pt 1 in reviving the android build (copied from pm 28a1, wish me luck)

mobile/android/thirdparty/com/adjust/sdk/plugin/MacAddressUtil.java

@@ -0,0 +1,82 @@
+package com.adjust.sdk.plugin;
+
+import android.content.Context;
+import android.net.wifi.WifiManager;
+import android.text.TextUtils;
+
+import java.io.BufferedReader;
+import java.io.FileReader;
+import java.io.IOException;
+import java.util.Locale;
+
+public class MacAddressUtil {
+    public static String getMacAddress(Context context) {
+        final String rawAddress = getRawMacAddress(context);
+        if (rawAddress == null) {
+            return null;
+        }
+        final String upperAddress = rawAddress.toUpperCase(Locale.US);
+        return removeSpaceString(upperAddress);
+    }
+
+    private static String getRawMacAddress(Context context) {
+        // android devices should have a wlan address
+        final String wlanAddress = loadAddress("wlan0");
+        if (wlanAddress != null) {
+            return wlanAddress;
+        }
+
+        // emulators should have an ethernet address
+        final String ethAddress = loadAddress("eth0");
+        if (ethAddress != null) {
+            return ethAddress;
+        }
+
+        // query the wifi manager (requires the ACCESS_WIFI_STATE permission)
+        try {
+            final WifiManager wifiManager = (WifiManager) context.getSystemService(Context.WIFI_SERVICE);
+            final String wifiAddress = wifiManager.getConnectionInfo().getMacAddress();
+            if (wifiAddress != null) {
+                return wifiAddress;
+            }
+        } catch (Exception e) {
+            /* no-op */
+        }
+
+        return null;
+    }
+
+    private static String loadAddress(final String interfaceName) {
+        try {
+            final String filePath = "/sys/class/net/" + interfaceName + "/address";
+            final StringBuilder fileData = new StringBuilder(1000);
+            final BufferedReader reader = new BufferedReader(new FileReader(filePath), 1024);
+            final char[] buf = new char[1024];
+            int numRead;
+
+            String readData;
+            while ((numRead = reader.read(buf)) != -1) {
+                readData = String.valueOf(buf, 0, numRead);
+                fileData.append(readData);
+            }
+
+            reader.close();
+            return fileData.toString();
+        } catch (IOException e) {
+            return null;
+        }
+    }
+
+    private static String removeSpaceString(final String inputString) {
+        if (inputString == null) {
+            return null;
+        }
+
+        String outputString = inputString.replaceAll("\\s", "");
+        if (TextUtils.isEmpty(outputString)) {
+            return null;
+        }
+
+        return outputString;
+    }
+}