1 /*
2  * Copyright (C) 2010 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 #ifndef _ANDROID_OS_MESSAGEQUEUE_H
18 #define _ANDROID_OS_MESSAGEQUEUE_H
19 
20 #include "jni.h"
21 #include <utils/Looper.h>
22 
23 namespace android {
24 
25 class MessageQueue : public virtual RefBase {
26 public:
27     /* Gets the message queue's looper. */
getLooper()28     inline sp<Looper> getLooper() const {
29         return mLooper;
30     }
31 
32     /* Checks whether the JNI environment has a pending exception.
33      *
34      * If an exception occurred, logs it together with the specified message,
35      * and calls raiseException() to ensure the exception will be raised when
36      * the callback returns, clears the pending exception from the environment,
37      * then returns true.
38      *
39      * If no exception occurred, returns false.
40      */
41     bool raiseAndClearException(JNIEnv* env, const char* msg);
42 
43     /* Raises an exception from within a callback function.
44      * The exception will be rethrown when control returns to the message queue which
45      * will typically cause the application to crash.
46      *
47      * This message can only be called from within a callback function.  If it is called
48      * at any other time, the process will simply be killed.
49      *
50      * Does nothing if exception is NULL.
51      *
52      * (This method does not take ownership of the exception object reference.
53      * The caller is responsible for releasing its reference when it is done.)
54      */
55     virtual void raiseException(JNIEnv* env, const char* msg, jthrowable exceptionObj) = 0;
56 
57 protected:
58     MessageQueue();
59     virtual ~MessageQueue();
60 
61 protected:
62     sp<Looper> mLooper;
63 };
64 
65 /* Gets the native object associated with a MessageQueue. */
66 extern sp<MessageQueue> android_os_MessageQueue_getMessageQueue(
67         JNIEnv* env, jobject messageQueueObj);
68 
69 } // namespace android
70 
71 #endif // _ANDROID_OS_MESSAGEQUEUE_H
72