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125 lines
3.9 KiB
125 lines
3.9 KiB
// For each opening emphasis-like marker find a matching closing one
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//
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function processDelimiters (delimiters) {
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const openersBottom = {}
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const max = delimiters.length
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if (!max) return
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// headerIdx is the first delimiter of the current (where closer is) delimiter run
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let headerIdx = 0
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let lastTokenIdx = -2 // needs any value lower than -1
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const jumps = []
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for (let closerIdx = 0; closerIdx < max; closerIdx++) {
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const closer = delimiters[closerIdx]
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jumps.push(0)
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// markers belong to same delimiter run if:
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// - they have adjacent tokens
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// - AND markers are the same
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//
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if (delimiters[headerIdx].marker !== closer.marker || lastTokenIdx !== closer.token - 1) {
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headerIdx = closerIdx
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}
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lastTokenIdx = closer.token
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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, each delimiter length modulo 3,
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// and for whether this closer can be an opener;
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// https://github.com/commonmark/cmark/commit/34250e12ccebdc6372b8b49c44fab57c72443460
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if (!openersBottom.hasOwnProperty(closer.marker)) {
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openersBottom[closer.marker] = [ -1, -1, -1, -1, -1, -1 ]
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}
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const minOpenerIdx = openersBottom[closer.marker][(closer.open ? 3 : 0) + (closer.length % 3)]
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let openerIdx = headerIdx - jumps[headerIdx] - 1
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let newMinOpenerIdx = openerIdx
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for (; openerIdx > minOpenerIdx; openerIdx -= jumps[openerIdx] + 1) {
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const opener = delimiters[openerIdx]
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if (opener.marker !== closer.marker) continue
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if (opener.open && opener.end < 0) {
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let 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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const lastJump = openerIdx > 0 && !delimiters[openerIdx - 1].open ?
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jumps[openerIdx - 1] + 1 :
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0
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jumps[closerIdx] = closerIdx - openerIdx + lastJump
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jumps[openerIdx] = lastJump
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closer.open = false
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opener.end = closerIdx
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opener.close = false
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newMinOpenerIdx = -1
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// treat next token as start of run,
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// it optimizes skips in **<...>**a**<...>** pathological case
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lastTokenIdx = -2
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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.open ? 3 : 0) + ((closer.length || 0) % 3)] = newMinOpenerIdx
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}
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}
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}
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export default function link_pairs (state) {
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const tokens_meta = state.tokens_meta
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const max = state.tokens_meta.length
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processDelimiters(state.delimiters)
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for (let curr = 0; curr < max; curr++) {
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if (tokens_meta[curr] && tokens_meta[curr].delimiters) {
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processDelimiters(tokens_meta[curr].delimiters)
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}
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}
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}
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