Method Write

agent/agentproc/headtail.go:80–113

Write implements io.Writer. It is safe for concurrent use. All bytes are accepted; the return value always equals len(p) with a nil error.

(p []byte)

// All bytes are accepted; the return value always equals
// len(p) with a nil error.
func (b *HeadTailBuffer) Write(p []byte) (int, error) {
	if len(p) == 0 {
		return 0, nil
	}

	b.mu.Lock()
	defer b.mu.Unlock()

	n := len(p)
	b.totalBytes += n

	// Fill head buffer if it is not yet full.
	if !b.headFull {
		remaining := b.maxHead - len(b.head)
		if remaining > 0 {
			take := remaining
			if take > len(p) {
				take = len(p)
			}
			b.head = append(b.head, p[:take]...)
			p = p[take:]
			if len(b.head) >= b.maxHead {
				b.headFull = true
			}
		}
		if len(p) == 0 {
			return n, nil
		}
	}

	// Write remaining bytes into the tail ring buffer.
	b.writeTail(p)
	return n, nil
}

// writeTail appends data to the tail ring buffer. The caller
// must hold b.mu.