From f7ed39ee173175f1154e6ad0be30fb03d2211d0e Mon Sep 17 00:00:00 2001
From: aquilescanta <aquilescanta@google.com>
Date: Mon, 12 Nov 2018 05:11:37 -0800
Subject: [PATCH] Add constructor to DefaultShuffleOrder to support sideloaded
 shuffle orders

Issue: #4915

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=221075615
---
 .../android/exoplayer2/source/ShuffleOrder.java | 11 +++++++++++
 .../exoplayer2/source/ShuffleOrderTest.java     | 17 +++++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/library/core/src/main/java/com/google/android/exoplayer2/source/ShuffleOrder.java b/library/core/src/main/java/com/google/android/exoplayer2/source/ShuffleOrder.java
index 750c42bbd0..90e2576d76 100644
--- a/library/core/src/main/java/com/google/android/exoplayer2/source/ShuffleOrder.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/source/ShuffleOrder.java
@@ -55,6 +55,17 @@ public interface ShuffleOrder {
       this(length, new Random(randomSeed));
     }
 
+    /**
+     * Creates an instance with a specified shuffle order and the specified random seed. The random
+     * seed is used for {@link #cloneAndInsert(int, int)} invocations.
+     *
+     * @param shuffledIndices The shuffled indices to use as order.
+     * @param randomSeed A random seed.
+     */
+    public DefaultShuffleOrder(int[] shuffledIndices, long randomSeed) {
+      this(Arrays.copyOf(shuffledIndices, shuffledIndices.length), new Random(randomSeed));
+    }
+
     private DefaultShuffleOrder(int length, Random random) {
       this(createShuffledList(length, random), random);
     }
diff --git a/library/core/src/test/java/com/google/android/exoplayer2/source/ShuffleOrderTest.java b/library/core/src/test/java/com/google/android/exoplayer2/source/ShuffleOrderTest.java
index e15c8f0aaa..06f39409e7 100644
--- a/library/core/src/test/java/com/google/android/exoplayer2/source/ShuffleOrderTest.java
+++ b/library/core/src/test/java/com/google/android/exoplayer2/source/ShuffleOrderTest.java
@@ -79,6 +79,23 @@ public final class ShuffleOrderTest {
     }
   }
 
+  @Test
+  public void testSideloadedShuffleOrder() {
+    int[] shuffledIndices = new int[] {2, 1, 0, 4, 3};
+    ShuffleOrder shuffleOrder = new DefaultShuffleOrder(shuffledIndices, RANDOM_SEED);
+    assertThat(shuffleOrder.getFirstIndex()).isEqualTo(2);
+    assertThat(shuffleOrder.getLastIndex()).isEqualTo(3);
+    for (int i = 0; i < 4; i++) {
+      assertThat(shuffleOrder.getNextIndex(shuffledIndices[i])).isEqualTo(shuffledIndices[i + 1]);
+    }
+    assertThat(shuffleOrder.getNextIndex(3)).isEqualTo(C.INDEX_UNSET);
+    for (int i = 4; i > 0; i--) {
+      assertThat(shuffleOrder.getPreviousIndex(shuffledIndices[i]))
+          .isEqualTo(shuffledIndices[i - 1]);
+    }
+    assertThat(shuffleOrder.getPreviousIndex(2)).isEqualTo(C.INDEX_UNSET);
+  }
+
   private static void assertShuffleOrderCorrectness(ShuffleOrder shuffleOrder, int length) {
     assertThat(shuffleOrder.getLength()).isEqualTo(length);
     if (length == 0) {