From d301a79dcf1f27bb389c33758f90ee79d39c58b8 Mon Sep 17 00:00:00 2001
From: Max Kellermann <max@musicpd.org>
Date: Thu, 26 Apr 2018 10:32:03 +0200
Subject: [PATCH] output/alsa: CopyRingToPeriodBuffer() returns bool

---
 src/output/plugins/AlsaOutputPlugin.cxx | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/src/output/plugins/AlsaOutputPlugin.cxx b/src/output/plugins/AlsaOutputPlugin.cxx
index 329e458cf..b7c9f256d 100644
--- a/src/output/plugins/AlsaOutputPlugin.cxx
+++ b/src/output/plugins/AlsaOutputPlugin.cxx
@@ -276,14 +276,17 @@ private:
 	 */
 	void CancelInternal() noexcept;
 
-	void CopyRingToPeriodBuffer() noexcept {
+	/**
+	 * @return false if no data was moved
+	 */
+	bool CopyRingToPeriodBuffer() noexcept {
 		if (period_buffer.IsFull())
-			return;
+			return false;
 
 		size_t nbytes = ring_buffer->pop(period_buffer.GetTail(),
 						 period_buffer.GetSpaceBytes());
 		if (nbytes == 0)
-			return;
+			return false;
 
 		period_buffer.AppendBytes(nbytes);
 
@@ -291,6 +294,8 @@ private:
 		/* notify the OutputThread that there is now
 		   room in ring_buffer */
 		cond.signal();
+
+		return true;
 	}
 
 	snd_pcm_sframes_t WriteFromPeriodBuffer() noexcept {