global: get rid of nonnull gradle hack

Hacking things up via gradle is not right, and package-info.java poses
problems with two modules, so instead we just apply it manually to every
class.

Remember to add this to new classes!

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

tunnel/src/main/java/com/wireguard/android/backend/Backend.java

@@ -5,6 +5,8 @@
 
 package com.wireguard.android.backend;
 
+import com.wireguard.util.NonNullForAll;
+
 import com.wireguard.config.Config;
 
 import java.util.Collection;
@@ -16,6 +18,7 @@ import androidx.annotation.Nullable;
  * Interface for implementations of the WireGuard secure network tunnel.
  */
 
+@NonNullForAll
 public interface Backend {
     /**
      * Enumerate names of currently-running tunnels.

tunnel/src/main/java/com/wireguard/android/backend/BackendException.java

@@ -5,6 +5,9 @@
 
 package com.wireguard.android.backend;
 
+import com.wireguard.util.NonNullForAll;
+
+@NonNullForAll
 public final class BackendException extends Exception {
     public enum Reason {
         UNKNOWN_KERNEL_MODULE_NAME,

tunnel/src/main/java/com/wireguard/android/backend/GoBackend.java

@@ -5,6 +5,8 @@
 
 package com.wireguard.android.backend;
 
+import com.wireguard.util.NonNullForAll;
+
 import android.content.Context;
 import android.content.Intent;
 import android.os.Build;
@@ -30,6 +32,7 @@ import java.util.concurrent.TimeoutException;
 
 import java9.util.concurrent.CompletableFuture;
 
+@NonNullForAll
 public final class GoBackend implements Backend {
     private static final String TAG = "WireGuard/" + GoBackend.class.getSimpleName();
     private static CompletableFuture<VpnService> vpnService = new CompletableFuture<>();

tunnel/src/main/java/com/wireguard/android/backend/Statistics.java

@@ -5,6 +5,8 @@
 
 package com.wireguard.android.backend;
 
+import com.wireguard.util.NonNullForAll;
+
 import android.os.SystemClock;
 import android.util.Pair;
 
@@ -13,6 +15,7 @@ import com.wireguard.crypto.Key;
 import java.util.HashMap;
 import java.util.Map;
 
+@NonNullForAll
 public class Statistics {
     private long lastTouched = SystemClock.elapsedRealtime();
     private final Map<Key, Pair<Long, Long>> peerBytes = new HashMap<>();

tunnel/src/main/java/com/wireguard/android/backend/Tunnel.java

@@ -5,12 +5,15 @@
 
 package com.wireguard.android.backend;
 
+import com.wireguard.util.NonNullForAll;
+
 import java.util.regex.Pattern;
 
 /**
  * Represents a WireGuard tunnel.
  */
 
+@NonNullForAll
 public interface Tunnel {
     enum State {
         DOWN,

tunnel/src/main/java/com/wireguard/android/backend/WgQuickBackend.java

@@ -5,6 +5,8 @@
 
 package com.wireguard.android.backend;
 
+import com.wireguard.util.NonNullForAll;
+
 import androidx.annotation.Nullable;
 
 import android.content.Context;
@@ -39,6 +41,7 @@ import java9.util.stream.Stream;
  * WireGuard backend that uses {@code wg-quick} to implement tunnel configuration.
  */
 
+@NonNullForAll
 public final class WgQuickBackend implements Backend {
     private static final String TAG = "WireGuard/" + WgQuickBackend.class.getSimpleName();