src/libsyntax_ext/source_util.rs

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