src/missed_spans.rs

   1 // Copyright 2015 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 utils::make_indent;
  12 use visitor::FmtVisitor;
  13
  14 use syntax::codemap::{self, BytePos};
  15
  16 impl<'a> FmtVisitor<'a> {
  17     // TODO these format_missing methods are ugly. Refactor and add unit tests
  18     // for the central whitespace stripping loop.
  19     pub fn format_missing(&mut self, end: BytePos) {
  20         self.format_missing_inner(end, |this, last_snippet, _| {
  21             this.buffer.push_str(last_snippet)
  22         })
  23     }
  24
  25     pub fn format_missing_with_indent(&mut self, end: BytePos) {
  26         self.format_missing_inner(end, |this, last_snippet, snippet| {
  27             this.buffer.push_str(last_snippet.trim_right());
  28             if last_snippet == snippet {
  29                 // No new lines in the snippet.
  30                 this.buffer.push_str("\n");
  31             }
  32             let indent = make_indent(this.block_indent);
  33             this.buffer.push_str(&indent);
  34         })
  35     }
  36
  37     fn format_missing_inner<F: Fn(&mut FmtVisitor, &str, &str)>(&mut self,
  38                                                                 end: BytePos,
  39                                                                 process_last_snippet: F) {
  40         let start = self.last_pos;
  41         debug!("format_missing_inner: {:?} to {:?}",
  42                self.codemap.lookup_char_pos(start),
  43                self.codemap.lookup_char_pos(end));
  44
  45         if start == end {
  46             // Do nothing if this is the beginning of the file.
  47             if start == self.codemap.lookup_char_pos(start).file.start_pos {
  48                 return;
  49             }
  50             process_last_snippet(self, "", "");
  51             return;
  52         }
  53
  54         assert!(start < end,
  55                 "Request to format inverted span: {:?} to {:?}",
  56                 self.codemap.lookup_char_pos(start),
  57                 self.codemap.lookup_char_pos(end));
  58
  59         self.last_pos = end;
  60         let span = codemap::mk_sp(start, end);
  61         let snippet = self.snippet(span);
  62
  63         self.write_snippet(&snippet,
  64                            true,
  65                            &process_last_snippet);
  66     }
  67
  68     fn write_snippet<F: Fn(&mut FmtVisitor, &str, &str)>(&mut self,
  69                                                          snippet: &str,
  70                                                          last_snippet: bool,
  71                                                          process_last_snippet: F) {
  72         // Trim whitespace from the right hand side of each line.
  73         // Annoyingly, the library functions for splitting by lines etc. are not
  74         // quite right, so we must do it ourselves.
  75         let mut line_start = 0;
  76         let mut last_wspace = None;
  77         for (i, c) in snippet.char_indices() {
  78             if c == '\n' {
  79                 if let Some(lw) = last_wspace {
  80                     self.buffer.push_str(&snippet[line_start..lw]);
  81                     self.buffer.push_str("\n");
  82                 } else {
  83                     self.buffer.push_str(&snippet[line_start..i+1]);
  84                 }
  85
  86                 line_start = i + 1;
  87                 last_wspace = None;
  88             } else {
  89                 if c.is_whitespace() {
  90                     if last_wspace.is_none() {
  91                         last_wspace = Some(i);
  92                     }
  93                 } else {
  94                     last_wspace = None;
  95                 }
  96             }
  97         }
  98         if last_snippet {
  99             process_last_snippet(self, &snippet[line_start..], snippet);
 100         } else {
 101             self.buffer.push_str(&snippet[line_start..]);
 102         }
 103     }
 104 }