Annotate libjingle_peerconnection_java with @Nullable.

Bug: webrtc:8881
Change-Id: Ida2ef6c003567d19529c21629c916ed40e8de3a6
Reviewed-on: https://webrtc-review.googlesource.com/63380
Commit-Queue: Sami Kalliomäki <sakal@webrtc.org>
Reviewed-by: Paulina Hensman <phensman@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#22563}

sdk/android/src/java/org/webrtc/Camera1Session.java

@@ -14,6 +14,7 @@ import android.content.Context;
 import android.media.MediaRecorder;
 import android.os.Handler;
 import android.os.SystemClock;
+import javax.annotation.Nullable;
 import android.view.Surface;
 import android.view.WindowManager;
 import java.io.IOException;
@@ -152,8 +153,8 @@ class Camera1Session implements CameraSession {
   }
 
   private Camera1Session(Events events, boolean captureToTexture, Context applicationContext,
-      SurfaceTextureHelper surfaceTextureHelper, MediaRecorder mediaRecorder, int cameraId,
-      android.hardware.Camera camera, android.hardware.Camera.CameraInfo info,
+      SurfaceTextureHelper surfaceTextureHelper, @Nullable MediaRecorder mediaRecorder,
+      int cameraId, android.hardware.Camera camera, android.hardware.Camera.CameraInfo info,
       CaptureFormat captureFormat, long constructionTimeNs) {
     Logging.d(TAG, "Create new camera1 session on camera " + cameraId);
 

sdk/android/src/java/org/webrtc/Camera2Session.java

@@ -24,6 +24,7 @@ import android.hardware.camera2.CaptureFailure;
 import android.hardware.camera2.CaptureRequest;
 import android.media.MediaRecorder;
 import android.os.Handler;
+import javax.annotation.Nullable;
 import android.util.Range;
 import android.view.Surface;
 import android.view.WindowManager;
@@ -51,7 +52,7 @@ class Camera2Session implements CameraSession {
   private final Context applicationContext;
   private final CameraManager cameraManager;
   private final SurfaceTextureHelper surfaceTextureHelper;
-  private final Surface mediaRecorderSurface;
+  @Nullable private final Surface mediaRecorderSurface;
   private final String cameraId;
   private final int width;
   private final int height;
@@ -65,11 +66,11 @@ class Camera2Session implements CameraSession {
   private CaptureFormat captureFormat;
 
   // Initialized when camera opens
-  private CameraDevice cameraDevice;
-  private Surface surface;
+  @Nullable private CameraDevice cameraDevice;
+  @Nullable private Surface surface;
 
   // Initialized when capture session is created
-  private CameraCaptureSession captureSession;
+  @Nullable private CameraCaptureSession captureSession;
 
   // State
   private SessionState state = SessionState.RUNNING;
@@ -304,7 +305,8 @@ class Camera2Session implements CameraSession {
 
   private Camera2Session(CreateSessionCallback callback, Events events, Context applicationContext,
       CameraManager cameraManager, SurfaceTextureHelper surfaceTextureHelper,
-      MediaRecorder mediaRecorder, String cameraId, int width, int height, int framerate) {
+      @Nullable MediaRecorder mediaRecorder, String cameraId, int width, int height,
+      int framerate) {
     Logging.d(TAG, "Create new camera2 session on camera " + cameraId);
 
     constructionTimeNs = System.nanoTime();

sdk/android/src/java/org/webrtc/CameraCapturer.java

@@ -14,6 +14,7 @@ import android.content.Context;
 import android.media.MediaRecorder;
 import android.os.Handler;
 import android.os.Looper;
+import javax.annotation.Nullable;
 import java.util.Arrays;
 
 @SuppressWarnings("deprecation")
@@ -37,9 +38,10 @@ abstract class CameraCapturer implements CameraVideoCapturer {
   private final static int OPEN_CAMERA_TIMEOUT = 10000;
 
   private final CameraEnumerator cameraEnumerator;
-  private final CameraEventsHandler eventsHandler;
+  @Nullable private final CameraEventsHandler eventsHandler;
   private final Handler uiThreadHandler;
 
+  @Nullable
   private final CameraSession.CreateSessionCallback createSessionCallback =
       new CameraSession.CreateSessionCallback() {
         @Override
@@ -125,6 +127,7 @@ abstract class CameraCapturer implements CameraVideoCapturer {
         }
       };
 
+  @Nullable
   private final CameraSession.Events cameraSessionEventsHandler = new CameraSession.Events() {
     @Override
     public void onCameraOpening() {
@@ -203,31 +206,31 @@ abstract class CameraCapturer implements CameraVideoCapturer {
 
   // Initialized on initialize
   // -------------------------
-  private Handler cameraThreadHandler;
+  @Nullable private Handler cameraThreadHandler;
   private Context applicationContext;
   private CapturerObserver capturerObserver;
-  private SurfaceTextureHelper surfaceHelper;
+  @Nullable private SurfaceTextureHelper surfaceHelper;
 
   private final Object stateLock = new Object();
   private boolean sessionOpening; /* guarded by stateLock */
-  private CameraSession currentSession; /* guarded by stateLock */
+  @Nullable private CameraSession currentSession; /* guarded by stateLock */
   private String cameraName; /* guarded by stateLock */
   private int width; /* guarded by stateLock */
   private int height; /* guarded by stateLock */
   private int framerate; /* guarded by stateLock */
   private int openAttemptsRemaining; /* guarded by stateLock */
   private SwitchState switchState = SwitchState.IDLE; /* guarded by stateLock */
-  private CameraSwitchHandler switchEventsHandler; /* guarded by stateLock */
+  @Nullable private CameraSwitchHandler switchEventsHandler; /* guarded by stateLock */
   // Valid from onDone call until stopCapture, otherwise null.
-  private CameraStatistics cameraStatistics; /* guarded by stateLock */
+  @Nullable private CameraStatistics cameraStatistics; /* guarded by stateLock */
   private boolean firstFrameObserved; /* guarded by stateLock */
 
   // Variables used on camera thread - do not require stateLock synchronization.
   private MediaRecorderState mediaRecorderState = MediaRecorderState.IDLE;
-  private MediaRecorderHandler mediaRecorderEventsHandler;
+  @Nullable private MediaRecorderHandler mediaRecorderEventsHandler;
 
-  public CameraCapturer(
-      String cameraName, CameraEventsHandler eventsHandler, CameraEnumerator cameraEnumerator) {
+  public CameraCapturer(String cameraName, @Nullable CameraEventsHandler eventsHandler,
+      CameraEnumerator cameraEnumerator) {
     if (eventsHandler == null) {
       eventsHandler = new CameraEventsHandler() {
         @Override
@@ -262,8 +265,8 @@ abstract class CameraCapturer implements CameraVideoCapturer {
   }
 
   @Override
-  public void initialize(SurfaceTextureHelper surfaceTextureHelper, Context applicationContext,
-      CapturerObserver capturerObserver) {
+  public void initialize(@Nullable SurfaceTextureHelper surfaceTextureHelper,
+      Context applicationContext, CapturerObserver capturerObserver) {
     this.applicationContext = applicationContext;
     this.capturerObserver = capturerObserver;
     this.surfaceHelper = surfaceTextureHelper;
@@ -412,14 +415,15 @@ abstract class CameraCapturer implements CameraVideoCapturer {
     }
   }
 
-  private void reportCameraSwitchError(String error, CameraSwitchHandler switchEventsHandler) {
+  private void reportCameraSwitchError(
+      String error, @Nullable CameraSwitchHandler switchEventsHandler) {
     Logging.e(TAG, error);
     if (switchEventsHandler != null) {
       switchEventsHandler.onCameraSwitchError(error);
     }
   }
 
-  private void switchCameraInternal(final CameraSwitchHandler switchEventsHandler) {
+  private void switchCameraInternal(@Nullable final CameraSwitchHandler switchEventsHandler) {
     Logging.d(TAG, "switchCamera internal");
 
     final String[] deviceNames = cameraEnumerator.getDeviceNames();
@@ -476,7 +480,7 @@ abstract class CameraCapturer implements CameraVideoCapturer {
   }
 
   private void reportUpdateMediaRecorderError(
-      String error, MediaRecorderHandler mediaRecoderEventsHandler) {
+      String error, @Nullable MediaRecorderHandler mediaRecoderEventsHandler) {
     checkIsOnCameraThread();
     Logging.e(TAG, error);
     if (mediaRecoderEventsHandler != null) {
@@ -485,7 +489,7 @@ abstract class CameraCapturer implements CameraVideoCapturer {
   }
 
   private void updateMediaRecorderInternal(
-      MediaRecorder mediaRecorder, MediaRecorderHandler mediaRecoderEventsHandler) {
+      @Nullable MediaRecorder mediaRecorder, MediaRecorderHandler mediaRecoderEventsHandler) {
     checkIsOnCameraThread();
     boolean addMediaRecorder = (mediaRecorder != null);
     Logging.d(TAG,

sdk/android/src/java/org/webrtc/EglBase10.java

@@ -13,6 +13,7 @@ package org.webrtc;
 import android.graphics.Canvas;
 import android.graphics.Rect;
 import android.graphics.SurfaceTexture;
+import javax.annotation.Nullable;
 import android.view.Surface;
 import android.view.SurfaceHolder;
 import javax.microedition.khronos.egl.EGL10;
@@ -31,7 +32,7 @@ class EglBase10 implements EglBase {
 
   private final EGL10 egl;
   private EGLContext eglContext;
-  private EGLConfig eglConfig;
+  @Nullable private EGLConfig eglConfig;
   private EGLDisplay eglDisplay;
   private EGLSurface eglSurface = EGL10.EGL_NO_SURFACE;
 
@@ -102,11 +103,13 @@ class EglBase10 implements EglBase {
       @Override
       public void setKeepScreenOn(boolean b) {}
 
+      @Nullable
       @Override
       public Canvas lockCanvas() {
         return null;
       }
 
+      @Nullable
       @Override
       public Canvas lockCanvas(Rect rect) {
         return null;
@@ -115,6 +118,7 @@ class EglBase10 implements EglBase {
       @Override
       public void unlockCanvasAndPost(Canvas canvas) {}
 
+      @Nullable
       @Override
       public Rect getSurfaceFrame() {
         return null;
@@ -301,7 +305,7 @@ class EglBase10 implements EglBase {
 
   // Return an EGLConfig, or die trying.
   private EGLContext createEglContext(
-      Context sharedContext, EGLDisplay eglDisplay, EGLConfig eglConfig) {
+      @Nullable Context sharedContext, EGLDisplay eglDisplay, EGLConfig eglConfig) {
     if (sharedContext != null && sharedContext.eglContext == EGL10.EGL_NO_CONTEXT) {
       throw new RuntimeException("Invalid sharedContext");
     }

sdk/android/src/java/org/webrtc/EglBase14.java

@@ -19,6 +19,7 @@ import android.opengl.EGLDisplay;
 import android.opengl.EGLExt;
 import android.opengl.EGLSurface;
 import android.os.Build;
+import javax.annotation.Nullable;
 import android.view.Surface;
 import org.webrtc.EglBase;
 
@@ -33,7 +34,7 @@ class EglBase14 implements EglBase {
   private static final int EGLExt_SDK_VERSION = android.os.Build.VERSION_CODES.JELLY_BEAN_MR2;
   private static final int CURRENT_SDK_VERSION = android.os.Build.VERSION.SDK_INT;
   private EGLContext eglContext;
-  private EGLConfig eglConfig;
+  @Nullable private EGLConfig eglConfig;
   private EGLDisplay eglDisplay;
   private EGLSurface eglSurface = EGL14.EGL_NO_SURFACE;
 
@@ -262,7 +263,7 @@ class EglBase14 implements EglBase {
 
   // Return an EGLConfig, or die trying.
   private static EGLContext createEglContext(
-      EglBase14.Context sharedContext, EGLDisplay eglDisplay, EGLConfig eglConfig) {
+      @Nullable EglBase14.Context sharedContext, EGLDisplay eglDisplay, EGLConfig eglConfig) {
     if (sharedContext != null && sharedContext.egl14Context == EGL14.EGL_NO_CONTEXT) {
       throw new RuntimeException("Invalid sharedContext");
     }

sdk/android/src/java/org/webrtc/HardwareVideoDecoder.java

@@ -15,6 +15,7 @@ import android.media.MediaCodec;
 import android.media.MediaCodecInfo.CodecCapabilities;
 import android.media.MediaFormat;
 import android.os.SystemClock;
+import javax.annotation.Nullable;
 import android.view.Surface;
 import java.io.IOException;
 import java.nio.ByteBuffer;
@@ -71,7 +72,7 @@ class HardwareVideoDecoder
   // Output thread runs a loop which polls MediaCodec for decoded output buffers.  It reformats
   // those buffers into VideoFrames and delivers them to the callback.  Variable is set on decoder
   // thread and is immutable while the codec is running.
-  private Thread outputThread;
+  @Nullable private Thread outputThread;
 
   // Checker that ensures work is run on the output thread.
   private ThreadChecker outputThreadChecker;
@@ -81,7 +82,7 @@ class HardwareVideoDecoder
   private ThreadChecker decoderThreadChecker;
 
   private volatile boolean running = false;
-  private volatile Exception shutdownException = null;
+  @Nullable private volatile Exception shutdownException = null;
 
   // Dimensions (width, height, stride, and sliceHeight) may be accessed by either the decode thread
   // or the output thread.  Accesses should be protected with this lock.
@@ -101,8 +102,8 @@ class HardwareVideoDecoder
 
   private final EglBase.Context sharedContext;
   // Valid and immutable while the decoder is running.
-  private SurfaceTextureHelper surfaceTextureHelper;
-  private Surface surface = null;
+  @Nullable private SurfaceTextureHelper surfaceTextureHelper;
+  @Nullable private Surface surface = null;
 
   private static class DecodedTextureMetadata {
     final int width;
@@ -123,14 +124,14 @@ class HardwareVideoDecoder
 
   // Metadata for the last frame rendered to the texture.
   private final Object renderedTextureMetadataLock = new Object();
-  private DecodedTextureMetadata renderedTextureMetadata;
+  @Nullable private DecodedTextureMetadata renderedTextureMetadata;
 
   // Decoding proceeds asynchronously.  This callback returns decoded frames to the caller.  Valid
   // and immutable while the decoder is running.
-  private Callback callback;
+  @Nullable private Callback callback;
 
   // Valid and immutable while the decoder is running.
-  private MediaCodec codec = null;
+  @Nullable private MediaCodec codec = null;
 
   HardwareVideoDecoder(
       String codecName, VideoCodecType codecType, int colorFormat, EglBase.Context sharedContext) {

sdk/android/src/java/org/webrtc/HardwareVideoEncoder.java

@@ -17,6 +17,7 @@ import android.media.MediaCodecInfo;
 import android.media.MediaFormat;
 import android.opengl.GLES20;
 import android.os.Bundle;
+import javax.annotation.Nullable;
 import android.view.Surface;
 import java.io.IOException;
 import java.nio.ByteBuffer;
@@ -81,16 +82,16 @@ class HardwareVideoEncoder implements VideoEncoder {
   private boolean automaticResizeOn;
 
   // --- Valid and immutable while an encoding session is running.
-  private MediaCodec codec;
+  @Nullable private MediaCodec codec;
   // Thread that delivers encoded frames to the user callback.
-  private Thread outputThread;
+  @Nullable private Thread outputThread;
 
   // EGL base wrapping the shared texture context.  Holds hooks to both the shared context and the
   // input surface.  Making this base current allows textures from the context to be drawn onto the
   // surface.
-  private EglBase14 textureEglBase;
+  @Nullable private EglBase14 textureEglBase;
   // Input surface for the codec.  The encoder will draw input textures onto this surface.
-  private Surface textureInputSurface;
+  @Nullable private Surface textureInputSurface;
 
   private int width;
   private int height;
@@ -102,7 +103,7 @@ class HardwareVideoEncoder implements VideoEncoder {
 
   // --- Only accessed on the output thread.
   // Contents of the last observed config frame output by the MediaCodec. Used by H.264.
-  private ByteBuffer configBuffer = null;
+  @Nullable private ByteBuffer configBuffer = null;
   private int adjustedBitrate;
 
   // Whether the encoder is running.  Volatile so that the output thread can watch this value and
@@ -110,7 +111,7 @@ class HardwareVideoEncoder implements VideoEncoder {
   private volatile boolean running = false;
   // Any exception thrown during shutdown.  The output thread releases the MediaCodec and uses this
   // value to send exceptions thrown during release back to the encoder thread.
-  private volatile Exception shutdownException = null;
+  @Nullable private volatile Exception shutdownException = null;
 
   /**
    * Creates a new HardwareVideoEncoder with the given codecName, codecType, colorFormat, key frame

sdk/android/src/java/org/webrtc/MediaCodecUtils.java

@@ -14,6 +14,7 @@ import android.annotation.TargetApi;
 import android.media.MediaCodec;
 import android.media.MediaCodecInfo;
 import android.media.MediaCodecInfo.CodecCapabilities;
+import javax.annotation.Nullable;
 
 /** Container class for static constants and helpers used with MediaCodec. */
 @TargetApi(18)
@@ -54,7 +55,8 @@ class MediaCodecUtils {
   // Color formats supported by texture mode encoding - in order of preference.
   static final int[] TEXTURE_COLOR_FORMATS = {MediaCodecInfo.CodecCapabilities.COLOR_FormatSurface};
 
-  static Integer selectColorFormat(int[] supportedColorFormats, CodecCapabilities capabilities) {
+  static @Nullable Integer selectColorFormat(
+      int[] supportedColorFormats, CodecCapabilities capabilities) {
     for (int supportedColorFormat : supportedColorFormats) {
       for (int codecColorFormat : capabilities.colorFormats) {
         if (codecColorFormat == supportedColorFormat) {

sdk/android/src/java/org/webrtc/VideoEncoderWrapper.java

@@ -11,6 +11,7 @@
 package org.webrtc;
 
 // Explicit imports necessary for JNI generation.
+import javax.annotation.Nullable;
 import org.webrtc.VideoEncoder;
 import java.nio.ByteBuffer;
 
@@ -23,11 +24,13 @@ class VideoEncoderWrapper {
     return scalingSettings.on;
   }
 
+  @Nullable
   @CalledByNative
   static Integer getScalingSettingsLow(VideoEncoder.ScalingSettings scalingSettings) {
     return scalingSettings.low;
   }
 
+  @Nullable
   @CalledByNative
   static Integer getScalingSettingsHigh(VideoEncoder.ScalingSettings scalingSettings) {
     return scalingSettings.high;

sdk/android/src/java/org/webrtc/audio/WebRtcAudioEffects.java

@@ -19,6 +19,7 @@ import android.media.audiofx.NoiseSuppressor;
 import android.os.Build;
 import java.util.List;
 import java.util.UUID;
+import javax.annotation.Nullable;
 import org.webrtc.Logging;
 
 // This class wraps control of three different platform effects. Supported
@@ -40,12 +41,12 @@ class WebRtcAudioEffects {
   // Contains the available effect descriptors returned from the
   // AudioEffect.getEffects() call. This result is cached to avoid doing the
   // slow OS call multiple times.
-  private static Descriptor[] cachedEffects = null;
+  private static @Nullable Descriptor[] cachedEffects = null;
 
   // Contains the audio effect objects. Created in enable() and destroyed
   // in release().
-  private AcousticEchoCanceler aec = null;
-  private NoiseSuppressor ns = null;
+  private @Nullable AcousticEchoCanceler aec = null;
+  private @Nullable NoiseSuppressor ns = null;
 
   // Affects the final state given to the setEnabled() method on each effect.
   // The default state is set to "disabled" but each effect can also be enabled
@@ -293,7 +294,7 @@ class WebRtcAudioEffects {
 
   // Returns the cached copy of the audio effects array, if available, or
   // queries the operating system for the list of effects.
-  private static Descriptor[] getAvailableEffects() {
+  private static @Nullable Descriptor[] getAvailableEffects() {
     if (cachedEffects != null) {
       return cachedEffects;
     }

sdk/android/src/java/org/webrtc/audio/WebRtcAudioManager.java

@@ -20,6 +20,7 @@ import android.media.AudioTrack;
 import android.os.Build;
 import java.util.Timer;
 import java.util.TimerTask;
+import javax.annotation.Nullable;
 import org.webrtc.Logging;
 import org.webrtc.CalledByNative;
 
@@ -100,7 +101,7 @@ class WebRtcAudioManager {
     private static final int TIMER_PERIOD_IN_SECONDS = 30;
 
     private final AudioManager audioManager;
-    private Timer timer;
+    private @Nullable Timer timer;
 
     public VolumeLogger(AudioManager audioManager) {
       this.audioManager = audioManager;

sdk/android/src/java/org/webrtc/audio/WebRtcAudioRecord.java

@@ -19,12 +19,13 @@ import java.lang.System;
 import java.nio.ByteBuffer;
 import java.util.Arrays;
 import java.util.concurrent.TimeUnit;
+import javax.annotation.Nullable;
+import org.webrtc.CalledByNative;
 import org.webrtc.Logging;
+import org.webrtc.NativeClassQualifiedName;
 import org.webrtc.ThreadUtils;
 import org.webrtc.audio.AudioDeviceModule.AudioRecordErrorCallback;
 import org.webrtc.audio.AudioDeviceModule.AudioRecordStartErrorCode;
-import org.webrtc.CalledByNative;
-import org.webrtc.NativeClassQualifiedName;
 import org.webrtc.audio.AudioDeviceModule.SamplesReadyCallback;
 
 class WebRtcAudioRecord {
@@ -56,24 +57,24 @@ class WebRtcAudioRecord {
 
   private final long nativeAudioRecord;
 
-  private WebRtcAudioEffects effects = null;
+  private @Nullable WebRtcAudioEffects effects = null;
 
-  private ByteBuffer byteBuffer;
+  private @Nullable ByteBuffer byteBuffer;
 
-  private AudioRecord audioRecord = null;
-  private AudioRecordThread audioThread = null;
+  private @Nullable AudioRecord audioRecord = null;
+  private @Nullable AudioRecordThread audioThread = null;
 
   private static volatile boolean microphoneMute = false;
   private byte[] emptyBytes;
 
-  private static AudioRecordErrorCallback errorCallback = null;
+  private static @Nullable AudioRecordErrorCallback errorCallback = null;
 
   public static void setErrorCallback(AudioRecordErrorCallback errorCallback) {
     Logging.d(TAG, "Set error callback");
     WebRtcAudioRecord.errorCallback = errorCallback;
   }
 
-  private static SamplesReadyCallback audioSamplesReadyCallback = null;
+  private static @Nullable SamplesReadyCallback audioSamplesReadyCallback = null;
 
   public static void setOnAudioSamplesReady(SamplesReadyCallback callback) {
     audioSamplesReadyCallback = callback;

sdk/android/src/java/org/webrtc/audio/WebRtcAudioTrack.java

@@ -20,6 +20,7 @@ import android.media.AudioTrack;
 import android.os.Process;
 import java.lang.Thread;
 import java.nio.ByteBuffer;
+import javax.annotation.Nullable;
 import org.webrtc.ContextUtils;
 import org.webrtc.Logging;
 import org.webrtc.ThreadUtils;
@@ -82,15 +83,15 @@ class WebRtcAudioTrack {
 
   private ByteBuffer byteBuffer;
 
-  private AudioTrack audioTrack = null;
-  private AudioTrackThread audioThread = null;
+  private @Nullable AudioTrack audioTrack = null;
+  private @Nullable AudioTrackThread audioThread = null;
 
   // Samples to be played are replaced by zeros if |speakerMute| is set to true.
   // Can be used to ensure that the speaker is fully muted.
   private static volatile boolean speakerMute = false;
   private byte[] emptyBytes;
 
-  private static AudioTrackErrorCallback errorCallback = null;
+  private static @Nullable AudioTrackErrorCallback errorCallback = null;
 
   public static void setErrorCallback(AudioTrackErrorCallback errorCallback) {
     Logging.d(TAG, "Set extended error callback");