
  18 // a given file into the current one.
  19
  20 /// line!(): expands to the current line number
  21 pub fn expand_line(cx: &mut ExtCtxt<'_>, sp: Span, tts: TokenStream)
  22                    -> Box<dyn base::MacResult+'static> {
  23     base::check_zero_tts(cx, sp, tts, "line!");
  24
  25     let topmost = cx.expansion_cause().unwrap_or(sp);
  26     let loc = cx.source_map().lookup_char_pos(topmost.lo());
  27
  28     base::MacEager::expr(cx.expr_u32(topmost, loc.line as u32))
  29 }
  30
  31 /* column!(): expands to the current column number */
  32 pub fn expand_column(cx: &mut ExtCtxt<'_>, sp: Span, tts: TokenStream)
  33                   -> Box<dyn base::MacResult+'static> {
  34     base::check_zero_tts(cx, sp, tts, "column!");
  35
  36     let topmost = cx.expansion_cause().unwrap_or(sp);
  37     let loc = cx.source_map().lookup_char_pos(topmost.lo());
  38
  39     base::MacEager::expr(cx.expr_u32(topmost, loc.col.to_usize() as u32 + 1))
  40 }
  41
  42 /// file!(): expands to the current filename */
  43 /// The source_file (`loc.file`) contains a bunch more information we could spit
  44 /// out if we wanted.
  45 pub fn expand_file(cx: &mut ExtCtxt<'_>, sp: Span, tts: TokenStream)
  46                    -> Box<dyn base::MacResult+'static> {
  47     base::check_zero_tts(cx, sp, tts, "file!");
  48
  49     let topmost = cx.expansion_cause().unwrap_or(sp);
  50     let loc = cx.source_map().lookup_char_pos(topmost.lo());
  51     base::MacEager::expr(cx.expr_str(topmost, Symbol::intern(&loc.file.name.to_string())))
  52 }
  53
  54 pub fn expand_stringify(cx: &mut ExtCtxt<'_>, sp: Span, tts: TokenStream)
  55                         -> Box<dyn base::MacResult+'static> {
  56     let s = pprust::tts_to_string(tts);
  57     base::MacEager::expr(cx.expr_str(sp, Symbol::intern(&s)))
  58 }
  59
  60 pub fn expand_mod(cx: &mut ExtCtxt<'_>, sp: Span, tts: TokenStream)
  61                   -> Box<dyn base::MacResult+'static> {
  62     base::check_zero_tts(cx, sp, tts, "module_path!");
  63     let mod_path = &cx.current_expansion.module.mod_path;
  64     let string = mod_path.iter().map(|x| x.to_string()).collect::<Vec<String>>().join("::");
  65
  66     base::MacEager::expr(cx.expr_str(sp, Symbol::intern(&string)))
  67 }
  68
  69 /// include! : parse the given file as an expr
  70 /// This is generally a bad idea because it's going to behave
  71 /// unhygienically.
  72 pub fn expand_include<'cx>(cx: &'cx mut ExtCtxt<'_>, sp: Span, tts: TokenStream)
  73                            -> Box<dyn base::MacResult+'cx> {
  74     let file = match get_single_str_from_tts(cx, sp, tts, "include!") {
  75         Some(f) => f,
  76         None => return DummyResult::any(sp),
  77     };
  78     // The file will be added to the code map by the parser
  79     let file = cx.resolve_path(file, sp);
  80     let directory_ownership = DirectoryOwnership::Owned { relative: None };
  81     let p = parse::new_sub_parser_from_file(cx.parse_sess(), &file, directory_ownership, None, sp);
  82
  83     struct ExpandResult<'a> {
  84         p: parse::parser::Parser<'a>,
  85     }
  86     impl<'a> base::MacResult for ExpandResult<'a> {
  87         fn make_expr(mut self: Box<ExpandResult<'a>>) -> Option<P<ast::Expr>> {
  88             let r = panictry!(self.p.parse_expr());
  89             if self.p.token != token::Eof {
  90                 self.p.sess.buffer_lint(
  91                     BufferedEarlyLintId::IncompleteInclude,
  92                     self.p.token.span,
  93                     ast::CRATE_NODE_ID,
  94                     "include macro expected single expression in source",
  95                 );
  96             }
  97             Some(r)
  98         }
  99
 100         fn make_items(mut self: Box<ExpandResult<'a>>) -> Option<SmallVec<[P<ast::Item>; 1]>> {
 101             let mut ret = SmallVec::new();
 102             while self.p.token != token::Eof {
 103                 match panictry!(self.p.parse_item()) {
 104                     Some(item) => ret.push(item),
 105                     None => self.p.sess.span_diagnostic.span_fatal(self.p.token.span,
 106                                                            &format!("expected item, found `{}`",
 107                                                                     self.p.this_token_to_string()))
 108                                                .raise()
 109                 }
 110             }
 111             Some(ret)
 112         }
 113     }
 114
 115     Box::new(ExpandResult { p })
 116 }
 117
 118 // include_str! : read the given file, insert it as a literal string expr
 119 pub fn expand_include_str(cx: &mut ExtCtxt<'_>, sp: Span, tts: TokenStream)
 120                           -> Box<dyn base::MacResult+'static> {
 121     let file = match get_single_str_from_tts(cx, sp, tts, "include_str!") {
 122         Some(f) => f,
 123         None => return DummyResult::any(sp)
 124     };
 125     let file = cx.resolve_path(file, sp);
 126     match cx.source_map().load_binary_file(&file) {
 127         Ok(bytes) => match std::str::from_utf8(&bytes) {
 128             Ok(src) => {
 129                 let interned_src = Symbol::intern(&src);
 130                 base::MacEager::expr(cx.expr_str(sp, interned_src))
 131             }
 132             Err(_) => {
 133                 cx.span_err(sp, &format!("{} wasn't a utf-8 file", file.display()));
 134                 DummyResult::any(sp)
 135             }
 136         },
 137         Err(e) => {
 138             cx.span_err(sp, &format!("couldn't read {}: {}", file.display(), e));
 139             DummyResult::any(sp)
 140         }
 141     }
 142 }
 143
 144 pub fn expand_include_bytes(cx: &mut ExtCtxt<'_>, sp: Span, tts: TokenStream)
 145                             -> Box<dyn base::MacResult+'static> {
 146     let file = match get_single_str_from_tts(cx, sp, tts, "include_bytes!") {
 147         Some(f) => f,
 148         None => return DummyResult::any(sp)
 149     };
 150     let file = cx.resolve_path(file, sp);
 151     match cx.source_map().load_binary_file(&file) {
 152         Ok(bytes) => {
 153             base::MacEager::expr(cx.expr_lit(sp, ast::LitKind::ByteStr(Lrc::new(bytes))))
 154         },
 155         Err(e) => {
 156             cx.span_err(sp, &format!("couldn't read {}: {}", file.display(), e));
 157             DummyResult::any(sp)
 158         }
 159     }
 160 }