1 files changed, 89 insertions, 0 deletions
diff --git a/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/upstream/cache/LeastRecentlyUsedCacheEvictor.java b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/upstream/cache/LeastRecentlyUsedCacheEvictor.java
new file mode 100644
index 0000000000..56eff06b25
--- /dev/null
+++ b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/upstream/cache/LeastRecentlyUsedCacheEvictor.java
@@ -0,0 +1,89 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.mozilla.thirdparty.com.google.android.exoplayer2.upstream.cache;
+
+import org.mozilla.thirdparty.com.google.android.exoplayer2.C;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.upstream.cache.Cache.CacheException;
+import java.util.TreeSet;
+
+/** Evicts least recently used cache files first. */
+public final class LeastRecentlyUsedCacheEvictor implements CacheEvictor {
+
+  private final long maxBytes;
+  private final TreeSet<CacheSpan> leastRecentlyUsed;
+
+  private long currentSize;
+
+  public LeastRecentlyUsedCacheEvictor(long maxBytes) {
+    this.maxBytes = maxBytes;
+    this.leastRecentlyUsed = new TreeSet<>(LeastRecentlyUsedCacheEvictor::compare);
+  }
+
+  @Override
+  public boolean requiresCacheSpanTouches() {
+    return true;
+  }
+
+  @Override
+  public void onCacheInitialized() {
+    // Do nothing.
+  }
+
+  @Override
+  public void onStartFile(Cache cache, String key, long position, long length) {
+    if (length != C.LENGTH_UNSET) {
+      evictCache(cache, length);
+    }
+  }
+
+  @Override
+  public void onSpanAdded(Cache cache, CacheSpan span) {
+    leastRecentlyUsed.add(span);
+    currentSize += span.length;
+    evictCache(cache, 0);
+  }
+
+  @Override
+  public void onSpanRemoved(Cache cache, CacheSpan span) {
+    leastRecentlyUsed.remove(span);
+    currentSize -= span.length;
+  }
+
+  @Override
+  public void onSpanTouched(Cache cache, CacheSpan oldSpan, CacheSpan newSpan) {
+    onSpanRemoved(cache, oldSpan);
+    onSpanAdded(cache, newSpan);
+  }
+
+  private void evictCache(Cache cache, long requiredSpace) {
+    while (currentSize + requiredSpace > maxBytes && !leastRecentlyUsed.isEmpty()) {
+      try {
+        cache.removeSpan(leastRecentlyUsed.first());
+      } catch (CacheException e) {
+        // do nothing.
+      }
+    }
+  }
+
+  private static int compare(CacheSpan lhs, CacheSpan rhs) {
+    long lastTouchTimestampDelta = lhs.lastTouchTimestamp - rhs.lastTouchTimestamp;
+    if (lastTouchTimestampDelta == 0) {
+      // Use the standard compareTo method as a tie-break.
+      return lhs.compareTo(rhs);
+    }
+    return lhs.lastTouchTimestamp < rhs.lastTouchTimestamp ? -1 : 1;
+  }
+}