android_os_MessageQueue.cpp revision 46b9ac0ae2162309774a7478cd9d4e578747bfc2 
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/PollLoop.h>
22#include <utils/Log.h>
23#include "android_os_MessageQueue.h"
24
25namespace android {
26
27// ----------------------------------------------------------------------------
28
29static struct {
30    jclass clazz;
31
32    jfieldID mPtr;   // native object attached to the DVM MessageQueue
33} gMessageQueueClassInfo;
34
35// ----------------------------------------------------------------------------
36
37class NativeMessageQueue {
38public:
39    NativeMessageQueue();
40    ~NativeMessageQueue();
41
42    inline sp<PollLoop> getPollLoop() { return mPollLoop; }
43
44    bool pollOnce(int timeoutMillis);
45    void wake();
46
47private:
48    sp<PollLoop> mPollLoop;
49};
50
51// ----------------------------------------------------------------------------
52
53NativeMessageQueue::NativeMessageQueue() {
54    mPollLoop = new PollLoop();
55}
56
57NativeMessageQueue::~NativeMessageQueue() {
58}
59
60bool NativeMessageQueue::pollOnce(int timeoutMillis) {
61    return mPollLoop->pollOnce(timeoutMillis);
62}
63
64void NativeMessageQueue::wake() {
65    mPollLoop->wake();
66}
67
68// ----------------------------------------------------------------------------
69
70static NativeMessageQueue* android_os_MessageQueue_getNativeMessageQueue(JNIEnv* env,
71        jobject messageQueueObj) {
72    jint intPtr = env->GetIntField(messageQueueObj, gMessageQueueClassInfo.mPtr);
73    return reinterpret_cast<NativeMessageQueue*>(intPtr);
74}
75
76static void android_os_MessageQueue_setNativeMessageQueue(JNIEnv* env, jobject messageQueueObj,
77        NativeMessageQueue* nativeMessageQueue) {
78    env->SetIntField(messageQueueObj, gMessageQueueClassInfo.mPtr,
79             reinterpret_cast<jint>(nativeMessageQueue));
80}
81
82sp<PollLoop> android_os_MessageQueue_getPollLoop(JNIEnv* env, jobject messageQueueObj) {
83    NativeMessageQueue* nativeMessageQueue =
84            android_os_MessageQueue_getNativeMessageQueue(env, messageQueueObj);
85    return nativeMessageQueue != NULL ? nativeMessageQueue->getPollLoop() : NULL;
86}
87
88static void android_os_MessageQueue_nativeInit(JNIEnv* env, jobject obj) {
89    NativeMessageQueue* nativeMessageQueue = new NativeMessageQueue();
90    if (! nativeMessageQueue) {
91        jniThrowRuntimeException(env, "Unable to allocate native queue");
92        return;
93    }
94
95    android_os_MessageQueue_setNativeMessageQueue(env, obj, nativeMessageQueue);
96}
97
98static void android_os_MessageQueue_nativeDestroy(JNIEnv* env, jobject obj) {
99    NativeMessageQueue* nativeMessageQueue =
100            android_os_MessageQueue_getNativeMessageQueue(env, obj);
101    if (nativeMessageQueue) {
102        android_os_MessageQueue_setNativeMessageQueue(env, obj, NULL);
103        delete nativeMessageQueue;
104    }
105}
106
107static void throwQueueNotInitialized(JNIEnv* env) {
108    jniThrowException(env, "java/lang/IllegalStateException", "Message queue not initialized");
109}
110
111static jboolean android_os_MessageQueue_nativePollOnce(JNIEnv* env, jobject obj,
112        jint timeoutMillis) {
113    NativeMessageQueue* nativeMessageQueue =
114            android_os_MessageQueue_getNativeMessageQueue(env, obj);
115    if (! nativeMessageQueue) {
116        throwQueueNotInitialized(env);
117        return false;
118    }
119    return nativeMessageQueue->pollOnce(timeoutMillis);
120}
121
122static void android_os_MessageQueue_nativeWake(JNIEnv* env, jobject obj) {
123    NativeMessageQueue* nativeMessageQueue =
124            android_os_MessageQueue_getNativeMessageQueue(env, obj);
125    if (! nativeMessageQueue) {
126        throwQueueNotInitialized(env);
127        return;
128    }
129    return nativeMessageQueue->wake();
130}
131
132// ----------------------------------------------------------------------------
133
134static JNINativeMethod gMessageQueueMethods[] = {
135    /* name, signature, funcPtr */
136    { "nativeInit", "()V", (void*)android_os_MessageQueue_nativeInit },
137    { "nativeDestroy", "()V", (void*)android_os_MessageQueue_nativeDestroy },
138    { "nativePollOnce", "(I)Z", (void*)android_os_MessageQueue_nativePollOnce },
139    { "nativeWake", "()V", (void*)android_os_MessageQueue_nativeWake }
140};
141
142#define FIND_CLASS(var, className) \
143        var = env->FindClass(className); \
144        LOG_FATAL_IF(! var, "Unable to find class " className); \
145        var = jclass(env->NewGlobalRef(var));
146
147#define GET_FIELD_ID(var, clazz, fieldName, fieldDescriptor) \
148        var = env->GetFieldID(clazz, fieldName, fieldDescriptor); \
149        LOG_FATAL_IF(! var, "Unable to find field " fieldName);
150
151int register_android_os_MessageQueue(JNIEnv* env) {
152    int res = jniRegisterNativeMethods(env, "android/os/MessageQueue",
153            gMessageQueueMethods, NELEM(gMessageQueueMethods));
154    LOG_FATAL_IF(res < 0, "Unable to register native methods.");
155
156    FIND_CLASS(gMessageQueueClassInfo.clazz, "android/os/MessageQueue");
157
158    GET_FIELD_ID(gMessageQueueClassInfo.mPtr, gMessageQueueClassInfo.clazz,
159            "mPtr", "I");
160
161    return 0;
162}
163
164} // namespace android
165