1/*
2 * Copyright (C) 2017 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.server.am;
18
19import android.annotation.NonNull;
20import android.app.IApplicationThread;
21import android.app.servertransaction.ClientTransaction;
22import android.app.servertransaction.ClientTransactionItem;
23import android.app.servertransaction.ActivityLifecycleItem;
24import android.os.Binder;
25import android.os.IBinder;
26import android.os.RemoteException;
27
28/**
29 * Class that is able to combine multiple client lifecycle transition requests and/or callbacks,
30 * and execute them as a single transaction.
31 *
32 * @see ClientTransaction
33 */
34class ClientLifecycleManager {
35    // TODO(lifecycler): Implement building transactions or global transaction.
36    // TODO(lifecycler): Use object pools for transactions and transaction items.
37
38    /**
39     * Schedule a transaction, which may consist of multiple callbacks and a lifecycle request.
40     * @param transaction A sequence of client transaction items.
41     * @throws RemoteException
42     *
43     * @see ClientTransaction
44     */
45    void scheduleTransaction(ClientTransaction transaction) throws RemoteException {
46        final IApplicationThread client = transaction.getClient();
47        transaction.schedule();
48        if (!(client instanceof Binder)) {
49            // If client is not an instance of Binder - it's a remote call and at this point it is
50            // safe to recycle the object. All objects used for local calls will be recycled after
51            // the transaction is executed on client in ActivityThread.
52            transaction.recycle();
53        }
54    }
55
56    /**
57     * Schedule a single lifecycle request or callback to client activity.
58     * @param client Target client.
59     * @param activityToken Target activity token.
60     * @param stateRequest A request to move target activity to a desired lifecycle state.
61     * @throws RemoteException
62     *
63     * @see ClientTransactionItem
64     */
65    void scheduleTransaction(@NonNull IApplicationThread client, @NonNull IBinder activityToken,
66            @NonNull ActivityLifecycleItem stateRequest) throws RemoteException {
67        final ClientTransaction clientTransaction = transactionWithState(client, activityToken,
68                stateRequest);
69        scheduleTransaction(clientTransaction);
70    }
71
72    /**
73     * Schedule a single callback delivery to client activity.
74     * @param client Target client.
75     * @param activityToken Target activity token.
76     * @param callback A request to deliver a callback.
77     * @throws RemoteException
78     *
79     * @see ClientTransactionItem
80     */
81    void scheduleTransaction(@NonNull IApplicationThread client, @NonNull IBinder activityToken,
82            @NonNull ClientTransactionItem callback) throws RemoteException {
83        final ClientTransaction clientTransaction = transactionWithCallback(client, activityToken,
84                callback);
85        scheduleTransaction(clientTransaction);
86    }
87
88    /**
89     * Schedule a single callback delivery to client application.
90     * @param client Target client.
91     * @param callback A request to deliver a callback.
92     * @throws RemoteException
93     *
94     * @see ClientTransactionItem
95     */
96    void scheduleTransaction(@NonNull IApplicationThread client,
97            @NonNull ClientTransactionItem callback) throws RemoteException {
98        final ClientTransaction clientTransaction = transactionWithCallback(client,
99                null /* activityToken */, callback);
100        scheduleTransaction(clientTransaction);
101    }
102
103    /**
104     * @return A new instance of {@link ClientTransaction} with a single lifecycle state request.
105     *
106     * @see ClientTransaction
107     * @see ClientTransactionItem
108     */
109    private static ClientTransaction transactionWithState(@NonNull IApplicationThread client,
110            @NonNull IBinder activityToken, @NonNull ActivityLifecycleItem stateRequest) {
111        final ClientTransaction clientTransaction = ClientTransaction.obtain(client, activityToken);
112        clientTransaction.setLifecycleStateRequest(stateRequest);
113        return clientTransaction;
114    }
115
116    /**
117     * @return A new instance of {@link ClientTransaction} with a single callback invocation.
118     *
119     * @see ClientTransaction
120     * @see ClientTransactionItem
121     */
122    private static ClientTransaction transactionWithCallback(@NonNull IApplicationThread client,
123            IBinder activityToken, @NonNull ClientTransactionItem callback) {
124        final ClientTransaction clientTransaction = ClientTransaction.obtain(client, activityToken);
125        clientTransaction.addCallback(callback);
126        return clientTransaction;
127    }
128}
129