Throw correct exception.

library/src/main/java/com/google/android/exoplayer/upstream/cache/CacheDataSource.java

@@ -27,6 +27,7 @@ import android.net.Uri;
 import android.util.Log;
 
 import java.io.IOException;
+import java.io.InterruptedIOException;
 
 /**
  * A {@link DataSource} that reads and writes a {@link Cache}. Requests are fulfilled from the cache
@@ -182,7 +183,6 @@ public final class CacheDataSource implements DataSource {
    * opened to read from the upstream source and write into the cache.
    */
   private void openNextSource() throws IOException {
-    try {
     DataSpec dataSpec;
     CacheSpan span;
     if (ignoreCache) {
@@ -193,7 +193,11 @@ public final class CacheDataSource implements DataSource {
       Log.w(TAG, "Cache bypassed due to unbounded length.");
       span = null;
     } else if (blockOnCache) {
+      try {
         span = cache.startReadWrite(key, readPosition);
+      } catch (InterruptedException e) {
+        throw new InterruptedIOException();
+      }
     } else {
       span = cache.startReadWriteNonBlocking(key, readPosition);
     }
@@ -218,10 +222,6 @@ public final class CacheDataSource implements DataSource {
           : upstreamDataSource;
     }
     currentDataSource.open(dataSpec);
-    } catch (InterruptedException e) {
-      // Should never happen.
-      throw new RuntimeException(e);
-    }
   }
 
   private void closeCurrentSource() throws IOException {