1  'use strict';
 2  
 3  const Mixin = require('../../utils/mixin');
 4  
 5  class PositionTrackingPreprocessorMixin extends Mixin {
 6      constructor(preprocessor) {
 7          super(preprocessor);
 8  
 9          this.preprocessor = preprocessor;
10          this.isEol = false;
11          this.lineStartPos = 0;
12          this.droppedBufferSize = 0;
13  
14          this.offset = 0;
15          this.col = 0;
16          this.line = 1;
17      }
18  
19      _getOverriddenMethods(mxn, orig) {
20          return {
21              advance() {
22                  const pos = this.pos + 1;
23                  const ch = this.html[pos];
24  
25                  //NOTE: LF should be in the last column of the line
26                  if (mxn.isEol) {
27                      mxn.isEol = false;
28                      mxn.line++;
29                      mxn.lineStartPos = pos;
30                  }
31  
32                  if (ch === '\n' || (ch === '\r' && this.html[pos + 1] !== '\n')) {
33                      mxn.isEol = true;
34                  }
35  
36                  mxn.col = pos - mxn.lineStartPos + 1;
37                  mxn.offset = mxn.droppedBufferSize + pos;
38  
39                  return orig.advance.call(this);
40              },
41  
42              retreat() {
43                  orig.retreat.call(this);
44  
45                  mxn.isEol = false;
46                  mxn.col = this.pos - mxn.lineStartPos + 1;
47              },
48  
49              dropParsedChunk() {
50                  const prevPos = this.pos;
51  
52                  orig.dropParsedChunk.call(this);
53  
54                  const reduction = prevPos - this.pos;
55  
56                  mxn.lineStartPos -= reduction;
57                  mxn.droppedBufferSize += reduction;
58                  mxn.offset = mxn.droppedBufferSize + this.pos;
59              }
60          };
61      }
62  }
63  
64  module.exports = PositionTrackingPreprocessorMixin;