109 lines
3.3 KiB
JavaScript
109 lines
3.3 KiB
JavaScript
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// For each opening emphasis-like marker find a matching closing one
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//
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'use strict';
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function processDelimiters(state, delimiters) {
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var closerIdx, openerIdx, closer, opener, minOpenerIdx, newMinOpenerIdx,
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isOddMatch, lastJump,
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openersBottom = {},
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max = delimiters.length;
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for (closerIdx = 0; closerIdx < max; closerIdx++) {
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closer = delimiters[closerIdx];
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// Length is only used for emphasis-specific "rule of 3",
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// if it's not defined (in strikethrough or 3rd party plugins),
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// we can default it to 0 to disable those checks.
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//
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closer.length = closer.length || 0;
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if (!closer.close) continue;
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// Previously calculated lower bounds (previous fails)
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// for each marker and each delimiter length modulo 3.
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if (!openersBottom.hasOwnProperty(closer.marker)) {
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openersBottom[closer.marker] = [ -1, -1, -1 ];
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}
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minOpenerIdx = openersBottom[closer.marker][closer.length % 3];
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newMinOpenerIdx = -1;
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openerIdx = closerIdx - closer.jump - 1;
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for (; openerIdx > minOpenerIdx; openerIdx -= opener.jump + 1) {
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opener = delimiters[openerIdx];
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if (opener.marker !== closer.marker) continue;
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if (newMinOpenerIdx === -1) newMinOpenerIdx = openerIdx;
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if (opener.open &&
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opener.end < 0 &&
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opener.level === closer.level) {
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isOddMatch = false;
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// from spec:
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//
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// If one of the delimiters can both open and close emphasis, then the
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// sum of the lengths of the delimiter runs containing the opening and
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// closing delimiters must not be a multiple of 3 unless both lengths
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// are multiples of 3.
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//
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if (opener.close || closer.open) {
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if ((opener.length + closer.length) % 3 === 0) {
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if (opener.length % 3 !== 0 || closer.length % 3 !== 0) {
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isOddMatch = true;
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}
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}
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}
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if (!isOddMatch) {
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// If previous delimiter cannot be an opener, we can safely skip
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// the entire sequence in future checks. This is required to make
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// sure algorithm has linear complexity (see *_*_*_*_*_... case).
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//
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lastJump = openerIdx > 0 && !delimiters[openerIdx - 1].open ?
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delimiters[openerIdx - 1].jump + 1 :
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0;
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closer.jump = closerIdx - openerIdx + lastJump;
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closer.open = false;
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opener.end = closerIdx;
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opener.jump = lastJump;
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opener.close = false;
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newMinOpenerIdx = -1;
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break;
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}
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}
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}
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if (newMinOpenerIdx !== -1) {
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// If match for this delimiter run failed, we want to set lower bound for
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// future lookups. This is required to make sure algorithm has linear
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// complexity.
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//
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// See details here:
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// https://github.com/commonmark/cmark/issues/178#issuecomment-270417442
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//
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openersBottom[closer.marker][(closer.length || 0) % 3] = newMinOpenerIdx;
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}
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}
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}
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module.exports = function link_pairs(state) {
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var curr,
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tokens_meta = state.tokens_meta,
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max = state.tokens_meta.length;
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processDelimiters(state, state.delimiters);
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for (curr = 0; curr < max; curr++) {
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if (tokens_meta[curr] && tokens_meta[curr].delimiters) {
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processDelimiters(state, tokens_meta[curr].delimiters);
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}
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}
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};
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