android_os_MessageQueue.cpp revision 17cc33a35729733aaa0a7706f38b1c45f0b1590a
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#define LOG_TAG "MessageQueue-JNI"
18
19#include "JNIHelp.h"
20
21#include <utils/Looper.h>
22#include <utils/Log.h>
23#include "android_os_MessageQueue.h"
24
25namespace android {
26
27// ----------------------------------------------------------------------------
28
29static struct {
30    jfieldID mPtr;   // native object attached to the DVM MessageQueue
31} gMessageQueueClassInfo;
32
33// ----------------------------------------------------------------------------
34
35class NativeMessageQueue {
36public:
37    NativeMessageQueue();
38    ~NativeMessageQueue();
39
40    inline sp<Looper> getLooper() { return mLooper; }
41
42    void pollOnce(int timeoutMillis);
43    void wake();
44
45private:
46    sp<Looper> mLooper;
47};
48
49// ----------------------------------------------------------------------------
50
51NativeMessageQueue::NativeMessageQueue() {
52    mLooper = Looper::getForThread();
53    if (mLooper == NULL) {
54        mLooper = new Looper(false);
55        Looper::setForThread(mLooper);
56    }
57}
58
59NativeMessageQueue::~NativeMessageQueue() {
60}
61
62void NativeMessageQueue::pollOnce(int timeoutMillis) {
63    mLooper->pollOnce(timeoutMillis);
64}
65
66void NativeMessageQueue::wake() {
67    mLooper->wake();
68}
69
70// ----------------------------------------------------------------------------
71
72static NativeMessageQueue* android_os_MessageQueue_getNativeMessageQueue(JNIEnv* env,
73        jobject messageQueueObj) {
74    jint intPtr = env->GetIntField(messageQueueObj, gMessageQueueClassInfo.mPtr);
75    return reinterpret_cast<NativeMessageQueue*>(intPtr);
76}
77
78static void android_os_MessageQueue_setNativeMessageQueue(JNIEnv* env, jobject messageQueueObj,
79        NativeMessageQueue* nativeMessageQueue) {
80    env->SetIntField(messageQueueObj, gMessageQueueClassInfo.mPtr,
81             reinterpret_cast<jint>(nativeMessageQueue));
82}
83
84sp<Looper> android_os_MessageQueue_getLooper(JNIEnv* env, jobject messageQueueObj) {
85    NativeMessageQueue* nativeMessageQueue =
86            android_os_MessageQueue_getNativeMessageQueue(env, messageQueueObj);
87    return nativeMessageQueue != NULL ? nativeMessageQueue->getLooper() : NULL;
88}
89
90static void android_os_MessageQueue_nativeInit(JNIEnv* env, jobject obj) {
91    NativeMessageQueue* nativeMessageQueue = new NativeMessageQueue();
92    if (! nativeMessageQueue) {
93        jniThrowRuntimeException(env, "Unable to allocate native queue");
94        return;
95    }
96
97    android_os_MessageQueue_setNativeMessageQueue(env, obj, nativeMessageQueue);
98}
99
100static void android_os_MessageQueue_nativeDestroy(JNIEnv* env, jobject obj) {
101    NativeMessageQueue* nativeMessageQueue =
102            android_os_MessageQueue_getNativeMessageQueue(env, obj);
103    if (nativeMessageQueue) {
104        android_os_MessageQueue_setNativeMessageQueue(env, obj, NULL);
105        delete nativeMessageQueue;
106    }
107}
108
109static void throwQueueNotInitialized(JNIEnv* env) {
110    jniThrowException(env, "java/lang/IllegalStateException", "Message queue not initialized");
111}
112
113static void android_os_MessageQueue_nativePollOnce(JNIEnv* env, jobject obj,
114        jint ptr, jint timeoutMillis) {
115    NativeMessageQueue* nativeMessageQueue = reinterpret_cast<NativeMessageQueue*>(ptr);
116    nativeMessageQueue->pollOnce(timeoutMillis);
117}
118
119static void android_os_MessageQueue_nativeWake(JNIEnv* env, jobject obj, jint ptr) {
120    NativeMessageQueue* nativeMessageQueue = reinterpret_cast<NativeMessageQueue*>(ptr);
121    return nativeMessageQueue->wake();
122}
123
124// ----------------------------------------------------------------------------
125
126static JNINativeMethod gMessageQueueMethods[] = {
127    /* name, signature, funcPtr */
128    { "nativeInit", "()V", (void*)android_os_MessageQueue_nativeInit },
129    { "nativeDestroy", "()V", (void*)android_os_MessageQueue_nativeDestroy },
130    { "nativePollOnce", "(II)V", (void*)android_os_MessageQueue_nativePollOnce },
131    { "nativeWake", "(I)V", (void*)android_os_MessageQueue_nativeWake }
132};
133
134#define FIND_CLASS(var, className) \
135        var = env->FindClass(className); \
136        LOG_FATAL_IF(! var, "Unable to find class " className);
137
138#define GET_FIELD_ID(var, clazz, fieldName, fieldDescriptor) \
139        var = env->GetFieldID(clazz, fieldName, fieldDescriptor); \
140        LOG_FATAL_IF(! var, "Unable to find field " fieldName);
141
142int register_android_os_MessageQueue(JNIEnv* env) {
143    int res = jniRegisterNativeMethods(env, "android/os/MessageQueue",
144            gMessageQueueMethods, NELEM(gMessageQueueMethods));
145    LOG_FATAL_IF(res < 0, "Unable to register native methods.");
146
147    jclass clazz;
148    FIND_CLASS(clazz, "android/os/MessageQueue");
149
150    GET_FIELD_ID(gMessageQueueClassInfo.mPtr, clazz,
151            "mPtr", "I");
152
153    return 0;
154}
155
156} // namespace android
157