Function processStraddle

src/utils/sessionStoragePortable.ts:570–609

(
  s: LoadState,
  chunk: Buffer,
  bytesRead: number,
)

// Line spanning the chunk seam. 0 = fall through to concat.
function processStraddle(
  s: LoadState,
  chunk: Buffer,
  bytesRead: number,
): number {
  s.straddleSnapCarryLen = 0
  s.straddleSnapTailEnd = 0
  if (s.carryLen === 0) return 0
  const cb = s.carryBuf!
  const firstNl = chunk.indexOf(LF)
  if (firstNl === -1 || firstNl >= bytesRead) return 0
  const tailEnd = firstNl + 1
  if (hasPrefix(cb, ATTR_SNAP_PREFIX, 0, s.carryLen)) {
    s.straddleSnapCarryLen = s.carryLen
    s.straddleSnapTailEnd = tailEnd
    s.lastSnapSrc = null
  } else if (s.carryLen < ATTR_SNAP_PREFIX.length) {
    return 0 // too short to rule out attr-snap
  } else {
    if (hasPrefix(cb, SYSTEM_PREFIX, 0, s.carryLen)) {
      const hit = parseBoundaryLine(
        cb.toString('utf-8', 0, s.carryLen) +
          chunk.toString('utf-8', 0, firstNl),
      )
      if (hit?.hasPreservedSegment) {
        s.hasPreservedSegment = true
      } else if (hit) {
        s.out.len = 0
        s.boundaryStartOffset = s.bufFileOff
        s.hasPreservedSegment = false
        s.lastSnapSrc = null
      }
    }
    sinkWrite(s.out, cb, 0, s.carryLen)
    sinkWrite(s.out, chunk, 0, tailEnd)
  }
  s.bufFileOff += s.carryLen + tailEnd
  s.carryLen = 0
  return tailEnd
}

// Strip attr-snaps, truncate on boundaries. Kept lines write as runs.
function scanChunkLines(