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  */
16 
17 package com.android.server.power;
18 
19 import android.util.proto.ProtoOutputStream;
20 
21 /**
22  * Low-level suspend blocker mechanism equivalent to holding a partial wake lock.
23  *
24  * This interface is used internally to avoid introducing internal dependencies
25  * on the high-level wake lock mechanism.
26  */
27 interface SuspendBlocker {
28     /**
29      * Acquires the suspend blocker.
30      * Prevents the CPU from going to sleep.
31      *
32      * Calls to acquire() nest and must be matched by the same number
33      * of calls to release().
34      */
acquire()35     void acquire();
36 
37     /**
38      * Acquires the suspend blocker.
39      * Prevents the CPU from going to sleep.
40      *
41      * Calls to acquire() nest and must be matched by the same number
42      * of calls to release().
43      *
44      * @param id Identifier for this particular acquire. Used for tracking/logging.
45      */
acquire(String id)46     void acquire(String id);
47 
48     /**
49      * Releases the suspend blocker.
50      * Allows the CPU to go to sleep if no other suspend blockers are held.
51      *
52      * It is an error to call release() if the suspend blocker has not been acquired.
53      * The system may crash.
54      */
release()55     void release();
56 
57     /**
58      * Releases the suspend blocker.
59      * Allows the CPU to go to sleep if no other suspend blockers are held.
60      *
61      * It is an error to call release() if the suspend blocker has not been acquired.
62      * The system may crash.
63      *
64      * @param id Identifier for this particular release. Used for tracking/logging.
65      */
release(String id)66     void release(String id);
67 
dumpDebug(ProtoOutputStream proto, long fieldId)68     void dumpDebug(ProtoOutputStream proto, long fieldId);
69 }
70