1package com.googlecode.android_scripting.service;
2
3import android.annotation.TargetApi;
4import android.os.Bundle;
5import android.os.Handler;
6import android.os.HandlerThread;
7import android.os.Message;
8import android.os.RemoteException;
9
10import com.googlecode.android_scripting.Log;
11import com.googlecode.android_scripting.jsonrpc.JsonRpcResult;
12import com.googlecode.android_scripting.jsonrpc.RpcReceiverManager;
13import com.googlecode.android_scripting.jsonrpc.RpcReceiverManagerFactory;
14import com.googlecode.android_scripting.rpc.MethodDescriptor;
15
16import org.json.JSONException;
17import org.json.JSONObject;
18
19/**
20 * Class responsible for Handling messages that came through the FacadeService
21 * interface.
22 * <br>
23 * Please refer to {@link FacadeService} for details on how to use.
24 */
25@TargetApi(3)
26public class MessageHandler extends Handler {
27
28    private static final int SL4A_ACTION = 0;
29    private static final int DEFAULT_SENDING_ID = 0;
30
31    // Android sets this to -1 when the message is not sent by a Messenger.
32    // see http://developer.android.com/reference/android/os/Message.html#sendingUid
33    private static final int DEFAULT_UNSET_SENDING_ID = 1;
34
35    // Keys for the Bundles.
36    private static final String SL4A_METHOD = "sl4aMethod";
37    private static final String SL4A_RESULT = "sl4aResult";
38
39    private final RpcReceiverManagerFactory mRpcReceiverManagerFactory;
40
41    public MessageHandler(HandlerThread handlerThread,
42                          RpcReceiverManagerFactory rpcReceiverManagerFactory) {
43        super(handlerThread.getLooper());
44        this.mRpcReceiverManagerFactory = rpcReceiverManagerFactory;
45    }
46
47    /**
48     * Handles messages for the service. It does this via the same mechanism used
49     * for RPCs through RpcManagers.
50     *
51     * @param message The message that contains the method and parameters to
52     *     execute.
53     */
54    @Override
55    public void handleMessage(Message message) {
56        Log.d("Handling Remote request");
57        int senderId = message.sendingUid == DEFAULT_UNSET_SENDING_ID ?
58                DEFAULT_SENDING_ID : message.sendingUid;
59        if (message.what == SL4A_ACTION) {
60            RpcReceiverManager receiverManager;
61            if (mRpcReceiverManagerFactory.getRpcReceiverManagers().containsKey(senderId)) {
62                receiverManager = mRpcReceiverManagerFactory.getRpcReceiverManagers().get(senderId);
63            } else {
64                receiverManager = mRpcReceiverManagerFactory.create(senderId);
65            }
66            Bundle sl4aRequest = message.getData();
67            String method = sl4aRequest.getString(SL4A_METHOD);
68            if (method == null || "".equals(method)) {
69                Log.e("No SL4A method specified on the Bundle. Specify one with "
70                        + SL4A_METHOD);
71                return;
72            }
73            MethodDescriptor rpc = receiverManager.getMethodDescriptor(method);
74            if (rpc == null) {
75                Log.e("Unknown RPC: \"" + method + "\"");
76                return;
77            }
78            try {
79                Log.d("Invoking method " + rpc.getName());
80                Object result = rpc.invoke(receiverManager, sl4aRequest);
81                // Only return a result if we were passed a Messenger. Otherwise assume
82                // client did not care for the response.
83                if (message.replyTo != null) {
84                    Message reply = Message.obtain();
85                    Bundle sl4aResponse = new Bundle();
86                    putResult(senderId, result, sl4aResponse);
87                    reply.setData(sl4aResponse);
88                    message.replyTo.send(reply);
89                }
90            } catch (RemoteException e) {
91                Log.e("Could not send reply back to client", e);
92            } catch (Throwable t) {
93                Log.e("Exception while executing sl4a method", t);
94            }
95        }
96    }
97
98    private void putResult(int id, Object result, Bundle reply) {
99        JSONObject json;
100        try {
101            if (result instanceof Throwable) {
102                json = JsonRpcResult.error(id, (Throwable) result);
103            } else {
104                json = JsonRpcResult.result(id, result);
105            }
106        } catch (JSONException e) {
107            // There was an error converting the result to JSON. This shouldn't
108            // happen normally.
109            Log.e("Caught exception when filling JSON result.", e);
110            reply.putString(SL4A_RESULT, e.toString());
111            return;
112        }
113        Log.d("Returning result: " + json.toString());
114        reply.putString(SL4A_RESULT, json.toString());
115    }
116}
117