global: Cleanup line lengths and misc lint warnings

I know we decided to ditch the idea of shutting up "Exception
thrown with empty param" warnings but this pesters me too
much and we can instead just treat this as a weird future proofing
thing if and when we end up needing the exception messages.

Signed-off-by: Harsh Shandilya <me@msfjarvis.dev>

10 files changed, 85 insertions, 71 deletions

diff --git a/app/src/main/java/com/wireguard/android/activity/SettingsActivity.java b/app/src/main/java/com/wireguard/android/activity/SettingsActivity.java
index 3d85e30b..2507db67 100644
--- a/app/src/main/java/com/wireguard/android/activity/SettingsActivity.java
+++ b/app/src/main/java/com/wireguard/android/activity/SettingsActivity.java
@@ -10,6 +10,7 @@ import android.content.pm.PackageManager;
 import android.os.Bundle;
 import android.support.annotation.NonNull;
 import android.support.v4.app.ActivityCompat;
+import android.support.v4.content.ContextCompat;
 import android.support.v7.app.AppCompatActivity;
 import android.support.v7.preference.Preference;
 import android.support.v7.preference.PreferenceFragmentCompat;
@@ -36,7 +37,8 @@ public class SettingsActivity extends AppCompatActivity {
     public void ensurePermissions(final String[] permissions, final PermissionRequestCallback cb) {
         final List<String> needPermissions = new ArrayList<>(permissions.length);
         for (final String permission : permissions) {
-            if (ActivityCompat.checkSelfPermission(this, permission) != PackageManager.PERMISSION_GRANTED)
+            if (ContextCompat.checkSelfPermission(this, permission)
+                    != PackageManager.PERMISSION_GRANTED)
                 needPermissions.add(permission);
         }
         if (needPermissions.isEmpty()) {
@@ -47,7 +49,8 @@ public class SettingsActivity extends AppCompatActivity {
         }
         final int idx = permissionRequestCounter++;
         permissionRequestCallbacks.put(idx, cb);
-        ActivityCompat.requestPermissions(this, needPermissions.toArray(new String[needPermissions.size()]), idx);
+        ActivityCompat.requestPermissions(this,
+                needPermissions.toArray(new String[needPermissions.size()]), idx);
     }
 
     @Override
@@ -72,7 +75,9 @@ public class SettingsActivity extends AppCompatActivity {
     }
 
     @Override
-    public void onRequestPermissionsResult(final int requestCode, @NonNull final String[] permissions, @NonNull final int[] grantResults) {
+    public void onRequestPermissionsResult(final int requestCode,
+                                           @NonNull final String[] permissions,
+                                           @NonNull final int[] grantResults) {
         final PermissionRequestCallback f = permissionRequestCallbacks.get(requestCode);
         if (f != null) {
             permissionRequestCallbacks.remove(requestCode);
diff --git a/app/src/main/java/com/wireguard/android/backend/WgQuickBackend.java b/app/src/main/java/com/wireguard/android/backend/WgQuickBackend.java
index 39deaeb2..1ffcfb41 100644
--- a/app/src/main/java/com/wireguard/android/backend/WgQuickBackend.java
+++ b/app/src/main/java/com/wireguard/android/backend/WgQuickBackend.java
@@ -109,7 +109,8 @@ public final class WgQuickBackend implements Backend {
         try (FileOutputStream stream = new FileOutputStream(tempFile, false)) {
             stream.write(config.toString().getBytes(StandardCharsets.UTF_8));
         }
-        final String command = String.format("wg-quick %s '%s'", state.toString().toLowerCase(), tempFile.getAbsolutePath());
+        final String command = String.format("wg-quick %s '%s'",
+                state.toString().toLowerCase(), tempFile.getAbsolutePath());
         final int result = rootShell.run(null, command);
         // noinspection ResultOfMethodCallIgnored
         tempFile.delete();
diff --git a/app/src/main/java/com/wireguard/android/fragment/TunnelEditorFragment.java b/app/src/main/java/com/wireguard/android/fragment/TunnelEditorFragment.java
index 91d5131b..f7ed5e77 100644
--- a/app/src/main/java/com/wireguard/android/fragment/TunnelEditorFragment.java
+++ b/app/src/main/java/com/wireguard/android/fragment/TunnelEditorFragment.java
@@ -46,7 +46,7 @@ public class TunnelEditorFragment extends BaseFragment {
         binding.setConfig(new Config.Observable(config, name));
     }
 
-    private void onConfigSaved(final Tunnel savedTunnel, final Config config,
+    private void onConfigSaved(final Tunnel savedTunnel,
                                final Throwable throwable) {
         final String message;
         if (throwable == null) {
@@ -141,7 +141,7 @@ public class TunnelEditorFragment extends BaseFragment {
                 } else {
                     Log.d(TAG, "Attempting to save config of " + tunnel.getName());
                     tunnel.setConfig(newConfig)
-                            .whenComplete((a, b) -> onConfigSaved(tunnel, a, b));
+                            .whenComplete((a, b) -> onConfigSaved(tunnel, b));
                 }
                 return true;
             default:
@@ -192,7 +192,7 @@ public class TunnelEditorFragment extends BaseFragment {
             Log.d(TAG, message);
             // Now save the rest of configuration changes.
             Log.d(TAG, "Attempting to save config of renamed tunnel " + tunnel.getName());
-            renamedTunnel.setConfig(newConfig).whenComplete((a, b) -> onConfigSaved(renamedTunnel, a, b));
+            renamedTunnel.setConfig(newConfig).whenComplete((a, b) -> onConfigSaved(renamedTunnel, b));
         } else {
             final String error = ExceptionLoggers.unwrap(throwable).getMessage();
             message = getString(R.string.tunnel_rename_error, error);
diff --git a/app/src/main/java/com/wireguard/android/fragment/TunnelListFragment.java b/app/src/main/java/com/wireguard/android/fragment/TunnelListFragment.java
index f7c5ddb5..fcbadbfe 100644
--- a/app/src/main/java/com/wireguard/android/fragment/TunnelListFragment.java
+++ b/app/src/main/java/com/wireguard/android/fragment/TunnelListFragment.java
@@ -94,7 +94,8 @@ public class TunnelListFragment extends BaseFragment {
         asyncWorker.supplyAsync(() -> {
             final String[] columns = {OpenableColumns.DISPLAY_NAME};
             String name = null;
-            try (Cursor cursor = contentResolver.query(uri, columns, null, null, null)) {
+            try (Cursor cursor = contentResolver.query(uri, columns,
+                    null, null, null)) {
                 if (cursor != null && cursor.moveToFirst() && !cursor.isNull(0))
                     name = cursor.getString(0);
             }
diff --git a/app/src/main/java/com/wireguard/android/util/ClipboardUtils.java b/app/src/main/java/com/wireguard/android/util/ClipboardUtils.java
index 04a5fe47..d855dc61 100644
--- a/app/src/main/java/com/wireguard/android/util/ClipboardUtils.java
+++ b/app/src/main/java/com/wireguard/android/util/ClipboardUtils.java
@@ -19,6 +19,7 @@ import android.widget.TextView;
 
 public final class ClipboardUtils {
     private ClipboardUtils() {
+        // Prevent instantiation
     }
 
     public static void copyTextView(final View view) {
diff --git a/app/src/main/java/com/wireguard/android/util/ObservableKeyedArrayList.java b/app/src/main/java/com/wireguard/android/util/ObservableKeyedArrayList.java
index 731af20d..70842052 100644
--- a/app/src/main/java/com/wireguard/android/util/ObservableKeyedArrayList.java
+++ b/app/src/main/java/com/wireguard/android/util/ObservableKeyedArrayList.java
@@ -25,28 +25,28 @@ public class ObservableKeyedArrayList<K, E extends Keyed<? extends K>>
     @Override
     public boolean add(final E e) {
         if (e == null)
-            throw new NullPointerException();
+            throw new NullPointerException("Trying to add a null element");
         return super.add(e);
     }
 
     @Override
     public void add(final int index, final E e) {
         if (e == null)
-            throw new NullPointerException();
+            throw new NullPointerException("Trying to add a null element");
         super.add(index, e);
     }
 
     @Override
     public boolean addAll(@NonNull final Collection<? extends E> c) {
         if (c.contains(null))
-            throw new NullPointerException();
+            throw new NullPointerException("Trying to add a collection with null element(s)");
         return super.addAll(c);
     }
 
     @Override
     public boolean addAll(final int index, @NonNull final Collection<? extends E> c) {
         if (c.contains(null))
-            throw new NullPointerException();
+            throw new NullPointerException("Trying to add a collection with null element(s)");
         return super.addAll(index, c);
     }
 
@@ -100,7 +100,7 @@ public class ObservableKeyedArrayList<K, E extends Keyed<? extends K>>
     @Override
     public E set(final int index, final E e) {
         if (e == null)
-            throw new NullPointerException();
+            throw new NullPointerException("Trying to set a null key");
         return super.set(index, e);
     }
 }
diff --git a/app/src/main/java/com/wireguard/android/util/ObservableSortedKeyedArrayList.java b/app/src/main/java/com/wireguard/android/util/ObservableSortedKeyedArrayList.java
index 7e41a696..0612deb5 100644
--- a/app/src/main/java/com/wireguard/android/util/ObservableSortedKeyedArrayList.java
+++ b/app/src/main/java/com/wireguard/android/util/ObservableSortedKeyedArrayList.java
@@ -95,7 +95,9 @@ public class ObservableSortedKeyedArrayList<K, E extends Keyed<? extends K>>
     @Override
     public K firstKey() {
         if (isEmpty())
-            throw new NoSuchElementException();
+            // The parameter in the exception is only to shut
+            // lint up, we never care for the exception message.
+            throw new NoSuchElementException("Empty set");
         return get(0).getKey();
     }
 
@@ -137,7 +139,9 @@ public class ObservableSortedKeyedArrayList<K, E extends Keyed<? extends K>>
     @Override
     public K lastKey() {
         if (isEmpty())
-            throw new NoSuchElementException();
+            // The parameter in the exception is only to shut
+            // lint up, we never care for the exception message.
+            throw new NoSuchElementException("Empty set");
         return get(size() - 1).getKey();
     }
 
diff --git a/app/src/main/java/com/wireguard/android/util/RootShell.java b/app/src/main/java/com/wireguard/android/util/RootShell.java
index a260c55f..7a73929c 100644
--- a/app/src/main/java/com/wireguard/android/util/RootShell.java
+++ b/app/src/main/java/com/wireguard/android/util/RootShell.java
@@ -50,7 +50,7 @@ public class RootShell {
         final File cacheDir = context.getCacheDir();
         localBinaryDir = new File(cacheDir, "bin");
         localTemporaryDir = new File(cacheDir, "tmp");
-        preamble = String.format("export CALLING_PACKAGE=com.wireguard.android; export PATH=\"%s:$PATH\" TMPDIR='%s'; id -u\n",
+        preamble = String.format("export CALLING_PACKAGE=com.wireguard.android PATH=\"%s:$PATH\" TMPDIR='%s'; id -u\n",
                 localBinaryDir, localTemporaryDir);
     }
 
diff --git a/app/src/main/java/com/wireguard/config/IPCidr.java b/app/src/main/java/com/wireguard/config/IPCidr.java
index dd649fc5..bfa92e07 100644
--- a/app/src/main/java/com/wireguard/config/IPCidr.java
+++ b/app/src/main/java/com/wireguard/config/IPCidr.java
@@ -15,6 +15,7 @@ public class IPCidr {
     private final InetAddress address;
     private int cidr;
 
+    @SuppressWarnings("MagicNumber")
     public IPCidr(String in) {
         cidr = -1;
         final int slash = in.lastIndexOf('/');
diff --git a/app/src/main/java/com/wireguard/crypto/Curve25519.java b/app/src/main/java/com/wireguard/crypto/Curve25519.java
index 694f557b..a20c9f97 100644
--- a/app/src/main/java/com/wireguard/crypto/Curve25519.java
+++ b/app/src/main/java/com/wireguard/crypto/Curve25519.java
@@ -21,28 +21,28 @@ import java.util.Arrays;
  * <p>
  * References: http://cr.yp.to/ecdh.html, RFC 7748
  */
-@SuppressWarnings("ALL")
+@SuppressWarnings("MagicNumber")
 public final class Curve25519 {
 
     // Numbers modulo 2^255 - 19 are broken up into ten 26-bit words.
     private static final int NUM_LIMBS_255BIT = 10;
     private static final int NUM_LIMBS_510BIT = 20;
-    private int[] A;
-    private int[] AA;
-    private int[] B;
-    private int[] BB;
-    private int[] C;
-    private int[] CB;
-    private int[] D;
-    private int[] DA;
-    private int[] E;
-    private long[] t1;
-    private int[] t2;
-    private int[] x_1;
-    private int[] x_2;
-    private int[] x_3;
-    private int[] z_2;
-    private int[] z_3;
+    private final int[] A;
+    private final int[] AA;
+    private final int[] B;
+    private final int[] BB;
+    private final int[] C;
+    private final int[] CB;
+    private final int[] D;
+    private final int[] DA;
+    private final int[] E;
+    private final long[] t1;
+    private final int[] t2;
+    private final int[] x_1;
+    private final int[] x_2;
+    private final int[] x_3;
+    private final int[] z_2;
+    private final int[] z_3;
 
     /**
      * Constructs the temporary state holder for Curve25519 evaluation.
@@ -74,11 +74,10 @@ public final class Curve25519 {
      * @param x      The first value.
      * @param y      The second value.
      */
-    private static void cswap(int select, int[] x, int[] y) {
-        int dummy;
+    private static void cswap(int select, final int[] x, final int[] y) {
         select = -select;
         for (int index = 0; index < NUM_LIMBS_255BIT; ++index) {
-            dummy = select & (x[index] ^ y[index]);
+            final int dummy = select & (x[index] ^ y[index]);
             x[index] ^= dummy;
             y[index] ^= dummy;
         }
@@ -93,17 +92,18 @@ public final class Curve25519 {
      * @param publicKey  The public key to use in the evaluation, or null
      *                   if the base point of the curve should be used.
      */
-    public static void eval(byte[] result, int offset, byte[] privateKey, byte[] publicKey) {
-        Curve25519 state = new Curve25519();
+    public static void eval(final byte[] result, final int offset,
+                            final byte[] privateKey, final byte[] publicKey) {
+        final Curve25519 state = new Curve25519();
         try {
             // Unpack the public key value.  If null, use 9 as the base point.
             Arrays.fill(state.x_1, 0);
             if (publicKey != null) {
                 // Convert the input value from little-endian into 26-bit limbs.
                 for (int index = 0; index < 32; ++index) {
-                    int bit = (index * 8) % 26;
-                    int word = (index * 8) / 26;
-                    int value = publicKey[index] & 0xFF;
+                    final int bit = (index * 8) % 26;
+                    final int word = (index * 8) / 26;
+                    final int value = publicKey[index] & 0xFF;
                     if (bit <= (26 - 8)) {
                         state.x_1[word] |= value << bit;
                     } else {
@@ -139,8 +139,8 @@ public final class Curve25519 {
 
             // Convert x_2 into little-endian in the result buffer.
             for (int index = 0; index < 32; ++index) {
-                int bit = (index * 8) % 26;
-                int word = (index * 8) / 26;
+                final int bit = (index * 8) % 26;
+                final int word = (index * 8) / 26;
                 if (bit <= (26 - 8))
                     result[offset + index] = (byte) (state.x_2[word] >> bit);
                 else
@@ -159,11 +159,11 @@ public final class Curve25519 {
      * @param x      The first number to add.
      * @param y      The second number to add.
      */
-    private void add(int[] result, int[] x, int[] y) {
-        int index, carry;
+    private void add(final int[] result, final int[] x, final int[] y) {
+        int carry;
         carry = x[0] + y[0];
         result[0] = carry & 0x03FFFFFF;
-        for (index = 1; index < NUM_LIMBS_255BIT; ++index) {
+        for (int index = 1; index < NUM_LIMBS_255BIT; ++index) {
             carry = (carry >> 26) + x[index] + y[index];
             result[index] = carry & 0x03FFFFFF;
         }
@@ -198,19 +198,17 @@ public final class Curve25519 {
      *
      * @param s The 32-byte secret key.
      */
-    private void evalCurve(byte[] s) {
+    private void evalCurve(final byte[] s) {
         int sposn = 31;
-        int sbit = 6;
         int svalue = s[sposn] | 0x40;
         int swap = 0;
-        int select;
 
         // Iterate over all 255 bits of "s" from the highest to the lowest.
         // We ignore the high bit of the 256-bit representation of "s".
-        for (; ; ) {
+        for (int sbit = 6; ; ) {
             // Conditional swaps on entry to this bit but only if we
             // didn't swap on the previous bit.
-            select = (svalue >> sbit) & 0x01;
+            final int select = (svalue >> sbit) & 0x01;
             swap ^= select;
             cswap(swap, x_2, x_3);
             cswap(swap, z_2, z_3);
@@ -264,8 +262,8 @@ public final class Curve25519 {
      * @param x      The first number to multiply.
      * @param y      The second number to multiply.
      */
-    private void mul(int[] result, int[] x, int[] y) {
-        int i, j;
+    private void mul(final int[] result, final int[] x, final int[] y) {
+        int i;
 
         // Multiply the two numbers to create the intermediate result.
         long v = x[0];
@@ -274,7 +272,7 @@ public final class Curve25519 {
         }
         for (i = 1; i < NUM_LIMBS_255BIT; ++i) {
             v = x[i];
-            for (j = 0; j < (NUM_LIMBS_255BIT - 1); ++j) {
+            for (int j = 0; j < (NUM_LIMBS_255BIT - 1); ++j) {
                 t1[i + j] += v * y[j];
             }
             t1[i + NUM_LIMBS_255BIT - 1] = v * y[NUM_LIMBS_255BIT - 1];
@@ -298,11 +296,10 @@ public final class Curve25519 {
      * @param result The result.
      * @param x      The number to multiply by a24.
      */
-    private void mulA24(int[] result, int[] x) {
-        long a24 = 121665;
+    private void mulA24(final int[] result, final int[] x) {
+        final long a24 = 121665;
         long carry = 0;
-        int index;
-        for (index = 0; index < NUM_LIMBS_255BIT; ++index) {
+        for (int index = 0; index < NUM_LIMBS_255BIT; ++index) {
             carry += a24 * x[index];
             t2[index] = ((int) carry) & 0x03FFFFFF;
             carry >>= 26;
@@ -317,8 +314,8 @@ public final class Curve25519 {
      * @param result The result.  Must not overlap with x.
      * @param x      The argument.
      */
-    private void pow250(int[] result, int[] x) {
-        int i, j;
+    private void pow250(final int[] result, final int[] x) {
+        int j;
 
         // The big-endian hexadecimal expansion of (2^250 - 1) is:
         // 03FFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF
@@ -335,7 +332,7 @@ public final class Curve25519 {
         for (j = 0; j < 9; ++j)
             square(A, A);
         mul(result, A, x);
-        for (i = 0; i < 23; ++i) {
+        for (int i = 0; i < 23; ++i) {
             for (j = 0; j < 10; ++j)
                 square(A, A);
             mul(result, result, A);
@@ -357,7 +354,7 @@ public final class Curve25519 {
      * @param result The result.  Must not overlap with x.
      * @param x      The argument.
      */
-    private void recip(int[] result, int[] x) {
+    private void recip(final int[] result, final int[] x) {
         // The reciprocal is the same as x ^ (p - 2) where p = 2^255 - 19.
         // The big-endian hexadecimal expansion of (p - 2) is:
         // 7FFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFEB
@@ -383,8 +380,10 @@ public final class Curve25519 {
      *               modified during the reduction.
      * @param size   The number of limbs in the high order half of x.
      */
-    private void reduce(int[] result, int[] x, int size) {
-        int index, limb, carry;
+    private void reduce(final int[] result, final int[] x, final int size) {
+        int index;
+        int limb;
+        int carry;
 
         // Calculate (x mod 2^255) + ((x / 2^255) * 19) which will
         // either produce the answer we want or it will produce a
@@ -436,8 +435,9 @@ public final class Curve25519 {
      *
      * @param x The number to reduce, and the result.
      */
-    private void reduceQuick(int[] x) {
-        int index, carry;
+    private void reduceQuick(final int[] x) {
+        int index;
+        int carry;
 
         // Perform a trial subtraction of (2^255 - 19) from "x" which is
         // equivalent to adding 19 and subtracting 2^255.  We add 19 here;
@@ -454,8 +454,8 @@ public final class Curve25519 {
         // correct answer but do it in a way that instruction timing will not
         // reveal which value was selected.  Borrow will occur if bit 21 of
         // "t2" is zero.  Turn the bit into a selection mask.
-        int mask = -((t2[NUM_LIMBS_255BIT - 1] >> 21) & 0x01);
-        int nmask = ~mask;
+        final int mask = -((t2[NUM_LIMBS_255BIT - 1] >> 21) & 0x01);
+        final int nmask = ~mask;
         t2[NUM_LIMBS_255BIT - 1] &= 0x001FFFFF;
         for (index = 0; index < NUM_LIMBS_255BIT; ++index)
             x[index] = (x[index] & nmask) | (t2[index] & mask);
@@ -467,7 +467,7 @@ public final class Curve25519 {
      * @param result The result.
      * @param x      The number to square.
      */
-    private void square(int[] result, int[] x) {
+    private void square(final int[] result, final int[] x) {
         mul(result, x, x);
     }
 
@@ -478,8 +478,9 @@ public final class Curve25519 {
      * @param x      The first number to subtract.
      * @param y      The second number to subtract.
      */
-    private void sub(int[] result, int[] x, int[] y) {
-        int index, borrow;
+    private static void sub(final int[] result, final int[] x, final int[] y) {
+        int index;
+        int borrow;
 
         // Subtract y from x to generate the intermediate result.
         borrow = 0;