Function getKeepStart

riverlog/river_log.go:294–328

(bounds []arrayElementBounds, newEntryLen, maxTotalBytes int)

}

func getKeepStart(bounds []arrayElementBounds, newEntryLen, maxTotalBytes int) int {
	if maxTotalBytes <= 0 {
		return 0
	}

	// Keep newest entry even if it's larger than the configured cap.
	newOnlyLen := 2 + newEntryLen // `[` + entry + `]`
	if newOnlyLen > maxTotalBytes {
		return len(bounds)
	}

	if len(bounds) == 0 {
		return 0
	}

	lastEnd := bounds[len(bounds)-1].End

	// Iterate from oldest to newest so we drop the minimum number of entries
	// necessary to fit the configured cap.
	for keepStart := 0; keepStart <= len(bounds); keepStart++ {
		contentLen := newEntryLen
		if keepStart < len(bounds) {
			// Use actual byte offsets from parsed elements so separator
			// whitespace is fully counted toward the cap.
			keptContentLen := lastEnd - bounds[keepStart].Start
			contentLen += 1 + keptContentLen // comma between kept suffix and new entry
		}
		totalLen := 2 + contentLen // `[` + content + `]`
		if totalLen <= maxTotalBytes {
			return keepStart
		}
	}

	return len(bounds)
}

func buildAppendedArray(existingArrayBytes []byte, bounds []arrayElementBounds, keepStart int, newEntryBytes []byte) []byte {
	totalLen := 0