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- var attention = {
- name: 'attention',
- tokenize: tokenizeAttention,
- resolveAll: resolveAllAttention
- }
- export default attention
-
- import assert from 'assert'
- import codes from '../character/codes.mjs'
- import constants from '../constant/constants.mjs'
- import types from '../constant/types.mjs'
- import chunkedPush from '../util/chunked-push.mjs'
- import chunkedSplice from '../util/chunked-splice.mjs'
- import classifyCharacter from '../util/classify-character.mjs'
- import movePoint from '../util/move-point.mjs'
- import resolveAll from '../util/resolve-all.mjs'
- import shallow from '../util/shallow.mjs'
-
- // Take all events and resolve attention to emphasis or strong.
- function resolveAllAttention(events, context) {
- var index = -1
- var open
- var group
- var text
- var openingSequence
- var closingSequence
- var use
- var nextEvents
- var offset
-
- // Walk through all events.
- //
- // Note: performance of this is fine on an mb of normal markdown, but it’s
- // a bottleneck for malicious stuff.
- while (++index < events.length) {
- // Find a token that can close.
- if (
- events[index][0] === 'enter' &&
- events[index][1].type === 'attentionSequence' &&
- events[index][1]._close
- ) {
- open = index
-
- // Now walk back to find an opener.
- while (open--) {
- // Find a token that can open the closer.
- if (
- events[open][0] === 'exit' &&
- events[open][1].type === 'attentionSequence' &&
- events[open][1]._open &&
- // If the markers are the same:
- context.sliceSerialize(events[open][1]).charCodeAt(0) ===
- context.sliceSerialize(events[index][1]).charCodeAt(0)
- ) {
- // If the opening can close or the closing can open,
- // and the close size *is not* a multiple of three,
- // but the sum of the opening and closing size *is* multiple of three,
- // then don’t match.
- if (
- (events[open][1]._close || events[index][1]._open) &&
- (events[index][1].end.offset - events[index][1].start.offset) % 3 &&
- !(
- (events[open][1].end.offset -
- events[open][1].start.offset +
- events[index][1].end.offset -
- events[index][1].start.offset) %
- 3
- )
- ) {
- continue
- }
-
- // Number of markers to use from the sequence.
- use =
- events[open][1].end.offset - events[open][1].start.offset > 1 &&
- events[index][1].end.offset - events[index][1].start.offset > 1
- ? 2
- : 1
-
- openingSequence = {
- type: use > 1 ? types.strongSequence : types.emphasisSequence,
- start: movePoint(shallow(events[open][1].end), -use),
- end: shallow(events[open][1].end)
- }
- closingSequence = {
- type: use > 1 ? types.strongSequence : types.emphasisSequence,
- start: shallow(events[index][1].start),
- end: movePoint(shallow(events[index][1].start), use)
- }
- text = {
- type: use > 1 ? types.strongText : types.emphasisText,
- start: shallow(events[open][1].end),
- end: shallow(events[index][1].start)
- }
- group = {
- type: use > 1 ? types.strong : types.emphasis,
- start: shallow(openingSequence.start),
- end: shallow(closingSequence.end)
- }
-
- events[open][1].end = shallow(openingSequence.start)
- events[index][1].start = shallow(closingSequence.end)
-
- nextEvents = []
-
- // If there are more markers in the opening, add them before.
- if (events[open][1].end.offset - events[open][1].start.offset) {
- nextEvents = chunkedPush(nextEvents, [
- ['enter', events[open][1], context],
- ['exit', events[open][1], context]
- ])
- }
-
- // Opening.
- nextEvents = chunkedPush(nextEvents, [
- ['enter', group, context],
- ['enter', openingSequence, context],
- ['exit', openingSequence, context],
- ['enter', text, context]
- ])
-
- // Between.
- nextEvents = chunkedPush(
- nextEvents,
- resolveAll(
- context.parser.constructs.insideSpan.null,
- events.slice(open + 1, index),
- context
- )
- )
-
- // Closing.
- nextEvents = chunkedPush(nextEvents, [
- ['exit', text, context],
- ['enter', closingSequence, context],
- ['exit', closingSequence, context],
- ['exit', group, context]
- ])
-
- // If there are more markers in the closing, add them after.
- if (events[index][1].end.offset - events[index][1].start.offset) {
- offset = 2
- nextEvents = chunkedPush(nextEvents, [
- ['enter', events[index][1], context],
- ['exit', events[index][1], context]
- ])
- } else {
- offset = 0
- }
-
- chunkedSplice(events, open - 1, index - open + 3, nextEvents)
-
- index = open + nextEvents.length - offset - 2
- break
- }
- }
- }
- }
-
- // Remove remaining sequences.
- index = -1
-
- while (++index < events.length) {
- if (events[index][1].type === 'attentionSequence') {
- events[index][1].type = 'data'
- }
- }
-
- return events
- }
-
- function tokenizeAttention(effects, ok) {
- var before = classifyCharacter(this.previous)
- var marker
-
- return start
-
- function start(code) {
- assert(
- code === codes.asterisk || code === codes.underscore,
- 'expected asterisk or underscore'
- )
- effects.enter('attentionSequence')
- marker = code
- return sequence(code)
- }
-
- function sequence(code) {
- var token
- var after
- var open
- var close
-
- if (code === marker) {
- effects.consume(code)
- return sequence
- }
-
- token = effects.exit('attentionSequence')
- after = classifyCharacter(code)
- open = !after || (after === constants.characterGroupPunctuation && before)
- close = !before || (before === constants.characterGroupPunctuation && after)
- token._open = marker === codes.asterisk ? open : open && (before || !close)
- token._close = marker === codes.asterisk ? close : close && (after || !open)
- return ok(code)
- }
- }
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