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1 /*
2 **
3 ** Copyright 2008, The Android Open Source Project
4 **
5 ** Licensed under the Apache License, Version 2.0 (the "License");
6 ** you may not use this file except in compliance with the License.
7 ** You may obtain a copy of the License at
8 **
9 **     http://www.apache.org/licenses/LICENSE-2.0
10 **
11 ** Unless required by applicable law or agreed to in writing, software
12 ** distributed under the License is distributed on an "AS IS" BASIS,
13 ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 ** See the License for the specific language governing permissions and
15 ** limitations under the License.
16 */
17 
18 //#define LOG_NDEBUG 0
19 #define LOG_TAG "Camera-JNI"
20 #include <utils/Log.h>
21 
22 #include "jni.h"
23 #include "JNIHelp.h"
24 #include "android_runtime/AndroidRuntime.h"
25 
26 #include <utils/Vector.h>
27 
28 #include <ui/Surface.h>
29 #include <ui/Camera.h>
30 #include <binder/IMemory.h>
31 
32 using namespace android;
33 
34 struct fields_t {
35     jfieldID    context;
36     jfieldID    surface;
37     jmethodID   post_event;
38 };
39 
40 static fields_t fields;
41 static Mutex sLock;
42 
43 // provides persistent context for calls from native code to Java
44 class JNICameraContext: public CameraListener
45 {
46 public:
47     JNICameraContext(JNIEnv* env, jobject weak_this, jclass clazz, const sp<Camera>& camera);
~JNICameraContext()48     ~JNICameraContext() { release(); }
49     virtual void notify(int32_t msgType, int32_t ext1, int32_t ext2);
50     virtual void postData(int32_t msgType, const sp<IMemory>& dataPtr);
51     virtual void postDataTimestamp(nsecs_t timestamp, int32_t msgType, const sp<IMemory>& dataPtr);
52     void addCallbackBuffer(JNIEnv *env, jbyteArray cbb);
53     void setCallbackMode(JNIEnv *env, bool installed, bool manualMode);
getCamera()54     sp<Camera> getCamera() { Mutex::Autolock _l(mLock); return mCamera; }
55     void release();
56 
57 private:
58     void copyAndPost(JNIEnv* env, const sp<IMemory>& dataPtr, int msgType);
59     void clearCallbackBuffers_l(JNIEnv *env);
60 
61     jobject     mCameraJObjectWeak;     // weak reference to java object
62     jclass      mCameraJClass;          // strong reference to java class
63     sp<Camera>  mCamera;                // strong reference to native object
64     Mutex       mLock;
65 
66     Vector<jbyteArray> mCallbackBuffers; // Global reference application managed byte[]
67     bool mManualBufferMode;              // Whether to use application managed buffers.
68     bool mManualCameraCallbackSet;       // Whether the callback has been set, used to reduce unnecessary calls to set the callback.
69 };
70 
get_native_camera(JNIEnv * env,jobject thiz,JNICameraContext ** pContext)71 sp<Camera> get_native_camera(JNIEnv *env, jobject thiz, JNICameraContext** pContext)
72 {
73     sp<Camera> camera;
74     Mutex::Autolock _l(sLock);
75     JNICameraContext* context = reinterpret_cast<JNICameraContext*>(env->GetIntField(thiz, fields.context));
76     if (context != NULL) {
77         camera = context->getCamera();
78     }
79     LOGV("get_native_camera: context=%p, camera=%p", context, camera.get());
80     if (camera == 0) {
81         jniThrowException(env, "java/lang/RuntimeException", "Method called after release()");
82     }
83 
84     if (pContext != NULL) *pContext = context;
85     return camera;
86 }
87 
JNICameraContext(JNIEnv * env,jobject weak_this,jclass clazz,const sp<Camera> & camera)88 JNICameraContext::JNICameraContext(JNIEnv* env, jobject weak_this, jclass clazz, const sp<Camera>& camera)
89 {
90     mCameraJObjectWeak = env->NewGlobalRef(weak_this);
91     mCameraJClass = (jclass)env->NewGlobalRef(clazz);
92     mCamera = camera;
93 
94     mManualBufferMode = false;
95     mManualCameraCallbackSet = false;
96 }
97 
release()98 void JNICameraContext::release()
99 {
100     LOGV("release");
101     Mutex::Autolock _l(mLock);
102     JNIEnv *env = AndroidRuntime::getJNIEnv();
103 
104     if (mCameraJObjectWeak != NULL) {
105         env->DeleteGlobalRef(mCameraJObjectWeak);
106         mCameraJObjectWeak = NULL;
107     }
108     if (mCameraJClass != NULL) {
109         env->DeleteGlobalRef(mCameraJClass);
110         mCameraJClass = NULL;
111     }
112     clearCallbackBuffers_l(env);
113     mCamera.clear();
114 }
115 
notify(int32_t msgType,int32_t ext1,int32_t ext2)116 void JNICameraContext::notify(int32_t msgType, int32_t ext1, int32_t ext2)
117 {
118     LOGV("notify");
119 
120     // VM pointer will be NULL if object is released
121     Mutex::Autolock _l(mLock);
122     if (mCameraJObjectWeak == NULL) {
123         LOGW("callback on dead camera object");
124         return;
125     }
126     JNIEnv *env = AndroidRuntime::getJNIEnv();
127     env->CallStaticVoidMethod(mCameraJClass, fields.post_event,
128             mCameraJObjectWeak, msgType, ext1, ext2, NULL);
129 }
130 
copyAndPost(JNIEnv * env,const sp<IMemory> & dataPtr,int msgType)131 void JNICameraContext::copyAndPost(JNIEnv* env, const sp<IMemory>& dataPtr, int msgType)
132 {
133     jbyteArray obj = NULL;
134 
135     // allocate Java byte array and copy data
136     if (dataPtr != NULL) {
137         ssize_t offset;
138         size_t size;
139         sp<IMemoryHeap> heap = dataPtr->getMemory(&offset, &size);
140         LOGV("postData: off=%d, size=%d", offset, size);
141         uint8_t *heapBase = (uint8_t*)heap->base();
142 
143         if (heapBase != NULL) {
144             const jbyte* data = reinterpret_cast<const jbyte*>(heapBase + offset);
145 
146             if (!mManualBufferMode) {
147                 LOGV("Allocating callback buffer");
148                 obj = env->NewByteArray(size);
149             } else {
150                 // Vector access should be protected by lock in postData()
151                 if(!mCallbackBuffers.isEmpty()) {
152                     LOGV("Using callback buffer from queue of length %d", mCallbackBuffers.size());
153                     jbyteArray globalBuffer = mCallbackBuffers.itemAt(0);
154                     mCallbackBuffers.removeAt(0);
155 
156                     obj = (jbyteArray)env->NewLocalRef(globalBuffer);
157                     env->DeleteGlobalRef(globalBuffer);
158 
159                     if (obj != NULL) {
160                         jsize bufferLength = env->GetArrayLength(obj);
161                         if ((int)bufferLength < (int)size) {
162                             LOGE("Manually set buffer was too small! Expected %d bytes, but got %d!",
163                                  size, bufferLength);
164                             env->DeleteLocalRef(obj);
165                             return;
166                         }
167                     }
168                 }
169 
170                 if(mCallbackBuffers.isEmpty()) {
171                     LOGW("Out of buffers, clearing callback!");
172                     mCamera->setPreviewCallbackFlags(FRAME_CALLBACK_FLAG_NOOP);
173                     mManualCameraCallbackSet = false;
174 
175                     if (obj == NULL) {
176                         return;
177                     }
178                 }
179             }
180 
181             if (obj == NULL) {
182                 LOGE("Couldn't allocate byte array for JPEG data");
183                 env->ExceptionClear();
184             } else {
185                 env->SetByteArrayRegion(obj, 0, size, data);
186             }
187         } else {
188             LOGE("image heap is NULL");
189         }
190     }
191 
192     // post image data to Java
193     env->CallStaticVoidMethod(mCameraJClass, fields.post_event,
194             mCameraJObjectWeak, msgType, 0, 0, obj);
195     if (obj) {
196         env->DeleteLocalRef(obj);
197     }
198 }
199 
postData(int32_t msgType,const sp<IMemory> & dataPtr)200 void JNICameraContext::postData(int32_t msgType, const sp<IMemory>& dataPtr)
201 {
202     // VM pointer will be NULL if object is released
203     Mutex::Autolock _l(mLock);
204     JNIEnv *env = AndroidRuntime::getJNIEnv();
205     if (mCameraJObjectWeak == NULL) {
206         LOGW("callback on dead camera object");
207         return;
208     }
209 
210     // return data based on callback type
211     switch(msgType) {
212     case CAMERA_MSG_VIDEO_FRAME:
213         // should never happen
214         break;
215     // don't return raw data to Java
216     case CAMERA_MSG_RAW_IMAGE:
217         LOGV("rawCallback");
218         env->CallStaticVoidMethod(mCameraJClass, fields.post_event,
219                 mCameraJObjectWeak, msgType, 0, 0, NULL);
220         break;
221     default:
222         // TODO: Change to LOGV
223         LOGD("dataCallback(%d, %p)", msgType, dataPtr.get());
224         copyAndPost(env, dataPtr, msgType);
225         break;
226     }
227 }
228 
postDataTimestamp(nsecs_t timestamp,int32_t msgType,const sp<IMemory> & dataPtr)229 void JNICameraContext::postDataTimestamp(nsecs_t timestamp, int32_t msgType, const sp<IMemory>& dataPtr)
230 {
231     // TODO: plumb up to Java. For now, just drop the timestamp
232     postData(msgType, dataPtr);
233 }
234 
setCallbackMode(JNIEnv * env,bool installed,bool manualMode)235 void JNICameraContext::setCallbackMode(JNIEnv *env, bool installed, bool manualMode)
236 {
237     Mutex::Autolock _l(mLock);
238     mManualBufferMode = manualMode;
239     mManualCameraCallbackSet = false;
240 
241     // In order to limit the over usage of binder threads, all non-manual buffer
242     // callbacks use FRAME_CALLBACK_FLAG_BARCODE_SCANNER mode now.
243     //
244     // Continuous callbacks will have the callback re-registered from handleMessage.
245     // Manual buffer mode will operate as fast as possible, relying on the finite supply
246     // of buffers for throttling.
247 
248     if (!installed) {
249         mCamera->setPreviewCallbackFlags(FRAME_CALLBACK_FLAG_NOOP);
250         clearCallbackBuffers_l(env);
251     } else if (mManualBufferMode) {
252         if (!mCallbackBuffers.isEmpty()) {
253             mCamera->setPreviewCallbackFlags(FRAME_CALLBACK_FLAG_CAMERA);
254             mManualCameraCallbackSet = true;
255         }
256     } else {
257         mCamera->setPreviewCallbackFlags(FRAME_CALLBACK_FLAG_BARCODE_SCANNER);
258         clearCallbackBuffers_l(env);
259     }
260 }
261 
addCallbackBuffer(JNIEnv * env,jbyteArray cbb)262 void JNICameraContext::addCallbackBuffer(JNIEnv *env, jbyteArray cbb)
263 {
264     if (cbb != NULL) {
265         Mutex::Autolock _l(mLock);
266         jbyteArray callbackBuffer = (jbyteArray)env->NewGlobalRef(cbb);
267         mCallbackBuffers.push(cbb);
268 
269         LOGV("Adding callback buffer to queue, %d total", mCallbackBuffers.size());
270 
271         // We want to make sure the camera knows we're ready for the next frame.
272         // This may have come unset had we not had a callbackbuffer ready for it last time.
273         if (mManualBufferMode && !mManualCameraCallbackSet) {
274             mCamera->setPreviewCallbackFlags(FRAME_CALLBACK_FLAG_CAMERA);
275             mManualCameraCallbackSet = true;
276         }
277     } else {
278        LOGE("Null byte array!");
279     }
280 }
281 
clearCallbackBuffers_l(JNIEnv * env)282 void JNICameraContext::clearCallbackBuffers_l(JNIEnv *env)
283 {
284     LOGV("Clearing callback buffers, %d remained", mCallbackBuffers.size());
285     while(!mCallbackBuffers.isEmpty()) {
286         env->DeleteGlobalRef(mCallbackBuffers.top());
287         mCallbackBuffers.pop();
288     }
289 }
290 
291 // connect to camera service
android_hardware_Camera_native_setup(JNIEnv * env,jobject thiz,jobject weak_this)292 static void android_hardware_Camera_native_setup(JNIEnv *env, jobject thiz, jobject weak_this)
293 {
294     sp<Camera> camera = Camera::connect();
295 
296     if (camera == NULL) {
297         jniThrowException(env, "java/lang/RuntimeException",
298                           "Fail to connect to camera service");
299         return;
300     }
301 
302     // make sure camera hardware is alive
303     if (camera->getStatus() != NO_ERROR) {
304         jniThrowException(env, "java/lang/RuntimeException", "Camera initialization failed");
305         return;
306     }
307 
308     jclass clazz = env->GetObjectClass(thiz);
309     if (clazz == NULL) {
310         jniThrowException(env, "java/lang/RuntimeException", "Can't find android/hardware/Camera");
311         return;
312     }
313 
314     // We use a weak reference so the Camera object can be garbage collected.
315     // The reference is only used as a proxy for callbacks.
316     sp<JNICameraContext> context = new JNICameraContext(env, weak_this, clazz, camera);
317     context->incStrong(thiz);
318     camera->setListener(context);
319 
320     // save context in opaque field
321     env->SetIntField(thiz, fields.context, (int)context.get());
322 }
323 
324 // disconnect from camera service
325 // It's okay to call this when the native camera context is already null.
326 // This handles the case where the user has called release() and the
327 // finalizer is invoked later.
android_hardware_Camera_release(JNIEnv * env,jobject thiz)328 static void android_hardware_Camera_release(JNIEnv *env, jobject thiz)
329 {
330     // TODO: Change to LOGV
331     LOGD("release camera");
332     JNICameraContext* context = NULL;
333     sp<Camera> camera;
334     {
335         Mutex::Autolock _l(sLock);
336         context = reinterpret_cast<JNICameraContext*>(env->GetIntField(thiz, fields.context));
337 
338         // Make sure we do not attempt to callback on a deleted Java object.
339         env->SetIntField(thiz, fields.context, 0);
340     }
341 
342     // clean up if release has not been called before
343     if (context != NULL) {
344         camera = context->getCamera();
345         context->release();
346         LOGV("native_release: context=%p camera=%p", context, camera.get());
347 
348         // clear callbacks
349         if (camera != NULL) {
350             camera->setPreviewCallbackFlags(FRAME_CALLBACK_FLAG_NOOP);
351             camera->disconnect();
352         }
353 
354         // remove context to prevent further Java access
355         context->decStrong(thiz);
356     }
357 }
358 
android_hardware_Camera_setPreviewDisplay(JNIEnv * env,jobject thiz,jobject jSurface)359 static void android_hardware_Camera_setPreviewDisplay(JNIEnv *env, jobject thiz, jobject jSurface)
360 {
361     LOGV("setPreviewDisplay");
362     sp<Camera> camera = get_native_camera(env, thiz, NULL);
363     if (camera == 0) return;
364 
365     sp<Surface> surface = NULL;
366     if (jSurface != NULL) {
367         surface = reinterpret_cast<Surface*>(env->GetIntField(jSurface, fields.surface));
368     }
369     if (camera->setPreviewDisplay(surface) != NO_ERROR) {
370         jniThrowException(env, "java/io/IOException", "setPreviewDisplay failed");
371     }
372 }
373 
android_hardware_Camera_startPreview(JNIEnv * env,jobject thiz)374 static void android_hardware_Camera_startPreview(JNIEnv *env, jobject thiz)
375 {
376     LOGV("startPreview");
377     sp<Camera> camera = get_native_camera(env, thiz, NULL);
378     if (camera == 0) return;
379 
380     if (camera->startPreview() != NO_ERROR) {
381         jniThrowException(env, "java/lang/RuntimeException", "startPreview failed");
382         return;
383     }
384 }
385 
android_hardware_Camera_stopPreview(JNIEnv * env,jobject thiz)386 static void android_hardware_Camera_stopPreview(JNIEnv *env, jobject thiz)
387 {
388     LOGV("stopPreview");
389     sp<Camera> c = get_native_camera(env, thiz, NULL);
390     if (c == 0) return;
391 
392     c->stopPreview();
393 }
394 
android_hardware_Camera_previewEnabled(JNIEnv * env,jobject thiz)395 static bool android_hardware_Camera_previewEnabled(JNIEnv *env, jobject thiz)
396 {
397     LOGV("previewEnabled");
398     sp<Camera> c = get_native_camera(env, thiz, NULL);
399     if (c == 0) return false;
400 
401     return c->previewEnabled();
402 }
403 
android_hardware_Camera_setHasPreviewCallback(JNIEnv * env,jobject thiz,jboolean installed,jboolean manualBuffer)404 static void android_hardware_Camera_setHasPreviewCallback(JNIEnv *env, jobject thiz, jboolean installed, jboolean manualBuffer)
405 {
406     LOGV("setHasPreviewCallback: installed:%d, manualBuffer:%d", (int)installed, (int)manualBuffer);
407     // Important: Only install preview_callback if the Java code has called
408     // setPreviewCallback() with a non-null value, otherwise we'd pay to memcpy
409     // each preview frame for nothing.
410     JNICameraContext* context;
411     sp<Camera> camera = get_native_camera(env, thiz, &context);
412     if (camera == 0) return;
413 
414     // setCallbackMode will take care of setting the context flags and calling
415     // camera->setPreviewCallbackFlags within a mutex for us.
416     context->setCallbackMode(env, installed, manualBuffer);
417 }
418 
android_hardware_Camera_addCallbackBuffer(JNIEnv * env,jobject thiz,jbyteArray bytes)419 static void android_hardware_Camera_addCallbackBuffer(JNIEnv *env, jobject thiz, jbyteArray bytes) {
420     LOGV("addCallbackBuffer");
421 
422     JNICameraContext* context = reinterpret_cast<JNICameraContext*>(env->GetIntField(thiz, fields.context));
423 
424     if (context != NULL) {
425         context->addCallbackBuffer(env, bytes);
426     }
427 }
428 
android_hardware_Camera_autoFocus(JNIEnv * env,jobject thiz)429 static void android_hardware_Camera_autoFocus(JNIEnv *env, jobject thiz)
430 {
431     LOGV("autoFocus");
432     JNICameraContext* context;
433     sp<Camera> c = get_native_camera(env, thiz, &context);
434     if (c == 0) return;
435 
436     if (c->autoFocus() != NO_ERROR) {
437         jniThrowException(env, "java/lang/RuntimeException", "autoFocus failed");
438     }
439 }
440 
android_hardware_Camera_cancelAutoFocus(JNIEnv * env,jobject thiz)441 static void android_hardware_Camera_cancelAutoFocus(JNIEnv *env, jobject thiz)
442 {
443     LOGV("cancelAutoFocus");
444     JNICameraContext* context;
445     sp<Camera> c = get_native_camera(env, thiz, &context);
446     if (c == 0) return;
447 
448     if (c->cancelAutoFocus() != NO_ERROR) {
449         jniThrowException(env, "java/lang/RuntimeException", "cancelAutoFocus failed");
450     }
451 }
452 
android_hardware_Camera_takePicture(JNIEnv * env,jobject thiz)453 static void android_hardware_Camera_takePicture(JNIEnv *env, jobject thiz)
454 {
455     LOGV("takePicture");
456     JNICameraContext* context;
457     sp<Camera> camera = get_native_camera(env, thiz, &context);
458     if (camera == 0) return;
459 
460     if (camera->takePicture() != NO_ERROR) {
461         jniThrowException(env, "java/lang/RuntimeException", "takePicture failed");
462         return;
463     }
464 }
465 
android_hardware_Camera_setParameters(JNIEnv * env,jobject thiz,jstring params)466 static void android_hardware_Camera_setParameters(JNIEnv *env, jobject thiz, jstring params)
467 {
468     LOGV("setParameters");
469     sp<Camera> camera = get_native_camera(env, thiz, NULL);
470     if (camera == 0) return;
471 
472     const jchar* str = env->GetStringCritical(params, 0);
473     String8 params8;
474     if (params) {
475         params8 = String8(str, env->GetStringLength(params));
476         env->ReleaseStringCritical(params, str);
477     }
478     if (camera->setParameters(params8) != NO_ERROR) {
479         jniThrowException(env, "java/lang/RuntimeException", "setParameters failed");
480         return;
481     }
482 }
483 
android_hardware_Camera_getParameters(JNIEnv * env,jobject thiz)484 static jstring android_hardware_Camera_getParameters(JNIEnv *env, jobject thiz)
485 {
486     LOGV("getParameters");
487     sp<Camera> camera = get_native_camera(env, thiz, NULL);
488     if (camera == 0) return 0;
489 
490     return env->NewStringUTF(camera->getParameters().string());
491 }
492 
android_hardware_Camera_reconnect(JNIEnv * env,jobject thiz)493 static void android_hardware_Camera_reconnect(JNIEnv *env, jobject thiz)
494 {
495     LOGV("reconnect");
496     sp<Camera> camera = get_native_camera(env, thiz, NULL);
497     if (camera == 0) return;
498 
499     if (camera->reconnect() != NO_ERROR) {
500         jniThrowException(env, "java/io/IOException", "reconnect failed");
501         return;
502     }
503 }
504 
android_hardware_Camera_lock(JNIEnv * env,jobject thiz)505 static void android_hardware_Camera_lock(JNIEnv *env, jobject thiz)
506 {
507     LOGV("lock");
508     sp<Camera> camera = get_native_camera(env, thiz, NULL);
509     if (camera == 0) return;
510 
511     if (camera->lock() != NO_ERROR) {
512         jniThrowException(env, "java/lang/RuntimeException", "lock failed");
513     }
514 }
515 
android_hardware_Camera_unlock(JNIEnv * env,jobject thiz)516 static void android_hardware_Camera_unlock(JNIEnv *env, jobject thiz)
517 {
518     LOGV("unlock");
519     sp<Camera> camera = get_native_camera(env, thiz, NULL);
520     if (camera == 0) return;
521 
522     if (camera->unlock() != NO_ERROR) {
523         jniThrowException(env, "java/lang/RuntimeException", "unlock failed");
524     }
525 }
526 
android_hardware_Camera_startSmoothZoom(JNIEnv * env,jobject thiz,jint value)527 static void android_hardware_Camera_startSmoothZoom(JNIEnv *env, jobject thiz, jint value)
528 {
529     LOGD("startSmoothZoom");
530     sp<Camera> camera = get_native_camera(env, thiz, NULL);
531     if (camera == 0) return;
532 
533     if (camera->sendCommand(CAMERA_CMD_START_SMOOTH_ZOOM, value, 0) != NO_ERROR) {
534         jniThrowException(env, "java/lang/RuntimeException", "start smooth zoom failed");
535     }
536 }
537 
android_hardware_Camera_stopSmoothZoom(JNIEnv * env,jobject thiz)538 static void android_hardware_Camera_stopSmoothZoom(JNIEnv *env, jobject thiz)
539 {
540     LOGD("stopSmoothZoom");
541     sp<Camera> camera = get_native_camera(env, thiz, NULL);
542     if (camera == 0) return;
543 
544     if (camera->sendCommand(CAMERA_CMD_STOP_SMOOTH_ZOOM, 0, 0) != NO_ERROR) {
545         jniThrowException(env, "java/lang/RuntimeException", "stop smooth zoom failed");
546     }
547 }
548 
549 //-------------------------------------------------
550 
551 static JNINativeMethod camMethods[] = {
552   { "native_setup",
553     "(Ljava/lang/Object;)V",
554     (void*)android_hardware_Camera_native_setup },
555   { "native_release",
556     "()V",
557     (void*)android_hardware_Camera_release },
558   { "setPreviewDisplay",
559     "(Landroid/view/Surface;)V",
560     (void *)android_hardware_Camera_setPreviewDisplay },
561   { "startPreview",
562     "()V",
563     (void *)android_hardware_Camera_startPreview },
564   { "stopPreview",
565     "()V",
566     (void *)android_hardware_Camera_stopPreview },
567   { "previewEnabled",
568     "()Z",
569     (void *)android_hardware_Camera_previewEnabled },
570   { "setHasPreviewCallback",
571     "(ZZ)V",
572     (void *)android_hardware_Camera_setHasPreviewCallback },
573   { "addCallbackBuffer",
574     "([B)V",
575     (void *)android_hardware_Camera_addCallbackBuffer },
576   { "native_autoFocus",
577     "()V",
578     (void *)android_hardware_Camera_autoFocus },
579   { "native_cancelAutoFocus",
580     "()V",
581     (void *)android_hardware_Camera_cancelAutoFocus },
582   { "native_takePicture",
583     "()V",
584     (void *)android_hardware_Camera_takePicture },
585   { "native_setParameters",
586     "(Ljava/lang/String;)V",
587     (void *)android_hardware_Camera_setParameters },
588   { "native_getParameters",
589     "()Ljava/lang/String;",
590     (void *)android_hardware_Camera_getParameters },
591   { "reconnect",
592     "()V",
593     (void*)android_hardware_Camera_reconnect },
594   { "lock",
595     "()V",
596     (void*)android_hardware_Camera_lock },
597   { "unlock",
598     "()V",
599     (void*)android_hardware_Camera_unlock },
600   { "startSmoothZoom",
601     "(I)V",
602     (void *)android_hardware_Camera_startSmoothZoom },
603   { "stopSmoothZoom",
604     "()V",
605     (void *)android_hardware_Camera_stopSmoothZoom },
606 };
607 
608 struct field {
609     const char *class_name;
610     const char *field_name;
611     const char *field_type;
612     jfieldID   *jfield;
613 };
614 
find_fields(JNIEnv * env,field * fields,int count)615 static int find_fields(JNIEnv *env, field *fields, int count)
616 {
617     for (int i = 0; i < count; i++) {
618         field *f = &fields[i];
619         jclass clazz = env->FindClass(f->class_name);
620         if (clazz == NULL) {
621             LOGE("Can't find %s", f->class_name);
622             return -1;
623         }
624 
625         jfieldID field = env->GetFieldID(clazz, f->field_name, f->field_type);
626         if (field == NULL) {
627             LOGE("Can't find %s.%s", f->class_name, f->field_name);
628             return -1;
629         }
630 
631         *(f->jfield) = field;
632     }
633 
634     return 0;
635 }
636 
637 // Get all the required offsets in java class and register native functions
register_android_hardware_Camera(JNIEnv * env)638 int register_android_hardware_Camera(JNIEnv *env)
639 {
640     field fields_to_find[] = {
641         { "android/hardware/Camera", "mNativeContext",   "I", &fields.context },
642         { "android/view/Surface",    "mSurface",         "I", &fields.surface }
643     };
644 
645     if (find_fields(env, fields_to_find, NELEM(fields_to_find)) < 0)
646         return -1;
647 
648     jclass clazz = env->FindClass("android/hardware/Camera");
649     fields.post_event = env->GetStaticMethodID(clazz, "postEventFromNative",
650                                                "(Ljava/lang/Object;IIILjava/lang/Object;)V");
651     if (fields.post_event == NULL) {
652         LOGE("Can't find android/hardware/Camera.postEventFromNative");
653         return -1;
654     }
655 
656 
657     // Register native functions
658     return AndroidRuntime::registerNativeMethods(env, "android/hardware/Camera",
659                                               camMethods, NELEM(camMethods));
660 }
661 
662