VPN Hotspot 2.0: Client+ (#39)

Fix #13, #38. I don't have a lot of confidence that this would work very well for every device.

Also here's an SQL command that hopefully somebody could make into the app for me: `SELECT TrafficRecord.mac, SUM(TrafficRecord.sentPackets), SUM(TrafficRecord.sentBytes), SUM(TrafficRecord.receivedPackets), SUM(TrafficRecord.receivedBytes) FROM TrafficRecord LEFT JOIN TrafficRecord AS Next ON TrafficRecord.id = Next.previousId WHERE Next.id IS NULL GROUP BY TrafficRecord.mac;`

mobile/src/main/java/be/mygod/vpnhotspot/util/Events.kt

@@ -12,11 +12,8 @@ open class Event0 : ConcurrentHashMap<Any, () -> Unit>() {
 }
 
 class StickyEvent0 : Event0() {
-    override fun put(key: Any, value: () -> Unit): (() -> Unit)? {
-        val result = super.put(key, value)
-        if (result == null) value()
-        return result
-    }
+    override fun put(key: Any, value: () -> Unit): (() -> Unit)? =
+            super.put(key, value).also { if (it == null) value() }
 }
 
 open class Event1<T> : ConcurrentHashMap<Any, (T) -> Unit>() {
@@ -26,9 +23,12 @@ open class Event1<T> : ConcurrentHashMap<Any, (T) -> Unit>() {
 }
 
 class StickyEvent1<T>(private val fire: () -> T) : Event1<T>() {
-    override fun put(key: Any, value: (T) -> Unit): ((T) -> Unit)? {
-        val result = super.put(key, value)
-        if (result == null) value(fire())
-        return result
+    override fun put(key: Any, value: (T) -> Unit): ((T) -> Unit)? =
+            super.put(key, value).also { if (it == null) value(fire()) }
+}
+
+open class Event2<T1, T2> : ConcurrentHashMap<Any, (T1, T2) -> Unit>() {
+    operator fun invoke(arg1: T1, arg2: T2) {
+        for ((_, handler) in this) handler(arg1, arg2)
     }
 }

mobile/src/main/java/be/mygod/vpnhotspot/util/RootSession.kt

@@ -1,11 +1,13 @@
 package be.mygod.vpnhotspot.util
 
+import android.os.Handler
+import android.os.HandlerThread
 import android.util.Log
 import androidx.core.os.postDelayed
-import be.mygod.vpnhotspot.App.Companion.app
 import com.crashlytics.android.Crashlytics
 import com.topjohnwu.superuser.Shell
 import java.util.*
+import java.util.concurrent.TimeUnit
 import java.util.concurrent.locks.ReentrantLock
 import kotlin.collections.ArrayList
 import kotlin.concurrent.withLock
@@ -14,6 +16,8 @@ class RootSession : AutoCloseable {
     companion object {
         private const val TAG = "RootSession"
 
+        val handler = Handler(HandlerThread("$TAG-HandlerThread").apply { start() }.looper)
+
         private val monitor = ReentrantLock()
         private fun onUnlock() {
             if (monitor.holdCount == 1) instance?.startTimeout()
@@ -72,8 +76,10 @@ class RootSession : AutoCloseable {
         shell.close()
         if (instance == this) instance = null
     }
-    private fun startTimeout() = app.handler.postDelayed(60 * 1000, this) { monitor.withLock { close() } }
-    private fun haltTimeout() = app.handler.removeCallbacksAndMessages(this)
+    private fun startTimeout() = handler.postDelayed(TimeUnit.MINUTES.toMillis(5), this) {
+        monitor.withLock { close() }
+    }
+    private fun haltTimeout() = handler.removeCallbacksAndMessages(this)
 
     /**
      * Don't care about the results, but still sync.
@@ -95,11 +101,12 @@ class RootSession : AutoCloseable {
         }).exec()
     }
     fun exec(command: String) = checkOutput(command, execQuiet(command))
-    fun execOut(command: String): String {
+    fun execOutUnjoined(command: String): List<String> {
         val result = execQuiet(command)
         checkOutput(command, result, false)
-        return result.out.joinToString("\n")
+        return result.out
     }
+    fun execOut(command: String): String = execOutUnjoined(command).joinToString("\n")
 
     /**
      * This transaction is different from what you may have in mind since you can revert it after committing it.

mobile/src/main/java/be/mygod/vpnhotspot/util/Utils.kt

@@ -1,20 +1,33 @@
 package be.mygod.vpnhotspot.util
 
 import android.content.*
+import android.os.Build
 import android.util.Log
 import android.view.View
 import android.widget.ImageView
 import androidx.annotation.DrawableRes
 import androidx.core.view.isVisible
 import androidx.databinding.BindingAdapter
-import be.mygod.vpnhotspot.App.Companion.app
 import be.mygod.vpnhotspot.BuildConfig
 import be.mygod.vpnhotspot.R
 import be.mygod.vpnhotspot.widget.SmartSnackbar
 import com.crashlytics.android.Crashlytics
+import java.net.InetAddress
 import java.net.NetworkInterface
 import java.net.SocketException
 
+/**
+ * This is a hack: we wrap longs around in 1 billion and such. Hopefully every language counts in base 10 and this works
+ * marvelously for everybody.
+ */
+fun Long.toPluralInt(): Int {
+    check(this >= 0)    // please don't mess with me
+    if (this <= Int.MAX_VALUE) return toInt()
+    return (this % 1000000000).toInt() + 1000000000
+}
+
+fun CharSequence?.onEmpty(otherwise: CharSequence): CharSequence = if (isNullOrEmpty()) otherwise else this!!
+
 fun debugLog(tag: String?, message: String?) {
     if (BuildConfig.DEBUG) Log.d(tag, message)
     Crashlytics.log("$tag: $message")
@@ -51,6 +64,19 @@ fun NetworkInterface.formatAddresses() =
                 }))
                 .joinToString("\n")
 
+private val parseNumericAddress by lazy {
+    // parseNumericAddressNoThrow is in dark grey list unfortunately
+    InetAddress::class.java.getDeclaredMethod("parseNumericAddress", String::class.java).apply {
+        isAccessible = true
+    }
+}
+fun parseNumericAddress(address: String) = parseNumericAddress.invoke(null, address) as InetAddress
+fun parseNumericAddressNoThrow(address: String): InetAddress? = try {
+    parseNumericAddress(address)
+} catch (_: IllegalArgumentException) {
+    null
+}
+
 /**
  * Wrapper for kotlin.concurrent.thread that silences uncaught exceptions.
  */
@@ -69,3 +95,6 @@ fun Context.stopAndUnbind(connection: ServiceConnection) {
     connection.onServiceDisconnected(null)
     unbindService(connection)
 }
+
+fun <K, V> HashMap<K, V>.computeIfAbsentCompat(key: K, value: () -> V) = if (Build.VERSION.SDK_INT >= 26)
+    computeIfAbsent(key) { value() } else this[key] ?: value().also { put(key, it) }