2 files changed, 28 insertions, 6 deletions
diff --git a/framework-t/src/android/net/NetworkStatsCollection.java b/framework-t/src/android/net/NetworkStatsCollection.java
index b59a890a2a..29ea772bc3 100644
--- a/framework-t/src/android/net/NetworkStatsCollection.java
+++ b/framework-t/src/android/net/NetworkStatsCollection.java
@@ -694,6 +694,26 @@ public class NetworkStatsCollection implements FileRotator.Reader, FileRotator.W
         }
     }
 
+    /**
+     * Remove histories which contains or is before the cutoff timestamp.
+     * @hide
+     */
+    public void removeHistoryBefore(long cutoffMillis) {
+        final ArrayList<Key> knownKeys = new ArrayList<>();
+        knownKeys.addAll(mStats.keySet());
+
+        for (Key key : knownKeys) {
+            final NetworkStatsHistory history = mStats.get(key);
+            if (history.getStart() > cutoffMillis) continue;
+
+            history.removeBucketsStartingBefore(cutoffMillis);
+            if (history.size() == 0) {
+                mStats.remove(key);
+            }
+            mDirty = true;
+        }
+    }
+
     private void noteRecordedHistory(long startMillis, long endMillis, long totalBytes) {
         if (startMillis < mStartMillis) mStartMillis = startMillis;
         if (endMillis > mEndMillis) mEndMillis = endMillis;
diff --git a/framework-t/src/android/net/NetworkStatsHistory.java b/framework-t/src/android/net/NetworkStatsHistory.java
index 301fef9441..b45d44dec1 100644
--- a/framework-t/src/android/net/NetworkStatsHistory.java
+++ b/framework-t/src/android/net/NetworkStatsHistory.java
@@ -680,19 +680,21 @@ public final class NetworkStatsHistory implements Parcelable {
     }
 
     /**
-     * Remove buckets older than requested cutoff.
+     * Remove buckets that start older than requested cutoff.
+     *
+     * This method will remove any bucket that contains any data older than the requested
+     * cutoff, even if that same bucket includes some data from after the cutoff.
+     *
      * @hide
      */
-    public void removeBucketsBefore(long cutoff) {
+    public void removeBucketsStartingBefore(final long cutoff) {
         // TODO: Consider use getIndexBefore.
         int i;
         for (i = 0; i < bucketCount; i++) {
             final long curStart = bucketStart[i];
-            final long curEnd = curStart + bucketDuration;
 
-            // cutoff happens before or during this bucket; everything before
-            // this bucket should be removed.
-            if (curEnd > cutoff) break;
+            // This bucket starts after or at the cutoff, so it should be kept.
+            if (curStart >= cutoff) break;
         }
 
         if (i > 0) {