com.facebook.buck.util.environment.MacWifiSsidFinder.java Source code

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Here is the source code for com.facebook.buck.util.environment.MacWifiSsidFinder.java

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/*
 * Copyright 2015-present Facebook, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may
 * not use this file except in compliance with the License. You may obtain
 * a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 */

package com.facebook.buck.util.environment;

import ca.weblite.objc.Client;
import ca.weblite.objc.Proxy;
import ca.weblite.objc.RuntimeUtils;

import com.facebook.buck.log.Logger;

import com.google.common.base.Optional;

import com.sun.jna.Library;
import com.sun.jna.Native;
import com.sun.jna.Pointer;

/**
 * Mac OS X implementation of finding the SSID of the default Wi-Fi interface.
 */
public class MacWifiSsidFinder {
    private static final Logger LOG = Logger.get(MacWifiSsidFinder.class);

    // Utility class, do not instantiate.
    private MacWifiSsidFinder() {
    }

    public static interface CoreWlan extends Library {
    }

    // Need to hold on to an instance of this library so CoreWLAN.framework is kept resident.
    public static final CoreWlan CORE_WLAN_INSTANCE = (CoreWlan) Native.loadLibrary("CoreWLAN", CoreWlan.class);

    /**
     * Finds the SSID of the default Wi-Fi interface using Mac OS X APIs.
     */
    public static Optional<String> findCurrentSsid() {
        LOG.debug("Getting current SSID..");

        // Grab a handle to the Objective-C runtime.
        Client objcClient = Client.getInstance();

        // Try the OS X 10.10 and later supported API, then fall
        // back to the OS X 10.6 API.
        Pointer wifiClientClass = RuntimeUtils.cls("CWWiFiClient");
        Optional<Proxy> defaultInterface;
        if (wifiClientClass != null) {
            LOG.verbose("Getting default interface using +[CWWiFiClient sharedWiFiClient]");
            defaultInterface = getDefaultWifiInterface(objcClient, wifiClientClass);
        } else {
            LOG.verbose("Getting default interface using +[CWInterface defaultInterface]");
            // CWInterface *defaultInterface = [CWInterface interface];
            defaultInterface = Optional.fromNullable(objcClient.sendProxy("CWInterface", "interface"));
        }
        return getSsidFromInterface(defaultInterface);
    }

    /**
     * Finds the SSID of the default Wi-Fi interface using Mac OS X 10.10 and later APIs.
     */
    private static Optional<Proxy> getDefaultWifiInterface(Client objcClient, Pointer wifiClientClass) {
        // CWWiFiClient *sharedWiFiClient = [CWWiFiClient sharedWiFiClient];
        Proxy sharedWiFiClient = objcClient.sendProxy(wifiClientClass, "sharedWiFiClient");
        if (sharedWiFiClient == null) {
            LOG.warn("+[CWWiFiClient sharedWiFiClient] returned null, could not find SSID.");
            return Optional.absent();
        }

        // CWInterface *defaultInterface = [sharedWiFiClient interface];
        Proxy defaultInterface = sharedWiFiClient.sendProxy("interface");
        if (defaultInterface == null) {
            LOG.warn("-[sharedWiFiClient interface] returned null, could not find SSID.");
            return Optional.absent();
        }

        return Optional.of(defaultInterface);
    }

    private static Optional<String> getSsidFromInterface(Optional<Proxy> defaultInterface) {
        if (!defaultInterface.isPresent()) {
            LOG.debug("No Wi-Fi interface found.");
            return Optional.absent();
        }
        LOG.debug("Getting SSID from Wi-Fi interface: %s", defaultInterface.get());

        // NSString *ssid = [defaultInterface ssid];
        Object ssid = defaultInterface.get().send("ssid");
        if (ssid == null) {
            LOG.debug("No SSID found for interface %s.", defaultInterface.get());
            return Optional.absent();
        }
        if (!(ssid instanceof String)) {
            LOG.error("Fetched SSID, but got unexpected non-string type (got: %s).", ssid);
            return Optional.absent();
        }

        String ssidString = (String) ssid;
        LOG.debug("Found SSID: %s", ssidString);
        return Optional.of(ssidString);
    }
}