Function stretchSpansOverChange

external/.scrollLibs.js:1235–1318

(doc, change)

  // spans partially within the change. Returns an array of span
  // arrays with one element for each line in (after) the change.
  function stretchSpansOverChange(doc, change) {
    if (change.full) {
      return null
    }
    var oldFirst = isLine(doc, change.from.line) && getLine(doc, change.from.line).markedSpans
    var oldLast = isLine(doc, change.to.line) && getLine(doc, change.to.line).markedSpans
    if (!oldFirst && !oldLast) {
      return null
    }

    var startCh = change.from.ch,
      endCh = change.to.ch,
      isInsert = cmp(change.from, change.to) == 0
    // Get the spans that 'stick out' on both sides
    var first = markedSpansBefore(oldFirst, startCh, isInsert)
    var last = markedSpansAfter(oldLast, endCh, isInsert)

    // Next, merge those two ends
    var sameLine = change.text.length == 1,
      offset = lst(change.text).length + (sameLine ? startCh : 0)
    if (first) {
      // Fix up .to properties of first
      for (var i = 0; i < first.length; ++i) {
        var span = first[i]
        if (span.to == null) {
          var found = getMarkedSpanFor(last, span.marker)
          if (!found) {
            span.to = startCh
          } else if (sameLine) {
            span.to = found.to == null ? null : found.to + offset
          }
        }
      }
    }
    if (last) {
      // Fix up .from in last (or move them into first in case of sameLine)
      for (var i$1 = 0; i$1 < last.length; ++i$1) {
        var span$1 = last[i$1]
        if (span$1.to != null) {
          span$1.to += offset
        }
        if (span$1.from == null) {
          var found$1 = getMarkedSpanFor(first, span$1.marker)
          if (!found$1) {
            span$1.from = offset
            if (sameLine) {
              ;(first || (first = [])).push(span$1)
            }
          }
        } else {
          span$1.from += offset
          if (sameLine) {
            ;(first || (first = [])).push(span$1)
          }
        }
      }
    }
    // Make sure we didn't create any zero-length spans