From 7536dd744ff84073b3b2d2ddea4dd15cd665869a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Mart=C3=AD?= <mvdan@mvdan.cc>
Date: Sun, 24 Apr 2016 19:03:01 +0100
Subject: [PATCH] devices: add maybeOneDevice()

---
 cmd/fdroidcl/devices.go | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/cmd/fdroidcl/devices.go b/cmd/fdroidcl/devices.go
index 1487788..85a4a27 100644
--- a/cmd/fdroidcl/devices.go
+++ b/cmd/fdroidcl/devices.go
@@ -40,14 +40,25 @@ func startAdbIfNeeded() {
 	}
 }
 
-func mustOneDevice() *adb.Device {
+func maybeOneDevice() *adb.Device {
 	startAdbIfNeeded()
 	devices, err := adb.Devices()
 	if err != nil {
 		log.Fatalf("Could not get devices: %v", err)
 	}
-	if len(devices) != 1 {
-		log.Fatalf("Exactly one connected device is needed")
+	if len(devices) > 1 {
+		log.Fatalf("At most one connected device can be used")
+	}
+	if len(devices) < 1 {
+		return nil
 	}
 	return devices[0]
 }
+
+func mustOneDevice() *adb.Device {
+	device := maybeOneDevice()
+	if device == nil {
+		log.Fatalf("A connected device is needed")
+	}
+	return device
+}