commit 7328a80ffc83729cc6252c79e0851a31af59c653
author Phil Burk <philburk@google.com> Wed Aug 30 09:29:48 2017 -0700
committer Phil Burk <philburk@google.com> Wed Sep 06 17:08:19 2017 -0700
tree 62c8ae222700101931459a8ee921a4c016d34871
parent 187dcd4eeaeace78665dafcee6acb074ef390545

aaudio: prevent retrograde motion in Legacy timestamps

Use MonotonicCounter for timestamp position.

Bug: 63918065
Test: write_sine_callback.cpp and test_timestamps.cpp
Change-Id: Iea58384e2d96adcfad586e8c522024baaecccb8c

media/libaaudio/src/legacy/AudioStreamTrack.cpp

diff --git a/media/libaaudio/src/legacy/AudioStreamTrack.cpp b/media/libaaudio/src/legacy/AudioStreamTrack.cpp
index 155362c..702b12a 100644
--- a/media/libaaudio/src/legacy/AudioStreamTrack.cpp
+++ b/media/libaaudio/src/legacy/AudioStreamTrack.cpp
@@ -285,6 +285,7 @@
     incrementFramesRead(getFramesWritten() - getFramesRead());
     mAudioTrack->flush();
     mFramesWritten.reset32();
+    mTimestampPosition.reset32();
     return AAUDIO_OK;
 }
 
@@ -298,8 +299,10 @@
     onStop();
     setState(AAUDIO_STREAM_STATE_STOPPING);
     incrementFramesRead(getFramesWritten() - getFramesRead()); // TODO review
+    mTimestampPosition.set(getFramesWritten());
     stop();
     mFramesWritten.reset32();
+    mTimestampPosition.reset32();
     return AAUDIO_OK;
 }
 
@@ -447,5 +450,18 @@
     if (status != NO_ERROR) {
         return AAudioConvert_androidToAAudioResult(status);
     }
-    return getBestTimestamp(clockId, framePosition, timeNanoseconds, &extendedTimestamp);
+    int64_t position = 0;
+    int64_t nanoseconds = 0;
+    aaudio_result_t result = getBestTimestamp(clockId, &position,
+                                              &nanoseconds, &extendedTimestamp);
+    if (result == AAUDIO_OK) {
+        if (position < getFramesWritten()) {
+            *framePosition = position;
+            *timeNanoseconds = nanoseconds;
+            return result;
+        } else {
+            return AAUDIO_ERROR_INVALID_STATE; // TODO review, documented but not consistent
+        }
+    }
+    return result;
 }