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 <nativehelper/JNIHelp.h>
20 #include <android_runtime/AndroidRuntime.h>
21
22 #include <utils/Looper.h>
23 #include <utils/Log.h>
24 #include "android_os_MessageQueue.h"
25
26 #include "core_jni_helpers.h"
27
28 namespace android {
29
30 static struct {
31 jfieldID mPtr; // native object attached to the DVM MessageQueue
32 jmethodID dispatchEvents;
33 } gMessageQueueClassInfo;
34
35 // Must be kept in sync with the constants in Looper.FileDescriptorCallback
36 static const int CALLBACK_EVENT_INPUT = 1 << 0;
37 static const int CALLBACK_EVENT_OUTPUT = 1 << 1;
38 static const int CALLBACK_EVENT_ERROR = 1 << 2;
39
40
41 class NativeMessageQueue : public MessageQueue, public LooperCallback {
42 public:
43 NativeMessageQueue();
44 virtual ~NativeMessageQueue();
45
46 virtual void raiseException(JNIEnv* env, const char* msg, jthrowable exceptionObj);
47
48 void pollOnce(JNIEnv* env, jobject obj, int timeoutMillis);
49 void wake();
50 void setFileDescriptorEvents(int fd, int events);
51
52 virtual int handleEvent(int fd, int events, void* data);
53
54 /**
55 * A simple proxy that holds a weak reference to a looper callback.
56 */
57 class WeakLooperCallback : public LooperCallback {
58 protected:
59 virtual ~WeakLooperCallback();
60
61 public:
62 WeakLooperCallback(const wp<LooperCallback>& callback);
63 virtual int handleEvent(int fd, int events, void* data);
64
65 private:
66 wp<LooperCallback> mCallback;
67 };
68
69 private:
70 JNIEnv* mPollEnv;
71 jobject mPollObj;
72 jthrowable mExceptionObj;
73 };
74
75
MessageQueue()76 MessageQueue::MessageQueue() {
77 }
78
~MessageQueue()79 MessageQueue::~MessageQueue() {
80 }
81
raiseAndClearException(JNIEnv * env,const char * msg)82 bool MessageQueue::raiseAndClearException(JNIEnv* env, const char* msg) {
83 if (env->ExceptionCheck()) {
84 jthrowable exceptionObj = env->ExceptionOccurred();
85 env->ExceptionClear();
86 raiseException(env, msg, exceptionObj);
87 env->DeleteLocalRef(exceptionObj);
88 return true;
89 }
90 return false;
91 }
92
NativeMessageQueue()93 NativeMessageQueue::NativeMessageQueue() :
94 mPollEnv(NULL), mPollObj(NULL), mExceptionObj(NULL) {
95 mLooper = Looper::getForThread();
96 if (mLooper == NULL) {
97 mLooper = new Looper(false);
98 Looper::setForThread(mLooper);
99 }
100 }
101
~NativeMessageQueue()102 NativeMessageQueue::~NativeMessageQueue() {
103 }
104
raiseException(JNIEnv * env,const char * msg,jthrowable exceptionObj)105 void NativeMessageQueue::raiseException(JNIEnv* env, const char* msg, jthrowable exceptionObj) {
106 if (exceptionObj) {
107 if (mPollEnv == env) {
108 if (mExceptionObj) {
109 env->DeleteLocalRef(mExceptionObj);
110 }
111 mExceptionObj = jthrowable(env->NewLocalRef(exceptionObj));
112 ALOGE("Exception in MessageQueue callback: %s", msg);
113 jniLogException(env, ANDROID_LOG_ERROR, LOG_TAG, exceptionObj);
114 } else {
115 ALOGE("Exception: %s", msg);
116 jniLogException(env, ANDROID_LOG_ERROR, LOG_TAG, exceptionObj);
117 LOG_ALWAYS_FATAL("raiseException() was called when not in a callback, exiting.");
118 }
119 }
120 }
121
pollOnce(JNIEnv * env,jobject pollObj,int timeoutMillis)122 void NativeMessageQueue::pollOnce(JNIEnv* env, jobject pollObj, int timeoutMillis) {
123 mPollEnv = env;
124 mPollObj = pollObj;
125 mLooper->pollOnce(timeoutMillis);
126 mPollObj = NULL;
127 mPollEnv = NULL;
128
129 if (mExceptionObj) {
130 env->Throw(mExceptionObj);
131 env->DeleteLocalRef(mExceptionObj);
132 mExceptionObj = NULL;
133 }
134 }
135
wake()136 void NativeMessageQueue::wake() {
137 mLooper->wake();
138 }
139
setFileDescriptorEvents(int fd,int events)140 void NativeMessageQueue::setFileDescriptorEvents(int fd, int events) {
141 if (events) {
142 int looperEvents = 0;
143 if (events & CALLBACK_EVENT_INPUT) {
144 looperEvents |= Looper::EVENT_INPUT;
145 }
146 if (events & CALLBACK_EVENT_OUTPUT) {
147 looperEvents |= Looper::EVENT_OUTPUT;
148 }
149 mLooper->addFd(fd, Looper::POLL_CALLBACK, looperEvents,
150 sp<WeakLooperCallback>::make(this),
151 reinterpret_cast<void*>(events));
152 } else {
153 mLooper->removeFd(fd);
154 }
155 }
156
handleEvent(int fd,int looperEvents,void * data)157 int NativeMessageQueue::handleEvent(int fd, int looperEvents, void* data) {
158 int events = 0;
159 if (looperEvents & Looper::EVENT_INPUT) {
160 events |= CALLBACK_EVENT_INPUT;
161 }
162 if (looperEvents & Looper::EVENT_OUTPUT) {
163 events |= CALLBACK_EVENT_OUTPUT;
164 }
165 if (looperEvents & (Looper::EVENT_ERROR | Looper::EVENT_HANGUP | Looper::EVENT_INVALID)) {
166 events |= CALLBACK_EVENT_ERROR;
167 }
168 int oldWatchedEvents = reinterpret_cast<intptr_t>(data);
169 int newWatchedEvents = mPollEnv->CallIntMethod(mPollObj,
170 gMessageQueueClassInfo.dispatchEvents, fd, events);
171 if (!newWatchedEvents) {
172 return 0; // unregister the fd
173 }
174 if (newWatchedEvents != oldWatchedEvents) {
175 setFileDescriptorEvents(fd, newWatchedEvents);
176 }
177 return 1;
178 }
179
180
181 // --- NativeMessageQueue::WeakLooperCallback ---
182
WeakLooperCallback(const wp<LooperCallback> & callback)183 NativeMessageQueue::WeakLooperCallback::WeakLooperCallback(const wp<LooperCallback>& callback) :
184 mCallback(callback) {
185 }
186
~WeakLooperCallback()187 NativeMessageQueue::WeakLooperCallback::~WeakLooperCallback() {
188 }
189
handleEvent(int fd,int events,void * data)190 int NativeMessageQueue::WeakLooperCallback::handleEvent(int fd, int events, void* data) {
191 sp<LooperCallback> callback = mCallback.promote();
192 if (callback != nullptr) {
193 return callback->handleEvent(fd, events, data);
194 }
195 return 0;
196 }
197
198
199 // ----------------------------------------------------------------------------
200
android_os_MessageQueue_getMessageQueue(JNIEnv * env,jobject messageQueueObj)201 sp<MessageQueue> android_os_MessageQueue_getMessageQueue(JNIEnv* env, jobject messageQueueObj) {
202 jlong ptr = env->GetLongField(messageQueueObj, gMessageQueueClassInfo.mPtr);
203 return reinterpret_cast<NativeMessageQueue*>(ptr);
204 }
205
android_os_MessageQueue_nativeInit(JNIEnv * env,jclass clazz)206 static jlong android_os_MessageQueue_nativeInit(JNIEnv* env, jclass clazz) {
207 NativeMessageQueue* nativeMessageQueue = new NativeMessageQueue();
208 if (!nativeMessageQueue) {
209 jniThrowRuntimeException(env, "Unable to allocate native queue");
210 return 0;
211 }
212
213 nativeMessageQueue->incStrong(env);
214 return reinterpret_cast<jlong>(nativeMessageQueue);
215 }
216
android_os_MessageQueue_nativeDestroy(JNIEnv * env,jclass clazz,jlong ptr)217 static void android_os_MessageQueue_nativeDestroy(JNIEnv* env, jclass clazz, jlong ptr) {
218 NativeMessageQueue* nativeMessageQueue = reinterpret_cast<NativeMessageQueue*>(ptr);
219 nativeMessageQueue->decStrong(env);
220 }
221
android_os_MessageQueue_nativePollOnce(JNIEnv * env,jobject obj,jlong ptr,jint timeoutMillis)222 static void android_os_MessageQueue_nativePollOnce(JNIEnv* env, jobject obj,
223 jlong ptr, jint timeoutMillis) {
224 NativeMessageQueue* nativeMessageQueue = reinterpret_cast<NativeMessageQueue*>(ptr);
225 nativeMessageQueue->pollOnce(env, obj, timeoutMillis);
226 }
227
android_os_MessageQueue_nativeWake(JNIEnv * env,jclass clazz,jlong ptr)228 static void android_os_MessageQueue_nativeWake(JNIEnv* env, jclass clazz, jlong ptr) {
229 NativeMessageQueue* nativeMessageQueue = reinterpret_cast<NativeMessageQueue*>(ptr);
230 nativeMessageQueue->wake();
231 }
232
android_os_MessageQueue_nativeIsPolling(JNIEnv * env,jclass clazz,jlong ptr)233 static jboolean android_os_MessageQueue_nativeIsPolling(JNIEnv* env, jclass clazz, jlong ptr) {
234 NativeMessageQueue* nativeMessageQueue = reinterpret_cast<NativeMessageQueue*>(ptr);
235 return nativeMessageQueue->getLooper()->isPolling();
236 }
237
android_os_MessageQueue_nativeSetFileDescriptorEvents(JNIEnv * env,jclass clazz,jlong ptr,jint fd,jint events)238 static void android_os_MessageQueue_nativeSetFileDescriptorEvents(JNIEnv* env, jclass clazz,
239 jlong ptr, jint fd, jint events) {
240 NativeMessageQueue* nativeMessageQueue = reinterpret_cast<NativeMessageQueue*>(ptr);
241 nativeMessageQueue->setFileDescriptorEvents(fd, events);
242 }
243
244 // ----------------------------------------------------------------------------
245
246 static const JNINativeMethod gMessageQueueMethods[] = {
247 /* name, signature, funcPtr */
248 { "nativeInit", "()J", (void*)android_os_MessageQueue_nativeInit },
249 { "nativeDestroy", "(J)V", (void*)android_os_MessageQueue_nativeDestroy },
250 { "nativePollOnce", "(JI)V", (void*)android_os_MessageQueue_nativePollOnce },
251 { "nativeWake", "(J)V", (void*)android_os_MessageQueue_nativeWake },
252 { "nativeIsPolling", "(J)Z", (void*)android_os_MessageQueue_nativeIsPolling },
253 { "nativeSetFileDescriptorEvents", "(JII)V",
254 (void*)android_os_MessageQueue_nativeSetFileDescriptorEvents },
255 };
256
register_android_os_MessageQueue(JNIEnv * env)257 int register_android_os_MessageQueue(JNIEnv* env) {
258 int res = RegisterMethodsOrDie(env, "android/os/MessageQueue", gMessageQueueMethods,
259 NELEM(gMessageQueueMethods));
260
261 jclass clazz = FindClassOrDie(env, "android/os/MessageQueue");
262 gMessageQueueClassInfo.mPtr = GetFieldIDOrDie(env, clazz, "mPtr", "J");
263 gMessageQueueClassInfo.dispatchEvents = GetMethodIDOrDie(env, clazz,
264 "dispatchEvents", "(II)I");
265
266 return res;
267 }
268
269 } // namespace android
270