util: Extract non-Android utility interfaces

As part of a refactoring that will likely introduce more custom
collection classes, move the non-Android-specific parts outside the
com.wireguard.android package.

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

app/src/main/java/com/wireguard/android/databinding/BindingAdapters.java

@@ -15,7 +15,7 @@ import android.widget.ListView;
 import android.widget.TextView;
 
 import com.wireguard.android.R;
-import com.wireguard.android.util.Keyed;
+import com.wireguard.util.Keyed;
 import com.wireguard.android.util.ObservableKeyedList;
 import com.wireguard.android.widget.ToggleSwitch;
 import com.wireguard.android.widget.ToggleSwitch.OnBeforeCheckedChangeListener;

app/src/main/java/com/wireguard/android/databinding/ObservableKeyedListAdapter.java

@@ -16,7 +16,7 @@ import android.view.ViewGroup;
 import android.widget.BaseAdapter;
 
 import com.wireguard.android.BR;
-import com.wireguard.android.util.Keyed;
+import com.wireguard.util.Keyed;
 import com.wireguard.android.util.ObservableKeyedList;
 
 import java.lang.ref.WeakReference;

app/src/main/java/com/wireguard/android/model/Tunnel.java

@@ -13,7 +13,7 @@ import android.support.annotation.Nullable;
 
 import com.wireguard.android.BR;
 import com.wireguard.android.util.ExceptionLoggers;
-import com.wireguard.android.util.Keyed;
+import com.wireguard.util.Keyed;
 import com.wireguard.config.Config;
 
 import java.util.regex.Pattern;

app/src/main/java/com/wireguard/android/util/Keyed.java

@@ -1,15 +0,0 @@
-/*
- * Copyright © 2018 Samuel Holland <samuel@sholland.org>
- * Copyright © 2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
- * SPDX-License-Identifier: GPL-2.0-or-later
- */
-
-package com.wireguard.android.util;
-
-/**
- * Interface for objects that have a identifying key of the given type.
- */
-
-public interface Keyed<K> {
-    K getKey();
-}

app/src/main/java/com/wireguard/android/util/KeyedList.java

@@ -1,29 +0,0 @@
-/*
- * Copyright © 2018 Samuel Holland <samuel@sholland.org>
- * Copyright © 2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
- * SPDX-License-Identifier: GPL-2.0-or-later
- */
-
-package com.wireguard.android.util;
-
-import java.util.Collection;
-import java.util.List;
-
-/**
- * A list containing elements that can be looked up by key. A {@code KeyedList} cannot contain
- * {@code null} elements.
- */
-
-public interface KeyedList<K, E extends Keyed<? extends K>> extends List<E> {
-    boolean containsAllKeys(Collection<K> keys);
-
-    boolean containsKey(K key);
-
-    E get(K key);
-
-    E getLast(K key);
-
-    int indexOfKey(K key);
-
-    int lastIndexOfKey(K key);
-}

app/src/main/java/com/wireguard/android/util/ObservableKeyedArrayList.java

@@ -9,6 +9,8 @@ package com.wireguard.android.util;
 import android.databinding.ObservableArrayList;
 import android.support.annotation.NonNull;
 
+import com.wireguard.util.Keyed;
+
 import java.util.Collection;
 import java.util.ListIterator;
 import java.util.Objects;

app/src/main/java/com/wireguard/android/util/ObservableKeyedList.java

@@ -8,6 +8,9 @@ package com.wireguard.android.util;
 
 import android.databinding.ObservableList;
 
+import com.wireguard.util.Keyed;
+import com.wireguard.util.KeyedList;
+
 /**
  * A list that is both keyed and observable.
  */

app/src/main/java/com/wireguard/android/util/ObservableSortedKeyedArrayList.java

@@ -8,6 +8,9 @@ package com.wireguard.android.util;
 
 import android.support.annotation.NonNull;
 
+import com.wireguard.util.Keyed;
+import com.wireguard.util.SortedKeyedList;
+
 import java.util.AbstractList;
 import java.util.Collection;
 import java.util.Collections;

app/src/main/java/com/wireguard/android/util/ObservableSortedKeyedList.java

@@ -6,6 +6,9 @@
 
 package com.wireguard.android.util;
 
+import com.wireguard.util.Keyed;
+import com.wireguard.util.SortedKeyedList;
+
 /**
  * A list that is both sorted/keyed and observable.
  */

app/src/main/java/com/wireguard/android/util/SortedKeyedList.java

@@ -1,28 +0,0 @@
-/*
- * Copyright © 2018 Samuel Holland <samuel@sholland.org>
- * Copyright © 2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
- * SPDX-License-Identifier: GPL-2.0-or-later
- */
-
-package com.wireguard.android.util;
-
-import java.util.Collection;
-import java.util.Comparator;
-import java.util.Set;
-
-/**
- * A keyed list where all elements are sorted by the comparator returned by {@code comparator()}
- * applied to their keys.
- */
-
-public interface SortedKeyedList<K, E extends Keyed<? extends K>> extends KeyedList<K, E> {
-    Comparator<? super K> comparator();
-
-    K firstKey();
-
-    Set<K> keySet();
-
-    K lastKey();
-
-    Collection<E> values();
-}