Add test for DefaultLoadControl.shouldContinueLoading

Also simplified shouldContinueLoading condition code and added a builder for DefaultLoadControl.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=188306213

library/core/src/main/java/com/google/android/exoplayer2/DefaultLoadControl.java

@@ -19,6 +19,7 @@ import com.google.android.exoplayer2.source.TrackGroupArray;
 import com.google.android.exoplayer2.trackselection.TrackSelectionArray;
 import com.google.android.exoplayer2.upstream.Allocator;
 import com.google.android.exoplayer2.upstream.DefaultAllocator;
+import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.PriorityTaskManager;
 import com.google.android.exoplayer2.util.Util;
 
@@ -60,6 +61,116 @@ public class DefaultLoadControl implements LoadControl {
   /** The default prioritization of buffer time constraints over size constraints. */
   public static final boolean DEFAULT_PRIORITIZE_TIME_OVER_SIZE_THRESHOLDS = true;
 
+  /** Builder for {@link DefaultLoadControl}. */
+  public static final class Builder {
+
+    private DefaultAllocator allocator;
+    private int minBufferMs;
+    private int maxBufferMs;
+    private int bufferForPlaybackMs;
+    private int bufferForPlaybackAfterRebufferMs;
+    private int targetBufferBytes;
+    private boolean prioritizeTimeOverSizeThresholds;
+    private PriorityTaskManager priorityTaskManager;
+
+    /** Constructs a new instance. */
+    public Builder() {
+      allocator = null;
+      minBufferMs = DEFAULT_MIN_BUFFER_MS;
+      maxBufferMs = DEFAULT_MAX_BUFFER_MS;
+      bufferForPlaybackMs = DEFAULT_BUFFER_FOR_PLAYBACK_MS;
+      bufferForPlaybackAfterRebufferMs = DEFAULT_BUFFER_FOR_PLAYBACK_AFTER_REBUFFER_MS;
+      targetBufferBytes = DEFAULT_TARGET_BUFFER_BYTES;
+      prioritizeTimeOverSizeThresholds = DEFAULT_PRIORITIZE_TIME_OVER_SIZE_THRESHOLDS;
+      priorityTaskManager = null;
+    }
+
+    /**
+     * Sets the {@link DefaultAllocator} used by the loader.
+     *
+     * @param allocator The {@link DefaultAllocator}.
+     * @return This builder, for convenience.
+     */
+    public Builder setAllocator(DefaultAllocator allocator) {
+      this.allocator = allocator;
+      return this;
+    }
+
+    /**
+     * Sets the buffer duration parameters.
+     *
+     * @param minBufferMs The minimum duration of media that the player will attempt to ensure is
+     *     buffered at all times, in milliseconds.
+     * @param maxBufferMs The maximum duration of media that the player will attempt to buffer, in
+     *     milliseconds.
+     * @param bufferForPlaybackMs The duration of media that must be buffered for playback to start
+     *     or resume following a user action such as a seek, in milliseconds.
+     * @param bufferForPlaybackAfterRebufferMs The default duration of media that must be buffered
+     *     for playback to resume after a rebuffer, in milliseconds. A rebuffer is defined to be
+     *     caused by buffer depletion rather than a user action.
+     * @return This builder, for convenience.
+     */
+    public Builder setBufferDurationsMs(
+        int minBufferMs,
+        int maxBufferMs,
+        int bufferForPlaybackMs,
+        int bufferForPlaybackAfterRebufferMs) {
+      this.minBufferMs = minBufferMs;
+      this.maxBufferMs = maxBufferMs;
+      this.bufferForPlaybackMs = bufferForPlaybackMs;
+      this.bufferForPlaybackAfterRebufferMs = bufferForPlaybackAfterRebufferMs;
+      return this;
+    }
+
+    /**
+     * Sets the target buffer size in bytes. If set to {@link C#LENGTH_UNSET}, the target buffer
+     * size will be calculated using {@link #calculateTargetBufferSize(Renderer[],
+     * TrackSelectionArray)}.
+     *
+     * @param targetBufferBytes The target buffer size in bytes.
+     * @return This builder, for convenience.
+     */
+    public Builder setTargetBufferBytes(int targetBufferBytes) {
+      this.targetBufferBytes = targetBufferBytes;
+      return this;
+    }
+
+    /**
+     * Sets whether the load control prioritizes buffer time constraints over buffer size
+     * constraints.
+     *
+     * @param prioritizeTimeOverSizeThresholds Whether the load control prioritizes buffer time
+     *     constraints over buffer size constraints.
+     * @return This builder, for convenience.
+     */
+    public Builder setPrioritizeTimeOverSizeThresholds(boolean prioritizeTimeOverSizeThresholds) {
+      this.prioritizeTimeOverSizeThresholds = prioritizeTimeOverSizeThresholds;
+      return this;
+    }
+
+    /** Sets the {@link PriorityTaskManager} to use. */
+    public Builder setPriorityTaskManager(PriorityTaskManager priorityTaskManager) {
+      this.priorityTaskManager = priorityTaskManager;
+      return this;
+    }
+
+    /** Creates a {@link DefaultLoadControl}. */
+    public DefaultLoadControl createDefaultLoadControl() {
+      if (allocator == null) {
+        allocator = new DefaultAllocator(true, C.DEFAULT_BUFFER_SEGMENT_SIZE);
+      }
+      return new DefaultLoadControl(
+          allocator,
+          minBufferMs,
+          maxBufferMs,
+          bufferForPlaybackMs,
+          bufferForPlaybackAfterRebufferMs,
+          targetBufferBytes,
+          prioritizeTimeOverSizeThresholds,
+          priorityTaskManager);
+    }
+  }
+
   private final DefaultAllocator allocator;
 
   private final long minBufferUs;
@@ -80,11 +191,8 @@ public class DefaultLoadControl implements LoadControl {
     this(new DefaultAllocator(true, C.DEFAULT_BUFFER_SEGMENT_SIZE));
   }
 
-  /**
+  /** @deprecated Use {@link Builder} instead. */
-   * Constructs a new instance, using the {@code DEFAULT_*} constants defined in this class.
+  @Deprecated
-   *
-   * @param allocator The {@link DefaultAllocator} used by the loader.
-   */
   public DefaultLoadControl(DefaultAllocator allocator) {
     this(
         allocator,
@@ -96,24 +204,8 @@ public class DefaultLoadControl implements LoadControl {
         DEFAULT_PRIORITIZE_TIME_OVER_SIZE_THRESHOLDS);
   }
 
-  /**
+  /** @deprecated Use {@link Builder} instead. */
-   * Constructs a new instance.
+  @Deprecated
-   *
-   * @param allocator The {@link DefaultAllocator} used by the loader.
-   * @param minBufferMs The minimum duration of media that the player will attempt to ensure is
-   *     buffered at all times, in milliseconds.
-   * @param maxBufferMs The maximum duration of media that the player will attempt buffer, in
-   *     milliseconds.
-   * @param bufferForPlaybackMs The duration of media that must be buffered for playback to start or
-   *     resume following a user action such as a seek, in milliseconds.
-   * @param bufferForPlaybackAfterRebufferMs The default duration of media that must be buffered for
-   *     playback to resume after a rebuffer, in milliseconds. A rebuffer is defined to be caused by
-   *     buffer depletion rather than a user action.
-   * @param targetBufferBytes The target buffer size in bytes. If set to {@link C#LENGTH_UNSET}, the
-   *     target buffer size will be calculated using {@link #calculateTargetBufferSize(Renderer[],
-   *     TrackSelectionArray)}.
-   * @param prioritizeTimeOverSizeThresholds Whether the load control prioritizes buffer time
-   */
   public DefaultLoadControl(
       DefaultAllocator allocator,
       int minBufferMs,
@@ -133,27 +225,8 @@ public class DefaultLoadControl implements LoadControl {
         null);
   }
 
-  /**
+  /** @deprecated Use {@link Builder} instead. */
-   * Constructs a new instance.
+  @Deprecated
-   *
-   * @param allocator The {@link DefaultAllocator} used by the loader.
-   * @param minBufferMs The minimum duration of media that the player will attempt to ensure is
-   *     buffered at all times, in milliseconds.
-   * @param maxBufferMs The maximum duration of media that the player will attempt buffer, in
-   *     milliseconds.
-   * @param bufferForPlaybackMs The duration of media that must be buffered for playback to start or
-   *     resume following a user action such as a seek, in milliseconds.
-   * @param bufferForPlaybackAfterRebufferMs The default duration of media that must be buffered for
-   *     playback to resume after a rebuffer, in milliseconds. A rebuffer is defined to be caused by
-   *     buffer depletion rather than a user action.
-   * @param targetBufferBytes The target buffer size in bytes. If set to {@link C#LENGTH_UNSET}, the
-   *     target buffer size will be calculated using {@link #calculateTargetBufferSize(Renderer[],
-   *     TrackSelectionArray)}.
-   * @param prioritizeTimeOverSizeThresholds Whether the load control prioritizes buffer time
-   *     constraints over buffer size constraints.
-   * @param priorityTaskManager If not null, registers itself as a task with priority {@link
-   *     C#PRIORITY_PLAYBACK} during loading periods, and unregisters itself during draining
-   */
   public DefaultLoadControl(
       DefaultAllocator allocator,
       int minBufferMs,
@@ -163,6 +236,16 @@ public class DefaultLoadControl implements LoadControl {
       int targetBufferBytes,
       boolean prioritizeTimeOverSizeThresholds,
       PriorityTaskManager priorityTaskManager) {
+    assertGreaterOrEqual(bufferForPlaybackMs, 0, "bufferForPlaybackMs", "0");
+    assertGreaterOrEqual(bufferForPlaybackAfterRebufferMs, 0, "bufferForPlaybackMs", "0");
+    assertGreaterOrEqual(minBufferMs, bufferForPlaybackMs, "minBufferMs", "bufferForPlaybackMs");
+    assertGreaterOrEqual(
+        minBufferMs,
+        bufferForPlaybackAfterRebufferMs,
+        "minBufferMs",
+        "bufferForPlaybackAfterRebufferMs");
+    assertGreaterOrEqual(maxBufferMs, minBufferMs, "maxBufferMs", "minBufferMs");
+
     this.allocator = allocator;
     minBufferUs = minBufferMs * 1000L;
     maxBufferUs = maxBufferMs * 1000L;
@@ -217,18 +300,11 @@ public class DefaultLoadControl implements LoadControl {
   public boolean shouldContinueLoading(long bufferedDurationUs, float playbackSpeed) {
     boolean targetBufferSizeReached = allocator.getTotalBytesAllocated() >= targetBufferSize;
     boolean wasBuffering = isBuffering;
-    if (prioritizeTimeOverSizeThresholds) {
+    if (bufferedDurationUs < minBufferUs) {
-      isBuffering =
+      isBuffering = prioritizeTimeOverSizeThresholds || !targetBufferSizeReached;
-          bufferedDurationUs < minBufferUs // below low watermark
+    } else if (bufferedDurationUs > maxBufferUs || targetBufferSizeReached) {
-              || (bufferedDurationUs <= maxBufferUs // between watermarks
+      isBuffering = false;
-                  && isBuffering
+    } // Else don't change the buffering state
-                  && !targetBufferSizeReached);
-    } else {
-      isBuffering =
-          !targetBufferSizeReached
-              && (bufferedDurationUs < minBufferUs // below low watermark
-                  || (bufferedDurationUs <= maxBufferUs && isBuffering)); // between watermarks
-    }
     if (priorityTaskManager != null && isBuffering != wasBuffering) {
       if (isBuffering) {
         priorityTaskManager.add(C.PRIORITY_PLAYBACK);
@@ -280,4 +356,7 @@ public class DefaultLoadControl implements LoadControl {
     }
   }
 
+  private static void assertGreaterOrEqual(int value1, int value2, String name1, String name2) {
+    Assertions.checkArgument(value1 >= value2, name1 + " cannot be less than " + name2);
+  }
 }

library/core/src/test/java/com/google/android/exoplayer2/DefaultLoadControlShouldContinueLoadingTest.java

@@ -0,0 +1,111 @@
+/*
+ * Copyright (C) 2018 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 com.google.android.exoplayer2;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import com.google.android.exoplayer2.DefaultLoadControl.Builder;
+import com.google.android.exoplayer2.upstream.DefaultAllocator;
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.RobolectricTestRunner;
+
+/** Unit test for {@link DefaultLoadControl#shouldContinueLoading(long, float)}. */
+@RunWith(RobolectricTestRunner.class)
+public class DefaultLoadControlShouldContinueLoadingTest {
+
+  private static final int PLAYBACK_SPEED = 1;
+  private static final int MIN_BUFFER_MS = DefaultLoadControl.DEFAULT_MIN_BUFFER_MS;
+  private static final int MAX_BUFFER_MS = DefaultLoadControl.DEFAULT_MAX_BUFFER_MS;
+  private static final int TARGET_BUFFER_BYTES = C.DEFAULT_BUFFER_SEGMENT_SIZE * 2;
+  private Builder builder;
+  private DefaultAllocator allocator;
+  private DefaultLoadControl defaultLoadControl;
+
+  @Before
+  public void setUp() throws Exception {
+    builder = new Builder();
+    allocator = new DefaultAllocator(true, C.DEFAULT_BUFFER_SEGMENT_SIZE);
+  }
+
+  @Test
+  public void testReturnsTrueUntilMaximumBufferExceeded() throws Exception {
+    createDefaultLoadControl();
+    assertThatShouldContinueLoadingReturnsTrue(0);
+    assertThatShouldContinueLoadingReturnsTrue(MIN_BUFFER_MS);
+    assertThatShouldContinueLoadingReturnsTrue(MAX_BUFFER_MS);
+    assertThatShouldContinueLoadingReturnsFalse(MAX_BUFFER_MS + 1);
+  }
+
+  @Test
+  public void testReturnsFalseUntilFallBelowMinimumBufferOnceBufferingStopped() throws Exception {
+    createDefaultLoadControl();
+    assertThatShouldContinueLoadingReturnsFalse(MAX_BUFFER_MS + 1);
+    assertThatShouldContinueLoadingReturnsFalse(MAX_BUFFER_MS);
+    assertThatShouldContinueLoadingReturnsFalse(MIN_BUFFER_MS);
+    assertThatShouldContinueLoadingReturnsTrue(MIN_BUFFER_MS - 1);
+  }
+
+  @Test
+  public void testReturnsTrueUntilMinimumBufferReachedAlthoughTargetBufferBytesReached()
+      throws Exception {
+    createDefaultLoadControl();
+    makeSureTargetBufferBytesReached();
+
+    assertThatShouldContinueLoadingReturnsTrue(0);
+    assertThatShouldContinueLoadingReturnsTrue(MIN_BUFFER_MS - 1);
+    assertThatShouldContinueLoadingReturnsFalse(MIN_BUFFER_MS);
+    assertThatShouldContinueLoadingReturnsFalse(MAX_BUFFER_MS + 1);
+  }
+
+  @Test
+  public void testAlwaysReturnsFalseIfMaximumBufferReachedAndNotPrioritizeTimeOverSizeThresholds()
+      throws Exception {
+    builder.setPrioritizeTimeOverSizeThresholds(false);
+    createDefaultLoadControl();
+    // Put defaultLoadControl in buffering state.
+    assertThatShouldContinueLoadingReturnsTrue(0);
+    makeSureTargetBufferBytesReached();
+
+    assertThatShouldContinueLoadingReturnsFalse(0);
+    assertThatShouldContinueLoadingReturnsFalse(MIN_BUFFER_MS);
+    assertThatShouldContinueLoadingReturnsFalse(MAX_BUFFER_MS + 1);
+  }
+
+  private void createDefaultLoadControl() {
+    builder.setAllocator(allocator);
+    builder.setTargetBufferBytes(TARGET_BUFFER_BYTES);
+    defaultLoadControl = builder.createDefaultLoadControl();
+    defaultLoadControl.onTracksSelected(new Renderer[0], null, null);
+  }
+
+  private void makeSureTargetBufferBytesReached() {
+    while (allocator.getTotalBytesAllocated() < TARGET_BUFFER_BYTES) {
+      allocator.allocate();
+    }
+  }
+
+  private void assertThatShouldContinueLoadingReturnsFalse(int bufferedDurationMs) {
+    assertThat(defaultLoadControl.shouldContinueLoading(bufferedDurationMs * 1000, PLAYBACK_SPEED))
+        .isFalse();
+  }
+
+  private void assertThatShouldContinueLoadingReturnsTrue(int bufferedDurationMs) {
+    assertThat(defaultLoadControl.shouldContinueLoading(bufferedDurationMs * 1000, PLAYBACK_SPEED))
+        .isTrue();
+  }
+}