Fix util nullness warnings.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=212276150

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

@@ -1409,10 +1409,8 @@ public final class Format implements Parcelable {
 
   // Utility methods
 
-  /**
-   * Returns a prettier {@link String} than {@link #toString()}, intended for logging.
-   */
-  public static String toLogString(Format format) {
+  /** Returns a prettier {@link String} than {@link #toString()}, intended for logging. */
+  public static String toLogString(@Nullable Format format) {
     if (format == null) {
       return "null";
     }

library/core/src/main/java/com/google/android/exoplayer2/metadata/emsg/EventMessageDecoder.java

@@ -19,6 +19,7 @@ import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.metadata.Metadata;
 import com.google.android.exoplayer2.metadata.MetadataDecoder;
 import com.google.android.exoplayer2.metadata.MetadataInputBuffer;
+import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.ParsableByteArray;
 import com.google.android.exoplayer2.util.Util;
 import java.nio.ByteBuffer;
@@ -39,8 +40,8 @@ public final class EventMessageDecoder implements MetadataDecoder {
     byte[] data = buffer.array();
     int size = buffer.limit();
     ParsableByteArray emsgData = new ParsableByteArray(data, size);
-    String schemeIdUri = emsgData.readNullTerminatedString();
-    String value = emsgData.readNullTerminatedString();
+    String schemeIdUri = Assertions.checkNotNull(emsgData.readNullTerminatedString());
+    String value = Assertions.checkNotNull(emsgData.readNullTerminatedString());
     long timescale = emsgData.readUnsignedInt();
     long presentationTimeUs = Util.scaleLargeTimestamp(emsgData.readUnsignedInt(),
         C.MICROS_PER_SECOND, timescale);

library/core/src/main/java/com/google/android/exoplayer2/util/AtomicFile.java

@@ -103,7 +103,7 @@ public final class AtomicFile {
       str = new AtomicFileOutputStream(baseName);
     } catch (FileNotFoundException e) {
       File parent = baseName.getParentFile();
-      if (!parent.mkdirs()) {
+      if (parent == null || !parent.mkdirs()) {
         throw new IOException("Couldn't create directory " + baseName, e);
       }
       try {

library/core/src/main/java/com/google/android/exoplayer2/util/EventLogger.java

@@ -42,6 +42,7 @@ import java.text.NumberFormat;
 import java.util.Locale;
 
 /** Logs events from {@link Player} and other core components using {@link Log}. */
+@SuppressWarnings("UngroupedOverloads")
 public class EventLogger implements AnalyticsListener {
 
   private static final String DEFAULT_TAG = "EventLogger";
@@ -435,7 +436,7 @@ public class EventLogger implements AnalyticsListener {
    * @param msg The message to log.
    * @param tr The exception to log.
    */
-  protected void loge(String msg, Throwable tr) {
+  protected void loge(String msg, @Nullable Throwable tr) {
     Log.e(tag, msg, tr);
   }
 
@@ -449,12 +450,15 @@ public class EventLogger implements AnalyticsListener {
     logd(getEventString(eventTime, eventName, eventDescription));
   }
 
-  private void loge(EventTime eventTime, String eventName, Throwable throwable) {
+  private void loge(EventTime eventTime, String eventName, @Nullable Throwable throwable) {
     loge(getEventString(eventTime, eventName), throwable);
   }
 
   private void loge(
-      EventTime eventTime, String eventName, String eventDescription, Throwable throwable) {
+      EventTime eventTime,
+      String eventName,
+      String eventDescription,
+      @Nullable Throwable throwable) {
     loge(getEventString(eventTime, eventName, eventDescription), throwable);
   }
 
@@ -548,8 +552,8 @@ public class EventLogger implements AnalyticsListener {
   // Suppressing reference equality warning because the track group stored in the track selection
   // must point to the exact track group object to be considered part of it.
   @SuppressWarnings("ReferenceEquality")
-  private static String getTrackStatusString(TrackSelection selection, TrackGroup group,
-      int trackIndex) {
+  private static String getTrackStatusString(
+      @Nullable TrackSelection selection, TrackGroup group, int trackIndex) {
     return getTrackStatusString(selection != null && selection.getTrackGroup() == group
         && selection.indexOf(trackIndex) != C.INDEX_UNSET);
   }

library/core/src/main/java/com/google/android/exoplayer2/util/ParsableBitArray.java

@@ -28,10 +28,10 @@ public final class ParsableBitArray {
   private int bitOffset;
   private int byteLimit;
 
-  /**
-   * Creates a new instance that initially has no backing data.
-   */
-  public ParsableBitArray() {}
+  /** Creates a new instance that initially has no backing data. */
+  public ParsableBitArray() {
+    data = Util.EMPTY_BYTE_ARRAY;
+  }
 
   /**
    * Creates a new instance that wraps an existing array.

library/core/src/main/java/com/google/android/exoplayer2/util/ParsableByteArray.java

@@ -15,6 +15,7 @@
  */
 package com.google.android.exoplayer2.util;
 
+import android.support.annotation.Nullable;
 import com.google.android.exoplayer2.C;
 import java.nio.ByteBuffer;
 import java.nio.charset.Charset;
@@ -30,10 +31,10 @@ public final class ParsableByteArray {
   private int position;
   private int limit;
 
-  /**
-   * Creates a new instance that initially has no backing data.
-   */
-  public ParsableByteArray() {}
+  /** Creates a new instance that initially has no backing data. */
+  public ParsableByteArray() {
+    data = Util.EMPTY_BYTE_ARRAY;
+  }
 
   /**
    * Creates a new instance with {@code limit} bytes and sets the limit.
@@ -131,7 +132,7 @@ public final class ParsableByteArray {
    * Returns the capacity of the array, which may be larger than the limit.
    */
   public int capacity() {
-    return data == null ? 0 : data.length;
+    return data.length;
   }
 
   /**
@@ -481,7 +482,7 @@ public final class ParsableByteArray {
    * @return The string not including any terminating NUL byte, or null if the end of the data has
    *     already been reached.
    */
-  public String readNullTerminatedString() {
+  public @Nullable String readNullTerminatedString() {
     if (bytesLeft() == 0) {
       return null;
     }
@@ -507,7 +508,7 @@ public final class ParsableByteArray {
    * @return The line not including any line-termination characters, or null if the end of the data
    *     has already been reached.
    */
-  public String readLine() {
+  public @Nullable String readLine() {
     if (bytesLeft() == 0) {
       return null;
     }

library/core/src/main/java/com/google/android/exoplayer2/util/ParsableNalUnitBitArray.java

@@ -35,6 +35,7 @@ public final class ParsableNalUnitBitArray {
    * @param offset The byte offset in {@code data} to start reading from.
    * @param limit The byte offset of the end of the bitstream in {@code data}.
    */
+  @SuppressWarnings({"initialization.fields.uninitialized", "method.invocation.invalid"})
   public ParsableNalUnitBitArray(byte[] data, int offset, int limit) {
     reset(data, offset, limit);
   }

library/core/src/main/java/com/google/android/exoplayer2/util/PriorityTaskManager.java

@@ -111,7 +111,7 @@ public final class PriorityTaskManager {
   public void remove(int priority) {
     synchronized (lock) {
       queue.remove(priority);
-      highestPriority = queue.isEmpty() ? Integer.MIN_VALUE : queue.peek();
+      highestPriority = queue.isEmpty() ? Integer.MIN_VALUE : Util.castNonNull(queue.peek());
       lock.notifyAll();
     }
   }

library/core/src/main/java/com/google/android/exoplayer2/util/Util.java

@@ -1678,9 +1678,9 @@ public final class Util {
    *
    * @param input Wraps the compressed input data.
    * @param output Wraps an output buffer to be used to store the uncompressed data. If {@code
-   *     output.data} is null or it isn't big enough to hold the uncompressed data, a new array is
-   *     created. If {@code true} is returned then the output's position will be set to 0 and its
-   *     limit will be set to the length of the uncompressed data.
+   *     output.data} isn't big enough to hold the uncompressed data, a new array is created. If
+   *     {@code true} is returned then the output's position will be set to 0 and its limit will be
+   *     set to the length of the uncompressed data.
    * @param inflater If not null, used to uncompressed the input. Otherwise a new {@link Inflater}
    *     is created.
    * @return Whether the input is uncompressed successfully.
@@ -1691,8 +1691,8 @@ public final class Util {
       return false;
     }
     byte[] outputData = output.data;
-    if (outputData == null) {
-      outputData = new byte[input.bytesLeft()];
+    if (outputData.length < input.bytesLeft()) {
+      outputData = new byte[2 * input.bytesLeft()];
     }
     if (inflater == null) {
       inflater = new Inflater();

library/core/src/main/java/com/google/android/exoplayer2/util/XmlPullParserUtil.java

@@ -15,6 +15,7 @@
  */
 package com.google.android.exoplayer2.util;
 
+import android.support.annotation.Nullable;
 import org.xmlpull.v1.XmlPullParser;
 import org.xmlpull.v1.XmlPullParserException;
 
@@ -93,7 +94,7 @@ public final class XmlPullParserUtil {
    * @return The value of the attribute, or null if the current event is not a start tag or if no
    *     such attribute was found.
    */
-  public static String getAttributeValue(XmlPullParser xpp, String attributeName) {
+  public static @Nullable String getAttributeValue(XmlPullParser xpp, String attributeName) {
     int attributeCount = xpp.getAttributeCount();
     for (int i = 0; i < attributeCount; i++) {
       if (xpp.getAttributeName(i).equals(attributeName)) {
@@ -112,7 +113,8 @@ public final class XmlPullParserUtil {
    * @return The value of the attribute, or null if the current event is not a start tag or if no
    *     such attribute was found.
    */
-  public static String getAttributeValueIgnorePrefix(XmlPullParser xpp, String attributeName) {
+  public static @Nullable String getAttributeValueIgnorePrefix(
+      XmlPullParser xpp, String attributeName) {
     int attributeCount = xpp.getAttributeCount();
     for (int i = 0; i < attributeCount; i++) {
       if (stripPrefix(xpp.getAttributeName(i)).equals(attributeName)) {