1/*
2 * Copyright (C) 2012 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 */
16package com.android.nfc.handover;
17
18import android.nfc.FormatException;
19import android.nfc.NdefMessage;
20import android.util.Log;
21
22import com.android.nfc.LlcpException;
23import com.android.nfc.NfcService;
24import com.android.nfc.DeviceHost.LlcpSocket;
25
26import java.io.ByteArrayOutputStream;
27import java.io.IOException;
28import java.util.Arrays;
29
30public final class HandoverClient {
31    private static final String TAG = "HandoverClient";
32    private static final int MIU = 128;
33    private static final boolean DBG = false;
34
35    private static final int DISCONNECTED = 0;
36    private static final int CONNECTING = 1;
37    private static final int CONNECTED = 2;
38
39    private static final Object mLock = new Object();
40
41    // Variables below synchronized on mLock
42    LlcpSocket mSocket;
43    int mState;
44
45    public void connect() throws IOException {
46        synchronized (mLock) {
47            if (mState != DISCONNECTED) {
48                throw new IOException("Socket in use.");
49            }
50            mState = CONNECTING;
51        }
52        NfcService service = NfcService.getInstance();
53        LlcpSocket sock = null;
54        try {
55            sock = service.createLlcpSocket(0, MIU, 1, 1024);
56        } catch (LlcpException e) {
57            synchronized (mLock) {
58                mState = DISCONNECTED;
59            }
60            throw new IOException("Could not create socket");
61        }
62        try {
63            if (DBG) Log.d(TAG, "about to connect to service " +
64                    HandoverServer.HANDOVER_SERVICE_NAME);
65            sock.connectToService(HandoverServer.HANDOVER_SERVICE_NAME);
66        } catch (IOException e) {
67            if (sock != null) {
68                try {
69                    sock.close();
70                } catch (IOException e2) {
71                    // Ignore
72                }
73            }
74            synchronized (mLock) {
75                mState = DISCONNECTED;
76            }
77            throw new IOException("Could not connect to handover service");
78        }
79        synchronized (mLock) {
80            mSocket = sock;
81            mState = CONNECTED;
82        }
83    }
84
85    public void close() {
86        synchronized (mLock) {
87            if (mSocket != null) {
88                try {
89                    mSocket.close();
90                } catch (IOException e) {
91                    // Ignore
92                }
93                mSocket = null;
94            }
95            mState = DISCONNECTED;
96        }
97    }
98    public NdefMessage sendHandoverRequest(NdefMessage msg) throws IOException {
99        if (msg == null) return null;
100
101        LlcpSocket sock = null;
102        synchronized (mLock) {
103            if (mState != CONNECTED) {
104                throw new IOException("Socket not connected");
105            }
106            sock = mSocket;
107        }
108        int offset = 0;
109        byte[] buffer = msg.toByteArray();
110        ByteArrayOutputStream byteStream = new ByteArrayOutputStream();
111
112        try {
113            int remoteMiu = sock.getRemoteMiu();
114            if (DBG) Log.d(TAG, "about to send a " + buffer.length + " byte message");
115            while (offset < buffer.length) {
116                int length = Math.min(buffer.length - offset, remoteMiu);
117                byte[] tmpBuffer = Arrays.copyOfRange(buffer, offset, offset+length);
118                if (DBG) Log.d(TAG, "about to send a " + length + " byte packet");
119                sock.send(tmpBuffer);
120                offset += length;
121            }
122
123            // Now, try to read back the handover response
124            byte[] partial = new byte[sock.getLocalMiu()];
125            NdefMessage handoverSelectMsg = null;
126            while (true) {
127                int size = sock.receive(partial);
128                if (size < 0) {
129                    break;
130                }
131                byteStream.write(partial, 0, size);
132                try {
133                    handoverSelectMsg = new NdefMessage(byteStream.toByteArray());
134                    // If we get here, message is complete
135                    break;
136                } catch (FormatException e) {
137                    // Ignore, and try to fetch more bytes
138                }
139            }
140            return handoverSelectMsg;
141        } catch (IOException e) {
142            if (DBG) Log.d(TAG, "couldn't connect to handover service");
143        } finally {
144            if (sock != null) {
145                try {
146                    if (DBG) Log.d(TAG, "about to close");
147                    sock.close();
148                } catch (IOException e) {
149                    // Ignore
150                }
151            }
152            try {
153                byteStream.close();
154            } catch (IOException e) {
155                // Ignore
156            }
157        }
158        return null;
159    }
160}
161