1/*
2 * Copyright (C) 2011 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.android.browser;
18
19import android.app.Activity;
20import android.nfc.NdefMessage;
21import android.nfc.NdefRecord;
22import android.nfc.NfcAdapter;
23import android.nfc.NfcEvent;
24import android.os.Handler;
25import android.os.Message;
26
27import java.util.concurrent.CountDownLatch;
28
29/** This class implements sharing the URL of the currently
30  * shown browser page over NFC. Sharing is only active
31  * when the activity is in the foreground and resumed.
32  * Incognito tabs will not be shared over NFC.
33  */
34public class NfcHandler implements NfcAdapter.CreateNdefMessageCallback {
35    static final int GET_PRIVATE_BROWSING_STATE_MSG = 100;
36
37    final Controller mController;
38
39    Tab mCurrentTab;
40    boolean mIsPrivate;
41    CountDownLatch mPrivateBrowsingSignal;
42
43    public static void register(Activity activity, Controller controller) {
44        NfcAdapter adapter = NfcAdapter.getDefaultAdapter(activity.getApplicationContext());
45        if (adapter == null) {
46            return;  // NFC not available on this device
47        }
48        NfcHandler handler = null;
49        if (controller != null) {
50            handler = new NfcHandler(controller);
51        }
52
53        adapter.setNdefPushMessageCallback(handler, activity);
54    }
55
56    public static void unregister(Activity activity) {
57        // Passing a null controller causes us to disable
58        // the callback and release the ref to out activity.
59        register(activity, null);
60    }
61
62    public NfcHandler(Controller controller) {
63        mController = controller;
64    }
65
66    final Handler mHandler = new Handler() {
67        @Override
68        public void handleMessage(Message msg) {
69            if (msg.what == GET_PRIVATE_BROWSING_STATE_MSG) {
70                mIsPrivate = mCurrentTab.getWebView().isPrivateBrowsingEnabled();
71                mPrivateBrowsingSignal.countDown();
72            }
73        }
74    };
75
76    @Override
77    public NdefMessage createNdefMessage(NfcEvent event) {
78        mCurrentTab = mController.getCurrentTab();
79        if ((mCurrentTab != null) && (mCurrentTab.getWebView() != null)) {
80            // We can only read the WebView state on the UI thread, so post
81            // a message and wait.
82            mPrivateBrowsingSignal = new CountDownLatch(1);
83            mHandler.sendMessage(mHandler.obtainMessage(GET_PRIVATE_BROWSING_STATE_MSG));
84            try {
85                mPrivateBrowsingSignal.await();
86            } catch (InterruptedException e) {
87                return null;
88            }
89        }
90
91        if ((mCurrentTab == null) || mIsPrivate) {
92            return null;
93        }
94
95        String currentUrl = mCurrentTab.getUrl();
96        if (currentUrl != null) {
97            NdefRecord record = NdefRecord.createUri(currentUrl);
98            NdefMessage msg = new NdefMessage(new NdefRecord[] { record });
99            return msg;
100        } else {
101            return null;
102        }
103    }
104}
105