Handle null value returned by MtpDevice#getRoots.

BUG=23169303

Change-Id: I9602dda01f3b8919a471c1f4c88acdd19f391684

1 files changed, 3 insertions, 0 deletions

diff --git a/packages/MtpDocumentsProvider/src/com/android/mtp/MtpManager.java b/packages/MtpDocumentsProvider/src/com/android/mtp/MtpManager.java
index 088315787e8f..3afc173fcc52 100644
--- a/packages/MtpDocumentsProvider/src/com/android/mtp/MtpManager.java
+++ b/packages/MtpDocumentsProvider/src/com/android/mtp/MtpManager.java
@@ -95,6 +95,9 @@ class MtpManager {
     synchronized MtpRoot[] getRoots(int deviceId) throws IOException {
         final MtpDevice device = getDevice(deviceId);
         final int[] storageIds = device.getStorageIds();
+        if (storageIds == null) {
+            throw new IOException("Failed to obtain storage IDs.");
+        }
         final MtpRoot[] results = new MtpRoot[storageIds.length];
         for (int i = 0; i < storageIds.length; i++) {
             results[i] = new MtpRoot(deviceId, device.getStorageInfo(storageIds[i]));