Speed up Acl.fromReader

It should run 9x faster than before now.

Past mistakes:

* InetAddress.parseNumericAddress throws TWO exceptions underthehood if the string passed is invalid. This caused a huge overhead;
* CharSequence.split in Kotlin is EXTREMELY SLOW.

mobile/src/main/java/com/github/shadowsocks/acl/Acl.kt

@@ -116,7 +116,8 @@ class Acl {
         var subnets: SortedList<Subnet>? = if (defaultBypass) proxySubnets else bypassSubnets
         reader.useLines {
             for (line in it) {
-                val blocks = line.split('#', limit = 2)
+                @Suppress("PLATFORM_CLASS_MAPPED_TO_KOTLIN")
+                val blocks = (line as java.lang.String).split("#", 2)
                 val url = networkAclParser.matchEntire(blocks.getOrElse(1, {""}))?.groupValues?.getOrNull(1)
                 if (url != null) urls.add(URL(url))
                 val input = blocks[0].trim()
@@ -135,10 +136,9 @@ class Acl {
                     }
                     "[reject_all]", "[bypass_all]" -> bypass = true
                     "[accept_all]", "[proxy_all]" -> bypass = false
-                    else -> if (subnets != null && input.isNotEmpty()) try {
-                        subnets!!.add(Subnet.fromString(input))
-                    } catch (_: IllegalArgumentException) {
-                        hostnames!!.add(input)
+                    else -> if (subnets != null && input.isNotEmpty()) {
+                        val subnet = Subnet.fromString(input)
+                        if (subnet == null) hostnames!!.add(input) else subnets!!.add(subnet)
                     }
                 }
             }

mobile/src/main/java/com/github/shadowsocks/acl/CustomRulesFragment.kt

@@ -333,8 +333,8 @@ class CustomRulesFragment : ToolbarFragment(), Toolbar.OnMenuItemClickListener {
     override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
         super.onViewCreated(view, savedInstanceState)
         if (savedInstanceState != null) {
-            selectedItems.addAll(savedInstanceState.getStringArray(SELECTED_SUBNETS)?.map(Subnet.Companion::fromString)
-                    ?: listOf())
+            selectedItems.addAll(savedInstanceState.getStringArray(SELECTED_SUBNETS)
+                    ?.mapNotNull(Subnet.Companion::fromString) ?: listOf())
             selectedItems.addAll(savedInstanceState.getStringArray(SELECTED_HOSTNAMES)
                     ?: arrayOf())
             selectedItems.addAll(savedInstanceState.getStringArray(SELECTED_URLS)?.map { URL(it) }

mobile/src/main/java/com/github/shadowsocks/bg/VpnService.kt

@@ -159,10 +159,10 @@ class VpnService : BaseVpnService(), LocalDnsService.Interface {
             Acl.ALL, Acl.BYPASS_CHN, Acl.CUSTOM_RULES -> builder.addRoute("0.0.0.0", 0)
             else -> {
                 resources.getStringArray(R.array.bypass_private_route).forEach {
-                    val subnet = Subnet.fromString(it)
+                    val subnet = Subnet.fromString(it)!!
                     builder.addRoute(subnet.address.hostAddress, subnet.prefixSize)
                 }
-                profile.remoteDns.split(",").map { it.trim().parseNumericAddress() }
+                profile.remoteDns.split(",").mapNotNull { it.trim().parseNumericAddress() }
                         .forEach { builder.addRoute(it, it.address.size shl 3) }
             }
         }

mobile/src/main/java/com/github/shadowsocks/utils/Subnet.kt

@@ -25,15 +25,15 @@ import java.util.*
 
 class Subnet(val address: InetAddress, val prefixSize: Int) : Comparable<Subnet> {
     companion object {
-        @Throws(IllegalArgumentException::class)
-        fun fromString(value: String): Subnet {
-            val parts = value.split('/')
-            val addr = parts[0].parseNumericAddress()
-            return when (parts.size) {
-                1 -> Subnet(addr, addr.address.size shl 3)
-                2 -> Subnet(addr, parts[1].toInt())
-                else -> throw IllegalArgumentException()
-            }
+        fun fromString(value: String): Subnet? {
+            @Suppress("PLATFORM_CLASS_MAPPED_TO_KOTLIN")
+            val parts = (value as java.lang.String).split("/", 2)
+            val addr = parts[0].parseNumericAddress() ?: return null
+            return if (parts.size == 2) try {
+                Subnet(addr, parts[1].toInt())
+            } catch (_: NumberFormatException) {
+                null
+            } else Subnet(addr, addr.address.size shl 3)
         }
     }
 

mobile/src/main/java/com/github/shadowsocks/utils/Utils.kt

@@ -11,31 +11,20 @@ import android.support.v4.app.FragmentManager
 import android.support.v7.util.SortedList
 import android.util.TypedValue
 import com.github.shadowsocks.App.Companion.app
+import com.github.shadowsocks.JniHelper
 import java.lang.reflect.InvocationTargetException
+import java.net.Inet4Address
 import java.net.InetAddress
 import java.net.URLConnection
 
-private val isNumericMethod by lazy { InetAddress::class.java.getMethod("isNumeric", String::class.java) }
-private val parseNumericAddressMethod by lazy {
-    try {
-        InetAddress::class.java.getMethod("parseNumericAddress", String::class.java)
-    } catch (_: NoSuchMethodException) {
-        null
-    }
-}
 private val fieldChildFragmentManager by lazy {
     val field = Fragment::class.java.getDeclaredField("mChildFragmentManager")
     field.isAccessible = true
     field
 }
 
-fun String.isNumericAddress(): Boolean = isNumericMethod.invoke(null, this) as Boolean
-fun String.parseNumericAddress(): InetAddress =
-        if (parseNumericAddressMethod == null) InetAddress.getByName(this) else try {
-            parseNumericAddressMethod!!.invoke(null, this) as InetAddress
-        } catch (exc: InvocationTargetException) {
-            throw exc.cause ?: exc
-        }
+fun String.isNumericAddress() = parseNumericAddress() != null
+fun String.parseNumericAddress() = JniHelper.parseNumericAddress(this)
 
 fun parsePort(str: String?, default: Int, min: Int = 1025): Int {
     val x = str?.toIntOrNull() ?: default