src/libsyntax/ext/source_util.rs

   1 // Copyright 2012-2013 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 use ast;
  12 use codemap::{Pos, Span};
  13 use codemap;
  14 use ext::base::*;
  15 use ext::base;
  16 use ext::build::AstBuilder;
  17 use parse::token;
  18 use parse;
  19 use print::pprust;
  20 use ptr::P;
  21 use util::small_vector::SmallVector;
  22
  23 use std::fs::File;
  24 use std::io::prelude::*;
  25 use std::path::{Path, PathBuf};
  26 use std::rc::Rc;
  27
  28 // These macros all relate to the file system; they either return
  29 // the column/row/filename of the expression, or they include
  30 // a given file into the current one.
  31
  32 /// line!(): expands to the current line number
  33 pub fn expand_line(cx: &mut ExtCtxt, sp: Span, tts: &[ast::TokenTree])
  34                    -> Box<base::MacResult+'static> {
  35     base::check_zero_tts(cx, sp, tts, "line!");
  36
  37     let topmost = cx.expansion_cause();
  38     let loc = cx.codemap().lookup_char_pos(topmost.lo);
  39
  40     base::MacEager::expr(cx.expr_u32(topmost, loc.line as u32))
  41 }
  42
  43 /* column!(): expands to the current column number */
  44 pub fn expand_column(cx: &mut ExtCtxt, sp: Span, tts: &[ast::TokenTree])
  45                   -> Box<base::MacResult+'static> {
  46     base::check_zero_tts(cx, sp, tts, "column!");
  47
  48     let topmost = cx.expansion_cause();
  49     let loc = cx.codemap().lookup_char_pos(topmost.lo);
  50
  51     base::MacEager::expr(cx.expr_u32(topmost, loc.col.to_usize() as u32))
  52 }
  53
  54 /// file!(): expands to the current filename */
  55 /// The filemap (`loc.file`) contains a bunch more information we could spit
  56 /// out if we wanted.
  57 pub fn expand_file(cx: &mut ExtCtxt, sp: Span, tts: &[ast::TokenTree])
  58                    -> Box<base::MacResult+'static> {
  59     base::check_zero_tts(cx, sp, tts, "file!");
  60
  61     let topmost = cx.expansion_cause();
  62     let loc = cx.codemap().lookup_char_pos(topmost.lo);
  63     let filename = token::intern_and_get_ident(&loc.file.name);
  64     base::MacEager::expr(cx.expr_str(topmost, filename))
  65 }
  66
  67 pub fn expand_stringify(cx: &mut ExtCtxt, sp: Span, tts: &[ast::TokenTree])
  68                         -> Box<base::MacResult+'static> {
  69     let s = pprust::tts_to_string(tts);
  70     base::MacEager::expr(cx.expr_str(sp,
  71                                    token::intern_and_get_ident(&s[..])))
  72 }
  73
  74 pub fn expand_mod(cx: &mut ExtCtxt, sp: Span, tts: &[ast::TokenTree])
  75                   -> Box<base::MacResult+'static> {
  76     base::check_zero_tts(cx, sp, tts, "module_path!");
  77     let string = cx.mod_path()
  78                    .iter()
  79                    .map(|x| token::get_ident(*x).to_string())
  80                    .collect::<Vec<String>>()
  81                    .connect("::");
  82     base::MacEager::expr(cx.expr_str(
  83             sp,
  84             token::intern_and_get_ident(&string[..])))
  85 }
  86
  87 /// include! : parse the given file as an expr
  88 /// This is generally a bad idea because it's going to behave
  89 /// unhygienically.
  90 pub fn expand_include<'cx>(cx: &'cx mut ExtCtxt, sp: Span, tts: &[ast::TokenTree])
  91                            -> Box<base::MacResult+'cx> {
  92     let file = match get_single_str_from_tts(cx, sp, tts, "include!") {
  93         Some(f) => f,
  94         None => return DummyResult::expr(sp),
  95     };
  96     // The file will be added to the code map by the parser
  97     let p =
  98         parse::new_sub_parser_from_file(cx.parse_sess(),
  99                                         cx.cfg(),
 100                                         &res_rel_file(cx,
 101                                                       sp,
 102                                                       Path::new(&file)),
 103                                         true,
 104                                         None,
 105                                         sp);
 106
 107     struct ExpandResult<'a> {
 108         p: parse::parser::Parser<'a>,
 109     }
 110     impl<'a> base::MacResult for ExpandResult<'a> {
 111         fn make_expr(mut self: Box<ExpandResult<'a>>) -> Option<P<ast::Expr>> {
 112             Some(self.p.parse_expr())
 113         }
 114         fn make_items(mut self: Box<ExpandResult<'a>>)
 115                       -> Option<SmallVector<P<ast::Item>>> {
 116             let mut ret = SmallVector::zero();
 117             while self.p.token != token::Eof {
 118                 match self.p.parse_item() {
 119                     Some(item) => ret.push(item),
 120                     None => panic!(self.p.span_fatal(
 121                         self.p.span,
 122                         &format!("expected item, found `{}`",
 123                                  self.p.this_token_to_string())
 124                     ))
 125                 }
 126             }
 127             Some(ret)
 128         }
 129     }
 130
 131     Box::new(ExpandResult { p: p })
 132 }
 133
 134 // include_str! : read the given file, insert it as a literal string expr
 135 pub fn expand_include_str(cx: &mut ExtCtxt, sp: Span, tts: &[ast::TokenTree])
 136                           -> Box<base::MacResult+'static> {
 137     let file = match get_single_str_from_tts(cx, sp, tts, "include_str!") {
 138         Some(f) => f,
 139         None => return DummyResult::expr(sp)
 140     };
 141     let file = res_rel_file(cx, sp, Path::new(&file));
 142     let mut bytes = Vec::new();
 143     match File::open(&file).and_then(|mut f| f.read_to_end(&mut bytes)) {
 144         Ok(..) => {}
 145         Err(e) => {
 146             cx.span_err(sp,
 147                         &format!("couldn't read {}: {}",
 148                                 file.display(),
 149                                 e));
 150             return DummyResult::expr(sp);
 151         }
 152     };
 153     match String::from_utf8(bytes) {
 154         Ok(src) => {
 155             // Add this input file to the code map to make it available as
 156             // dependency information
 157             let filename = format!("{}", file.display());
 158             let interned = token::intern_and_get_ident(&src[..]);
 159             cx.codemap().new_filemap(filename, src);
 160
 161             base::MacEager::expr(cx.expr_str(sp, interned))
 162         }
 163         Err(_) => {
 164             cx.span_err(sp,
 165                         &format!("{} wasn't a utf-8 file",
 166                                 file.display()));
 167             return DummyResult::expr(sp);
 168         }
 169     }
 170 }
 171
 172 pub fn expand_include_bytes(cx: &mut ExtCtxt, sp: Span, tts: &[ast::TokenTree])
 173                             -> Box<base::MacResult+'static> {
 174     let file = match get_single_str_from_tts(cx, sp, tts, "include_bytes!") {
 175         Some(f) => f,
 176         None => return DummyResult::expr(sp)
 177     };
 178     let file = res_rel_file(cx, sp, Path::new(&file));
 179     let mut bytes = Vec::new();
 180     match File::open(&file).and_then(|mut f| f.read_to_end(&mut bytes)) {
 181         Err(e) => {
 182             cx.span_err(sp,
 183                         &format!("couldn't read {}: {}", file.display(), e));
 184             return DummyResult::expr(sp);
 185         }
 186         Ok(..) => {
 187             // Add this input file to the code map to make it available as
 188             // dependency information, but don't enter it's contents
 189             let filename = format!("{}", file.display());
 190             cx.codemap().new_filemap(filename, "".to_string());
 191
 192             base::MacEager::expr(cx.expr_lit(sp, ast::LitBinary(Rc::new(bytes))))
 193         }
 194     }
 195 }
 196
 197 // resolve a file-system path to an absolute file-system path (if it
 198 // isn't already)
 199 fn res_rel_file(cx: &mut ExtCtxt, sp: codemap::Span, arg: &Path) -> PathBuf {
 200     // NB: relative paths are resolved relative to the compilation unit
 201     if !arg.is_absolute() {
 202         let mut cu = PathBuf::from(&cx.codemap().span_to_filename(sp));
 203         cu.pop();
 204         cu.push(arg);
 205         cu
 206     } else {
 207         arg.to_path_buf()
 208     }
 209 }